Kind: captions
Language: en
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a lot has changed in the last 50 years
especially in our understanding of the
cosmos the last 50 years I think have
been the most exciting ever our entire
understanding of the universe just
turned upside down welcome to the Dark
Universe where powerful yet invisible
dark matter holds Cosmic sway shaping
even the very Galaxy we call home dark
matter is four times or five times more
abundant than the stuff we can see it is
fundamentally
disturbing what we're on the hunt we're
entering Discovery
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territory and the Darkness doesn't end
there a ghostly form of dark energy
dominates the universe dry its expansion
maybe even choosing its fate I don't
think we possibly could have grasped
just how profound it was this is a huge
Discovery it remains a total Enigma we
have absolutely no idea what dark
energies the more we learn about our
universe The
Stranger it becomes this is something
that can't just be wished away that's
where to look for the next breakthrough
it's potentially no prize winning
decoding the universe right now on
[Music]
Nova as an american-based supplier to
the construction industry Carlile is
committed to developing a diverse
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car.com September 5th
1977 3 2 1 and we have Li off a Titan
Centaur rocket carrying the space probe
Voyager 1 launches from cap
canav the Voyager spacecraft to extend
man's senses farther into the solar
system than ever before the Voyager
program would become NASA's longest
mission to date I Absolut remember the
coverage remember watching the launch it
was really exciting and I had no sense
of the scale of where that thing was
heading to where no human built things
had ever gone
before in 1979
Voyager One flies past
Jupiter about a year and a half later
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Saturn though it will continue its
journey in 1990 it sends its last images
looking back at the solar
system earth is just a tiny
Speck in Carl Sean's words a pale blue
dot the pale blue dot it's telling us
we're incredibly small at the same time
it also tells us that we've gone
incredibly
far I mean in cosmology we're looking
we're looking at Supernova we're looking
at other galaxies we're looking at the
beginning of the universe but there's so
much more than is to be done
during Voyager 1's nearly 50 yearlong
Mission our scientific understanding of
the universe has grown
immensely and even radically
changed the last 50 years I think have
been the most exciting ever our entire
understanding of the universe has
changed it's just turned upside down
over the past 50 years there's really
been sever several Revolutions in our
understanding of the universe we can
both be proud of how far we've come but
also be excited about how much we don't
know looking back the discoveries of the
last 50 years are remarkable in the
1970s Luke Skywalker's home twine was as
close as we got to seeing an alien
planet in the
1970s we knew of precisely zero planets
outside of our solar system and and in
the decades since then we've moved that
number up into the
thousands we've discovered planets are
incredibly common in our galaxy there
are more planets out there than there
are stars so go out and look at the
night sky for every one of those stars
there are probably several
planets and in recent decades we've also
learned our Milky Way galaxy isn't even
one in a million
a fact made evident by this astonishing
series of images taken by the Hubble
Space Telescope in
1995 just about every single bright
point is a
Galaxy scientists now think galaxies in
the universe may number in the
trillions the Hubble pictures tell us
that the universe is the same everywhere
it's also a reminder that we're
definitely not the same center of the
universe one of the most shocking
discoveries of the last 50 years was
made in our own Cosmic
backyard in
1998 astrophysicist Andrea gz and her
team surprised the world when they
revealed evidence of a super massive
black hole at the center of our own
Milky Way from watching Stars orbit the
center of the Galaxy the mass that we
infer is 4 million times the mass of the
Sun that is the proof of a black
hole astronomers now believe that just
about every galaxy has
one black holes are crucial to how we
understand galaxies that is a huge new
role for black holes in our
understanding of
them but perhaps the biggest discovery
of the last 50 years is just how much we
don't
know somehow we've missed much much more
than we've
discovered there's some new form of
matter out in the universe and it is
four times or five times more abundant
than the stuff we can see and so that is
the shocking truth of Dark
Matter Dark Matter only accepted as real
during the last 50 years and now one of
the biggest mysteries in the history of
science so far its effects have only
been detected on the cosmic
stage but understanding it may hold the
key to the very structure of the
universe my mom is always like you know
why do we have to care about D matter
and and the truth is that without D
matter we simply wouldn't exist dark
matter is in part the story of why and
how we're here
and yet in recent decades scientists
have uncovered evidence of something
that today is even more powerful than
dark
matter I just I don't think we possibly
could have grasped just how profound and
how much it would change our view of the
universe it would be like as though you
had only ever experienced land and then
one day you discover the
oceans it's called Dark Energy
scientists now believe it's the most
power power ful force in the universe
expanding its very fabric pushing
galaxies apart and it may even be
driving the universe's ultimate
fate but it remains an enigma we have
absolutely no idea what dark energy is
to this day how did our vision of the
universe get completely overturned in
just a few
decades and what new surprises might Li
just over the horizon
ni the past 50 years of astrophysics has
shown that the universe is
extraordinarily creative and what is out
there and it's very determined to
consistently subvert our
expectations we are so struggling to
figure out the nature of our Cosmos and
that's very humbling very humbling yet
very empowering it's a it's a strange
combination of the two things
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together since Voyager 1 left
Earth astrophysicists and astronomers
have overtaken the Intrepid
probe reaching farther and farther out
into
space to gather data written across vast
expanses of time and on colossal
scales and Stars
nebulas
supernovas distant galaxies and Galaxy
clusters here's the Galaxy we're at the
object and in the
1970s it was just such data meticulous
observations gathered by an
astronomer that forced scientists to
confront the idea of dark matter the
astronomer's name was was Vera Reuben
you'll get a guide star I'll set up for
the
observation Reuben was born in 1928 in
Philadelphia from a young age she was
hooked on the Stars by about age 12 I
would prefer to stay up and watch the
star of draria sleep there was just
nothing as interesting in my life as
watching stars there me not I do I
wanted to be an astronomer
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in
1963 Vera Rubin traveled here to the kit
Peak National observatory in the shuk
doic district on the th atham
Nation 56 Mi Southwest of Tucson
Arizona despite having Advanced degrees
for over a decade Reuben had never been
able to collect her own
data astronomy had few women and many
observator weren't
welcoming some officially did not allow
women but the national Observatory at
kit Peak had just recently
opened and accepted her
application she would return to Kit Peak
several times over her
career as she began to focus more on
Galaxies so Vin really was what I would
call a true observ ational astronomer
she L to go to the telescope do the
observation take it to her office and
analyze them and try to see what it told
her about the
galaxies today in more ways than one
Stanford cosmologist Risa Wexler follows
in Ruben's
footsteps so this instrument behind me
is the 84 in telescope at kit Peak your
Ruben started using it in 1968 when she
started making measurements of the
Andromeda galaxy and looking at how
different regions in Andromeda were
moving Reuben wanted to check a common
assumption among astronomers about
galaxies the presumption was Stars near
the center of a galaxy would be orbiting
very rapidly and stars at the outside
would be going very
slowly that idea came from the way the
planets in our solar system orbit our
massive
sun because the attractive force of the
Sun's gravity falls off with distance
the farther away from the sun a planet
orbits the slower its orbital
speed astronomers assumed the stars in a
galaxy would behave the same way like
the sun in our solar system the bright
star packed center of a galaxy appeared
to hold most of the Galaxy's Mass so a
Galaxy's orbiting Stars should act like
the planets with orbits slowing toward
the Galaxy's outer edges but no one had
done the work to know for
sure partly it was a technical issue
which Ruben solved by teaming up with
instrument maker Kent Ford he had
developed a device that enhanced a
telescope's light
sensitivity making it possible to
finally see the faint stars on the far
edges of
galaxies and what they saw was
surprising they found that the regions
of Andromeda that were quite far out
were still rotating quite fast faster
than you would have expected by the
amount of light that was there it was a
strange
observation what was keeping those fast
moving outer stars from flying
off during the 1970s Reuben and Ford
along with other astronomers gathered
more and more data from more and more
galaxies
almost none showed the speed of orbiting
Stars dropping as had been
expected still it would take years for
the astronomy Community to accept the
astonishing explanation that Reuben and
others
proposed that there was a vast amount of
hidden matter surrounding each Galaxy
gravitationally holding it
together aside from that effect it was
undetected detectable if you didn't have
some invisible mass in the Galaxy the
Stars would not be bound in this in this
orbit they would fly
out we now know that in every Galaxy we
study the stars at very large distances
are orbiting with very high velocities
and that tells us that there is a lot of
matter at very large distances from the
center so we see a lot of matter where
we don't see very much light and that
has led to the con cep of Dark
Matter Dark
Matter astronomer Fritz zi had proposed
the name in the 1930s to describe an
unseen Mass to explain some puzzling
observations of a nearby Galaxy
cluster but the idea had been largely
ignored until Reuben and Ford came
along today scientists estimate There is
five times more Dark Matter than
ordinary matter in the
universe it's arranged in a vast webike
structure of filaments and
nodes in the early Universe those nodes
through gravity attracted regular matter
which eventually evolved into
galaxies but what is dark matter over
the last 50 years
this question has become a guiding
question for huge swads of the physics
Community we've had some of the smartest
people in the world banging heads
against the wall for decades this is a
really hard
problem there aren't many
Clues aside from its gravitational
effect Dark Matter appears to interact
very little with normal matter and can
pass right through it it also emits no
electromagnetic
radiation no
light they're forms of matter that
simply don't glow like stars do but
actually they're also not responding to
light so they are invisible except
through their gravitational force it
probably is something quite exotic it
isn't any of the ordinary stuff so who
are the suspects for dark matter
there are the machos the massive compact
Halo
objects like primordial black holes
black holes that go back to very
earliest eras of the universe could be a
major component of dark
matter for a primordial black hole to
fit the bill as dark matter it would
have about the mass of an asteroid and
be about the size of an
atom and there are Aion
minuscule particles theorized by
physicists an Axion if it exists
interacts only very infrequently with
light and it does have some Mass so it
could be dark
matter but the suspects who garnered
early fans were the wimps weakly
interacting massive
particles the search for wimps leads
here
to the Black Hills of South
Dakota Native Americans have long
considered the area
sacred and the fort laramy Treaty of
1868 included the Black Hills in the
great Sue
reservation but just a few years later
the discovery of gold and an influx of
miners led to the great Sue war of
1876 the US government seized the area
and forcibly relocated its Sue
inhabitants the dispute over the broken
treaty remains
unresolved today in the town of lead a
retired Gold Mine houses the Sanford
underground research facility
CH cor God a professor at University
College London is a founding member of a
team of researchers drawn from
universities around the world that's on
the hunt for dark matter in the form of
wimps to get down a mile um it takes a
bit of
time why build a dark matter wimp
detector so far
underground so a mile of rock above us
here in the Black Hills of South Dakota
that Shield us from cosmic radiation
that is bombarding us all the time and
being underground we're able to reduce
that by factors of millions so this
experiment up on the surface just
wouldn't be able to run at all it's just
far too
sensitive and then go ahead hop on the
Chain ready y to the 10-minute ride down
it's on to a battery-powered locomotive
followed by a brief
hike to get to the cavern that holds the
lab of the Lux Zeppelin or LZ detector
experiment the core of the experiment is
Zenon it's liquid Zenon it's Zenon gas
that's been condensed and we've got to
keep that clean and we've got to keep it
cold and so much of what we'll see
around here is all for that
really here is the main experiment at
its Center is a container of 7 metric
tons of very pure cooled liquid
Xenon the concept is
straightforward the cooled xenot is
extremely
sensitive even just a single collision
between one of the theoretical wimps and
the nucleus of a Xenon atom would cause
the atom to collide with others emitting
a flash of ultraviolet light which would
be picked up by the detectors at the top
and bottom of the
tank the interaction would also liberate
electrons they drift up to the top and
emit an even bigger
flash so we get two flashes of light
here and based on how these two signals
look relative to one another we can tell
whether this was background radiation or
if this was a dark matter particle that
came in and hit the nucleus of a Zenon
atom LZ isn't the only experiment using
cooled
Xenon but it now leads the pack in
sensitivity it's the front runner now
and so we're entering Discovery
territory direct Dark Matter detection
experiments go back to the
1980s xenon-based experiments similar in
design to LZ to the
2000s so far all the experiments
combined have
detected
nothing we can see them crushing but the
process constantly Narrows down what
Dark Matter could possibly be we do see
the S and currently LZ has time on its
side the plan is to acrew a total of
three years worth of data
hopefully there'll be a direct detection
and we'll start to understand the nature
of it it could be that dark matter isn't
a simple one size fits all wimp it could
be that there's multiple different types
of dark matter different species of this
stuff and we started to understand the
Dark Sector as more of a
zoo I'm deeply interested in trying to
make some Headway into the unknown so
the bigger the unknown the better for me
so you know dark matter being 8 5% of
the mass of the universe that we have no
real clue about what this stuff is but
it is profoundly
important it's been a striking
transformation in the past 50 years
thanks to Vera Rubin and others dark
matter has become an essential
scientific building block at the
foundation of our understanding of the
universe there is no way out of dark
matter if you believe in general
relativity in Newton's law if you
believe in that no way out of dark meow
you have to have dark
metal in 1998 as Voyager 1 traveled to
the far reaches of our solar system it
surpassed the record of a previous space
probe Pioneer 10 as the most distant
human maid
object it was 6 and2 billion miles from
Earth 1998 was also the year of one of
the greatest discoveries in the history
of science what seemed to be a force
that literally creates new space out of
nothing today's issue of the journal
science reports new information about
the evolution of the universe a lead
author of one of the studies was
cosmologist Adam Ree thanks for being
with us thank you why did some
scientists react with what one called
amazement and horror to these
conclusions why was it such a shock to
them so we were hoping we'd find a more
simple explanation something mundane um
but but instead you found a new force in
the universe well it would appear that
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way one of Baltimore's hidden gems is
the George peab budy library at Johns
Hopkins
University it has been been called one
of the most beautiful Library spaces in
the
world these five tiers hold 300,000
volumes including astronomical Works
written over the centuries that try to
answer a question that has troubled
humankind perhaps
always when we look up at the night
sky what is it we are seeing
and has it been there
forever Adam Reese an astrophysicist
from Johns Hopkins played a key role in
formulating the current scientific
answer to that
question
wow this is really the original Earth
Centric model like many in astronomy he
has a deep appreciation that he stands
upon the shoulders of giants this is
really my favorite
here cap cernus puts the sun in the
right
place this is progress in
science but Reese has also added to our
understanding of
cosmology sharing a Nobel Prize in 2011
with Saul pearlmutter and Brian P
Schmidt for a discovery that profoundly
changed our view of the
universe here's somebody after my own
heart taking the observations Tao
each of these influential thinkers from
prior to the 20th century have
contributed to our understanding of the
heavens and here comes Isaac Newton who
really develops the mathematics and he
really lays out how gravity
works but they all shared something in
common whatever the heavens were they
seemed Eternal Earth may be at the
center surrounded by Celestial spheres
or the sun may be at the center with the
planets orbiting
it comets may come into view and
disappear but all of these took place on
a gigantic but static
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stage even Albert Einstein initially
agreed by the early 20th century he had
already revolutionized the Newtonian
view of the world
by connecting space and time into one
concept he called
SpaceTime and then theorizing that
gravity was the warping of that
SpaceTime fabric by mass and
energy in
1917 he applied his new ideas to the
entire
universe but he already had a final
result in mind the one generally
accepted by astronomers
Einstein's Universe would be a largely
static and unchanging one though gravity
posed a
problem Einstein had kind of a a puzzle
in his mind because if the universe was
static and yet all the matter in it was
attractive gravity would pull things
together how did it stay static what
kept it static and he made a remarkable
Discovery in his theory of general
relativity the gravity of matter can be
attractive but that the gravity of empty
space could be repulsive he called this
the cosmological constant and he thought
it was a possibility that these two
kinds of gravities the attractive and
the repulsive kind from two different
kinds of aspects of space were causing
this kind of
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stalemate Einstein's solution didn't
stand for long and here at the Mount
Wilson Observatory outside of Los
Angeles is where astronomers gathered
some of the data that led to its
fall these days you may be lucky enough
to hear a woodwind quintet playing in
one of its stored
domes the Acoustics are
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exceptional and it is an inspiring place
for theoretical physicist and graphic
non-fiction author Clifford Johnson to
let his mind
explore in the
1920s this Observatory produced two of
the most important discoveries about the
nature of the
universe both by astronomer Edwin Hubble
the same Hubble the famous Space
Telescope is named for Hubble changes
our entire view of what the universe is
and how vast it
is at the time a debate raged in
astronomy was the Milky Way the entire
universe or was there more to the
story in
1925 Hubble settled the issue by proving
that the Andromeda nebula existed
outside of the Milky Way it along with
other distant nebulas were renamed
galaxies
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the whole notion of a galaxy started to
become a thing only in the mid1 1920s
people started immediately get
interested in what these things
are especially Edwin Hubble he began
measuring the distance from Earth to
various galaxies and when he combined
his work with that of other astronomers
he discovered something deeply
mysterious it had to do with the Doppler
effect we typically think of the Doppler
effect in terms of
sound a siren coming toward you has a
higher pitch because the sound waves
catch up to each other and become
compressed a siren heading away from you
sounds lower because the sound waves
stretch
out a similar thing happens with light
waves if the source of light is headed
toward the Observer the light it emits
will be shifted toward blue if the
source is moving away the light is
shifted toward
red in fact astronomers working parallel
to Hubble encountered exactly
that the light coming from almost every
Galaxy they observed was shifted toward
red indicating that galaxies were moving
away from
Earth and when Hubble checked the red
shifts against his own distance
measurements he discovered not only were
the galaxies racing away from us but the
ones farther away were racing away
faster what did that
mean given that we're not in a special
place in the universe we're not at the
center of the universe the conclusion is
is that the whole universe is expanding
everything is moving away from
everything else this is another huge
discovery about the nature of our
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universe some astronomers like Belgian
cosmologist and Catholic priest George
ledra were already exploring the
implications of an expanding
Universe if you rewind the expansion
like a
film where does the Universe start does
it have a
beginning the idea is that there was
some earlier phase in the universe where
everything was much closer together some
very dense early phase of the universe
and something happened to begin to push
things
apart that line of thinking led to the
theory
labeled by its detractors as the Big
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Bang it wasn't until the mid 1960s that
observational evidence quieted the Big
Bang
critics when two astronomers Robert
Wilson and Arno penus using this antenna
in homedel New Jersey stumbled across
one of its predicted
artifacts after the big bang it took
hundreds of thousands of years for the
universe to cool enough to Transit light
that initial burst has left a faint
residual
glow today we call it the cosmic
microwave background or
CMB Cosmic micro background is actually
a remnant of the big bag it's the
radiation from that big bang that we can
observe from when the universe was about
380,000 years
old later ground and space-based
experiments would study this fossil
radiation in ever finer
detail because its extremely slight
variations shown here in different
colors can reveal insights into the
structure of the early
Universe by the
1970s thanks to the CMB most astronomers
had accepted the Big Bang Theory and
that the Universe was
expanding but they also thought the
expansion was likely slowing because of
the attractive force of gravity on
matter matter decelerates the expansion
it deer cerates it either a little bit
if there's only a little matter and the
universe expands forever or it
decelerates it a great deal halting the
expansion at some point in the future
and causing the universe to
collapse measuring how fast the
expansion was decelerating would reveal
the fate of the
universe and the key to doing that was
this
one of the brightest explosions observed
in
space when a star becomes a
supernova there are two types of
supernovas and distinctions within those
but a type 1A
Supernova is fairly common about a
quarter of all
supernovas incredibly bright sometimes
brighter than a entire
galaxy and remarkably
consistent that makes it an excellent
candidate to be what astronomers call a
standard
candle a kind of cosmic measuring
stick if enough of them could be
found so that was the goal of the newly
formed highz Supernova search team Adam
Reese was a
member they planned to discover distant
type 1A supernovas compare them to
nearby
ones and definitively answer how much
the expansion of the universe was
slowing down but they weren't alone
there was another team the Supernova
cosmology project which had started a
number of years before us they were more
particle physicists and we were more I
would say Supernova
astronomers but both comp meeting
realistically for the same telescope
facilities which were very precious
Commodities to get to do this
research by
1997 the highz team had collected a
large enough sample of
supernovas to get a first read on the
universe hey look at that but initially
the results made no
sense so we went from saying you know
this has got to be wrong to like this
looks like what the data says we have to
report that
in early
1998 both teams announced the same
shocking
conclusion the universe was not slowing
in its
expansion it was speeding
up like an invisible hand some
undiscovered force was at war with
gravity and pushing the universe apart
faster and faster
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from what we can see there's really uh
not too much left besides the
possibility of this repulsive force does
that mean that the Universe could just
keep on expanding forever if you take
this result at face value if this is
really true the implication is yes that
the Universe would expand
Forever The Mysterious repulsive Force
came to be known as dark
energy dark energy is really the name we
give to our ignorance of what's causing
the accelerating expansion of the
universe it's a pushing out that it does
it's a pressure and outward pressure
that the gravitational force is pushing
against overall the universe is
accelerating in its expansion because of
this dark energy
effect today scientists estimate it is
overwhelmingly the most prevalent form
of energy in the universe
we thought we knew the constituents of
the universe and how it was evolving
over time all of a sudden we found out
that no we didn't know because the
biggest component of the universe wasn't
Dark Matter it was dark
energy so what exactly is dark
energy one of the simplest ideas is that
it's actually a property of space and
time
itself scientists had always assumed the
energy level of a perfect vacuum was
Zero but what if it wasn't what if as
the universe expanded and created more
space a repulsive energy inherent to
that space grew as
well on massive scales it would oppose
and maybe even overcome the
gravitational attraction of
matter and ironically that's exactly the
kind of thing that Einstein had come up
with long ago when he was trying to make
the universe
static in his formula to describe the
universe Einstein had added a
cosmological constant to perfectly
balance the attractive effect of gravity
and create his static
Universe when astronomers in the 1920s
and 30s concluded that the Universe
wasn't static at all but expanding he
dropped his cosmological constant and is
said to have called it his biggest
blunder but with the discovery of an
accelerating expansion cosmologists
revived the term makes absolutely no
sense in fact it was an idea Adam Reese
turned to early in his
analysis after convincing myself I
hadn't made a mistake uh I introduced
that possibility into the analysis that
Einstein's cosmological constant existed
and the fit grabbed on to it and said
yes this you know a pretty high
confidence this is indeed part of the
recipe of the
universe so how did astronomers miss
this most consequential of
phenomena perhaps a reason we hadn't
noticed it before is because the way you
measure it is in terms of how much is it
per unit of SpaceTime perhaps a little
chunk of uh uh space right here so you
have to divide the entire effect by the
volume of the observable universe so
that makes it a very small number
imagine the energy released by a match
head
burning the estimated equivalent in dark
energy is spread across a cube of empty
space with an edge about 7 and a half
miles long or the amount of space
contained by about 1 and 1/2 million
astrodon so it's small and maybe in the
early history of the universe when it
contained a lot less empty space not
even that important if we were in a
period of time much much earlier in the
history of the universe Dark Energy was
a very very small component of the
universe and it wouldn't have
necessarily been
noticeable but that changed about 6
billion years ago by then the universe
had grown big enough for dark energy to
overcome the attractive force of gravity
and start speeding beating up the
expansion today Dark Energy dominates
the universe and it may even
determine its ultimate fate now we are
in the dark energy era of the universe
which means that the universe is
expanding at an accelerated rate if the
universe would keep on expanding and
expanding and expanding then we seem to
be looking at a a a far distant future
in which the universe is basically empty
it's been diluted of all the stuff that
we otherwise can see lighting up and and
and dancing around us galaxies would
just continue moving further and further
apart from each
other our nearest galaxies will go
beyond our visible Horizon beyond what
we can see in the universe space would
stretch even faster than light could
catch up to tell us as a Galaxy over
there eventually we will not be able to
see the light coming from another galaxy
we can't see any other Galaxy anymore
because dark energy and the expansion of
the universe has driven this all away
that would be kind of sad we might not
be S of um uh torn apart we just become
extremely extremely lonely the end of
the universe will be very cold and very
dark and and we won't see the nearby
galaxies and so on that's the future
expansion of the
universe if it makes any anyone feel
better there is still a lot of
uncertainty about Dark Energy especially
whether it has been consistent over
time at the moment we think it's been
consistent but it's potentially Nobel
prize winning if it's been changing over
time and so secretly not so secretly
cosmologists are really hoping to find
something different because that'll be
really
exciting a cosmological constant that
isn't really constant could be the
solution to another vexing mystery which
some have called a cosmological crisis
this is a real problem there are some
tensions in what we're seeing this has
been a great challenge for us in the
last 10 years this is something that
can't just be wished
away it has to do with how fast the
universe is currently expanding that's
known as the Hubble
constant to calculate it scientists have
mainly used two different approaches one
is based on the baby picture of the
universe the
CMB which itself has been measured in
ever increasing detail three different
generations of specially built
satellites in the sky to just do this
one thing measure the CMB to my mind
mindboggling Precision the measurements
that we have from the cosmic microwave
background right now they are the gold
standard in our field so high quality
that when you make measurements from it
they are extremely high
precision meanwhile other groups
including one led by Adam Reese have
calculated the Hubble constant using
measurements of distant
supernovas distant things from us but
not nearly so distant as the cosmic
micro background phenomena that are old
in Cosmic history but not quite so old
we call them late
Universe two different techniques one
based on the early Universe the CMB and
the other on the late universe
using
supernovas we have the ability to
bookend the universe to essentially see
how fast the universe was expanding at
the beginning and how fast it's
expanding now we're measuring the same
universe whether we're measuring the
cosmic microwave background or a
population of supern to see if you can
go from one to the other if you can
predict how fast the universe ought to
be expanding and there's all kinds of
reasons to think that either one of
these kinds of physical systems should
give the same answer it essentially lets
us test our standard model over Cosmic
time and and that sets up a very
beautiful robustness test for does this
model
work but as the accuracy of each
approach has grown the estimates for the
Hubble constant the speed the universe
is
expanding have diverged a problem known
as the Hubble tension many of us are
quite fascinated by the implication that
we could be missing something still in
our understand of the universe or this
might be another clue about the nature
of some of these unknown parts of the
universe the dark matter the dark energy
things like that when we get mismatches
we get pretty excited about it in our
field because these tensions tell us
that maybe something is not quite right
in the model maybe that's the hint of of
where to look for the next breakthrough
this is where we find new physics this
is where we find Discovery is it just
measurements being made wrong is it
modeling being made wrong or are we
fundamentally not understanding
something about our universe we don't
know yet but it's telling us that
cosmology is still very
exciting 3 2
1 so the jury is still out but more data
is on the way the European space
agency's uclid Space Telescope launched
on July 1st
2023 it's design to look 10 billion
years into the past with unprecedented
accuracy and uid is not alone in its
pursuit of
answers it will soon be joined by NASA's
Nancy Grace Roman Space
Telescope which will measure distances
and positions for millions of
galaxies but perhaps most fitting will
be the work done done here in the soon
to be completed Vera C ruin observatory
in
Chile it will house the Simon survey
telescope that will photograph the
entire night sky every few nights using
the largest digital camera ever
constructed I think it's wonderful that
the Vera SE Rubin Observatory has been
named after Vera ruin she was Fearless
and undaunted she just kept going my
number one belief is that the universe
is for everyone we all have this right
to understand our place in the universe
and how the universe works and I think
that's really A fitting part of her
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Legacy in 2012 Voyager one left our
solar system in the sun's protective
heliosphere sending home the First
Direct observations of interstellar
space today the space probe continues on
its lonely
Journey as it likely
will long after we're
gone since the days of the Voyager
launch about 50 years ago much has
changed about our fundamental
understanding of the
universe but what will happen in the
next 50
years the last 50 years was about posing
some of these very big questions I think
the next 50 years is going to be about
answering them now we're left with the
very very hard problem to solve trying
to understand what dark matter is trying
to understand what dark energy is those
are not going to be easy to
solve it's a hugely exciting time to be
involved in physics astronomy cosmology
all the things that are now coming
together to help understand our universe
at large we're doing the experiments now
that might allow us in 50 years to say
wow there was another revolution in the
mid 2020s or around the time
2030 that gave us a whole new way to
look at the
universe dark matter is going to be the
most exciting thing that's going to
happen in the next 50 years because
either they're going to find it or it's
going to be incredibly exciting because
they're going to not find it and then
people are going to tear their hairs out
because what are we going to do
now it really is truly hard to imagine
what's our model and what our thinking
will be we will find new things it's
undeniable what I would love to learn
more about if I had a time capsule Zoom
forward right now is to ask what are the
questions we didn't even think to ask
today what what's really going to
surprise us that we didn't even wonder
to wonder about
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