Kind: captions
Language: en
the following is a conversation with
Alex filipenko an astrophysicist and
professor of astronomy from Berkeley he
was a member of both the Supernova
cosmology project and the high Supernova
search team which used observations of
the extra Galactic Supernova to discover
that the universe is accelerating and
that this implies the existence of dark
energy this discovery resulted in the
2011 nobba prize for physics outside of
his groundbreak can research he is a
great science communicator and is one of
the most widely admired Educators in the
world I really enjoyed this conversation
and I'm sure Alex will be back again in
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at Lex fredman and now here's my
conversation with Alex
filipenko let's start by talking about
the biggest possible thing the universe
sure will the universe expand forever or
collapse on itself well you know that's
a great question that's one of the big
questions of cosmology and of course we
have evidence that the matter density is
sufficiently low that the universe will
expand forever but not only that there's
this weird repulsive effect we call it
dark energy for want of a better term
and it appears to be accelerating the
expansion of the universe so if that
continues the universe will expand
forever but it need not necessarily
continue it could reverse sign in which
case the universe could in principle
collapse at some point in the Far Far
Future so like in terms of investment
advice if you were to give me and then
to bet all my money on one or the other
where did does your intuition currently
lie well right now I would say that it
would expand forever because I think
that the dark energy is likely to be
just Quantum fluctuations of the vacuum
the vacuum Zero Energy state is not a
state of zero energy that is the ground
state is a a state of some elevated
energy which has a repulsive effect to
it and that will never go away because
it's not something that changes with
time so if the universe is accelerating
now it will forever continue to do so
and yet I mean you're so effortlessly
mentioned Dark Energy do we have any
understanding of of what the heck that
thing is well not really but we're
getting progressively better
observational constraints so you know
different theories of what it might be
predict different sorts of behavior for
the evolution of the universe and we've
been measuring the evolution of the
universe now and the data appear to
agree with the predictions of a con
density vacuum energy a z Point
Energy but one can't prove that that's
what it is because one would have to
show that the numbers that the measured
numbers agree with the predictions to an
arbitrary number of decimal places and
of course even if you've got 8 9 10 12
decimal places what if in the 13th one
the measurements significantly differ
from the prediction then the dark energy
isn't this vacuum State uh ground state
energy of the of the vacuum and so then
it could be some sort of a a field some
sort of a new energy a little bit like
like light like electromagnetism but
very different from light that fills
space and that type of energy could in
principle change in the distant future
it could become gravitationally
attractive for all we know there is a
historical precedent to that and that is
that the inflation with which the
universe began when the universe was
just a tiny blink of an of an eye old a
trillionth of a trillionth of a
trillionth of a second you know the
universe went whoosh it exponentially
expanded that dark energy likee
substance we call it the inflaton that
which inflated the universe later
decayed into more or less normal
gravitationally attractive matter so the
exponential early expansion of the
universe did transition to a
deceleration which then dominated the
universe for about 9 billion years and
now this small amount of dark
energy started causing an acceleration
about five billion years ago and whether
that will continue or not is something
that we'd like to answer but I don't
know that we will anytime soon so there
could be this interesting field that we
don't yet understand that's morphing
over time that's changing the way the
universe is is expanding I mean it it's
funny that you were thinking through
this rigorously like an
experimentalist yeah but the what about
like the fundamental physics of dark
energy is there any
understanding of uh what the heck it is
or is or is this the kind of uh the the
god of the gaps or the field of the gaps
uh so like it there must be something
there because of what we're observing
I'm very much a person who believes that
there's all always a cause you know
there there are no um
miracles of a supernatural nature okay
uh so I mean there are two broad
categories either it's the vacuum Zero
Point Energy or it's some sort of a a
new energy field that pervades the
Universe the latter could change with
time the former the vacuum energy cannot
right so if it turns out that it's one
of these new fields and there many many
possibilities they go by the name of you
know quintessence and things like that
but there are many categories of those
sorts of fields we try with data to rule
them out by comparing the actual
measurements with the predictions and
some have been ruled out but many many
others remain to be tested and the data
just have to become a lot better before
we can rule out most of them and become
reasonably convinced
that this is a vacuum energy so there is
hypotheses for different fields like
with names and stuff like that yeah yeah
you know generically quintessence like
the Aristotelian fifth Essence but there
are many many versions of quintessence
there's K Essence there's even ideas
that you know this isn't something from
within this dark energy but rather there
are a bunch of say bubble universes
surrounding our universe and this whole
idea of the Multiverse is not some crazy
Mad Men type idea anymore it's you know
real card carrying physicists are
seriously considering this possibility
of a Multiverse and some types of
multiverses could have you know a bunch
of bubbles on the outside which
gravitationally act outward on our
bubble because gravity or gravitons the
the quantum particle that is thought to
carry gravity is is thought to Traverse
the bulk the space between these
different little bubble membranes and
stuff and so it's conceivable that these
other verus are pulling outward on us
that's not a favored explanation right
now but but really nothing has been
ruled out no class of models has been
ruled out completely certain examples
within classes of models have been ruled
out but in general I think we still have
really a lot to learn about what's
causing this observed acceleration of
the expansion of the universe be it dark
energy or some forces from the outside
or or perhaps you know I guess it's
conceivable that and sometimes I wake up
in the middle of the night screaming the
dark energy that which causes the
acceleration and dark matter that which
causes galaxies and clusters of galaxies
to be bound gravitationally even though
there's not enough visible matter to do
so maybe these are our 20th and 21st
century toic epicycles so toy had a
geocentric and Aristotelian view of the
world everything goes around Earth but
in order to explain the backward motion
of planets Among the Stars that happens
every year or two or sometimes several
times a year for Mercury and Venus you
needed the planets to go around in
little circles called epicycles which
themselves then went around Earth yes
and in this in this part of the epicycle
where the planet is going in the
direction opposite to the direction of
the overall epicycle it can appear in
projection to be going backward Among
the Stars socaled retrograde motion and
it was a brilliant mathematical scheme
in fact he could have added epicycles on
top of
epicycles and reproduce The observed
positions of planets to arbitrary
accuracy yeah and this is really the
beginning of what we now call forier
analysis right any periodic function can
be represented by a sum of signs and Co
signs of different periods amplitudes
and phases so it could have worked
arbitrarily well but other data you know
show that in fact Earth is going around
the Sun um so are dark energy and dark
matter just these Band-Aids that we now
have to try to explain the data but
they're just completely wrong that
that's a possibility as well and as a
scientist I have to be open to that
possibility as an open-minded scientist
how do you how do you put yourself in
the mindset of somebody that or majority
of the scientific Community or majority
of people believe that the Earth
everything rotates around
Earth how do you put yourself in that
mindset and then take a leap to uh
propose a model that the sun is in fact
at the center of this the solar system
sure I mean so that puts us back in the
shoes of cernus right 500 years ago
where he had this philosophical
preference for the sun being the
dominant body in what we now call the
solar system the observational evidence
in terms of the measured positions of
planets was not better explained by the
heliocentric Sun centered system it's
just that you know cernus saw that the
sun is the source of all our light and
heat oh wow
and he had you know he he knew from
other studies that it's it's far away so
the fact that it appears as big as the
moon means it's actually way way bigger
because even at that time it was known
that the sun is much farther away than
the moon so um you know he just felt wow
it's big it's bright what if it's the
central thing but the observed positions
of planets at the time in the early to
mid 16th century under the heliocentric
system was not a better match at least
not a significantly better match than
tmy system which was quite accurate and
lasted 1500 years yeah
yeah that's so fascinating to think that
the philosophical predispositions that
you bring to the table are essent so
like you have to have a young person
come along that has a weird infatuation
with the son yeah that like almost
philosophically is like however their
upbringing is they're more ready for
whatever the more the simpler answer is
right oh that's um it's kind of sad it's
uh sad from an individual descendant of
ape perspective because then that means
like me like you as a
scientist you're stuck with whatever the
heck philosophies you brought to the
table you might be almost completely
unable to to think outside this
particular box you've built right this
is why I'm saying that you know as an
objective scientist one needs needs to
have an open mind to Crazy sounding new
ideas and you know even cernus was very
much a man of his time and dedicated his
work to the pope he still used circular
orbits the Sun was a little bit off
center it turns out and a slightly
off-center Circle looks like a slightly
eccentric elliptical orbit so then when
Kepler in fact showed that the orbits
are actually in general ellipses not
circles the reason that you know he
needed tuob bra's really great data to
show that distinction was that a
slightly off-center circle is not much
different from a slightly eccentric
ellipse and so there wasn't much
difference between Kepler's View and uh
kernus is View and and Kepler needed the
better data uh tuo's toob bra's data and
so that's again a great example of of of
science
and OBS observations and experiments
working together with hypotheses and
they they kind of bounce off each other
they play off of each other and you
continually need more observations and
it wasn't until Galileo's work uh around
1610 that actual evidence for the
heliocentric hypothesis emerged it came
in the form of Venus the planet Venus
going through all of the possible phases
from new to Crescent to to quarter to
gibbus to full to waning gibbus third
quarter waning crescent and then new
again it turns out in the toic system
with Venus between Earth and the Sun but
always roughly in the direction of the
sun you could only get the new and
Cresent phases of Venus but the
observations showed a full set of phases
and moreover when Venus was gibbus or
full that meant it was on the far side
of the Sun that meant it was farther
from Earth than when it's Crescent so it
should appear smaller and indeed it did
so that was a that was you know the nail
and the coffin in a sense and then you
know Galileo's other great observation
was that Jupiter has moons going around
it the four Galilean satellites and even
though Jupiter moves through space so
too do the moons go with it so first of
all Earth is not the only thing that has
other things going around it and
secondly Earth could be moving as
Jupiter does and you know
things would move with with it we we
wouldn't fly off the surface and our
moon wouldn't be left behind and all
this kind of stuff so that was a a big
breakthrough as well but it wasn't as
definitive in my opinion as the phases
of Venus perhaps I'm revealing my
ignorance but I didn't realize how much
data they were working with yeah so
there's uh so it wasn't
Einstein or Freud thinking in theories
it was a lot of data and you're playing
with it and seeing how to make sense of
it so isn't it it isn't just coming up
with completely abstract thought
experiments yeah it's looking at the
data sure and you Newton's great work
right the prinkipia it was based in part
on Galileo's observations of balls
rolling down inclined planes supposedly
fall falling off the Leaning Tower of
Pisa but that's probably apocryphal in
any case you know um the the the
Inquisition actually did or the R
Catholic Church uh did did history a
favor not that I'm condoning them but
they placed Galileo under house arrest
yeah and that gave Galileo time to
publish to assemble and publish the
results of his experiments that he had
done decades earlier it's not clear he
would have had time to do that you know
had he not been under house arrest and
so Newton of course Very Much used
Galileo's
observations let me ask uh the old
Russian overly philosophical question
about death so we're talking about the
expanding Universe sure how do you think
human civilization will come to an end
if we avoid the uh the near-term issues
we're
having uh will it be our sun burning out
will it be comets okay will it be uh
what is it oh do you think we we have a
shot at reaching the the heat death of
the universe yeah yeah so we're going to
leave out the
anthropogenic uhle causes of our
potential destruction yes which I
actually think are greater than the
celestial uh causes so um so if we get
lucky yeah if we get and intelligent I
don't know yeah so no way will we as
humans reach the heat death of the
Universe I mean it's conceivable that uh
machines which I think will be our
evolutionary descendants might reach
that although even they will have less
and less energy with which to work as
time progresses because eventually even
the lowest mass stars burn out although
it takes them trillions of years to do
so um so the point is is that certainly
on Earth uh there are other Celestial
threats existential threats comets
exploding Stars the sun burning out so
we will definitely need to move away
away from our solar system to other
solar systems and then you know the
question is can they keep on propagating
to other planetary systems sufficiently
long um in our own solar system the sun
burning out is is not the the immediate
existential threat um that'll happen in
about you know five billion years when
it becomes a red giant although I should
hasten to add that within the next one
or two billion years years the sun will
have brightened enough that unless
they compensatory atmospheric changes
the oceans will will evaporate away you
know and and you need much less carbon
dioxide for the temperatures to be
maintained roughly at their present
temperature and plants wouldn't like
that very much so you can't lower the
carbon dioxide content too much so so
within one or two billion years probably
the oceans will evaporate away yeah but
on a sooner time scale than that
I would say an asteroid Collision
leading to a potential mass extinction
or at least an Extinction of complex
beings such as ourselves that require
quite special conditions unlike
cockroaches and amibas you know to
survive um you know one of
these civilization changing asteroids is
only one kilometer or so in diameter and
bigger and a true mass extinction event
is 10 kilometers or larger now it's true
that we can find and track the orbits of
asteroids that might be headed toward
Earth and if we find them 50 or 100
years before they impact us then clever
applied physicists and Engineers can
figure out ways to deflect them but at
some point you know some Comet will come
in from the deep freeze of the solar
system and there we have very little
warning months to a to a year what's the
Deep Freeze sorry oh the Deep Freeze is
sort of out Beyond Neptune there's this
thing called the Kyper belt M and it
consists of a bunch of you know dirty
ice balls or icy dirt balls it's the
source of the Comets that occasionally
come close to the Sun and then there's a
even bigger area called the scattered
disc which is sort of a big doughnut
surrounding the solar system way out
there from which other comets come and
then there's the orc Cloud
WT after uh Yan ort a Dutch
astrophysicist and it's the better part
of a lightyear away from the Sun so a
good fraction of the distance to the
nearest star but that's like a trillion
or 10
trillion comet-like objects that
occasionally get disturbed by a passing
star or whatever and most of them go
flying out of the solar system but some
go toward the Sun and they they come in
with little warning you know by the time
we can see them they're only a year or
two away from us and moreover not only
is it hard to determine their
trajectories sufficiently accurately to
know whether they'll hit a tiny thing
like Earth but outgassing from the comet
of um gases you know when the IES
sublimate that
outgassing can change the trajectory
just because of conservation of momentum
right it's the rocket effect gases go
out in One Direction the object moves in
the other direction and so since we
can't predict how much outgassing there
will be and in exactly what direction
because these things are tumbling and
rotating and stuff it's hard to predict
the trajectory with sufficient accuracy
to know that it will hit and you
certainly don't want to deflect a comet
that would have missed but you thought
it was going to hit and end up having it
hit that would be like the ultimate
Charlie Brown you know goat instead of
trying to be the hero right he ended up
being the goat what would you uh what
would you do
if it seemed like in a matter of months
that there is some nonzero prob ility
maybe a high probability that there will
be a collision so from a scientific
perspective from an engineering
perspective I imagine you would actually
be in the room of people deciding what
to do what uh yeah philosophically too
it's a tough one right because if you
only have a few months that's not much
time in which to deflect it early
detection and and um early action or key
because when it's far away you only have
to deflect it by a tiny little angle
yeah and then by a time it reaches us
the perpendicular motion is big enough
to you know to to Miss Earth all you
need is one radius or or one diameter of
the earth
right that actually means that all you
would need to do is slow it down so it
arrives four minutes later or speed it
up so it arrives four minutes earlier
and Earth will have moved through one
radius in in that time so it doesn't
take much but you can imagine if a thing
is about to hit you you you have to
deflect at 90 degrees or more right you
know and you don't have much time to do
so and you have to slow it down or speed
it up a lot if that's what you're trying
to do to it and so decades is sufficient
time but months is not sufficient time
so at that point I would think the the
name of the game would be to try to
predict where it would
hit and if it's in a heavily populated
region try to
try to start an orderly evacuation
perhaps but you know that might cause
just so much Panic that I'm how would
you do it with New York City or or Los
Angeles or something like that right I
might have I might have a different
opinion a year ago I'm uh a bit U
disheartened by you know in the movies
the um there's always extreme competence
from the
government competence yeah competence
right but we expect extreme incompetence
if anything right yes now so I'm quite
disappointed but sort of from a medical
perspective I think you're saying there
in a scientific one it's almost better
to get better and better maybe
telescopes and data collection to be
able to predict the movement of these
things or like come up with totally new
technologies like you can imagine
actually sending out like probes out
there to be able to sort of almost have
little finger sensors throughout our
solar system to be able to detect stuff
well that's right yeah monitoring the
asteroid belt is very important and 99%
of the so-called neear objects
ultimately come from the asteroid belt
and so there we can track the
trajectories and even if there's you
know a close encounter between two
asteroids which deflects one of them
toward Earth it's unlikely to be on a
collision course with Earth in the
immediate future it's more like you know
tens of years so that gives us time but
we would need to improve our ability to
detect the objects that come in from a
great distance unfortunately those are
are much rarer the the Comets come in
you know 1% of the collisions perhaps
are with comets that come in without any
warning hardly and
so so that might be more like you know a
billion or two billion years before one
of those hits us um so maybe we have to
worry about the sun getting brighter on
that time scale I mean there's the
possibility that a star will explode
near us in the next couple of billion
years but over the course of the history
of life on Earth the estimates are
that
maybe only one of the mass extinctions
you know was caused by a star blowing up
in particular a special kind called a
Gamay burst and the I think it's the
oriv I
solarian uh saluan or divis saluan
Extinction 420 or so 440 million years
ago that is speculated to have come from
one of these particular types of
exploding Stars called Gamay bursts but
even there the the evidence is
circumstantial so those kinds of
existential threats are are reasonably
rare the greater danger I think is
civilization changing events where it's
a much smaller asteroid uh which those
are hard harder to detect or or a giant
solar
flare that shorts out the Grid in all of
North America let's say now you know
astronomers are monitoring the sun 247
with various satellites and we can tell
when there's a a flare or a coronal mass
ejection and we can tell that in a day
or two a giant bundle of energetic
particles will arrive and twang the
magnetic field of Earth and send all
kinds of currents through long-distance
power lines and that's what shorts out
the Transformers and Transformers are
you know expensive and and hard to
replace and hard to transport and all
that kind of stuff
so if we can warn the power companies
and they can shut down the grid before
the big bundle of particle hits then we
will have mitigated much of this now for
a big enough bundle of particles you can
get short circuits even over small
distance scales so not everything will
be saved but at least the whole grid
might not go out so again you know
astronomers I like to say support your
local astronomer they may help someday
save Humanity by telling the power
companies to shut down the grid finding
the asteroid 50 or 100 years before it
hits then having clever physicists and
Engineers deflect it so many of these
Cosmic threats Cosmic existential
threats we can actually
predict and do something about or
observe before they hit and do something
about so it's it's terrifying to think
that people would listen to this
conversation it's like when you listen
to Bill Gates talk about pandemics and
his Ted Talk a few years ago yeah and
realizing we should have supported our
local astronomer more well I don't know
whether it's more because that's I said
I actually think uh human induced
threats or things that occur naturally
on Earth either a natural pandemic or
perhaps you know a bioengineering type
pandemic or you know something like a
super volcano right um there was one
event Toba I think it was 70 plus
thousand years ago that that caused a
gigantic decrease in temperatures on
Earth because it sends up it sent up so
much soot that it blocked the sun right
it's the nuclear winter type disaster
scenario that some people including Carl
Sean talked about decades ago but we can
see in the history of volcanic eruptions
even more recently in the 19th century
Tambora and other ones you look at the
record and you see rather large dips in
temperature associated with massive
volcanic eruptions well these super
volcanoes one of which by the way exists
under Yellowstone you know in the
central us I mean it's not just it's not
just one or two states it's a it's a
gigantic region and there's controversy
as to whether it's likely to blow any
time in the next 100,000 years or so but
that would be perhaps not a mass
extinction because you really need to or
or perhaps not a complete existential
threat because you have to get rid of
sort of the very last humans for that
but but at least getting rid of um you
know killing off so many humans truly
billions and billions of humans the one
there have been
ones tens of thousands of years ago
including this one um Toba I think it's
called where it's estimated that the
human population was down to 10,000 or
5,000 individuals something like that
right if you have a 15 degree drop in
temperature over quite a short time it's
not clear that even with today's
advanced technology we would be able to
adequately respond at least for the vast
majority of people maybe some would be
in these underground caves where you'd
keep the president and a bunch of other
important people you know but the the
typical person is not going to be prot
protected when when all of Agriculture
is is cut off right and when it could be
hundreds of millions or billions of
people yeah starving to death exactly
that's right they don't all die
immediately but they use up their
supplies or again this electrical grid
first toilet paper there you go stash
that toilet paper you know um or the
electrical grid I mean imagine North
America without power for a year right I
mean we've become so dependent we're no
longer the cave people
they would do just fine right what do
they care about the electrical grid
right what do they care about
agriculture they're hunters and
gatherers but we now have become so used
to our way of life that the only real
survivors would be those rugged
individualists who live somewhere out in
the forest or in a cave somewhere
completely independent of anyone else
yeah I've recently I recommend it it's
totally new to me this kind of
survivalist uh folks but there's a a few
show there's a lot lot of shows of those
but I saw one on Netflix and I started
watching them and
there's they make a lot of sense they
they reveal to you how dependent we are
on all aspects of this beautiful systems
we human have built right and how
fragile they are incredibly fragile and
yeah this this whole conversation is
making me realize how lucky we are oh
we're we're incredibly lucky but we've
set ourselves up to be very very fragile
and we are intrinsically complex
biological creatures that except for the
fact that we have brains and Minds with
which we can you know try to prevent
some of these things or respond to them
we as a living organism require quite a
narrow set of conditions in order to
survive you know we're not cockroaches
we're not going to survive a nuclear war
so we're kind of there's this beautiful
dance between um we've been talking
about a astronomy that astronomy the
Stars like
inspires everybody and at the same time
there's this pragmatic aspect that we're
talking about and so I see space
exploration as the same kind of way that
it's uh reaching out to other planets
reaching out to the stars is this really
beautiful idea but if you listen to
somebody like uh Elon Musk he talks
about space exploration as very
pragmatic like we have to if we we have
to
be he has this ridiculous way of
sounding like an engineer about it which
is like it's obvious we need to become a
multiplanetary species if we were to
survive long term so maybe both
philosophically in terms of beauty and
in terms of practical what's your
thoughts on um space exploration on the
challenges of it on how much we should
be investing in it and on a personal
level like how excited you are about by
the possibility of going to Mars
colonizing Mars and maybe going outside
the solar system yeah you know great
question uh there's a lot to unpack
there of course you know humans are by
their very nature explorers Pioneers
they want to go out climb the next
Mountain see what's behind it um explore
the oan depths explore space this is our
destiny to go out there and and of
course from a pragmatic perspective yes
we need to um plant our seeds elsewhere
really because things could go wrong
here on Earth now some people
say that's that's an excuse to not take
care of our planet that well we say
we're elsewhere and so we don't have to
take good care of our planet no you know
we should take the best possible care of
our planet we should be cognizant of the
potential impact of what we're doing
nevertheless it's prudent to have us be
elsewhere as well so in that regard I
actually agree with Elon uh it'd be good
to be on Mars that would be yet another
place for us to from which to you know
explore further would that be a good
Next Step would you say well that's the
good it's a good next step I have happen
I happen to disagree with him as to how
quickly it will happen right I mean I
think he's very optimistic now you need
Visionary people like Elon to to get
people going and to inspire them I mean
look at the success he's had with
multiple companies uh so maybe he gives
this very optimistic timeline in order
to be inspirational to those who are who
are going out there and certainly his
Success With You know the rocket that is
reusable because it landed upright and
all that I mean you know what that
that's a GameChanger sort of like every
time you flew from San Francisco to Los
Angeles you discard the airplane right I
mean that's crazy right so that's a game
Cher but nevertheless the time scale
over which he thinks that there could be
a real thriving colony on Mars I think
is far too optimistic what's the biggest
challenges to you one is just getting
Rockets not Rockets but people out there
and two is the
colonization like what do you have
thoughts about this um challenges of
this kind of prospect yeah I haven't
thought about it in in great detail uh
other than recognizing that Mars is a
harsh environment yeah you don't have
much of an atmosphere there you've got
less than a percent of Earth's
atmosphere um so you you to build some
sort of a dome right away right and and
that that would take time you need to
melt the water that's in the permafrost
or have canals dug from which you
transport it from the from the polar ice
caps you know I I was reading recently
in terms of like what's the most
efficient source of nutrition for humans
that were to live on Mars and uh people
should look into this but it turns out
to be insects insects yeah yeah so you
want you want to build GI colony of
insects and just be eating insects have
a lot of protein right a lot of protein
and they're easy
to like you can think of them as farming
right but it's not going to be easy as
easy as growing a whole plot of potatoes
like in the movie The Martian you know
or something right it's not going to be
that easy but you know so there's
there's this thin atmosphere it's got
the wrong composition it's mostly carbon
dioxide there are these violent dust
storms the temperatures are generally
cold you know you'd need to do a lot of
things you need to terraform it
basically in order to make it nicely
livable without some Dome surrounding
you and if you and if you insist on a
dome well that's not going to house that
many people right you know well so let's
look let's look briefly then you know
we're looking for a new apartment to
move into so let's look outside the
solar system do you think you've you've
spoken about exoplanets as well do you
think there's um possible homes out
there for us uh outside of our solar
system there are lots and lots of homes
possible homes I mean they're there's a
planetary system around nearly every
Star you see in the sky and one in five
of those is thought to have a roughly
earth like Planet you know and that's a
relatively new yeah it's a new discovery
I mean that the Kepler satellite which
was flying around uh above Earth's
atmosphere was able to monitor the
brightness of stars with exquisite
detail and they could detect planets
crossing the line of sight between us
and the star thereby dimming its light
for a short time ever so slightly and
it's it's amazing so there are now
thousands and thousands of these
exoplanet candidates of which something
like 90% are probably genuine exoplanets
and you have to remember that only about
1% of stars have their planetary system
oriented Edge on to your line of sight
which is what you need for this Transit
method to work right some arbitrary
angle won't work and certainly
perpendicular uh to your line of sight
that is in the plane of the sky won't
work because the the the planet is
orbiting the star and never crossing
your line of sight so the fact that um
you know they
found planets orbiting about 1% of the
stars that they looked at in this field
of 150 plus thousand
stars they found planets around 1% you
then multiply by the inverse of 1% which
is you know right 1% is about how many
what the fraction of the of the stars
that have their planetary system
oriented the right way and that already
back of the envelope calculation tells
you that of order 50 to 100% of all
stars have planets okay and then they've
been finding these earthlike planets etc
etc so there are many potential homes
the problem is getting there okay so
then a typical bright star serus uh the
brightest star in the sky maybe not a
typical bright star but it's 8.7 light
years away okay so uh that's that means
the light took 8.7 years to reach us
we're seeing it as it was about nine
years ago okay so then you know you ask
how long would a rocket take to get
there at Earth's escape speed which is
11 kilometers per second okay and it
turns out it's about a quarter of a
million years okay now that's 10,000
Generations okay let's say a generation
of humans is 25 years right so you need
this colony of people that is able to
sustain itself all their food all their
waste disposal all their water all their
recycling of everything for 10,000
Generations they have to commit
themselves to living on this vehicle
right I just see it happening what I see
potentially happening if we avoid
self-destruction intentional or
unintentional here on Earth is that
machines will do it robots that can
essentially hibernate they don't need to
do much of anything for a long long time
as they're traveling and moreover if
some energetic charged particle some
Cosmic gray hits the circuitry it fixes
itself right machines can do this
uh I mean it it's a form of artificial
intelligence you just tell the thing fix
yourself basically and then when you
land on the on the planet start
producing copies of yourself initially
from materials that perhaps sent or you
just have a bunch of copies there and
then they set up you know factories with
which to do this I mean this is very
very futuristic but it's much more
feasible I think than sending Flesh and
Blood over Interstellar distances a
quarter of a million years to even the
nearest Stars you're subject to all
kinds of charged particles and radiation
you have to you know Shield yourself
really well that's by the way one of the
problems of going to Mars is that it's
not a three-day Journey like going to
the Moon you're out there for the better
part of a year or two and you're exposed
to lots of radiation you know which
typically doesn't do well with living
tissue right or living tissue doesn't do
well with the radiation okay and and the
hope is that the robots that AI systems
might be able to carry the carry
the the fire of Consciousness whatever
makes us humans yeah like a little drop
of whatever makes us humans so special
not to be too poetic about it but no but
I I like being poetic about it because
it's a it's an amazing question you know
is there something Beyond just the bits
the ones and zeros to us you know it's
an interesting question um I like to
think that there there isn't anything
and that how beautiful it is that our
thoughts our emotions our feelings our
compassion all come from these ones and
zeros right that to me actually is a a
beautiful thought and the idea that
machines silicon based life effectively
could be our natural evolutionary
descendants not from a DNA perspective
but they are our creations and they then
carry on that to me is a a beautiful
thought in some ways but others find it
to be a horrific thought right exciting
to you I it is exciting to me as well
yeah because to me from a purely an
engineering perspective it's I believe
it's impossible to create like
whatever systems we create that take
over the world it's impossible for me to
imagine that those systems will not
carry some aspect of what makes humans
beautiful yeah so like that a lot of
people have these kind of paperclip
ideas that will we bring will'll build
machines that are cold inside or
philosophers call them zombies you know
they're they're that
naturally the systems that will out
compete us on this Earth will be cold
and non
nonconscious not capable of all the
human emotions and empathy compassion
and love and hate every the the
beautiful uh mix of uh what makes us
human but to me intelligence requires
all of that so in order order to
outcompete humans you better be good at
the full picture right so artificial
general intelligence in my view
encompasses a lot of these attributes
that you just talked about yeah
curiosity inquisitiveness you know right
it might look very different than us
humans but you have some of the magic
but it'll but it'll also be much more
able to survive the onslaught of
existential threats that either we bring
upon ourselves or don't anticipate here
on Earth or that occasionally come from
Beyond and there's nothing much we can
do about a supernova explosion that just
suddenly you know goes off and and and
really if we want to move to other
planets outside our solar system I think
realistically that's a much better
option than thinking that humans will
actually make these gigantic Journeys
and you know then I do this calculation
from my class you know Einstein's
special theory of relativity says that
you can do it in a short amount of time
in your own frame of reference if you go
close to the speed of light but then you
bring in eal mc^2 and you figure out how
much energy it takes to get you
accelerated to close enough to the speed
of light to make the time scales short
in your own frame of reference and the
amount of energy is just unfathomable
right we can do it at the large hron
collider with with protons you know we
can accelerate them to
99.9999% of this speat of light but
that's just a proton we're gazillions of
protons okay and that doesn't even count
the rocket that would carry us the
payload and you would need to either
store the fuel in the rocket which then
requires even more mass for the rocket
or collect fuel along the way which you
know is difficult and so getting close
to the speed of light I think is not an
option either other than for a little
tiny thing like you know Yuri Milner and
others are thinking about this this star
shot project where they'll a little tiny
camera to Alpha centuri 4.2 light years
away they'll zip past it take a picture
of the exoplanets that we know orbit
that three or more star system and uh
say hello real quick say hello real
quickly and then send the images back to
us okay yeah so that that's a tiny
little thing right maybe you can
accelerate that to they're hoping 20% of
the speed of light with a whole bunch of
high-powered lasers aimed at it it's now
clear that other countries will allow us
to do that by the way but that's a very
forward looking thought I mean I very
much support the idea but there's a big
difference between sending a little tiny
camera and sending a payload of people
with equipment that could then mine the
um the resources on the exoplanet that
they reach and and then go forth and
multiply right well let's let's talk
about the big Galactic things and how we
might be able to leverage them to travel
fast I know this is a little bit science
fiction
but you know know uh ideas of wormholes
and yeah the ideas at the edge of black
holes that reveal to us that this fabric
of SpaceTime is
uh could be messed with yeah perhaps is
that at all an interesting thing for you
uh I mean in in your in looking out at
the universe and studying it as you have
is that also a possible like a dream for
you that we might be able to find Clues
how we can actually use it to improve
our transportation it's an interesting
thought I'm certainly excited by the
potential physics that suggest this kind
of faster than light travel effectively
or you know cutting the distance to make
it very very short through a wormhole or
something like that possible no well you
know col me not very imaginative but
based on today's knowledge of physics
which I realize you know people have
gone down that rabbit hole
you know aury ago Lord Kelvin one of the
greatest physicists of all time said
that all of fundamental physics is done
the rest is just engineering and guess
what then came special relativity
quantum physics general relativity how
wrong he was so let me not be another L
Lord Kelvin on the other hand I think we
know a lot more now about what we know
and what we don't know and what the
physical limitations are and to me most
of these schemes if not all of them seem
very far-fetched if not impossible so
travel through wormholes for example you
know it appears that for a non-rotating
black hole that's just a complete no-o
because the The Singularity is a
point-like singularity and you have to
reach it to Traverse the Wormhole and
you get squished by The Singularity okay
now for a rotating black hole it turns
out there is a way to pass through the
Event Horizon the boundary of the black
hole and avoid the singularity and go
out the other side or even Traverse the
the doughnut hole like singularity in
the case of a rotating black hole it's a
ring Singularity so there's actually two
theoretical ways you could get through a
rotating black hole or a Charged black
hole not that we expect charged black
holes to exist in nature because they
would quickly bring in the opposite
charge so as to neutralize themselves
but rotating black holes definitely
reality we we now have good evidence for
them do they have Travers ible wormholes
probably not because it's still the case
that when you go in you go in with so
much energy that it it it either
squeezes the Wormhole shut or you
encounter a whole bunch of incoming and
outgoing energy that vaporizes you it's
called the mass inflation instability
and it just sort of vaporizes you
nevertheless you know you could imagine
well you're in some vapor form but if
you make it through maybe you could you
know re form or something so it's still
information yeah it's still information
it's scrambled information but there's a
way maybe of bringing it back right but
then the thing that really bothers me is
that as soon as you have this
possibility of traversal of a wormhole
you have to come to grips with a
fundamental problem and that is that you
could come back to your Universe At A
Time prior to your leaving and you could
essentially prevent your grandparents
from meeting this is called the
grandfather Paradox right and if they
never met and if your parents were never
born and if you were never born how
would you have made the journey to
prevent the history from allowing you to
exist right it's it's a it's a causal
it's a violation of causality of cause
and effect now physicists such as myself
take causality violation very very
seriously we've never seen it you took a
stand yeah I mean you know I mean it's
one of these right Back to the Future
type movies right and you have to work
things out in such a way that you don't
mess things up right some people say
that well you come back to the universe
but you come back in such a way that you
cannot affect your journey um but then I
mean that that seems kind of uh
contrived to me or some say that you end
up in a different universe and this also
goes into the the many different types
of the Multiverse hypoth esis and the
many worlds interpretation and all that
but again then it's not the universe
from which you left right and you don't
come back to the universe from which you
left and so you're not really going back
in time to the same universe and you're
not even going forward in time
necessarily then to the same universe
right you're ending up in some other
universe so so you've you what have you
achieved right you you've traveled you
traveled you uh you ended up in a
different place than you started in more
ways than one yeah and then then there's
this idea um the aluer drive where you
warp space time in front of you so as to
greatly reduce the distance and you can
expand the space time behind you so
you're sort of riding a wave through
SpaceTime but the problem I see with
that beyond the Practical difficulties
and the energy requirements and by the
way how do you get out of this bubble
through which you're you know riding
this wave of space time
miguelier acknowledged all these things
he said this is purely theoretical
fanciful and all that but a fundamental
problem I see is that you'd have to get
to those places in front of you so as to
change the shape of SpaceTime so as to
make the journey quickly but but to get
there you you got there in the normal
way at a speed considerably less than
that of light so in a sense you you
haven't saved any time right you might
as well have just taken that journey and
and gotten to where you were
going yeah there's a right you what have
you done you it's not like you snap your
fingers and say okay let that space
there be compressed and then I'll make
it over to Alpha centuri in the next
month you can't snap your fingers and do
that yeah and but yeah we're sort of
assuming that we can fix all the
biological stuff that requires for
humans to persist uh uh persist through
that whole process because ultimately it
might boil down to just extending the
life of the of the human in some form
whether it's through the robot through
the digital form or through or actually
just figuring out genetically how to
live forever CU that Journey that you
mentioned the long journey might be
different if somehow our understanding
of genetics of our understanding of our
own biology all that kind of stuff would
uh that's another trajectory if you
could put us into some sort of suspended
animation you know hibernation or
something and greatly increase the
lifetime and so these 10,000 Generations
I talked about what do they care it's
just one generation and they're asleep
okay long nap so then you can do it it's
still not easy right because you got
some big old huge colony and that just
through E equals MC squ right that's a
lot of mass that's a lot of stuff to um
to accelerate the Newtonian kinetic
energy is gigantic right so you're still
not home free but at least you're not
trying to do it in a short amount of
clock time right which if you look at
eal mc^2 requires truly unfathomable
amounts of energy because the energy is
sort of it's it's your rest mass m c^2
divided by the square root of 1us v^2
over c^2 and if your listeners want to
just sort of stick into their pocket
calculator as V over C approaches
one that one over the root of 1us v^2
over c^2 approaches Infinity MH so if
you wanted to do it in zero time you'd
need an infinite amount of energy that's
basically why you can't reach let alone
exceed the speed of light for a particle
moving through a pre-existing space it's
that it takes an infinite amount of
energy to do so so that's talking about
us going somewhere what
about one of the things that inspires a
lot of folks including myself is the
possibility that there's other that this
this conversation is happening and
another planet in different forms with
uh intelligent life
forms well first we could
start as a cosmologist what's your
intuition about whether there is or
isn't intelligent life out there outside
of our own yeah I would say I'm one of
the pessimists in that I I don't
necessarily think that we're the only
ones in the observable universe which
goes out you
know roughly 14 billion years in light
travel time and more like you know 46
billion years when you take into account
the expansion of space so the diameter
of our observable universe is something
like you know 90 992 billion Lighty
years that
encompasses you know 100 billion to a
trillion galaxies with um you know 100
billion stars each so now you're talking
about something like 10 to the 22nd 10
to the 23rd power stars and roughly an
equal number of earthlike planets and so
on
um so there there there may well be uh
other intelligent life but your your
sense is our Galaxy's not teaming with
life yeah our galaxy our Milky Way
galaxy with several hundred billion
stars and and potentially habitable
planets is not teeming with intelligent
life intelligent yeah I wouldn't well
I'll get to the Primitive life the
bacteria in a moment but um you know we
we may well be the only ones in our
Milky Way galaxy at most a handful I'd
say but I'd probably side with the
school of thought that suggests we're
the only ones in our own Galaxy just
because I don't see human intelligence
as being a a natural evolutionary path
for life um I mean there's a there's a
number of arguments first of all there's
been more than 10 billion species of
life on Earth in its history yes uh
nothing has approached our level of
intelligence and mechanical ability and
curiosity you know whales and dolphins
appear to be reasonably intelligent but
there's no evidence that they can think
abstract thoughts that they're curious
about the world they certainly can't
build machines with which to study the
world um so that's one argument
secondly we came about as early hominids
only four or five million years ago and
as H Homo sapiens only about a quarter
of a million years ago so for the vast
majority of the history of life on Earth
an intelligent alien zipping by Earth
would have said there's nothing
particularly intelligent or mechanically
able on Earth okay yeah thirdly it's not
clear that our intelligence is a
long-term evolutionary Advantage now
it's clear that in the last 100 years
200 years we've improved the lives of
millions hundreds of millions of people
but at the risk of potentially
destroying ourselves either
intentionally or unintentionally or
through neglect as we discussed before
that's a really interesting point which
is it's possible that their huge amount
of intelligent civilizations have been
born even through our galaxy but they
live very briefly and they die flash
bulbs in theight
Flight that brings me to the fourth the
fourth issue and that is the you know
the fairy Paradox if they're common
where the hell are they you know yeah
not withstanding the various UFO reports
in Roswell and all that they just don't
don't meet the bar they don't clear the
bar of scientific scientific evidence in
my opinion okay so you know there's
there's no clear evidence that they've
ever visited us on Earth here so and you
know SEI has been now the search for
extraterrestrial intelligence has been
scanning the skies and true we've only
looked a couple hundred light years out
and that's a tiny fraction of the whole
galaxy a tiny fraction of these 100
billion plus Stars nevertheless you know
I if if the if the Galaxy were teaming
with life especially intelligent life
you'd expect some of it to have been far
more advanced than ours okay there's no
special nothing special about when the
Industrial Revolution started on earth
right the chemical evolution of our
galaxy was such that billions of years
ago nuclear processing and stars had
built up clouds of gas after their
explosion that were Rich enough in heavy
elements to have formed earthlike
planets even billions of years ago so
there could be civiliz that are billions
of years ahead of ours and if you look
at the exponential growth of
Technology among Homo sapiens in the
last couple 100 years and you just
project that forward I mean there's no
telling what they could have achieved
even in 1,000 or 10,000 years let alone
a million or 10 million or a billion
years and if they reach this capability
of interstellar travel and colonization
then you can show that within 10 million
years or certainly a 100 million years
you can populate the whole galaxy all
right and they you know so then you
don't have to have tried to detect them
Beyond 100 or a thousand Lighty years
they would already be here do you think
as a thought experiment do you think it
it's possible that they are already here
but we humans are so human Centric that
we're just not like our conception of
what intelligent life looks like yeah is
is um we don't want to acknowledge it
like what what if trees right right
right like okay I guess the in a form of
a question do you think we'll actually
detect intelligent life if it came to
visit us yeah I mean it's like you know
you're an ant crawling around on a
sidewalk somewhere and do you notice the
humans wandering around exactly and and
the Empire State Building and you know
rocket ships flying to the moon and all
that kind of stuff right it's
conceivable that um we haven't detected
it and that we're so primitive compared
to them that we're just not able to do
so like if you look at dark energy Maybe
we call it as a field it's just that my
own feeling is that in science now
through observations and
experiments we've measured so many
things
and basically we understand a lot of
stuff okay fabric of reality yeah the
fabric of reality we understand quite
well and there are a few little things
like dark matter and dark energy that
may be some sign of some super
intelligence but I doubt it okay you
know why would some super intelligence
be holding clusters of galaxies together
why would they be responsible for
accelerating the expansion of the
universe so the point is is that through
science and applied science and
engineering we understand so much now
that I'm not saying we know everything
but but we know a hell of a lot okay and
so there's it's not like there are lots
of mysteries flying around there that
are completely outside our level of um
of of exploration or understanding yeah
from a I would say from from uh the
mystery perspective it seems like the
mystery of our own like cognition and
Consciousness is much grander than like
the degrees of freedom of possible
explanations for what the heck is going
on is much greater there than in the in
the physics of the absor how the brain
works how did life
arise yeah that's big big questions but
they to me don't indicate uh the
existence of of of an alien or something
I mean unless we are the aliens you know
we we could have been contamination from
some rocket ship that that hit here a
long long time ago and all evidence of
it has been destroyed but again that
alien would have started out somewhere
they're not they're not here watching us
right now right they're not among us and
so though there are exp potential
explanations for the fmy Paradox and one
of them that I kind of like is that the
truly intelligent creature
are those that decided not to colonize
the whole galaxy cuz they'd quickly run
out of room there CU it's exponential
right you send a probe to a planet it
makes two copies they go out they make
two copies each and it's an exponential
right they quickly colonize the whole
galaxy but then the distance to the next
galaxy the next big one like Andromeda
that's two and a half million light
years yeah that's a much grander scale
now right and so it it also could be
that the reason they surv this long is
that they got over this tendency that
may well exist among sufficiently
intelligent creatures this tendency for
aggression and self-destruction right if
they bypass that and that may be one of
the great filters if there are more than
one right then they may not be a type of
creature that feels the need to go and
say oh there's a nice looking planet um
and there's a bunch of you know ants on
it let's go squish him and colonize it
no it could even be the kind of Star
Trek like prime directive where you go
and explore worlds but you don't
interfere in any way right and and also
we call it exploration is beautiful and
everything but there is underlying this
desire to explore is a desire to
conquer yeah I I mean if we're just
being really honest about right now for
us it is right and you're saying it's
possible to separate but I would venture
to say
that you wouldn't that those are coupled
so I could I could imagine a
civilization that lives on for billions
of years that just stays on its like
figures out the minimal effort way of
just peacefully existing it's like a
monastery yeah and it limits itself yeah
it limits itself you know it's it's
planted its seeds in a number of places
so it's not vulnerable to a single point
failure right Supernova going off near
one of these s or something or an
asteroid or a comet coming in from the
arc Cloud equivalent of that planetary
system and without warning you know
thrashing them to bits so they've got
their seeds in a bunch of places but
they chose not to colon colonize the
Galaxy and they also choose not to
interfere with this incredibly priv
primitive organism Homo sapiens right um
or or they uh this is like a they enjoy
this like a TV show for them yeah could
a TV show right so they just tuned in
right so those are possible explanations
yet I I think that to me the most likely
explanation for the FME Paradox is that
they really are very very rare and you
know Carl Sean estimated a 100,000 of
them if there's that many some of them
would have been way ahead of us and and
I think we would have seen them by now
if there were a handful maybe they're
there but at that point you're right on
this dividing line between being a
pessimist and an optimist yeah and and
what are the odds for that right if you
look at all the things that had to go
right for us yeah and the then you know
getting back to something you said
earlier let's discuss you know primitive
life yeah that could be the thing that's
difficult to achieve just getting the
random molecules together to a point
where they start self-replicating and
evolving and becoming better and all
that that that's an inordinately
difficult thing I think though I'm not
you know some molecular cell biologist
but just it's it's it's the usual
argument you know you're wandering
around in the Sahara Desert and you
stumble across a watch is your is your
initial response oh you know a bunch of
sand grains just came together randomly
and formed this watch no you you think
that something formed it or it came from
some simpler structure that then became
you know more complex all right it
didn't just form well even the simplest
life is is a very very complex structure
even the even the simplest procaryotic
cells not to mention eukaryotic cells
although that transition may have been
this so-called great filter as well
maybe the cells without a nucleus are
relatively easy to form and then the big
next step is where you have a nucleus
which then provides a lot of energy
which allows the cell to become much
much more complex and so on
interestingly going from eukaryotic
cells single cells to multicellular
organisms does not appear to be at least
on Earth one of these great filters
because there's evidence that it
happened dozens of times independently
on Earth so by by a really great filter
something that happens very very rarely
I mean that we had to get
through um an obstacle that is just
incredibly rare to get through and one
of the really exciting scientific things
is that that particular
Point U is something that we might be
able to discover Even in our lifetimes
that find life elsewhere like Europa or
yeah be able to see that would be bad
news right because if we find lots of
pretty Advanced life yeah that would
suggest and and especially if we found
some you know defunct you know
fossilized civilization or something
somewhere else that would be you mean of
like what's that defunct civilization of
like I'm sorry I switched gear there if
we if we found some intelligent or
rather you know even even trilobites
right and stuff you know elsewhere that
would be bad news for us because that
would mean that the great filter is
ahead of us you know right because it
would mean that lots of lots of things
have gotten roughly to our level yeah
but but given the fmy Paradox if you
accept that the fmy Paradox means that
there's no one else out there you don't
necessarily have to accept that but if
you accept that it means that no one
else is out there and yet there are lots
of things we found that are at or
roughly at our level that means that the
great filter is ahead of us and that
bodess poorly for our long-term future
you know it's funny you said uh you
started by saying you're a little bit on
the pessimistic side but it's funny
because we're doing this kind of dance
between pessimism and optimism because
I'm not sure if us being alone in the
observable universe as intelligent
beings is
pessimistic well it's good news in a
sense for us because means that we made
it through oh right see if we're the
only ones and there are such great
filters maybe more than one formation of
life might be one of them formation of
eukaryotic that is with the nucleus
cells be another development of
humanlike intelligence might be another
right there might be several such
filters and we were the lucky ones and
you know then people say well then that
means you're putting yourself into a
special perspective and every time we've
done that we've been wrong and yeah yeah
I know all those arguments but it still
could be the case that there's one of us
at least per Galaxy or per 10 or 100 or
a thousand galaxies and we're sitting
here having this conversation because we
exist and so there's a there's an
observational selection effect there
right just because we're special doesn't
mean that we shouldn't have these
conversations about whether or not we're
special
right yeah so that's that's exciting
that's optimistic so that's the that's
the optimistic part that if we don't
find other intelligent life there it
might mean that we're the ones that made
it uh and and in general outside the
great filter and so on you know it's not
obvious that uh the Stephen Hawkin thing
which is it's not obvious that life out
there is is going to be kind to us
oh yeah so you know I knew Hawking and I
greatly respect his his scientific work
and in particular the early work on the
unification of general theory of
relativity and quantum physics to two
great pillars of modern physics you know
Hawking radiation and all that fantastic
work you know if he were alive he should
have been a recipient of this year's
physics Nobel Prize which was for the
discovery of black holes and also uh by
Roger Penrose for the theoretical work
showing that given
a star that's massive enough you you
basically can't avoid having a black
hole anyway Hawking fantastic I I tip my
hat to him may he rest in peace that
would have been a heck of a Nobel Prize
black holes heck of a good group but but
but going back to what he said that we
shouldn't be um broadcasting our
presence to others there I actually
disagree with him respectfully
because first of all we've been
unintentionally broadcasting our
presence for a 100 years since the
develop velopment of radio and TV okay
um secondly any alien that has the
capability of coming here and squashing
us uh either already knows about us and
you know doesn't care because we're just
like little ants and when they're ants
in your kitchen you tend to squash them
but if they're ants on the sidewalk and
you're walking by do you feel some great
conviction that you have to squash any
of them no you you generally don't right
we're irrelevant to them all they need
to do is keep an eye on on us to see
whether we're approaching the kind of
technological capability and know about
them and have intentions of attacking
them and then they can squash us right
um they you know they could have done it
long ago yeah they'll do it if they want
to whether we advertise our presence or
not is is irrelevant so I really think
that that's not a huge existential
threat so this is a good place to bring
up a difficult topic you mentioned um
they're they might they would be paying
attention to us to see if we come up
with any crazy
technology there's folks who have uh
reported UFO sightings there's actually
I've recently found out there's uh
websites that track this the D the data
of these reportings and there's millions
of them in the past uh several decades
so seven decades and so on that they've
been
recorded and the yist community as they
refer to themselves you know one of the
ideas that I find compelling from an
alien perspective that they kind of
started showing up ever since we figured
out how to build nuclear weapons MH that
we should what a coincidence yeah uh so
I mean you know if I was an alien I
would start showing up then as well just
well why not just observe us from afar
no I know right I would figure out
but that's why I'm always uh keeping a
distance and staying blurry right
but very pixelated very pixelated you
know there there is a something in the
human condition that a cognition that
wants to see wants to believe beautiful
things and uh some are terrifying some
are
exciting uh goats Bigfoot is a big
Fascination for folks yeah and uh UFO
sightings I think falls into that
there's people that look at lights in
the night sky
and I
mean there's it's kind of a downer to
think in a skeptical sense to think that
that's just a light yeah you want to
feel like there's something magical
there sure uh I mean I felt that first
when my dad my dad's a physicist when he
first told me about ball lightning yeah
when I was like a little kid very weird
very like weird physical phenomena and
you said his intuition was telling me
this as a little kid uh like I really
like math his intuition was whoever
figures out ball lightning will get a
Nobel Prize mhm like he I think that was
a side comment he gave me and I I
decided there when I was like 5 years
old or whatever that I'm going to win a
Nobel Prize for figuring out B that was
like one of the first sort of Sparks of
the scientific mindset those Mysteries
they capture your imagination I I think
when I speak to people that report UFOs
that's that fire that's what I see that
excitement yeah I understand that MH but
what what do we do with that because
there's hundreds of thousands if not
millions and then the scientific
Community you're like the perfect person
you you have an awesome Einstein sure I
what what do we do with those reports
it's uh most of the scientific Community
kind of rolls their eyes and dismisses
it is it is it possible that a Time % of
those folks saw something that's worth
deeply investigating sure we should
investigate it it's just one of these
things where you know they've not
brought us a hunk of kryptonite or
something like that right they haven't
brought us actual tangible physical
evidence with which experiments can be
done in Laboratories right it's it's
anecdotal evidence the photographs are
um in some cases in most cases I would
say quite ambiguous I don't know what to
think about so David fraver is the first
person he's a Navy pilot Commander yeah
and there's a bunch of them but he's
sort of one of the most legit pilots in
people I've ever met right the fact that
he saw something weird he doesn't know
what the heck it is yeah he saw
something weird I mean I don't know what
to do with that and one on the psych
psychological side so I'm pretty
confident he saw what he says he saw
which he's not Prov he's saying it's
something weird
right one of the interesting
psychological things that worries me is
that
everybody in the Navy everybody in the
US government everybody in the
scientific Community just kind of like
uh pretended that nothing happened mhm
that kind of instinct that's what makes
me believe if aliens show up we would
all like just ignore their presence
that's what bothered me that you
don't you don't investigate it more
carefully and use this opportunity to
inspire the world like so in terms of
kryptonite I think the conspiracy theory
folks say that whenever there is some
good hard evidence that scientists would
be excited about the U there's this kind
of conspiracy that I don't like cuz it's
ultimately negative that the US
government will somehow hide the good
evidence yeah uh to uh to protect it of
course there's some legitimacy to it cuz
you want to protect military uh Secrets
all that kind of stuff
but yeah I I don't know I don't know
what to do with this beautiful mess
because um I think think millions of
people are inspired by UFOs right and it
feels like an opportunity to inspire
people about science so I would say you
know as Carl hean used to say
extraordinary claims require
extraordinary evidence right I've quoted
him a number of times
uh we would we would welcome such
evidence uh on the other hand you know a
lot of the things that are seen or
perhaps even hidden from us you could
imagine for military purposes
surveillance purposes the US government
doesn't want us to know or maybe some of
these Pilots saw Soviet or Israeli or
whatever uh satellites right a lot of
the or some of the crashes that have
occurred were later found to be you know
weather balloons or whatever you know
when there are more conventional
explanations science tends to stay away
from the um from The Sensational ones
right and so it may be that someone
else's calling in life is to investigate
these phenomena and I welcome that as a
scientist I I don't categorically
actually deny the possibility
that ships of some sort could have
visited us because as I said earlier at
slow speeds there's no problem in
reaching other stars in fact our Voyager
and Pioneer spacecraft in a few million
years are going to be in the vicinity of
different Stars we can even calculate
which ones they're going to be in the
vicinity of right uh so there's nothing
that breaks any laws of physics if you
do it slowly but that's different you
know just having Voyager or Pioneer fly
by some star that's different from
having active aliens altering the
trajectory of their vehicle in real time
spying on us and then either zipping
back to their home planet or sending
signals that tell them about us because
they are likely many years many light
years away and they're not going to have
broken that barrier as well okay right
so so I I just you
know go ahead study them great I you
know for some young kid who wants to do
it it might be their calling and that's
how they might find meaning in their
lives is to be the scientist who really
explores these things I chose not to
because at a very young age I found the
evidence to the degree that I
investigated it to be really quite
unconvincing and I had other things that
I wanted to do but I don't categorically
deny the possibility and I think it
should be investigated yep I mean this
is uh this is one of those phenomena
that um
99.9% of people are almost definitely
there's conventional explanations and
then there's like mysterious things that
probably have explanations that are a
little bit more complicated yeah it's
but there's not enough to work with I
tend to believe that if aliens showed up
there will be plenty of evidence uh for
scientists to study that like it exactly
U as you
said a voyager type of spacecraft I
could see sort of um some kind of kind
of a dumb thing almost like a sensor to
like probing like statistically speaking
flying by maybe lands maybe there's some
kind of robot type of thingies that just
like move around and so on yeah like in
ways that we don't understand but but I
feel like
well I feel like there'll be plenty of
hard
hard to dismiss evidence and I also
especially this year believe that the US
government is not sufficiently competent
given the huge amount of evidence that
would be revealed from this kind of
thing to conceal all of it right uh at
least in modern times you can say maybe
decades ago but in modern times but you
know I uh the the people I speak to and
the reason I bring it up is because so
many people write to me they're inspired
by it by the way I wanted to comment on
something you said earlier um yeah I had
said that I'm sort of an a pessimist in
that I think there are very few other
intelligent mechanically able creatures
out there but then I said yes in a sense
I'm an optimist as you pointed out
because it means that we made it through
the great filter right I I meant
originally that I'm a pessimist in that
I'm pessimistic about the possibility
that there are many many of us out there
you mathematically speaking in the Drake
equation exactly right right but but it
may mean a good thing for our ultimate
survival right so I'm glad you caught me
on that yeah I I definitely agree with
you I it is ultimately an optimistic
statement but anyway I think you know
UFO research is is interesting and I
guess one of the reasons I've not been
terribly convinced is that I think there
are some scientists who are
investigating this and they've not found
any clear evidence now I must admit I
have not looked through the literature
to convince myself that there are many
scientists doing systematic studies of
these various reports so I can't say for
sure that there's a critical mass of
them it's just that you you never get
these reports from Hardcore scientists
that's other thing and astronomers you
know what do we do we spend our time
studying the heavens and you'd think
we'd be the ones that are most likely
aside from Pilots perhaps at seeing
weird things in the sky and we just
never do of the unexplained UFO type
nature yeah I definitely I I try to keep
an open mind but for people who listen
um it's actually really difficult for a
scientist like I get
probably like this year I probably
gotten over probably maybe maybe over a
thousand emails on on the topic of AGI
mhm it's very difficult to uh you know
people write to me it's like how can you
ignore this in AI side like this model
this is obviously the model that's going
to achieve general intelligence how can
you IGN know it I'm giving you the
answer here's my document and there
always just these large writeups the
problem is it's very difficult to we
weed through a bunch of BS right it's
it's very possible that you had actually
saw the UFO but you have to
acknowledge by UFO I mean an extr
terrestrial life right you have to
acknowledge the hundreds of thousands of
people who
are a little bit if not a lot full of BS
and from a scientist perspective it just
it's really hard work and it's um when
there's amazing stuff out there it's
like why investigate Bigfoot when
evolution in all of its richness is
beautiful who cares about a monkey that
walks on two feet like there's a zillion
decoys right at
observatories true fact we get lots and
lots of phone calls when Venus the
evening star but just really a a bright
Planet happens to be close to the
Crescent Moon because it's such a
striking pair this happens once in a
while so we get these phone calls oh
there's a UFO next to the moon and no
it's Venus and so they're just and I'm
not saying the the best UFO reports are
of that nature no there are some much
more convincing cases and I've seen some
of the footage and blah blah blah um but
it's just there's so many decoys right
so much so much noise that you have to
filter out Y and there's only so many
scientists so it's there's so there's
only so much time as well and you have
to choose what problems you work on you
know this might be a fun question asked
to kind of
explore the idea of the expanding
Universe yeah so the the radius of the
observable universe is
45.7 billion light years yeah and the
age of the universe is
13.7 yeah billion years MH mhm that's
less right than the radius of the
universe yeah how's that possible so
that's a great question so the and I
meant to bring a little a little prop I
have with pingpong balls on a rubber
hose a rubber band I I use it in many of
the lectures that one can find of me
online but you have in an expanding
Universe the space itself between
galaxies or more correctly clusters of
galaxies expanding so imagine light
going from one cluster to another it
traverses some distance and then while
it's traversing the rest that part that
it already traveled through continues to
expand now 13.7 billion years might have
gone by since the light that we are say
seeing from the early stages the
so-called Cosmic microwave background
radiation which is the the Afterglow of
the Big Bang or the echo of the big Bang
Yeah 13.7 billion years have gone by
that's how long it's taken that light to
reach us but while it's been traveling
that distance the parts that it already
traveled continue to expand MH so it's
like you're walking on at an airport you
know on one of these walkways and you're
walking along because you're trying to
get to your terminal but the walkway is
continuing as well you end up traveling
a greater distance or the same distance
faster is another way of putting it
right that's why you get on one of these
traveling walkways but so you get a
roughly a roughly a factor of Pi you
know but it's more like 3.2 I think but
when you work it all out you multiply
the number of years the universe has
been in existence by you know three and
a quarter or so and that's how you get
this 46 billion Lightyear
radius
but how is that let me ask some nice
dumb questions uh how is that not
traveling faster than the speed of light
yeah it's not traveling faster than the
speed of light because locally at any
point if you were to measure the light
the photon zipping past it would not be
exceeding the speed of light the speed
of light is a locally measured quantity
after light has traversed some distance
if the rubber band keeps on stretching
then yes it looks like the light
traveled a greater distance than it
would have had the space not been
expanding but locally it never was
exceeding the speed of light it's just
that the distance through which it
already traveled then went off and
expanded on its own some more and if you
give the light credit so to speak for
having traversed that distance well then
it looks like it's going faster than the
speed of light but but that's not that's
not how spe that's happen right that's
not how Speed Works speed and in
relativity also the other thing um that
is interesting is that you know if you
take two ping-pong balls that are
sufficiently far apart especially in an
accelerating universe you can easily
have them moving apart from one another
faster than the speed of light so you
know take two pingpong balls that were
originally 400,000 kilometers from each
other and let every centimeter in your
rubber band expand to two in one second
then suddenly this 400,000 kilometer
distance is 800,000
km it went out by 400,000 km in 1 second
that exceeds the 300,000 kilom perss
speed of light but that light limit that
that particle limit in special
relativity applies to objects moving
through a pre-existing space there's
nothing in either special or general
relativity that prevents space itself
from expanding faster than the speed of
light that's no problem Einstein
wouldn't have had a problem with with a
with an with a universe and observed Now
by cosmologists yeah I um I'm not sure
I'm yet ready to deal emotionally with
expanding space it's like that to me is
one of the most a inspiring things you
know starting from the Big Bang it's
definit abstract it space itself is
expanding right could you can we talk
about the big bang a little bit sure
yeah yeah what uh so like the entirety
of it
the universe yeah was very small right
but it was not a point it was not a
point because if if we live in what's
called a closed Universe now a sphere or
the three-dimensional version of that
would be a
hypersphere you know then regardless of
how far back in time you go it was
always that topological shape you can't
turn a point suddenly into a shell okay
it always had to be a a shell yeah so
when when people say well the universe
started out as a point that that's being
kind of flippant kind of glib it didn't
really it just started out a at a very
high density and we don't know actually
whether it was finite or infinite I
think personally that it was finite at
the time but it expanded very very
quickly indeed if it exponentiated and
continued in some places to exponentiate
then it could in fact be infinite right
now and most cosmologists think that it
is infinite wait yeah sorry what uh
infinite which dimension MTH
si infite in space infinite in space and
by that I mean that if you were trying
to meure use light to measure its size
You' you'd never be able to measure its
size because it would always be bigger
than the distance light can travel
that's what you get in a universe that's
accelerating in its expansion okay but
if a thing was a hypersphere it's very
small not a point yeah how can that
thing be infinite well it it expands
exponentially that's what the inflation
theory is all about indeed at your home
institution Alan Guth is one of The
Originators of the whole inflationary
Universe idea along with Andre Lind at
at Stanford University here in the Bay
Area and others Alexis stabinsky and
others had similar sorts of ideas but in
an exponentially expanding Universe if
you actually try to make this
measurement you you send light out to
try to see it curve back around and and
hit you in the back of the head if next
exponentially expanding Universe the
amount of space remaining to be
traversed is always a bigger and bigger
quantity so you'll never get there from
here you'll never you you'll never reach
the back of your head so observationally
or operationally it can be thought of as
being infl INF that's one of the best
definitions of infinity by the way
that's what's that that's one of the
best sort of uh physical manifestations
of infinity that yeah yeah because you
have to ask how would you actually
measure it now sometimes say to my
cosmology theoretical friends well if I
took if I were God and I were outside
this whole thing and I took a Godlike
slice in time wouldn't it be finite no
matter how big it is and they object and
they say Alex you you can't be outside
and take a Godlike slice of time you
know because there's nothing outside
well I'm not you
know or also you know what slice of time
you're taking depends on your motion and
that's true even in special relativity
that slices of time get tilted in a
sense if you're moving quickly the axes
x and t actually become tilted not not
perpendicular to one another um and you
know you can look at Brian Green's books
and lectures and other things where he
he imagines taking a loaf loaf of bread
and slicing it in units of time as you
progress forward but then if you're
zipping along relative to that loaf of
bread the slices of time actually become
tilted and so it's not even clear what
slices of time mean but I I'm an
observational astronomer I know which
end of the telescope to look through and
the way I understand the infinity is as
I just told you that operationally or
observationally there no there'd be no
way of seeing that it's a finite
Universe of measuring a finite universe
and so in that sense it's it's infinite
even if it started out as a finite
little dot well you know not a DOT I'm
sorry a finite little
hypersphere but it didn't really start
out there cuz what what what what
happened before that well we don't know
so this is where it gets into a lot of
speculation and let's go I mean let's go
there okay sure so you know nobody can
prove wrong the idea right what happened
before T equals z and whether there are
other universes out there I like to say
that these are sort of on the bound
boundaries of science they're not just
ideas that we wake up at 3 in the
morning to go to the bathroom and say oh
well let's think about what happened
before the Big Bang or let there be a
multiplicity of universes in other words
we have real testable physics that we
can use to draw certain
conclusions that are plausibility
arguments based on what we know now
admittedly there are not really direct
tests of these hypotheses
that's why I call them hypotheses
they're they're not really elevated to a
theory because a theory in science is
really something that has a lot of
experimental or observational support
behind it so they're they're hypotheses
but they're they're not unreasonable
hypotheses based on what we know about
general relativity and quantum physics
okay and they may have indirect tests in
that if you adopt this hypothesis then
there might be a bunch of things you
expect of the universe and lo and behold
that's what we measure but we're not
actually measuring anything at T less
than zero or we're not actually
measuring the presence of Another
Universe in this Multiverse and yet
there are these indirect ideas that stem
forth so it's hard to prove uniqueness
and it's hard to completely convince
oneself that a certain hypothesis must
be
true but you know the more and more
tests you have that it satisfies let's
say there are 50 predictions it makes
and 49 of them are in are are things
that you can measure and then the 50th
one is the one where you you want to
measure the actual existence of that
other universe or what happened before T
equals z and you can't do that but but
you've satisfied 49 of the other
testable predictions and so that's
science right now A a conventional
condensed matter physicist or someone
who deals with real data in the
laboratory might say oh you cosmologists
you know that's not really science
because it's not directly testable but I
would say it's sort of testable but but
it's not completely testable and so it's
at the boundary but it's not like we're
coming up with these crazy ideas among
them Quantum fluctuations out of nothing
and then inflating into a universe with
you might say well you created a giant
amount of energy but in fact this
Quantum fluctuation out of nothing you
know in a Quantum way violates the
conservation of energy but you know who
cares that was a classical law anyway
and then an inflating Universe maintains
whatever energy it had be it zero or
some infinites amount in a sense the
stuff of the universe has a positive
energy but there's a negative
gravitational energy associated with it
it's like I drop an apple I got kinetic
energy energy of motion out of that but
I did work on it to bring it to that
height mhm so by going down and gaining
energy of motion
positive 1 2 3 4 5 units of kinetic
energy it's also gaining or losing
depending on one how you want to think
of it negative 1 2 3 four five units of
potential energy so the total energy
Remains the Same an inflating Universe
can can do that or other physicists say
that energy isn't conserved in general
relativity that's another way out of
creating a universe out of nothing you
know but the point is that this is all
based on reasonably well tested physics
and although these these
extrapolations seem kind of outrageous
at first they're not completely
outrageous they're they're within the
realm of what we call science already
and maybe some Y young whipper snapper
will be able to figure out a way to
directly test what happened before T
equals z or to test for the presence of
these other universes but right now we
don't have a way of doing that so
speaking of uh young whipper snappers
Roger Penrose yeah uh so he kind of has
a
you know idea that we there may be some
information that travels from whatever
the heck happened before the Big Bang
yeah maybe I kind of doubt it so do you
think it's possible to detect some like
actually experimentally be able to
detect
some I don't know what it is radiation
some some sort of yeah and the cosmic
microwave background radiation there may
be ways of doing that is but is it is it
philosophically or practically possible
to detect signs that this was before the
Big Bang or is it or is it what you said
which is like everything we observe will
as we currently understand will have to
be a creation of this particular
observable universe yeah I mean you know
if you it's very difficult to answer
right now because we don't have a single
verified fully self-consistent
experimentally tested quantum theory of
gravity right and of course the
beginning of the universe is a large
amount of stuff in a very small space so
you need both quantum mechanics and
general relativity same thing if our
universe Recaps and then bounces back to
another big bang you know there's also
ideas there that some of the information
leaks through or survives I don't know
that we can answer that question right
now because we don't have a quantum
theory of gravity that most physicists
uh believe in and belief is perhaps the
wrong word that most physicists trust
because the experimental evidence favors
it yeah right you know there are various
forms of string theory there's Quantum
Loop gravity there are various ideas but
which if any will be the one that
survives the test of time and more
importantly within that the test of
experiment and observation yeah so my
own feeling is probably these things
don't survive I don't think we've seen
any evidence in the cosmic microwave
background radiation of of information
leaking through similarly um the one way
or one of the few ways in which we might
test for the presence of other universes
is if they were to collide with ours
that would leave a a pattern a
temperature signature in the cosmic
microwave background radiation some
astrophysicists claim to have found it
but in my opinion it's not statistically
significant to the level that would be
necessary to have such a an amazing
claim right you know it's just a 5%
chance that the microwave background had
that distribution just by chance yeah
five % isn't very long odds if you're
claiming that instead that you're that
you're finding you know evidence from
Another Universe I mean it's like if the
Large Hadron Collider people had
claimed after gathering enough data to
show the higs particle when there was a
5% chance it could be just a statistical
fluctuation in their data no they they
required five Sigma five stand
deviations which is roughly One Chance
in 2 million that this is a statistical
fluctuation of no
physical greater significance you know
extraordinary claims require
extraordinary go it all boils down to
that and the and the greater your claim
the greater is the evidence that is
needed and the more evidence you need
from independent ways of measuring or of
coming to that deduction you know a good
example was the the accelerating
universe you know when we found it
evidence for it in 1998 with supern noi
with exploding Stars it was great that
there were two teams that lent some
credibility to the Discovery but it was
not until other astrophysicists used not
only that technique but more importantly
other independent techniques that had
their own potential sources of
systematic error or whatever but they
all came to the same conclusion and that
started giving a much more complete
picture of what was going on in a
picture in which most astrophysicists
quickly gained confidence that's why
that idea caught on so quickly is that
there were other
physicists and astronomers doing
observations completely independent of
supern noi that seemed to indicate the
same thing yeah that period of
uh of your life that work with a
incredible team of people that um won
the Nobel Prize
is just fascinating work oh gosh you
know never in my wildest dreams as a kid
did I think that I would be
involved much less so heavily involved
in a discovery that's so revolutionary I
mean you know as a kid as a scientist if
you're realistic once you learn a little
bit more about how science is done and
you're not going to win a Nobel Prize
and be the next Newton or Einstein or
whatever you just hope that you'll
contribute something to humankind's
understanding of how nature works and
you'll be satis ified with that you know
but here I was in the right place at the
right time a lot of luck a lot of hard
work um and there it was you know we
discovered something that was really
amazing and that that was the the
greatest thrill right I couldn't have
asked for anything more uh than being
involved in that Discovery so one so the
the couple of teams of supernova
cosmology project and the high Supernova
search team so the what was the Nobel
Prize given for it was given for the
discovery of the expansion of the
universe not for the elucidation of what
dark energy is or what causes that
expansion uh that acceleration be it
universes on the outside or whatever it
was only for the observational fact so
first of all what is the accelerating
universe so the accelerating universe is
simply that if we look at the galaxies
moving away from us right now we would
expect them to be moving away more
slowly than they were billions of years
ago and because Galaxies have visible
matter which is gravitationally
attractive and dark matter of an unknown
sort that holds galaxies together and
holds clusters of galaxies together and
of course they then pull on one another
and they would tend to the
expansion of the universe just as when I
toss an apple up you know even ignoring
air resistance the mutual gravitational
attraction between Earth and the Apple
slows the Apple down and if that
attraction is great enough then the
Apple will they stop and even come back
the Big Crunch you could call it or the
gnab Gibb which is Big Bang backwards
right that's what could have happened to
the universe but even if the universe's
original expansion energy was so great
that it avoids the Big Crunch that's
like an apple thrown at Earth's escape
speed it's like that the the the the
rockets that go to Mars someday right
you know uh with
people even then you'd expect the
universe to be slowing down with time
but we looked back through through the
history of the universe by looking at
progressively more distant galaxies and
by seeing that the evolution of this
expansion rate is that in the first N9
billion years yeah it was slowing down
but in the last five billion years it's
been speeding up so who asked for that
right you know um I think it's
interesting to talk about a little bit
of the human story of the Nobel Prize
sure which is
I mean fascinating it's a really first
of all the prize itself it's kind of
fascinating in the psychological level
that uh prizes uh I know we kind of
think that prizes don't matter but
somehow they kind of focus the mind
about some of the most special things we
have ACC the recognition the funding you
know but and also inspiration for like I
said when I was a little kid they get
The Nobel Prize like I I didn't you know
it inspires millions of young scientists
at the same time there's a sadness to it
a little bit that uh especially in the
field like depending on the field but
experimental fields that involve teams
of I don't know sometimes hundreds I
mean of brilliant
people the Nobel Prize is only given to
just a handful I that's right is it Ma
Max a three yeah yeah and it's not even
written in Alfred nobel's will it turns
out one of our teammates looked into it
in a museum in Stockholm when we went
there for Nobel week in 2011 the the
leaders who got the prize formally knew
that without the rest of us working hard
in the trenches the result would not
have you know been discovered so they
invited us to participate in Nobel week
and so one of the team members looked in
the will and it's not there it's just
tradition that's but it's archaic you
know that's the way science used to be
done and it's not the way a lot of
science is done now and you look at
gravitational wave discovery which was
you know recognized with the Nobel Prize
in 2017 Ray weet MIT got it and Kip
Thorne and um and um Barry beish at
Caltech and Ron DAV one of the
masterminds had passed away earlier in
the year so again one of the rules of
Nobel is that it's not given pusle yeah
or at least the one exception might be
if they've made their decision and
they're busy making their press releases
right before October the first week in
October or whatever and then the person
passes away I think they don't change
their minds then but yeah you know it it
it doesn't square with today's reality
that a lot of science is done by big
teams in that case a team of a thousand
people in our case it was two teams
consisting of about 50 people and we
used techniques that were arguably
developed in part by people who
astrophysicists who weren't even on
those two papers I mean some of them
were but other papers were written by by
other people you know know and so it's
like we're standing on the shoulders of
giants and none of those people was
officially recognized and to me it was
okay you know again it was the thrill of
doing the work and ultimately the work
the discovery was recognized with the
prize and you know we got to participate
in Nobel week and you know it's okay
with me I I've known other physicists
whose lives were ruined because they did
not get the Nobel Prize and they felt
strongly that they should have Ralph
alfer um of the alfha beta gamma you
know paper predicting the microwave
background radiation he should have
gotten it his adviser gamov was dead by
that point but um you know penus and
Wilson got it for the discovery and and
alfur apparently from colleagues who
knew him well I've talked to them his
life was ruined by this he just it just
nod at his inard so much it's uh very
possible that uh and a small handful of
people even three that you would be one
of the Nobel one of the winners of the
Nobel Prize that doesn't weigh heavy on
you well you know there were the two
team leaders Saul pearlmutter and Brian
Schmidt and usually it's the team
leaders that are recognized and then
Adam Reese was my postto um first first
author I guess yeah first author I was
second author of that paper yeah uh so I
was his direct Mentor at the time
although he was you know one of these
people who just you know runs with
things he was an MIT undergraduate by
the way um Harvard graduate student and
then a postto as a so-called Miller
fellow for basic research in science at
Berkeley something that I was back in '
84 to 86 but you're you're you know
you're largely a free agent but he
worked quite closely with me and he came
to Burkle to work with me and on
Schmidt's team he was charged with
analyzing the data and he measured the
brightnesses of these distant supern noi
showing that they're fainter and thus
more distant than anticipated and that
led to this conclusion that the Universe
had to have accelerated in order to push
them out to such great distances and I
was shocked when he showed me the data
the results of his calculations and
measurements um but it's very you know
so he deserved it but and on Sal G gon g
gold hobber deserved it but he died I
think a year earlier in 2010 but that
would have been four and
so and me well I was on both teams but
you know was I number four five six
seven I don't know well it's it's also
very so if I were to it's possible that
you're I mean I I could make a very good
case for you're in in the three and does
thaty kind you know so but is that
psychologically I mean listen it weighs
on me a little bit because I yeah
I I don't know what to do with that it
it U perhaps it should
motivate uh the rethinking like Time
magazine started doing like you know
person of the year yeah and like they
they would start doing like Concepts and
almost like the black hole gets the
Nobel Prize
or Universe gets the Nobel Prize and
here's the list of people so like ult or
like the Oscar that you could say yeah
because it it's a team effort now you
know and it should be redone and the
Breakthrough prize in fundamental
physics which was started by Yuri Milner
and Zuckerberg is involved and others as
well you know uh they recogniz a larger
team yeah they they recognized teams and
so in fact both teams in the
accelerating universe were recognized
with the Breakthrough prize in 2015
nevertheless the same three people reys
pearlmutter and Schmidt got the red
carpet rolled out for them and were at
the big ceremony and shared half of the
prize money and the rest of us roughly
50 shared the other half and didn't get
to go to the ceremony so but I I I feel
for them I mean for the gravitational
waves it was a thous people what are
they going to do invite everyone for the
higs particle it was 6 to 8,000
physicists and engineers in fact because
of the whole issue of who gets it
experimentally that Discovery still has
not been recognized right the
theoretical work by Peter higs and uh
angir got recognized but there was a
troa of other people who WR perhaps
wrote the most complete paper and they
were they were left out and um another
guy died you know and yeah it's heart
it's all of it's heartbreaking some
people argue that the Nobel Prize has
been deluded to because if you look at
Roger Penrose you can make an argument
that he should get the prize by himself
like it's she separate those like could
have and should have perhaps he should
have perhaps gotten it with Hawking
before Hawking's death right the problem
was Hawking radiation had not been
detected but you could argue that
Hawking made enough other fundamental
contributions to the theoretical study
of black holes and The observed data
were already good enough at the time of
before Hawking's death okay I mean the
latest results by Reinhardt gel's group
is that they see the time dilation
effect of a star that's passing very
close to the black hole in the middle of
our galaxy that's cool but and it adds
additional evidence but hardly anyone
doubted the existence of the super
massive black hole and Andrea gz's group
I believe hadn't yet shown that
relativistic effect and yet she got part
of the prize as well so clearly it was
given for the the original evidence that
was really good and that evidence is at
least a decade old you know so one could
make the case for for Hawking um one
could make the case that in 2016 when
mayor and Kao won the Nobel Prize for
the discovery of the first exoplanet um
51b pegasi well there was a fellow at
Penn State Alex walon who in
1992 three years preceding 1995 found a
a p a planet orbiting a pulsar a very
weird kind of star a neutron star and
that wouldn't have been a normal Planet
sure and so the Nobel committee you know
they gave it for the discovery of
planets around normal sunlike stars but
but hell you know Wan found a planet so
they could have given it to him as the
third person instead of to Jim Peebles
for the development of what's called
physical cosmology he's at Princeton he
deserved it but they could have given
Nobel for the development of physical
cosmology to pees and I would claim some
other people were pretty important in
that development as well you know and
they could have given it some other year
um so there's there's a lot of
controversy I try not to dwell on it was
I number three probably not you know
Adam Reese did the work um you know I
helped bounce ideas off of him but it we
wouldn't have had the result without him
yeah and I was on both teams for reasons
I mean you know I the the St of the
first team the Supernova cosmology
project didn't match mine they came
largely from experimental high energy
particle physic physics where there's
these hierarchical teams and stuff and
it's hard for the little guy to to have
a say at least that's what I kind of
thought whereas the team of astronomers
led by Brian Schmidt was first of all a
bunch of my friends and they grew up as
astronomers making contributions on
little teams and we decided to band
together but all of us had our voices
heard so it was sort of a a culture a
style that I preferred really but let me
tell you a story at the Nobel banquet
okay I'm sitting there between two
physicists who are who are members of
the committee of the Swedish National
Academy of Sciences you know and I
strategically kept you know offering
them wine and stuff during this long
drawn out Nobel ceremony right and I got
them to be pretty talkative and then in
a in a polite diplomatic way I started
asking them pointed questions m M and
basically they admitted that if there
are four or more people M equally
deserving they wait for one of them to
die or they just don't give the prize at
all when it's unclear who the three are
at least unclear to them but unclear to
them it's they're not even right part of
the time I mean Joselyn Bell discovered
pulsars MH with a radio antenna a set of
radio antennas that her adviser Anthony
hsh conceived and built so he deserves
some credit but but he didn't discover
the Pulsar she did and his initial
reaction to the data that she showed him
was a condescending rubbish my
dear yeah I'm not kidding now I know JN
Bell and she did not let this destroy
her life yeah she won every other prize
Under the Sun okay um Vera ruin
arguably one of the discoverers of Dark
Matter although there if you look at the
history there were a number of people
that was the issue I think there were a
number of people four or more who had
similar data and similar ideas at about
the same time Ruben won every prize
Under the Sun the new big large scale
survey telescope being built in Chile is
being renamed the Vera rubben telescope
because she passed away in December of
2015 I think um you know it'll conduct
this survey large scale survey with the
Reuben telescope so she's been
recognized but never with the Nobel
Prize and I would say that to her credit
she did not let that consume her life
either and perhaps it was a bit easier
because there had been no no Bell given
for the discovery of Dark Matter whereas
in the case of pulsars and Joselyn Bell
there was a prize given for the
discovery of the freaking pulsar and she
didn't get it what I mean what a Trav of
justice so I I also
think as a fan of fiction as a fan of
stories that the the the travesty and
the tragedy and the
unfairness and the tension of it is what
makes the prize and similar prize is
beautiful the the decisions of other
humans that result in dreams being
broken and you know like I that's why we
love the Olympics as so so many you know
people athletes give their whole life
for this particular moment and and then
there's referee decisions and like
little slips of here and there like the
little misfortunes that destroy entire
dreams and that's it's it's weird to say
but it feels like that makes the
entirety of it even more special yeah if
it was perfect it wouldn't be
interesting well humans like competition
and they like Heroes and unfortunately
it gives the impression to youngsters
today that science is still done by by
white men with gray beards wearing white
lab coats and I'm very pleased to see
that this year you know Andrea gz the
fourth woman in the history of the
physics prize to have received it and
then uh two women one at Berkeley uh one
elsewhere won the Nobel Prize in
chemistry without any male co-recipient
and so that's sending a message I think
to girls that they can do science and
they have um Role Models I think uh the
Breakthrough prize and other such prizes
show that teams get recognized as well
and and if you pay attention to the
newspapers you know most of the good
authors like you know Dennis Overby of
the New York Times and others said that
these were teams of people and they they
emphasized that and you know they all
played a role um and you know maybe if
some grad student hadn't soldered some
circuit maybe the whole thing wouldn't
have worked you know um but still you
know Ray Weiss Kip Thorne was the
theoretical uh you know impetus for the
whole search for gravitational waves
Barry bearish brought the MIT and
Caltech teams together to get them to
cooperate at a time when the project was
nearly dead from what I understand and
contributed greatly to the experimental
setup as well he's a great experimental
physicist but he was really good at
bringing these two teams together
instead of having them duke it out in
blows and leaving both of them bleeding
and dying you know that National Science
Foundation was going to cut the funding
from what I understand you know so so
there's human drama involved in this
whole thing and the Olympics yeah you
know a runner a swimmer a rummer runner
you know they they slip just at the
moment that they were taking off from
the first thing and that costs them some
fraction of a second and that's it they
didn't win you know and in that case I
mean the the coaches the families which
I've met a lot of Olympic athletes and
the coaches and the families of the
athletes are really the winners of the
medals I mean but they don't get the
medal and it's it's you know credit
assignment is a fascinating thing I mean
that's the full human story we have yeah
we have and and uh outside of
prizes it's fascinating I mean uh just
to be in the middle of it for artificial
intelligence there's a field of deep
learning that's really exciting and
people have been there's a yet another
award uh the touring award given for
deep learning to to three folks who are
very much responsible for the field but
so are a lot of others that's right and
there's a few there's uh uh
there's a fellow by the name of Schmid
Huber who uh sort of symbolizes the the
Forgotten folks in in the Deep Learning
Community but you know that's that's the
unfortunate set thing we
remember we remember Isaac Newton we
remember uh these these these special
figures and the ones that flew close to
them uh we forget well that's right and
you know often the breakthroughs are
made based on the body of knowledge that
had been assimilated prior to that but
you know again people like to worship
Heroes you you mentioned the Oscars
earlier and you know you look at the
direct I mean well I mean okay directors
and stuff sometimes get Awards and stuff
but um you know you look at even
something like I don't know songwriters
musicians Elton John or something right
Bernie topin right wrote many of the
words
or he's not as well known
or or the Beatles or something like that
I was heartbroken to learn that Elvis
didn't write most of his songs yeah
Elvis That's right there there you go
but he was the King right and he had
such a personality and and he it was
such a performer right but it's the
unsung heroes in many cases yeah so
maybe taking a step back we talked about
the Nobel Prize for the accelerating
universe but uh your work and the ideas
uh around Supernova were
important uh in detecting this
accelerating universe can we go to the
very basics of what is this uh beautiful
mysterious object of a supernova right
so a supernova is an exploding star most
stars die a relatively quiet death our
our own sun will despite the fact that
it'll become a red giant and incinerate
Earth it'll do that reasonably slowly
but there's a small minority of stars
that end their lives in a Titanic
explosion and that's not only exciting
to watch from afar but it's critical to
our existence because it is in these
explosions that the heavy elements
synthesize through nuclear reactions
during the normal course of the Stars
Evolution and during the explosion
itself get ejected into the cosmos
making them available as raw material
for new stars planets and ultimately
life you know and that's just a great
story um the best in in some ways so you
know we like to study these things and
and our Origins but it turns out these
are incredibly useful beacons as well
because if you know how
powerful uh an exploding star really is
by measuring the apparent brightness at
its peak
in galaxies whose distances we already
know through having made other
measurements and you can thus calibrate
how powerful the thing really is and
then you find ones that are much more
distant then you can use their observed
brightness compared with their true
intrinsic power or Luminosity to judge
their distance and hence the distance of
the Galaxy in which they're located so
okay it's like looking at if you'll uh
let me just give this one analogy you
know you judge the distance of an
oncoming car at Night by looking at how
bright its headlights appear to be and
you've calibrated how bright the
headlights are of a car that's two or
three meters away of known distance and
you go who that's a a faint headlight
and so that's pretty far away you also
use the apparent angular separation
between the two headlights as a
consistency check in your brain but
that's what your brain is doing so we
can do that for cars we can do that for
stars nice I like that but you know with
cars the headlights are all there's some
variation there's but but uh they're
somewhat similar so you can make those
kinds of conclusions what uh how much uh
variation is there between Supernova
that you can yeah that in can you detect
them right so first of all there are
several different ways that stars can
explode and it depends on their mass and
whether they're in a binary system and
things like that and the ones that we
used for these cosmological purposes
studying the expansion of the history
history of the universe are the
so-called type Roman numeral one
lowercase a type 1 a super noi they come
from a weird type of a star called a
white dwarf our own son will turn into a
white dwarf in about 7 billion years
it'll have about half its present Mass
compressed into a volume just the size
of Earth so that's an inordinate density
okay it's incredibly dense and the
matter is what's called by Quantum
physic degenerate matter not because
it's morally reprehensible or anything
like that but this is just the name no
judgments here yeah Quantum physicists
give to electrons that are squeezed into
a very tight space the electrons take on
a motion due to Heisenberg uncertain
Heisenberg's uncertainty principle and
also due to the poly exclusion principle
that electrons don't like to be in the
same place they like to avoid each other
so those two things mean that a lot of
electrons are moving very rapidly which
gives the star an extra pressure
far above the thermal pressure
associated with just the random motions
of particles inside the star so it's a
weird type of star but normally it
wouldn't explode and our sun won't
explode except that if such a white
dwarf is in a pair with another more or
less normal star it can steal material
from that nor normal star until it gets
to an unstable limit rough roughly 1 and
a half times the mass of our sun 1. four
or so this is known as the chandar CH
Chandra sear limit after subber Manan
Chandra sear an Indian astrophysicist
who figured this out when he was about
20 years old on a voyage from India to
England where he was to be educated and
then he did this and then 50 years later
he won the Nobel Prize in physics in
1984 largely for this work okay that he
did as a youngster who was on his way to
be educated you know oh and his advisor
the great AR Edington in England who had
done a lot of great things and was a
great astrophysicist nevertheless he too
was human and had his faults he
ridiculed chandra's scientific work at a
conference in England and you know most
of us have we had been Chandra would
have just given up astrophysics at that
time you know when the Great Arthur
Edington you know ridicules our our work
and that's another inspirational story
for the youngster you know just just
keep going you know but anyway your
advisor yeah no matter what your advisor
says right so or don't always pay
attention to your advisor right don't
don't be uh don't lose hope if you
really think you're on to something that
doesn't mean never listen to your
adviser they may have Sage advice as
well yeah but anyway um you know when a
white dwarf grows to a certain Mass it
becomes unstable and one of the ways it
can end its life is to go through a
thermonuclear runaway so basically the
carbon nuclei and inside the white dwarf
starts start fusing together to form
heavier nuclei and the energy that those
Fusion reactions
emit emits doesn't go into um you know
being dissipated out of the star or you
know whatever U or expanding it the way
you know if you take a blowtorch to the
middle of the sun you heat up its gases
the gases would expand and cool but this
degenerate star can't expand and cool so
the energy pumped in through these
Fusion reactions goes into making the
nuclei move faster and that gets more of
them sufficiently close together that
they can undergo nuclear fusion thereby
releasing more energy that goes into
speeding up more nuclei and thus you
have a a runaway a bomb an uncontrolled
nuclear fusion reactor right instead of
the controlled Fusion which is what our
sun does okay our sun is a marvelous
controlled Fusion reactor this is what
we need here on Earth Fusion Energy to
solve our energy crisis right uh but the
sun holds the stuff in you know through
gravity and you need a big Mass to do
that so this uncon uncontrolled fusion
reaction blows up a star that's pretty
much the same in all
cases and you measure it to be almost
the same in all cases but the devil is
in the details and in fact we observe
them to not be all the same and
theoretically they might not be all the
same because the rate of the fusion
reactions might depend on the amount of
Trace heavier elements in the white
dwarf and that could depend on how old
it is when it was you know whether it
was born billions of years ago when
there weren't many heavier elements or
whether it's a relatively young white
dwarf and all kinds of other things and
part of my work was to show that indeed
not all the type 1as are the same you
have to be careful when you use them you
have to calibrate them they're not
standard candles
the way it just if all headlights or all
candles were the same lumens or whatever
you'd say they're standard and it would
be standard candles is an awesome term
okay standard candles is what
astronomers like to say I don't like
that term because there aren't any
standard candles but there are
standardizable candles and by looking at
these yeah you calibratable
standardizable calibratable you look at
enough of them in nearby galaxies whose
distances you know independently and
what you can tell is that you know uh
this is something that a colleague of
mine Mark Phillips did who was on
Schmidt's team and arguably one of the
was one of the people who deserved the
Nobel Prize but he showed that the
intrinsically more powerful type 1as um
decline in brightness and it turns out
rise in brightness as well more slowly
than the less luminous onea and so if
you calibrate this by measuring a whole
bunch of nearby ones and then you look
at a distance one instead of saying well
it's a 100 watt type 1 a supernova
they're much more powerful than that by
the way plus or minus 50 you can say no
it's it's 112 plus or minus 15 or it's
or it's 84 plus or minus 17 it it tells
you where it is in the power scale and
it greatly decreases the uncertainties
and that's what makes these things
cosmologically useful I showed that if
you spread the light out into a spectrum
you can tell spectroscopically that
these things are different as well and
in 1991 I happened to study two of the
extreme peculiar ones the low Luminosity
ones and the high Luminosity ones 1991
BG and
1991t this showed that not all the 1 A's
are the same and indeed at the time of
1991 I was a little bit skeptical that
we could use type 1a's because of this
diversity that I was observing but in
1993 Mark Phillips wrote a paper that
showed this correlation between the
light curve the brightness versus time
and the peak luminosity and once gives
you enough information to calibrate yeah
then they become calibratable and that
was a game changer how many type 1 a are
out there oh gosh to use for data now
there are thousands of them but at the
time the high Z team had
16 and the um Supernova cosmology
project had 40 but the 16 were better
measured than the 40 and so our
statistical uncertainties were
comparable if you look at the two papers
that were published how's that make you
uh feel that there's these gigantic
explosions just sprinkled out there is
that well I certainly don't want one to
be very nearby and it would have to be
within something like 10 light years to
be an existential threat so they can
happen in our uh Galaxy oh yeah you
uh in most cases we'd be okay because
our galaxy is 100,000 light years across
and you'd need one of these things to be
within about 10 light years to be an
existential threat and it gives birth to
a bunch of other um stars I guess yeah
it gives birth to expanding gases that
are chemically enriched and those
expanding gases mix with other
chemically enriched expanding gases or
primordial clouds of hydrogen and helium
I mean th this is um in a sense the The
Greatest Story Ever Told right I try to
I teach this introductory astronomy
course at at Berkeley and I tell them
there's only five or six things that I I
want them to really understand and
remember and I'm going to come to their
deathbed and I'm going to ask them about
this and if they get it wrong I will
retroactively fail their whole career
will have been shot that and they don't
observe a total solar eclipse and yet
they had the opportunity to do so I will
retroactively fail them but one of them
is you know where did we come from where
did the elements in our DNA come from
the carbon in our cells the oxygen that
we breathe the calcium in our bones the
iron in our red blood cells those
elements the phosphorus in our DNA they
they all came from stars from nuclear
reactions in stars and they were ejected
into the
cosmos and in some cases like iron made
during the explosions and those gases
drifted out mixed with other clouds made
a new star or a star cluster some of
whose members then evolved and exploded
thus enriching the gases in the Galaxy
progressively more with time until
finally 4 and a half billion years ago
from one of these chemically enriched
clouds our solar system formed with a
rocky earthlike planet and somewhere
somehow these self-replicating evolving
molecules bacteria formed and evolved D
through paramia and amibas and slugs and
and apes and and us and here we are
sensient beings that can ask these
questions about our very Origins and
with our intellect and with the machines
we
make come to a reasonable understanding
of our
Origins what a beautiful Story I mean if
that does not put you at least in awe if
not in love with science and its power
of deduction I don't know what will
right it's it's one of the greatest
stories if not the greatest story
obviously that's you know personality
dependent and all that it's it's a
subjective opinion but it's perhaps The
Greatest Story over ever told I mean you
could link it to the big bang and go
even farther right to make an even more
complete story but as as a subset that's
even in some ways a greater story than
than even the existence of the universe
in some ways cuz you could end up you
could just imagine some really boring
universe that never leads to sensient
creatures such as ourselves and is this
Supernova usually the the introduction
to that story so are are they usually
the thing that launches the is there
other engines of creation well the
Supernova is the one I mean I I I touch
upon the subject earlier in my course in
fact right about now in my lectures
because I talk about how our sun right
now is fusing hydrogen to form helium
nuclei and later it'll form carbon and
oxygen nuclei but that's where the
process will stop for our sun it's not
massive enough some Stars can that are
more massive can go somewhat beyond that
so that's the beginning of right this
idea of the birth of the heavy elements
since they couldn't have been born at
the time of the Big Bang conditions of
temperature and pressure weren't
sufficient to make any significant
quantities of the heavier elements and
so so that's the beginning but then you
need some of these stars to explode
right because if those heavy elements
remained forever trapped in the cores of
stars then they would not be available
for the production of new stars planets
and ultimately life so indeed the
Supernova my main area of Interest plays
a a leading role in this whole
story I saw that you got a chance uh to
call Richard Fineman a mentor of yours
when you were at Caltech yeah uh do you
have any fond memories of Fineman any
lessons that stick with you oh yeah he
was quite a character uh and one of the
deepest thinkers of all time probably
and at least in my life the physicist
who had the single most intuitive
understanding of how nature works of
anyone I've met uh he I I learned a
number of things from he was not my
thesis adviser I worked with Wallace
Sergeant at galtech on what are called
active galaxies big black holes in the
centers of galaxies that are accreting
or swallowing material a little bit like
the stuff of of this year's Nobel Prize
in physics 2020 uh but Fineman I had for
for two courses one was general theory
of relativity at The Graduate level and
one was applications of quantum physics
to all kinds of interesting things and
he you know he had this very intuitive
way of of looking at things that he
tried
to that he tried to bring to his
students and he felt that if you can't
explain something in a reasonably simple
way to a non scientist or at least a you
know someone who is versed a little bit
with science but is not a professional
scientist then you probably don't
understand it very well yourself very
thoroughly so that in me um you know
made a desire to to to be able to
explain science to the to the general
public and I've often found that in
explaining things yeah there's a certain
part that I didn't really understand
myself that's one reason I like to teach
the introductory courses to the lay
public is that I sometimes find that my
explanations are lacking in my own mind
you know so he did that for me is there
uh if I could just pause for a second
you said he had one of the most
intuitive understanding of nature what
if you could break apart what intuitive
means like it is it on a philosophical
level no sort of physical how do you
draw a mental picture or a picture on
paper of what's going on and he's
perhaps most famous in this regard for
his Fineman diagrams which in what's
called Quantum electrodynamics a Quantum
field theory of electricity and
magnetism what you have are actually you
know an exchange of photons between
charged particles and they might even be
virtual photons
if the particles are at rest relative to
one another and there are ways of doing
calculations that are brute force that
take pages on pages and pages of
calculations and Julian schwinger uh
developed some of the mathematics for
that and won the Nobel Prize for it but
feineman had these diagrams that he made
and he had a set of rules of what to do
at the vertex you know you have two
particles coming together and then a
particle going out and then two
particles coming out again and he'd have
these rules Associated when there were
vertices and when there were particles
splitting off from one another and all
that and it looked a little bit like a
bunch of a hodgepodge at first but to
those who learned the rules and
understood them he you know they they
saw that you could do these complex
calculations in a much simpler way and
indeed in some ways Freeman Dyson had an
even better knck for explaining really
what Quantum electrodynamics actually
was but I didn't know Freeman Dyson I I
knew Fineman maybe he did have a more
intuitive view of the world than Fineman
did but of the people I knew finean was
the most intuitive most sort of is there
a picture is there a simple way you can
understand this and in in um in the path
that a particle follows even you know
you can figure out the you can get the
classical path at least you know for a
baseball or something like that by using
quantum physics if you want but you know
in a sense the baseball sniffs out all
possible paths it goes out to Andromeda
galaxy and then goes to the to the
batter but the probability of doing that
is very very small because tiny little
paths next door to Any Given path cancel
out that path and the ones that all add
together they they are the ones that are
more likely to be followed and this
actually ties in with font's principle
of least action and their ideas and
Optics that go into this as well and and
it just sort of beautifully brings
everything together but the particle
sniffs out all possible paths what a
crazy idea but if you do the mathematics
associated with that it ends at being
actually useful a useful way of looking
at the world so you're also I mean you
you're widely acknowledges I mean
outside of your science work is being
one of the greatest Educators in the
world and Fineman is famous yeah for for
being that is there something about
being a teacher that you've well it's
it's very very rewarding when you have
students who are really into it and you
know going back to Fineman at Caltech I
was taking these graduate courses and
there were two of us myself and Jeff
richond who's now a professor of physics
at University of California Santa
Barbara who asked lots of questions and
a lot of the Caltech students are
nervous about asking questions they they
want to save face they seem to think
that if they ask a question their peers
might think it's a stupid question well
I didn't really care what people thought
and Jeff Richmond didn't either and we
ask all these questions and in fact in
many cases they were quite good
questions and Fineman said well the rest
of you should be having questions like
this and I remember one time in
particular when he said you know he said
to the rest of the class why is it
always these two aren't you aren't the
rest of you curious about what I'm
saying do you really understand it all
that well if so why aren't you asking
the next most logical question no you
guys are too scared to ask these
questions that these two are asking so
he actually invited us to lunch a couple
of times where just the three of us sat
and had lunch with one of the greatest
thinkers of 20th century physics and so
yeah he he rubbed off on me and so you
encourage questions as well I encourage
questions you know and uh yeah you know
definitely I mean you know I encourage
questions I I like it when students ask
questions I tell them that they
shouldn't feel shy about asking a
question question probably half the
students in the class would have that
same question if they even understood
the material enough to ask that question
yeah curiosity is the first step of um
absolutely of seeing the beauty of
something so yeah and the question is
the ultimate form of curiosity yeah let
me ask uh what is the meaning of
life the meaning of life you know from a
cosmologist perspective or from a human
perspective or from my personal you know
life is what you make of it really right
it's um each of us has to have our own
meaning and it doesn't have to be well I
I think that in many cases meaning is is
to some degree associated with goals you
set some goals or expectations for
yourself things you want to accomplish
things you want to do U things you want
to experience and to the degree that you
experience those and do those things it
can give you meaning
you don't have to change the world the
way Newton or Michelangelo or Da Vinci
did I mean people often say don't change
the world but look come on there's seven
and a half close to eight billion of us
now most of us are not going to change
the world and does that mean that most
of us are leading meaningful lives no it
it just has to be something that gives
you meaning that gives you
satisfaction that gives you a good
feeling about what you did and and often
based on nature which can be very good
and also very bad but often it's the
things that help others that give us
meaning and a feeling of
satisfaction you taught someone to read
you cared for someone who was terminally
ill you brought up a a nice family you
brought up your kids um you did a good
job you you put your heart and soul into
it you read a lot of books if that's
what you wanted to do had a lot of
perspectives on life you you traveled
the world if that's what you wanted to
do um but if some of these things are
not within reach you're in a
socioeconomic position where you can't
travel the world or whatever you find
other forms of of
meaning uh it doesn't it it doesn't have
to be some profound I'm going to change
the world I'm going to be the one who
everyone
remembers type thing right in the
context of The Greatest Story Ever Told
like the fact that we came from
stars and now we're two Apes asking
about the meaning of life yeah how does
that fit
together does that make any sense you
know it does it does and this is sort of
what I I was referring to that it's a
beautiful universe that allows us to
come into creation right it's a way that
the Universe found of knowing
of understanding itself because I don't
think that you know inanimate rocks and
stars and black holes and things have
any real capability of of abstract
thoughts and of learning about the rest
of the universe or or even their Origins
I mean they're just they're just a pile
of atoms that's that's has no conscience
has no ability to think has no ability
to explore and we do
and you know I'm not saying we're the
epitome of all life forever but at least
for life on Earth so far the evidence
suggests that we are the epitome in
terms of the richness of our thoughts
the degree to which we can explore the
universe do experiments build
machines understand our Origins and I
just hope that we use science for good
not evil and that we don't end up
destroying ourselves I mean the whales
and dolphins are plenty intelligent
they're they don't ask abstract
questions they don't read books but on
the other hand they're not in any danger
of destroying themselves and everything
else as well and so maybe maybe that's a
better form of intelligence but at least
in terms of our ability to explore and
make use of our minds I mean to me it
it's this it it's this that gives me um
the potential for meaning yeah right the
fact that I can understand and explore
it's kind of fascinating to think that
the universe created
us and eventually we've built telescopes
to look back at it to look back at its
Origins and to wonder how the heck the
thing works it's
magnificent needn't have been that
way right and this is one of the you
know the Multiverse sort of things you
know you can alter the laws of physics
or or even the constants of nature
seemingly inconsequential things like
the mass ratio of the proton and the
neutron you know wake me up when it's
over right what could be more boring but
it turns out you play with things a
little bit like the ratio of the mass of
the neutron to the proton and you
generally get boring universes only
hydrogen or only helium or only iron you
don't even get the rich periodic table
let alone bacteria paramia slugs and
humans okay I'm not even anthropomorph
an anthropos centz this to the degree
that I could even a rich periodic table
mhm wouldn't be possible if if certain
constants weren't this way but but they
are and that to me leads to the idea of
of a Multiverse that you know that the
dice were thrown many many times and
there's this Cosmic archipelago where
most the universes are are boring and
some might be more interesting but we
are in The Rare Breed that's really
quite darn interesting and if there were
only one and maybe there is only one
well then that's that's truly amazing
we're lucky we're lucky but I actually
think there are lots and loss just like
there are lots of planets Earth isn't
special for any particular reason there
are lots of planets in our solar system
and especially around other stars and
occasionally they're going to be ones
that are conducive to the development of
complexity culminating in Life as we
know it and that's a beautiful story I
don't think there's a better way to end
it Alex it's a huge honor one of my
favorite conversations I've had in this
podcast thank you thank so much for
talking for for the honor of of having
been asked to do this thanks for
listening to this conversation with Alex
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now let me leave you with some words
from Carl Sean the nitrogen in our DNA
the calcium in our teeth the iron in our
blood the carbon in our apple pies were
made in the Interiors of collapsing
Stars we are made of star
stuff thank you for listening and hope
to see you next time