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?
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Narrator: Aliens...
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Little green men.
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A thousand eyes or one-eyed.
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Narrator:
...Sci-fi movie monsters.
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Free-floating with tentacles.
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Some unknown
hyper-advanced civilization.
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Narrator: Could science fiction
ever become fact?
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I think it's really simple
why Hollywood
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is fascinated with the concept
of first contact with aliens,
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because that would be
probably the greatest
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scientific discovery
in all of human history.
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Narrator:
Problem is, our universe creates massive barriers
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to meeting extraterrestrials.
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It's almost as if
the universe is deliberately
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stopping us
from making first contact.
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Narrator:
We're searching the cosmos.
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Will we ever find
intelligent alien life?
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Or are we alone?
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-- Captions by vitac --
www.vitac.com
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captions paid for by
discovery communications
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[ explosion ]
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?
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Arecibo observatory,
Puerto Rico.
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45 years ago,
it sent a powerful radio message
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deep into space,
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kickstarting our efforts
to make first contact.
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Pacini: The arecibo message was
the first communication
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or attempt to communicate
with a possible civilization
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out there in the galaxy
or outside of our galaxy.
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Narrator: Today, that message
is speeding towards
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the m13 galaxy cluster
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25,000 light-years away.
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It contains information
about our world --
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where we are,
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even the makeup of our DNA.
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Pacini: The purpose of
this message was, of course,
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like, trying to say hi,
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and also, like, to light up
this question about,
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are we alone in the universe?
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Narrator:
But what chances are there
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that an intelligent alien race
is out there
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waiting to receive our message?
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Do I think there's other
intelligent life
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out there in the universe?
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The answer is a resounding yes.
Yes, I do.
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We know that life began on earth
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pretty much as soon
as our planet solidified.
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So why wouldn't that
have happened somewhere else?
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Narrator: If life has evolved
on other worlds,
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just how many
alien civilizations
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are out there that
we could potentially contact?
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Astronomer frank Drake
developed an equation
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to help answer
this crucial question.
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The Drake equation
is a really admirable attempt
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to apply
some quantitative reasoning
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to the probability,
or the possibility,
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that there is life
beyond the earth.
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Freese: You multiply
the star formation rate
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for stars in our galaxy
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times the number of planets
that each star has
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times the probability
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that you would have life forming
on that planet
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times the probability that that
life form becomes intelligent.
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And they estimated
that there were about
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10,000 intelligent civilizations
within our galaxy.
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?
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Narrator: Since the Drake
equation was first proposed,
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our understanding of the galaxy
has radically transformed.
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We have now discovered worlds
outside our solar system --
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exoplanets.
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Filippenko: Exoplanets are being
discovered all over the place.
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There are about 4,000 of them
now known,
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and techniques are finding more
every day.
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Narrator: Scientists believe
what we've found
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is the tip of the iceberg.
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So if the cosmos is so good
at making planets,
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perhaps it can produce
the conditions
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to make life
throughout the universe.
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When the Drake equation was
devised all those decades ago,
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we didn't know
that exoplanets existed.
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And now we think that there are
quite literally more planets
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than there are stars
in the universe.
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So even if life is really rare,
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there are an enormous number
of chances
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for it to take hold
in the universe.
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And for this reason,
it is very likely that
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there is life relatively
abundant in the universe,
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including an uncountable number
of advanced alien civilizations.
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This isn't science fiction.
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It's just basic probability.
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Narrator:
Probability suggests
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a multitude of alien
civilizations are out there.
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So isn't it a little strange
we haven't made first contact?
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Thaller: I think there's
every reason to believe
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that there are civilizations
out there,
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but we have
no evidence of them yet.
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Why haven't we found
other civilizations out there?
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Narrator:
One answer could be
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the sheer vastness
of the cosmos.
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Bullock: Look at all these
lights out here
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over the cityscape.
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You could think of these lights
as, like, stars in the galaxy.
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Now, if there's 10,000
communicating civilizations
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out there in the galaxy,
you might think, "oh, man, look.
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There's one right there
right down the street."
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The problem is
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there are hundreds of billions
of stars in the galaxy,
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which means that maybe
our nearest neighbor
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that we can communicate with
is not right there
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but way across the city.
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Narrator: We live in the suburbs
of the milky way
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75,000 light-years from
the furthest edge.
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Radio signals travel
at the speed of light.
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This speed limit means
that any signal sent
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to the opposite side
of the galaxy
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would take 75,000 years
to reach its destination.
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Bullock: The thing
you have to remember
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is the galaxy is gigantic.
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Even if there are 10,000
civilizations in the galaxy,
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it's possible that the distances
between stars are just so huge
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that we're never gonna be able
communicate with each other.
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Narrator: So the 45-year-old
arecibo radio message
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could still be tens of thousands
of years away
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from any potential
alien civilization.
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The target was 25,000
light-years from here.
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The message is now
45 light-years from here
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'cause it's traveling
the speed of light,
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so it's really far
from the target.
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Narrator: The vast size of
the universe is a huge roadblock
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to making first contact,
and the laws of physics
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prevent radio signals
from overcoming it.
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You just cannot go faster
than the speed of light.
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So our galaxy may be filled with
life, filled with civilizations,
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but they're so far away.
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Tremblay: I don't want to be
the bearer of bad news.
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But the universe is just
really, really far too large.
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Narrator:
The universe may be large,
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but we're putting the most
advanced technology on earth
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into action to try
and speed up the search.
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There really is a serious,
scientifically valid way
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to go looking for
other civilizations.
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And the breakthrough
listen project is really
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the best thing
we have right now.
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State-of-the-art facilities
around the world --
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radio telescopes,
optical telescopes, as well --
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are all looking up to the sky
together.
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Narrator: Breakthrough listen is
targeting the 1 million stars
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and 100 galaxies
closest to earth.
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It is the most
comprehensive search
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for alien communications
ever undertaken.
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If there was an aircraft
giving off a radar signal,
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and that aircraft was around
any of the 1,000 nearest stars,
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the breakthrough listen project
could hear that.
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So if there's
something out there
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that's actually giving off
a signal,
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breakthrough listen
has a chance to find it.
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Narrator: Breakthrough has
started by listening in
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on the nearest 1,700 stars
to earth.
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So far?
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Silence.
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Thaller:
This is the wonderfully,
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beautifully frustrating position
that we find ourselves in.
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We haven't heard anything yet.
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So we're in this position
where a negative result
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doesn't mean
there aren't civilizations,
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but we have no proof
that there are.
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Narrator: Breakthrough listen is
just beginning its hunt.
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There's much more
real estate in the cosmos
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for it to search.
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It's a big job,
demanding a lot of Patience.
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Plait: If you go through
Drake's equation
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and find this number
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of 10,000 intelligent
civilizations out there,
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there are something like
250 billion stars in the galaxy,
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so that's only 1 civilization
per 25 million stars.
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That's a lot of cold calling.
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Narrator:
The size of our universe
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means we could be waiting
a very long time
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to pick up
any alien communication.
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But even if we pick up a signal,
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it may have arrived too late.
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Oluseyi:
If we do receive a message,
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given that it probably
took years to get here,
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that civilization
could be long gone.
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Narrator:
So are we simply too late?
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Have any aliens out there
already died out?
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[ Explosion ]
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Narrator:
Earth has orbited the sun
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for over 4.5 billion years,
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time enough for humankind
to evolve into an intelligent
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and technologically advanced
species.
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But compared to the age
of the universe,
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planet earth is just a kid.
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00:10:08,342 --> 00:10:10,308
Plait: The earth is over
4 1/2 billion years old,
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and we think it's taken
this long
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to create the first
technological civilization --
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us.
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There are star systems out there
much older than we are.
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The universe is
13.8 billion years old.
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Carroll: We tend to think
we're hot stuff, right?
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We're technologically capable,
we can build rockets,
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and we can listen to
radio waves.
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But a typical other intelligent
advanced civilization
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would be literally
millions of years ahead of us
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00:10:36,403 --> 00:10:38,036
in technology.
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Narrator: So if an alien society
has been around longer than us,
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how much more technologically
advanced could they be?
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One method of measuring
just how much
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00:10:52,753 --> 00:10:55,220
is provided by
the kardashev scale.
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Tremblay:
The kardashev scale classifies
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00:10:57,391 --> 00:11:00,025
potential alien civilizations
into three types
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based on the amount of energy
that they're able to harness
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from their local environment.
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00:11:03,830 --> 00:11:05,730
A type-one civilization
can harness the energy
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00:11:05,732 --> 00:11:07,465
of only its home planet.
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00:11:07,467 --> 00:11:09,434
Type-two could hypothetically
harness the energy
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00:11:09,436 --> 00:11:10,869
of its own solar system.
219
00:11:10,871 --> 00:11:13,071
And a type-three could harness
the energy
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00:11:13,073 --> 00:11:16,708
potentially of an entire galaxy.
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00:11:16,710 --> 00:11:19,477
Narrator: If you're wondering
where we fit on that scale,
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00:11:19,479 --> 00:11:22,614
prepare for some bad news.
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We are somewhere between
zero and a one.
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We can't use
all of earth's resources.
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So we're at about a 0.7.
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00:11:30,657 --> 00:11:34,059
Narrator: An advanced species
reaching kardashev level two
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00:11:34,061 --> 00:11:35,493
or even three
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00:11:35,495 --> 00:11:38,463
could create
highly advanced structures
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00:11:38,465 --> 00:11:42,200
that can harness
the power of a star.
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00:11:42,202 --> 00:11:45,070
Plait: If you get to be
an advanced enough civilization,
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00:11:45,072 --> 00:11:48,306
eventually if your
energy demands are so huge,
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you might build solar panels
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00:11:49,676 --> 00:11:52,444
that you have enveloped
your star.
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00:11:52,446 --> 00:11:55,013
This was first thought of
by Freeman Dyson,
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00:11:55,015 --> 00:11:57,148
and so we call these
Dyson spheres.
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00:12:00,087 --> 00:12:02,454
Narrator: If such epic
engineering occurs
237
00:12:02,456 --> 00:12:06,524
in other star systems
or even other galaxies,
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00:12:06,526 --> 00:12:08,393
could we pick up some evidence
239
00:12:08,395 --> 00:12:12,297
and then make first contact?
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00:12:12,299 --> 00:12:13,998
Plait: The thing about
a Dyson sphere is that
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00:12:14,000 --> 00:12:15,500
you've completely blocked
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00:12:15,502 --> 00:12:18,269
all the light
coming out from a star,
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00:12:18,271 --> 00:12:20,438
except for the infrared
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00:12:20,440 --> 00:12:22,674
because these panels are
absorbing that sunlight
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and warming up.
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00:12:23,910 --> 00:12:25,210
When you warm up an object,
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00:12:25,212 --> 00:12:28,246
it gives off what's called
thermal infrared light.
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00:12:28,248 --> 00:12:30,949
You can scan the skies looking
for that signature
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00:12:30,951 --> 00:12:35,086
to see if there are
any Dyson spheres out there.
250
00:12:35,088 --> 00:12:38,356
Narrator: 2015 --
251
00:12:38,358 --> 00:12:41,659
NASA's wide field
infrared survey explorer
252
00:12:41,661 --> 00:12:44,829
scanned 100,000 nearby galaxies
253
00:12:44,831 --> 00:12:48,800
to locate advanced
kardashev civilizations
254
00:12:48,802 --> 00:12:54,739
by observing infrared light
leaking away from Dyson spheres.
255
00:12:54,741 --> 00:12:56,541
They detected...
256
00:12:56,543 --> 00:12:57,709
Nothing.
257
00:12:57,711 --> 00:13:00,044
Filippenko:
No such galaxy was found,
258
00:13:00,046 --> 00:13:03,314
so they didn't find
any infrared smoking gun.
259
00:13:03,316 --> 00:13:05,517
Narrator:
Given our universe is so old,
260
00:13:05,519 --> 00:13:09,854
surely other civilizations
should have had time to evolve.
261
00:13:09,856 --> 00:13:13,491
If so,
maybe we've simply missed them.
262
00:13:13,493 --> 00:13:16,628
Plait: It's entirely possible
that civilizations arose,
263
00:13:16,630 --> 00:13:19,063
tried to communicate
with the galaxy around them,
264
00:13:19,065 --> 00:13:22,233
and the problem was they were
asking too early for us.
265
00:13:22,235 --> 00:13:23,468
They're trying to
knock on our door,
266
00:13:23,470 --> 00:13:26,905
but our house wasn't built yet.
267
00:13:26,907 --> 00:13:29,507
Narrator: Earth has been around
for under one-third
268
00:13:29,509 --> 00:13:34,212
of the universe's
13.8-billion-year lifespan,
269
00:13:34,214 --> 00:13:38,349
the human race
just 300,000 years,
270
00:13:38,351 --> 00:13:41,653
a relatively tiny window
of opportunity
271
00:13:41,655 --> 00:13:43,555
to make first contact.
272
00:13:43,557 --> 00:13:46,391
We've been looking at the sky
for tens of years,
273
00:13:46,393 --> 00:13:47,659
something like that.
274
00:13:47,661 --> 00:13:50,061
What is the likelihood
that at that exact moment
275
00:13:50,063 --> 00:13:54,199
someone is gonna be beaming
a signal toward us?
276
00:13:54,201 --> 00:13:56,434
Narrator:
Perhaps the universe prevents
277
00:13:56,436 --> 00:14:01,372
intelligent civilizations
from surviving for very long,
278
00:14:01,374 --> 00:14:04,442
making our chances
for first contact
279
00:14:04,444 --> 00:14:06,544
even more unlikely.
280
00:14:06,546 --> 00:14:07,779
Plait: Maybe there is
something out there
281
00:14:07,781 --> 00:14:10,782
that is filtering us
from seeing them.
282
00:14:10,784 --> 00:14:12,750
We actually call this
the great filter.
283
00:14:12,752 --> 00:14:14,018
Maybe there is something
that says,
284
00:14:14,020 --> 00:14:16,187
"yeah, you're not getting
past here."
285
00:14:16,189 --> 00:14:19,958
Narrator:
Rocky planets like ours are ideal for hosting life,
286
00:14:19,960 --> 00:14:22,927
but they're fragile.
287
00:14:22,929 --> 00:14:25,997
And this fragility means
the universe
288
00:14:25,999 --> 00:14:29,234
could filter out
intelligent life quickly.
289
00:14:29,236 --> 00:14:34,305
?
290
00:14:34,307 --> 00:14:37,008
We've discovered
very violent star explosions
291
00:14:37,010 --> 00:14:39,210
like gamma-ray bursts.
292
00:14:39,212 --> 00:14:41,880
These are powerful enough,
they may sterilize planets
293
00:14:41,882 --> 00:14:43,982
even across an entire galaxy.
294
00:14:47,654 --> 00:14:49,654
Narrator:
And even if intelligent species
295
00:14:49,656 --> 00:14:52,090
survive natural phenomenon,
296
00:14:52,092 --> 00:14:54,792
they may still be filtered out
297
00:14:54,794 --> 00:14:58,363
by hitting
the self-destruct button.
298
00:14:58,365 --> 00:15:00,698
Loeb: As we can tell from
our own experience,
299
00:15:00,700 --> 00:15:03,735
the moment that we started
developing technology,
300
00:15:03,737 --> 00:15:06,738
we also developed the means
for our own destruction
301
00:15:06,740 --> 00:15:09,273
by changing the climate
on our planet,
302
00:15:09,275 --> 00:15:11,943
by developing weapons
of mass destruction.
303
00:15:11,945 --> 00:15:13,912
And so it's quite possible
that civilizations
304
00:15:13,914 --> 00:15:17,081
that are advanced enough
are short-lived.
305
00:15:17,083 --> 00:15:18,816
And if they're short-lived,
306
00:15:18,818 --> 00:15:21,152
that would explain why,
at this point in time,
307
00:15:21,154 --> 00:15:23,721
there are very few of them
that might be around
308
00:15:23,723 --> 00:15:25,523
to communicate with us.
309
00:15:27,761 --> 00:15:31,829
Narrator: Finding the relics
of an extinct alien civilization
310
00:15:31,831 --> 00:15:36,167
could be the ultimate cosmic
warning for the human race.
311
00:15:36,169 --> 00:15:38,236
Stricker: If we were to find
a civilization out there
312
00:15:38,238 --> 00:15:40,805
that may have destroyed
themselves by pollution
313
00:15:40,807 --> 00:15:42,140
or conflict,
314
00:15:42,142 --> 00:15:45,643
it would be almost like
staring into a mirror,
315
00:15:45,645 --> 00:15:48,112
and it would be
a very grim foreshadowing
316
00:15:48,114 --> 00:15:52,183
and maybe a lessons-learned
for us humans here on earth.
317
00:15:52,185 --> 00:15:55,687
Narrator: We can only hope
that some advanced alien species
318
00:15:55,689 --> 00:15:58,389
escaped the universe's
deadly filter.
319
00:16:01,795 --> 00:16:04,696
But even if e.T.S still exist
out there,
320
00:16:04,698 --> 00:16:08,333
the odds are still stacked
against first contact.
321
00:16:08,335 --> 00:16:13,504
?
322
00:16:13,506 --> 00:16:17,642
One other way that we've got
this alien-contact story
323
00:16:17,644 --> 00:16:22,313
a bit wrong is just down to
the laws of physics.
324
00:16:22,315 --> 00:16:25,583
Narrator: Every day,
the physics of the cosmos
325
00:16:25,585 --> 00:16:28,252
makes our chances
of contact worse
326
00:16:28,254 --> 00:16:31,356
because our universe
is expanding,
327
00:16:31,358 --> 00:16:34,492
and it's expanding fast.
328
00:16:41,401 --> 00:16:44,302
[ Explosion ]
329
00:16:46,006 --> 00:16:49,407
?
330
00:16:49,409 --> 00:16:52,377
Narrator:
February 2018 --
331
00:16:52,379 --> 00:16:55,480
astrophysicists
at the university of Oklahoma
332
00:16:55,482 --> 00:16:58,683
find a potential series
of rogue planets
333
00:16:58,685 --> 00:17:01,519
3.8 billion light-years away.
334
00:17:04,124 --> 00:17:08,092
Ranging between the size
of our moon and Jupiter,
335
00:17:08,094 --> 00:17:10,795
these would be
the first alien worlds
336
00:17:10,797 --> 00:17:13,398
ever discovered
outside our galaxy...
337
00:17:16,436 --> 00:17:19,837
...and maybe the first of many.
338
00:17:19,839 --> 00:17:22,673
Our galaxy alone
has trillions of planets.
339
00:17:22,675 --> 00:17:25,476
The observable universe
has trillions of galaxies --
340
00:17:25,478 --> 00:17:27,445
it's estimated about 2 trillion.
341
00:17:27,447 --> 00:17:30,381
So trillions of trillions?
342
00:17:30,383 --> 00:17:33,051
Come on.
343
00:17:33,053 --> 00:17:35,219
Narrator: But finding
exoplanets is no guarantee
344
00:17:35,221 --> 00:17:37,789
of finding alien life.
345
00:17:37,791 --> 00:17:41,025
And when it comes to contacting
extraterrestrials,
346
00:17:41,027 --> 00:17:44,695
our efforts
have met with silence.
347
00:17:44,697 --> 00:17:46,898
Oluseyi: Our search for life
has come up empty.
348
00:17:46,900 --> 00:17:48,366
Do we need
to change our tactics?
349
00:17:48,368 --> 00:17:50,001
Are we doing something wrong?
350
00:17:52,639 --> 00:17:54,005
Carroll: I think it's gonna be
very, very hard
351
00:17:54,007 --> 00:17:56,240
to find
extraterrestrial intelligence
352
00:17:56,242 --> 00:17:57,675
the way that
we're looking for it.
353
00:17:57,677 --> 00:18:00,878
We would have to get
really, really lucky.
354
00:18:00,880 --> 00:18:02,246
But I don't think
we're gonna get lucky.
355
00:18:02,248 --> 00:18:03,448
I think that if we want to know
356
00:18:03,450 --> 00:18:05,016
whether there's life out there
in the cosmos,
357
00:18:05,018 --> 00:18:06,684
we have to go visit it.
358
00:18:08,855 --> 00:18:10,555
Narrator: We've sent
the new horizons probe
359
00:18:10,557 --> 00:18:15,293
billions of miles across
the solar system to pluto.
360
00:18:15,295 --> 00:18:18,930
Perhaps one day we'll be able
to send spacecraft
361
00:18:18,932 --> 00:18:20,398
across the universe
362
00:18:20,400 --> 00:18:24,035
to search for alien life
on distant rogue planets.
363
00:18:24,037 --> 00:18:30,608
?
364
00:18:30,610 --> 00:18:35,146
But if a craft left our galaxy
to visit these new worlds,
365
00:18:35,148 --> 00:18:37,348
its mission would be tough
366
00:18:37,350 --> 00:18:40,718
thanks to the physics
of the cosmos.
367
00:18:40,720 --> 00:18:44,322
From our perspective
here in the milky way,
368
00:18:44,324 --> 00:18:49,126
every galaxy is, on average,
receding away from us.
369
00:18:49,128 --> 00:18:51,429
It looks like nobody likes us
370
00:18:51,431 --> 00:18:55,933
and is trying to get as far away
from us as possible.
371
00:18:55,935 --> 00:19:01,906
Narrator: This is because
our giant universe is expanding.
372
00:19:01,908 --> 00:19:04,142
Freese: When we talk about
the expanding universe,
373
00:19:04,144 --> 00:19:06,911
we don't mean that galaxies
are doing something active
374
00:19:06,913 --> 00:19:09,747
to run away from one another.
375
00:19:09,749 --> 00:19:13,050
Actually, it's the underlying
space that's expanding,
376
00:19:13,052 --> 00:19:14,619
and the galaxies
are embedded in that,
377
00:19:14,621 --> 00:19:16,821
and that's what causes
everything to move apart
378
00:19:16,823 --> 00:19:19,590
from everything else.
379
00:19:19,592 --> 00:19:21,058
Narrator:
The regions of the universe
380
00:19:21,060 --> 00:19:23,661
within 3 million light-years
of us
381
00:19:23,663 --> 00:19:27,632
are expanding
at around 45 miles a second.
382
00:19:27,634 --> 00:19:31,969
That's over 160,000 miles
an hour.
383
00:19:31,971 --> 00:19:33,804
Thaller:
So with our current technology,
384
00:19:33,806 --> 00:19:35,606
do we have any chance
of actually seeing
385
00:19:35,608 --> 00:19:37,675
what these other planets
are like?
386
00:19:37,677 --> 00:19:39,777
Well, think about the fastest
and farthest things
387
00:19:39,779 --> 00:19:42,246
we have right now,
like the voyager spacecraft.
388
00:19:42,248 --> 00:19:44,215
They've been in space
for more than 30 years
389
00:19:44,217 --> 00:19:48,452
going incredibly fast --
38,000 miles an hour.
390
00:19:48,454 --> 00:19:52,857
Narrator:
38,000 miles an hour is fast.
391
00:19:52,859 --> 00:19:55,092
But the closest galaxies to us
392
00:19:55,094 --> 00:19:59,564
are moving away at over
four times that speed.
393
00:19:59,566 --> 00:20:02,266
And the further away a probe
is sent to travel,
394
00:20:02,268 --> 00:20:04,936
the tougher its task.
395
00:20:04,938 --> 00:20:06,437
The thing about the expansion
of the universe
396
00:20:06,439 --> 00:20:08,606
is that the farther away
something is,
397
00:20:08,608 --> 00:20:11,542
the faster it's moving
away from you.
398
00:20:11,544 --> 00:20:14,812
The more distant two objects
are away from each other,
399
00:20:14,814 --> 00:20:17,415
the more space there is
between them,
400
00:20:17,417 --> 00:20:19,183
and the more space
there is between them,
401
00:20:19,185 --> 00:20:23,854
the more space there is
to expand.
402
00:20:23,856 --> 00:20:25,356
Oluseyi: The rate at which
they're moving away
403
00:20:25,358 --> 00:20:27,024
is proportional
to their distance.
404
00:20:27,026 --> 00:20:30,428
If it's twice as far away,
it moves away twice as fast.
405
00:20:30,430 --> 00:20:31,829
It is three times farther away,
406
00:20:31,831 --> 00:20:34,899
and moves away
three times as fast.
407
00:20:34,901 --> 00:20:37,034
Narrator: Scale it up to
the planets we've discovered
408
00:20:37,036 --> 00:20:40,004
3.8 billion light-years away,
409
00:20:40,006 --> 00:20:42,540
and thanks to the expansion
of the universe,
410
00:20:42,542 --> 00:20:46,344
those extra-galactic worlds
are moving away from us
411
00:20:46,346 --> 00:20:51,749
at over 49,000 miles per second.
412
00:20:51,751 --> 00:20:54,018
Imagine that you're a runner,
and you see the finish line.
413
00:20:54,020 --> 00:20:55,886
You're getting
a bit closer to it,
414
00:20:55,888 --> 00:20:58,856
but now, actually,
the track itself is expanding.
415
00:20:58,858 --> 00:21:01,292
And as the track expands
faster and faster,
416
00:21:01,294 --> 00:21:04,262
it's expanding faster
than you can possibly run.
417
00:21:04,264 --> 00:21:06,530
All of a sudden, that
finish line starts receding,
418
00:21:06,532 --> 00:21:08,899
and you're never, ever
gonna reach it.
419
00:21:12,505 --> 00:21:15,373
Narrator: Say one day
we're able to build probes
420
00:21:15,375 --> 00:21:19,677
that travel at the fastest speed
physics allows --
421
00:21:19,679 --> 00:21:21,279
the speed of light.
422
00:21:23,850 --> 00:21:26,017
Even that might not be enough
423
00:21:26,019 --> 00:21:29,620
because sometimes
the universe itself
424
00:21:29,622 --> 00:21:31,722
doesn't play by the rules.
425
00:21:31,724 --> 00:21:34,925
It's not possible for things
to travel through space
426
00:21:34,927 --> 00:21:38,462
faster than the speed of light,
but it is possible for space
427
00:21:38,464 --> 00:21:40,898
to expand faster
than the speed of light.
428
00:21:40,900 --> 00:21:43,634
Tremblay: Everywhere we look,
we see very distant galaxies
429
00:21:43,636 --> 00:21:46,237
that are apparently receding,
or moving away from earth,
430
00:21:46,239 --> 00:21:48,439
at greater than
the speed of light.
431
00:21:48,441 --> 00:21:50,641
Bullock:
There are distant galaxies we can see in the sky that,
432
00:21:50,643 --> 00:21:53,611
even if we were to build the
most advanced spaceship possible
433
00:21:53,613 --> 00:21:55,246
that could even move
at the speed of light,
434
00:21:55,248 --> 00:21:57,348
we could never get there.
435
00:21:57,350 --> 00:22:01,319
97% of the galaxies that we can
see in the distant sky
436
00:22:01,321 --> 00:22:05,189
are actually unreachable to us.
437
00:22:05,191 --> 00:22:07,525
Narrator: So for all
the galaxies out there
438
00:22:07,527 --> 00:22:10,394
and all the planets
that could harbor life,
439
00:22:10,396 --> 00:22:12,963
most of them
are out of our reach.
440
00:22:15,702 --> 00:22:18,636
The physics of the universe
has dealt an immense blow
441
00:22:18,638 --> 00:22:20,604
to first contact.
442
00:22:20,606 --> 00:22:23,974
The true reality of the universe
will always be hidden from us
443
00:22:23,976 --> 00:22:27,812
because of this,
because of this expansion.
444
00:22:27,814 --> 00:22:29,980
Narrator: The further we look
out into the universe,
445
00:22:29,982 --> 00:22:35,086
the more unlikely
first contact becomes.
446
00:22:35,088 --> 00:22:37,888
We might need
an advanced alien race
447
00:22:37,890 --> 00:22:41,325
to come and visit us instead.
448
00:22:41,327 --> 00:22:43,260
Suppose we get that lucky.
449
00:22:43,262 --> 00:22:48,432
Even then, would first contact
actually be feasible?
450
00:22:48,434 --> 00:22:49,934
Oluseyi:
We think aliens are like us.
451
00:22:49,936 --> 00:22:51,102
They're not.
452
00:22:51,104 --> 00:22:53,170
We're assuming that
the life is like us
453
00:22:53,172 --> 00:22:56,273
and that their planetary
environment is like ours.
454
00:22:56,275 --> 00:22:58,242
I don't think
that's gonna be the case
455
00:22:58,244 --> 00:23:00,978
for most of the life
in the universe.
456
00:23:00,980 --> 00:23:03,581
Narrator:
So, could extraterrestrials
457
00:23:03,583 --> 00:23:08,018
even survive first contact
with us and our planet?
458
00:23:15,895 --> 00:23:18,095
[ Explosion ]
459
00:23:22,635 --> 00:23:26,036
Narrator: July 2019 --
460
00:23:26,038 --> 00:23:29,707
the test satellite
discovered a new alien world
461
00:23:29,709 --> 00:23:32,276
31 light-years from us
462
00:23:32,278 --> 00:23:36,013
named gj 357 d.
463
00:23:36,015 --> 00:23:38,916
At over six times the mass
of our home planet,
464
00:23:38,918 --> 00:23:41,385
it's thought to be
a super earth.
465
00:23:41,387 --> 00:23:43,454
And from our observations,
466
00:23:43,456 --> 00:23:47,291
super earths appear to be
prime real estate.
467
00:23:47,293 --> 00:23:48,926
What we see is that
the most common type
468
00:23:48,928 --> 00:23:52,263
of terrestrial planet
is what we call a super earth.
469
00:23:52,265 --> 00:23:54,298
So that means
it's a terrestrial planet,
470
00:23:54,300 --> 00:23:57,535
but much more massive.
471
00:23:57,537 --> 00:24:00,504
Narrator: More massive can mean
more gravity,
472
00:24:00,506 --> 00:24:04,942
creating a planetary environment
completely unlike our own
473
00:24:04,944 --> 00:24:08,712
and life completely unlike ours.
474
00:24:08,714 --> 00:24:10,748
Oluseyi: If they're on
the surface of a super earth,
475
00:24:10,750 --> 00:24:14,452
it could be that gravity
is gonna be way stronger.
476
00:24:14,454 --> 00:24:17,321
So these aliens
aren't gonna be very tall,
477
00:24:17,323 --> 00:24:21,091
but they are gonna be
very strong.
478
00:24:21,093 --> 00:24:23,661
Narrator: Super earths are just
one of the many avenues
479
00:24:23,663 --> 00:24:25,763
the universe creates.
480
00:24:25,765 --> 00:24:29,200
There are other exoplanets
orbiting red stars
481
00:24:29,202 --> 00:24:31,602
10 times smaller than our sun
482
00:24:31,604 --> 00:24:34,405
and others making binary systems
483
00:24:34,407 --> 00:24:38,509
comprising two stars
instead of one.
484
00:24:38,511 --> 00:24:42,746
We see planets of all shapes
and sizes around stars
485
00:24:42,748 --> 00:24:46,851
of all shapes and sizes,
of all sorts of configurations.
486
00:24:46,853 --> 00:24:52,323
The potential for life
is much more rich and varied
487
00:24:52,325 --> 00:24:54,425
than we ever thought before.
488
00:24:54,427 --> 00:24:59,163
Retro rockets
five and six fired.
489
00:24:59,165 --> 00:25:00,598
Narrator:
Images of science fiction
490
00:25:00,600 --> 00:25:03,834
have fueled numerous fantasies
of first contact,
491
00:25:03,836 --> 00:25:06,237
but our knowledge
of the universe suggests
492
00:25:06,239 --> 00:25:09,440
reality could be
far, far stranger.
493
00:25:09,442 --> 00:25:10,841
If anything,
Hollywood has kind of
494
00:25:10,843 --> 00:25:12,710
constrained our imagination
495
00:25:12,712 --> 00:25:15,212
in terms of presenting
so many aliens
496
00:25:15,214 --> 00:25:17,214
that basically look like,
you know,
497
00:25:17,216 --> 00:25:19,550
humans wearing a rubber suit
or something.
498
00:25:19,552 --> 00:25:20,851
Lower landing legs.
499
00:25:23,022 --> 00:25:26,590
We have to, have to,
let go of this obsession
500
00:25:26,592 --> 00:25:28,926
that they're gonna be
anything like us.
501
00:25:28,928 --> 00:25:32,563
So if we're looking for
two-legged dudes, forget it.
502
00:25:32,565 --> 00:25:39,436
?
503
00:25:39,438 --> 00:25:42,139
Narrator: Say an intelligent
alien species lives
504
00:25:42,141 --> 00:25:44,141
in our stellar neighborhood
505
00:25:44,143 --> 00:25:46,777
and wants to make
first contact with us.
506
00:25:46,779 --> 00:25:49,513
If that alien evolved
on a super earth
507
00:25:49,515 --> 00:25:53,250
or orbited a red star
instead of a yellow one,
508
00:25:53,252 --> 00:25:55,452
it's wildly different biology
509
00:25:55,454 --> 00:25:58,088
may prevent it
from ever setting foot,
510
00:25:58,090 --> 00:26:00,758
or tentacle, on planet earth.
511
00:26:04,463 --> 00:26:06,597
Stricker: When you look at life
here on earth,
512
00:26:06,599 --> 00:26:08,532
it's almost as if it was
custom-made
513
00:26:08,534 --> 00:26:10,334
for this temperature,
for these elements,
514
00:26:10,336 --> 00:26:11,735
for this environment.
515
00:26:11,737 --> 00:26:14,371
An exoplanet with conditions
to support life
516
00:26:14,373 --> 00:26:16,173
could still be
completely different
517
00:26:16,175 --> 00:26:18,576
than life here on earth.
518
00:26:18,578 --> 00:26:20,578
Plait: What are things gonna be
like on an alien world
519
00:26:20,580 --> 00:26:23,380
which has a little bit
more potassium
520
00:26:23,382 --> 00:26:25,182
or is warmer than average
on earth
521
00:26:25,184 --> 00:26:27,351
or has a thicker atmosphere?
522
00:26:27,353 --> 00:26:29,420
Each one of these
small variations
523
00:26:29,422 --> 00:26:34,391
can mean a completely different
ecosystem.
524
00:26:34,393 --> 00:26:36,760
Narrator:
So could an alien organism
525
00:26:36,762 --> 00:26:40,798
really adapt to our ecosystem
when it lands on earth?
526
00:26:43,069 --> 00:26:44,902
Maybe we haven't made
first contact
527
00:26:44,904 --> 00:26:48,372
because they can't
actually visit us.
528
00:26:48,374 --> 00:26:50,240
Dartnell: They could step
through the airlock
529
00:26:50,242 --> 00:26:52,476
of their spaceship
and onto the earth
530
00:26:52,478 --> 00:26:55,546
and just find something toxic
with our environment,
531
00:26:55,548 --> 00:26:57,448
some some reason
they're not compatible
532
00:26:57,450 --> 00:26:59,350
with the surface of the earth.
533
00:26:59,352 --> 00:27:03,253
It's almost as if
the universe is out there
534
00:27:03,255 --> 00:27:07,324
deliberately trying to stop us
meeting any aliens.
535
00:27:07,326 --> 00:27:09,059
Narrator: Biology creates
another obstacle
536
00:27:09,061 --> 00:27:11,095
for making first contact,
537
00:27:11,097 --> 00:27:14,298
but as planetary scientist
jani radebough finds,
538
00:27:14,300 --> 00:27:17,134
even life on earth
can get pretty weird,
539
00:27:17,136 --> 00:27:18,969
taking extreme measures to adapt
540
00:27:18,971 --> 00:27:21,805
to a potentially hostile
environment.
541
00:27:21,807 --> 00:27:23,340
Radebough:
This is the great salt lake.
542
00:27:23,342 --> 00:27:25,109
It is the remains
of what used to be
543
00:27:25,111 --> 00:27:27,244
a much larger lake in the past.
544
00:27:27,246 --> 00:27:32,916
And when it evaporated away,
it left behind all of the salt.
545
00:27:32,918 --> 00:27:35,919
Narrator: The great salt lake
is nearly 10 times saltier
546
00:27:35,921 --> 00:27:38,155
than earth's oceans.
547
00:27:38,157 --> 00:27:39,857
The extreme salt content
548
00:27:39,859 --> 00:27:44,428
should make it an inhospitable
place for life.
549
00:27:44,430 --> 00:27:48,666
Despite this, there are
organisms thriving in the water.
550
00:27:50,569 --> 00:27:52,903
Radebough: As we look at life
in this vast lake
551
00:27:52,905 --> 00:27:55,406
and find that there are billions
of microbes living here
552
00:27:55,408 --> 00:27:58,609
in this unexpected environment,
then we start to realize,
553
00:27:58,611 --> 00:28:01,812
well, life forms in ways
that we just don't expect,
554
00:28:01,814 --> 00:28:03,781
in places we don't expect.
555
00:28:03,783 --> 00:28:07,718
Narrator: Microbial life
known as extremophiles
556
00:28:07,720 --> 00:28:11,422
have developed an ingenious way
to survive in the lake.
557
00:28:11,424 --> 00:28:13,524
Well, they actually use
these solar-powered pumps
558
00:28:13,526 --> 00:28:15,826
to pull the salt
out of their cells
559
00:28:15,828 --> 00:28:18,128
so that they can operate
more normally.
560
00:28:18,130 --> 00:28:19,530
But in order to do that,
they have to live
561
00:28:19,532 --> 00:28:20,831
very close to the surface,
562
00:28:20,833 --> 00:28:23,734
which means they get
a huge amount of U.V. radiation.
563
00:28:23,736 --> 00:28:26,837
So all this pink color
that you see behind me
564
00:28:26,839 --> 00:28:29,139
is actually the pink
of the organisms,
565
00:28:29,141 --> 00:28:31,208
and it's sort of like
a built-in sunscreen
566
00:28:31,210 --> 00:28:34,611
that helps protect them against
the U.V. radiation.
567
00:28:34,613 --> 00:28:38,482
Narrator: Extremophiles are
rewriting our expectations
568
00:28:38,484 --> 00:28:41,218
of where life can survive
on earth.
569
00:28:41,220 --> 00:28:45,956
Could alien biology be much
more resilient than we think?
570
00:28:45,958 --> 00:28:48,726
These extremophiles
should be a little reminder
571
00:28:48,728 --> 00:28:52,429
that we haven't been
thinking big enough.
572
00:28:52,431 --> 00:28:56,667
Narrator:
Maybe e.T. Could readily adapt to our environment,
573
00:28:56,669 --> 00:28:59,636
or perhaps they've got
other ideas,
574
00:28:59,638 --> 00:29:04,441
using technology to overcome
any biological barriers.
575
00:29:04,443 --> 00:29:09,146
Maybe the first aliens we meet
will be robots.
576
00:29:09,148 --> 00:29:11,315
They can build
much more powerful life
577
00:29:11,317 --> 00:29:14,017
if they don't limit themselves
to meat bags.
578
00:29:14,019 --> 00:29:15,786
Narrator: Advanced aliens
could have left
579
00:29:15,788 --> 00:29:18,922
their biological brains
and bodies behind,
580
00:29:18,924 --> 00:29:24,495
traveling instead as
mobile artificial intelligence.
581
00:29:24,497 --> 00:29:27,064
Tegmark: We tend to think of
intelligence and consciousness
582
00:29:27,066 --> 00:29:29,299
as something mysterious
that can only exist
583
00:29:29,301 --> 00:29:31,969
inside of biological organisms
like us
584
00:29:31,971 --> 00:29:36,006
and somehow therefore
can't be copied.
585
00:29:36,008 --> 00:29:39,076
But what's given us the whole
a.I. Revolution, right --
586
00:29:39,078 --> 00:29:40,277
the idea that, no,
587
00:29:40,279 --> 00:29:42,446
intelligence and probably
consciousness, too,
588
00:29:42,448 --> 00:29:44,381
is just information processing,
589
00:29:44,383 --> 00:29:47,017
and it's just the information
processing that really matters.
590
00:29:47,019 --> 00:29:50,087
Perhaps an alien would be
able to download
591
00:29:50,089 --> 00:29:53,190
its consciousness
into some sort of computer
592
00:29:53,192 --> 00:29:58,395
and travel as
a disembodied consciousness.
593
00:29:58,397 --> 00:30:01,498
In this state,
you'd be essentially immortal.
594
00:30:06,005 --> 00:30:09,106
Narrator: So it's possible an
advanced species could find ways
595
00:30:09,108 --> 00:30:13,544
to face the challenges
of first contact.
596
00:30:13,546 --> 00:30:16,780
But if an alien civilization
is out there
597
00:30:16,782 --> 00:30:18,515
and more advanced than us,
598
00:30:18,517 --> 00:30:22,486
could there be
an even bigger issue at play?
599
00:30:22,488 --> 00:30:25,489
Maybe the reason
that intelligent aliens
600
00:30:25,491 --> 00:30:28,392
haven't ever come to the earth
to visit us
601
00:30:28,394 --> 00:30:32,129
is maybe we're just
not that interesting.
602
00:30:32,131 --> 00:30:35,132
Narrator: So maybe the biggest
barrier for first contact
603
00:30:35,134 --> 00:30:39,169
is the fact that aliens
don't actually want to meet us.
604
00:30:48,347 --> 00:30:50,414
[ Explosion ]
605
00:30:52,818 --> 00:30:55,786
?
606
00:30:55,788 --> 00:30:58,622
Narrator: In the movies,
first contact usually leads
607
00:30:58,624 --> 00:31:01,325
to an alien invasion.
608
00:31:01,327 --> 00:31:03,360
Cities get zapped.
609
00:31:03,362 --> 00:31:05,495
[ Explosion ]
610
00:31:09,068 --> 00:31:12,035
Humanity faces annihilation.
611
00:31:12,037 --> 00:31:12,936
[ People screaming ]
612
00:31:12,938 --> 00:31:15,339
Maybe a visit from e.T.
613
00:31:15,341 --> 00:31:18,242
Isn't such a good thing,
after all.
614
00:31:18,244 --> 00:31:21,979
Imagine if we if we got
an intergalactic e-mail,
615
00:31:21,981 --> 00:31:25,983
so from, you know,
superioraliencivilization. Org,
616
00:31:25,985 --> 00:31:29,219
saying, "hey, we're gonna
show up in 30 years."
617
00:31:29,221 --> 00:31:30,621
Would we just be like,
"oh, all right,
618
00:31:30,623 --> 00:31:33,390
let's get back to
watching our reality TV shows
619
00:31:33,392 --> 00:31:34,958
and worry about that
when they get here"?
620
00:31:34,960 --> 00:31:37,628
No, we would seriously
freak out.
621
00:31:37,630 --> 00:31:41,265
Narrator:
People might freak out,
622
00:31:41,267 --> 00:31:44,534
but the truth is we've been
sign-posting our location
623
00:31:44,536 --> 00:31:47,037
into the cosmos for decades.
624
00:31:47,039 --> 00:31:51,074
Dartnell: The earth has been
a detectably technological world
625
00:31:51,076 --> 00:31:52,576
for about 100 years.
626
00:31:52,578 --> 00:31:55,012
We've been broadcasting signals,
627
00:31:55,014 --> 00:32:00,250
and yet, that apparently hasn't
attracted anyone's attention.
628
00:32:00,252 --> 00:32:01,985
It's pretty noteworthy
629
00:32:01,987 --> 00:32:04,521
that none of them
has shown any interest,
630
00:32:04,523 --> 00:32:06,957
when they could have
turned earth into a parking lot
631
00:32:06,959 --> 00:32:09,393
if they wanted, right?
632
00:32:09,395 --> 00:32:12,362
Narrator: Perhaps no one
has redeveloped planet earth
633
00:32:12,364 --> 00:32:15,032
because an advanced civilization
634
00:32:15,034 --> 00:32:18,669
simply doesn't want to
make first contact.
635
00:32:18,671 --> 00:32:20,203
Frankly, if they're
that intelligent,
636
00:32:20,205 --> 00:32:23,106
they're not gonna be
very interested in us.
637
00:32:23,108 --> 00:32:26,209
So maybe that's why they haven't
bothered to make contact.
638
00:32:26,211 --> 00:32:28,412
Filippenko: And if the alien
is that advanced,
639
00:32:28,414 --> 00:32:31,548
we're probably not
very interesting to it.
640
00:32:31,550 --> 00:32:33,717
It's a little bit like,
you know,
641
00:32:33,719 --> 00:32:38,021
wandering around outside
and seeing ants on the sidewalk.
642
00:32:40,059 --> 00:32:43,694
Narrator: Alien invasion makes
for great science fiction,
643
00:32:43,696 --> 00:32:45,829
but what do we actually
have on earth
644
00:32:45,831 --> 00:32:49,299
that's worth
all that alien effort?
645
00:32:49,301 --> 00:32:51,001
Dartnell:
How realistic really are
646
00:32:51,003 --> 00:32:53,971
these depictions from Hollywood?
647
00:32:53,973 --> 00:32:59,676
One common trope is the aliens
coming to devour the human race.
648
00:32:59,678 --> 00:33:03,113
But the science doesn't really
support this being possible.
649
00:33:03,115 --> 00:33:09,019
Would an alien even be able
to digest the human body?
650
00:33:09,021 --> 00:33:12,289
Narrator: When eating,
enzymes in our digestive system
651
00:33:12,291 --> 00:33:15,392
break down molecules
in our food.
652
00:33:15,394 --> 00:33:19,663
The food we can eat, and these
enzymes are very specific
653
00:33:19,665 --> 00:33:23,600
to the molecules
they can attack and break down.
654
00:33:23,602 --> 00:33:27,404
The same rules would apply
to a hungry alien.
655
00:33:27,406 --> 00:33:29,072
Dartnell:
To be able to digest us
656
00:33:29,074 --> 00:33:31,074
and for us to be nutritious
for them,
657
00:33:31,076 --> 00:33:33,944
we'd have to have a very, very
similar biochemistry
658
00:33:33,946 --> 00:33:36,680
to what exists
on the alien's home world,
659
00:33:36,682 --> 00:33:39,850
what their bodies
have adapted to.
660
00:33:39,852 --> 00:33:42,052
Narrator:
So it seems highly unlikely
661
00:33:42,054 --> 00:33:44,621
that aliens would come
looking for food.
662
00:33:44,623 --> 00:33:47,257
But how about a drink?
663
00:33:47,259 --> 00:33:50,227
In order for life as we know it
to exist,
664
00:33:50,229 --> 00:33:52,596
one needs liquid water.
665
00:33:52,598 --> 00:33:55,866
Narrator: If aliens live
on a barren desert planet,
666
00:33:55,868 --> 00:34:00,537
a water world like ours
could be highly attractive.
667
00:34:00,539 --> 00:34:03,206
While we call ourselves
the blue planet,
668
00:34:03,208 --> 00:34:05,842
our oceans are not unique.
669
00:34:05,844 --> 00:34:10,614
The universe offers
far greater water resources.
670
00:34:10,616 --> 00:34:12,282
Sutter: In our solar system,
we're finding that
671
00:34:12,284 --> 00:34:18,555
most of the liquid water exists
in moons around the gas giants.
672
00:34:18,557 --> 00:34:20,957
Narrator: We believe
Jupiter's moon europa
673
00:34:20,959 --> 00:34:25,462
has a layer of water ice
around 15 miles thick
674
00:34:25,464 --> 00:34:29,533
floating on an ocean
up to 100 miles deep.
675
00:34:29,535 --> 00:34:32,869
This single moon may have
twice as much water
676
00:34:32,871 --> 00:34:36,206
as all earth's oceans combined.
677
00:34:36,208 --> 00:34:39,543
Europa is the water world
of our solar system
678
00:34:39,545 --> 00:34:41,178
and not the earth.
679
00:34:41,180 --> 00:34:44,581
So if you were an alien
looking for water,
680
00:34:44,583 --> 00:34:47,951
you wouldn't bother going to
a big planet like the earth
681
00:34:47,953 --> 00:34:50,720
to suck it up through
some kind of giant straw.
682
00:34:50,722 --> 00:34:52,856
You'd go to
the outer solar system.
683
00:34:52,858 --> 00:34:56,960
You might harvest icy moons.
684
00:34:56,962 --> 00:34:58,628
Narrator:
Instead of working against
685
00:34:58,630 --> 00:35:01,865
the powerful gravitational pull
of earth,
686
00:35:01,867 --> 00:35:05,469
an alien race could draw water
from europa,
687
00:35:05,471 --> 00:35:09,473
where gravity is almost
10 times weaker.
688
00:35:09,475 --> 00:35:13,410
So what other resources
have we got to offer?
689
00:35:13,412 --> 00:35:17,948
Maybe aliens come to strip mine
the earth's crust
690
00:35:17,950 --> 00:35:22,652
for metals -- iron or titanium
or platinum.
691
00:35:22,654 --> 00:35:24,121
Aliens might use these metals
692
00:35:24,123 --> 00:35:26,356
for exactly the same things
that we do --
693
00:35:26,358 --> 00:35:29,993
for building spaceships,
for building their technology.
694
00:35:32,464 --> 00:35:34,297
Narrator:
Such materials could be useful
695
00:35:34,299 --> 00:35:38,802
for any alien civilization
short on mineral resources.
696
00:35:38,804 --> 00:35:41,505
Problem is,
a lot of our planet's metals
697
00:35:41,507 --> 00:35:45,008
are buried deep
in the earth's interior.
698
00:35:45,010 --> 00:35:48,545
When the earth formed,
the great deal of its iron
699
00:35:48,547 --> 00:35:50,947
sunk down into the core
of our planet
700
00:35:50,949 --> 00:35:52,482
and took a lot of metals
with it.
701
00:35:52,484 --> 00:35:56,453
So they're actually quite hard
to mine on the earth.
702
00:35:56,455 --> 00:35:58,989
Narrator: An alien race would be
better off prospecting
703
00:35:58,991 --> 00:36:04,694
for more accessible minerals
situated in the asteroid belt.
704
00:36:04,696 --> 00:36:07,597
In the asteroid belt, there's
an asteroid called psyche,
705
00:36:07,599 --> 00:36:10,000
which is made up
of pure iron nickel,
706
00:36:10,002 --> 00:36:12,802
just like the core of the earth.
707
00:36:12,804 --> 00:36:16,039
Narrator: Psyche provides
a near-150-mile
708
00:36:16,041 --> 00:36:19,376
exposed strip of iron nickel,
709
00:36:19,378 --> 00:36:24,447
yet another reason e.T.
Wouldn't need to bother with us.
710
00:36:24,449 --> 00:36:26,883
For my money,
none of those reasons
711
00:36:26,885 --> 00:36:29,553
would draw aliens to earth.
712
00:36:29,555 --> 00:36:32,889
All these things can be found
far more easily elsewhere.
713
00:36:32,891 --> 00:36:34,824
Narrator: The possibility
of first contact
714
00:36:34,826 --> 00:36:37,928
is beginning to sound
increasingly remote.
715
00:36:37,930 --> 00:36:40,430
The universe throws up
massive barriers
716
00:36:40,432 --> 00:36:44,801
stopping us from communicating
with an intelligent alien race,
717
00:36:44,803 --> 00:36:48,205
a race that might very well
have absolutely no interest
718
00:36:48,207 --> 00:36:50,106
in contacting us,
719
00:36:50,108 --> 00:36:53,276
unless, of course,
they already have.
720
00:36:53,278 --> 00:36:55,312
Is it possible that
there have been alien signals
721
00:36:55,314 --> 00:36:58,782
that we've already detected but
we didn't realize what they are?
722
00:36:58,784 --> 00:37:00,350
Narrator:
Scientists have discovered
723
00:37:00,352 --> 00:37:05,155
a powerful cosmic signal
that they cannot explain.
724
00:37:05,157 --> 00:37:08,825
Could this finally be
first contact?
725
00:37:16,835 --> 00:37:18,868
[ Explosion ]
726
00:37:23,275 --> 00:37:26,710
Narrator: July 2018 --
727
00:37:26,712 --> 00:37:29,179
the chime telescope
in British Columbia
728
00:37:29,181 --> 00:37:32,249
detected a short flash
of radio energy
729
00:37:32,251 --> 00:37:34,451
quicker than a blinking eye.
730
00:37:34,453 --> 00:37:38,221
It's called a fast radio burst.
731
00:37:38,223 --> 00:37:41,057
These are intensely powerful,
very, very short
732
00:37:41,059 --> 00:37:43,793
lived radio bursts
that can be 1,000 times brighter
733
00:37:43,795 --> 00:37:45,862
than the sun
at radio wavelengths,
734
00:37:45,864 --> 00:37:49,466
that arrive and disappear
in an instant.
735
00:37:52,170 --> 00:37:54,871
Narrator: Most fast radio bursts
are one-offs,
736
00:37:54,873 --> 00:37:59,242
blinking into existence,
then disappearing forever.
737
00:37:59,244 --> 00:38:01,077
But not this one.
738
00:38:01,079 --> 00:38:05,749
A few days later, scientists
caught the flash again.
739
00:38:05,751 --> 00:38:07,984
The amount of energy
that it takes to produce
740
00:38:07,986 --> 00:38:09,185
a burst like this,
741
00:38:09,187 --> 00:38:10,987
for us to detect it
here on earth
742
00:38:10,989 --> 00:38:14,257
from billions of light-years,
is immense.
743
00:38:14,259 --> 00:38:17,060
And we've run across
things like this before --
744
00:38:17,062 --> 00:38:19,362
exploding stars,
gamma-ray bursts.
745
00:38:19,364 --> 00:38:21,765
These are all
very strange objects,
746
00:38:21,767 --> 00:38:23,700
but that does not explain these
747
00:38:23,702 --> 00:38:26,903
because some of these
fast radio bursts repeat.
748
00:38:26,905 --> 00:38:29,673
So whatever it is that can
generate this kind of energy,
749
00:38:29,675 --> 00:38:31,441
it can do it more than once.
750
00:38:36,114 --> 00:38:39,149
Narrator: Light comes in
many different wavelengths.
751
00:38:39,151 --> 00:38:41,951
Radio waves are the longest,
making them good
752
00:38:41,953 --> 00:38:44,087
for long-distance communication.
753
00:38:46,358 --> 00:38:49,159
We've used radio waves
for over 100 years,
754
00:38:49,161 --> 00:38:52,929
from wireless radio to TV,
755
00:38:52,931 --> 00:38:55,565
from cellphone calls
to communications
756
00:38:55,567 --> 00:38:58,101
with space probes.
757
00:38:58,103 --> 00:39:01,304
Could alien civilizations
be using radio waves,
758
00:39:01,306 --> 00:39:04,574
but on a much larger scale?
759
00:39:04,576 --> 00:39:07,344
What if we already intercepted
alien communications,
760
00:39:07,346 --> 00:39:10,480
but we just don't know it?
761
00:39:10,482 --> 00:39:12,349
Narrator:
Our radio and television signals
762
00:39:12,351 --> 00:39:17,220
only use a very narrow band
of the radio spectrum.
763
00:39:17,222 --> 00:39:19,923
Fast radio bursts are different,
764
00:39:19,925 --> 00:39:22,192
and that's a problem.
765
00:39:22,194 --> 00:39:24,160
Here's the thing
about fast radio bursts --
766
00:39:24,162 --> 00:39:26,629
they are emitting
a broad range of wavelengths,
767
00:39:26,631 --> 00:39:28,765
so it's not the best way
to communicate.
768
00:39:28,767 --> 00:39:33,636
If these are aliens,
they're not very smart aliens.
769
00:39:33,638 --> 00:39:36,606
Narrator: It turns out
that broad-range wavelengths
770
00:39:36,608 --> 00:39:38,475
are easy to distort.
771
00:39:38,477 --> 00:39:42,445
There is a very thin gas
out there between the stars,
772
00:39:42,447 --> 00:39:44,180
and when you emit radio waves,
773
00:39:44,182 --> 00:39:46,616
the radio waves interact
with this gas.
774
00:39:46,618 --> 00:39:47,951
And the way they interact
775
00:39:47,953 --> 00:39:51,554
depends on the wavelength
you're talking about.
776
00:39:51,556 --> 00:39:53,757
If you use a broad range
of wavelengths
777
00:39:53,759 --> 00:39:56,259
to send a signal
across interstellar space,
778
00:39:56,261 --> 00:39:57,727
by the time
somebody receives it,
779
00:39:57,729 --> 00:39:59,929
it can be a little distorted
and weird.
780
00:40:02,801 --> 00:40:05,402
Narrator: If aliens are
sending out radio bursts,
781
00:40:05,404 --> 00:40:09,839
the signal would get so degraded
that by the time it reaches us,
782
00:40:09,841 --> 00:40:13,877
we wouldn't be able
to decipher it.
783
00:40:13,879 --> 00:40:18,081
As a calling card,
not incredibly useful.
784
00:40:18,083 --> 00:40:20,283
Narrator: Whether these
mysterious bursts really are
785
00:40:20,285 --> 00:40:24,687
aliens trying to say hello
or just a natural phenomenon,
786
00:40:24,689 --> 00:40:27,157
this is not first contact,
787
00:40:27,159 --> 00:40:29,125
at least not yet.
788
00:40:29,127 --> 00:40:30,727
I want to be careful here,
right?
789
00:40:30,729 --> 00:40:33,730
I'm not a naysayer.
I'm not gonna pooh-pooh aliens.
790
00:40:33,732 --> 00:40:35,598
But, you know, let's go through
the other things first
791
00:40:35,600 --> 00:40:38,268
because the universe is filled
with weird stuff,
792
00:40:38,270 --> 00:40:39,836
and let's see what that is.
793
00:40:39,838 --> 00:40:43,006
And if we eliminate all those,
and all that's left is aliens,
794
00:40:43,008 --> 00:40:45,475
yeah, let's talk.
795
00:40:45,477 --> 00:40:49,212
Narrator: If extraterrestrial
species are out there,
796
00:40:49,214 --> 00:40:51,748
our universe makes it
extremely difficult
797
00:40:51,750 --> 00:40:54,784
to contact them.
798
00:40:54,786 --> 00:40:57,120
But in spite
of all the obstacles,
799
00:40:57,122 --> 00:40:59,088
maybe there's still hope.
800
00:41:01,393 --> 00:41:03,893
We once thought that
there could be 10,000
801
00:41:03,895 --> 00:41:07,964
intelligent civilizations
in the milky way alone.
802
00:41:07,966 --> 00:41:11,468
Now we know that our cosmos
is filled with planets
803
00:41:11,470 --> 00:41:14,070
just waiting to be found.
804
00:41:14,072 --> 00:41:16,172
Our technology is evolving.
805
00:41:16,174 --> 00:41:18,408
Searches are expanding.
806
00:41:18,410 --> 00:41:22,245
The truth about our mission
to make first contact is this --
807
00:41:22,247 --> 00:41:27,584
we are only
just getting started.
808
00:41:27,586 --> 00:41:32,188
I'd love for tomorrow morning
some sort of interstellar tweet
809
00:41:32,190 --> 00:41:33,890
to be beamed at the earth,
810
00:41:33,892 --> 00:41:35,391
and we would then realize
811
00:41:35,393 --> 00:41:38,695
that we are not alone
in this cosmos.
812
00:41:38,697 --> 00:41:39,929
Pacini:
I'm all ready to celebrate.
813
00:41:39,931 --> 00:41:42,665
Here we have already
a champagne on ice
814
00:41:42,667 --> 00:41:46,035
[laughs]
To pop when they find it.
815
00:41:46,037 --> 00:41:49,072
Thaller: Scientists really do
hope we find evidence
816
00:41:49,074 --> 00:41:51,274
of extraterrestrial life
someday.
817
00:41:51,276 --> 00:41:54,644
We have observatories and
satellites that look at the sky.
818
00:41:54,646 --> 00:41:58,481
All day, all night, every day.
819
00:41:58,483 --> 00:42:01,951
The discovery of alien life
would simultaneously be,
820
00:42:01,953 --> 00:42:03,786
in a way, unsurprising
821
00:42:03,788 --> 00:42:07,257
and yet the greatest discovery
in all of human history.
822
00:42:07,259 --> 00:42:09,125
Even if life
is really, really rare,
823
00:42:09,127 --> 00:42:11,060
the universe
is really, really big,
824
00:42:11,062 --> 00:42:14,397
and so there could be countless
alien civilizations out there.
825
00:42:14,399 --> 00:42:17,200
But the actual discovery
or confirmation of that --
826
00:42:17,202 --> 00:42:19,969
I can think of no greater
scientific discovery.
827
00:42:19,971 --> 00:42:23,139
It would quite literally change
our entire civilization.
828
00:42:23,141 --> 00:42:27,677
?
829
00:42:27,727 --> 00:42:32,277
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