Kind: captions
Language: en
we are planning to uh test out how you
would defend earth from an incoming
asteroid
for the first time helping humanity um
save itself from a threat of a killer
asteroid
an impact on earth doesn't happen very
often
that doesn't mean they don't happen this
isn't the sort of thing that we want to
address at the last minute
an asteroid impact is a blockbuster kind
of disaster
the comments are still headed for earth
but is the threat of global destruction
something we should actually fear
66 million years ago an asteroid the
size of a mountain
wiped out the dinosaurs and altered the
global climate for years
so could we suffer the same fate
we don't want to be dinosaurs but we are
not as worried about it because we have
been cataloging all the different sizes
of asteroids and
tracking them at this point we feel like
we know 100
of all of the dinosaur killers
and they're not coming towards earth
space agencies including nasa are
confident they're tracking asteroids big
enough to cause a major extinction event
and none of them are headed our way in
the foreseeable future
but this doesn't mean we're safe
scientists are mostly worried about
asteroids
that are in a 100 meter kind of range
they are difficult to see because
they're small because they are
dark and because they are really far
away
but even though they're hard to spot
these smaller asteroids can still do a
lot of damage
take the chelyabinsk meteor which lit up
headlines in 2013
meteoroid or perhaps more than one
passed over southern russia
eventually exploding in mid-air it
detonated in the atmosphere and the
detonation was about two to three times
as much as a nuclear bomb
the shockwave can actually break windows
and the windows
they are going to harm people and that
asteroid was only about
65 feet wide even relatively small
asteroids could cause
catastrophic damage so what are
scientists doing to prevent
the next major asteroid disaster
we have a fantastic team of planetary
defenders
trying to find the near-earth asteroids
that perhaps
uh pose an impact threat there are
campaigns
not only in the u.s but all around the
world trying to observe them and trying
to classify them and try to
to understand their orbits of this 140
meter and larger size range it's
estimated there's 25 000 of those
to date we're probably just a little
over a third of the way
in finding all of those asteroids nasa
has been doing this a long time and it
became more formalized in 2016
into the planetary defense coordination
office
yes planetary defense
by 2022 it plans to launch its very
first spacecraft mission
called dart short for double asteroid
redirection test
we want to know whether or not we will
be able to
redirect the master redirect that means
changing the path
of an asteroid to test if this technique
could work
it needs to find not one but two
asteroids
one is didamos the main asteroid and
then it has a small moon that orbits
around it called dimorphous
so dart's goal is to hit dimorphous
that's right it's trying to move a moon
to see whether or not we can change
its orbit even though the ditimo system
is considered a potentially hazardous
object which means it comes actually
pretty close to earth
there's no way by us hitting the moon of
the object that it changes the
trajectory of the larger asteroid
we are testing out a technique called
kinetic impactor
about four hours out before the impact
the spacecraft becomes fully autonomous
it will
point itself towards the moon make all
the maneuvers necessary to
slam itself into this really small
object so
really from 60 000 miles away you
basically
started off and you guided yourself into
160 meter
object it is very impressive and hard
to determine whether the nudge was
successful scientists will look for
changes in the moon's orbit
if the mission is a success that means
this might be an effective method to
deflect an asteroid discovered to be on
a collision course
if we catch this asteroid early enough
in its trajectory
we should be able to deviate it enough
so that it just misses the earth
but what if there isn't enough time to
deflect an asteroid
the answer is not purely scientific it
also has to do with
politics of how to deal with this even
though
this is called planetary defense there
are a few countries that really can do
something and those countries are those
that have space mission capabilities
and the countries who don't have such
capabilities will have to depend on the
goodwill of those who do
will those countries be able and willing
to do something
right now experts are conducting
regional risk assessments and drawing up
notification and evacuation plans
at the planetary defense conference
which is a gathering
of uh researchers who work in planetary
defense from around the world
we'll have these exercises where it's a
hypothetical scenario where an asteroid
is discovered that
has some probability of impacting earth
what their roles might be
in addressing an impact threat and
ideally you would find that object
perhaps a couple of orbits before
it ever poses an impact threat so that
you would have
years or decades of notice to plan for
it
[Music]