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Aliens...
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Little green men.
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A thousand eyes or one-eyed.
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...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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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One answer could be
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the sheer vastness
of the cosmos.
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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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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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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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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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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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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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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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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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00:08:03,070 --> 00:08:04,376
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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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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This is the wonderfully,
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00:08:19,750 --> 00:08:21,966
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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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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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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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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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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So are we simply too late?
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Have any aliens out there
already died out?
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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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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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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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00:10:33,750 --> 00:10:36,396
would be literally
millions of years ahead of us
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00:10:36,420 --> 00:10:38,050
in technology.
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00:10:42,060 --> 00:10:46,276
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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00:10:50,300 --> 00:10:52,746
One method of measuring
just how much
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00:10:52,770 --> 00:10:55,216
is provided by
the Kardashev scale.
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00:10:55,240 --> 00:10:57,386
The Kardashev scale classifies
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00:10:57,410 --> 00:11:00,016
potential alien civilizations
into three types
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00:11:00,040 --> 00:11:02,226
based on the amount of energy
that they're able to harness
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00:11:02,250 --> 00:11:03,826
from their local environment.
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00:11:03,850 --> 00:11:05,726
A type-one civilization
can harness the energy
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00:11:05,750 --> 00:11:07,456
of only its home planet.
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00:11:07,480 --> 00:11:09,426
Type-two could hypothetically
harness the energy
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00:11:09,450 --> 00:11:10,866
of its own solar system.
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00:11:10,890 --> 00:11:13,066
And a type-three could harness
the energy
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00:11:13,090 --> 00:11:16,706
potentially of an entire galaxy.
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00:11:16,730 --> 00:11:19,476
If you're wondering
where we fit on that scale,
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00:11:19,500 --> 00:11:22,606
prepare for some bad news.
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00:11:22,630 --> 00:11:24,946
We are somewhere between
zero and a one.
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00:11:24,970 --> 00:11:27,846
We can't use
all of earth's resources.
220
00:11:27,870 --> 00:11:30,646
So we're at about a 0.7.
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00:11:30,670 --> 00:11:34,056
An advanced species
reaching Kardashev level two
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00:11:34,080 --> 00:11:35,486
or even three
223
00:11:35,510 --> 00:11:38,456
could create
highly advanced structures
224
00:11:38,480 --> 00:11:42,196
that can harness
the power of a star.
225
00:11:42,220 --> 00:11:45,066
If you get to be
an advanced enough civilization,
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00:11:45,090 --> 00:11:48,296
eventually if your
energy demands are so huge,
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00:11:48,320 --> 00:11:49,666
you might build solar panels
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00:11:49,690 --> 00:11:52,436
that you have enveloped
your star.
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00:11:52,460 --> 00:11:55,006
This was first thought of
by Freeman Dyson,
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00:11:55,030 --> 00:11:57,160
and so we call these
Dyson spheres.
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00:12:00,100 --> 00:12:02,446
If such epic engineering occurs
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00:12:02,470 --> 00:12:06,516
in other star systems
or even other galaxies,
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00:12:06,540 --> 00:12:08,386
could we pick up some evidence
234
00:12:08,410 --> 00:12:12,296
and then make first contact?
235
00:12:12,320 --> 00:12:13,996
The thing about
a Dyson sphere is that
236
00:12:14,020 --> 00:12:15,496
you've completely blocked
237
00:12:15,520 --> 00:12:18,266
all the light
coming out from a star,
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00:12:18,290 --> 00:12:20,436
except for the infrared
239
00:12:20,460 --> 00:12:22,666
because these panels are
absorbing that sunlight
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00:12:22,690 --> 00:12:23,906
and warming up.
241
00:12:23,930 --> 00:12:25,206
When you warm up an object,
242
00:12:25,230 --> 00:12:28,236
it gives off what's called
thermal infrared light.
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00:12:28,260 --> 00:12:30,946
You can scan the skies looking
for that signature
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00:12:30,970 --> 00:12:35,076
to see if there are
any Dyson spheres out there.
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00:12:35,100 --> 00:12:38,346
2015...
246
00:12:38,370 --> 00:12:41,656
NASA's wide field
infrared survey explorer
247
00:12:41,680 --> 00:12:44,826
scanned 100,000 nearby galaxies
248
00:12:44,850 --> 00:12:48,796
to locate advanced
Kardashev civilizations
249
00:12:48,820 --> 00:12:54,736
by observing infrared light
leaking away from Dyson spheres.
250
00:12:54,760 --> 00:12:56,536
They detected...
251
00:12:56,560 --> 00:12:57,706
Nothing.
252
00:12:57,730 --> 00:13:00,036
No such galaxy was found,
253
00:13:00,060 --> 00:13:03,306
so they didn't find
any infrared smoking gun.
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00:13:03,330 --> 00:13:05,516
Given our universe is so old,
255
00:13:05,540 --> 00:13:09,846
surely other civilizations
should have had time to evolve.
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00:13:09,870 --> 00:13:13,486
If so,
maybe we've simply missed them.
257
00:13:13,510 --> 00:13:16,626
It's entirely possible
that civilizations arose,
258
00:13:16,650 --> 00:13:19,056
tried to communicate
with the galaxy around them,
259
00:13:19,080 --> 00:13:22,226
and the problem was they were
asking too early for us.
260
00:13:22,250 --> 00:13:23,466
They're trying to
knock on our door,
261
00:13:23,490 --> 00:13:26,896
but our house wasn't built yet.
262
00:13:26,920 --> 00:13:29,506
Earth has been around
for under one-third
263
00:13:29,530 --> 00:13:34,206
of the universe's
13.8-billion-year lifespan,
264
00:13:34,230 --> 00:13:38,346
the human race
just 300,000 years,
265
00:13:38,370 --> 00:13:41,646
a relatively tiny window
of opportunity
266
00:13:41,670 --> 00:13:43,546
to make first contact.
267
00:13:43,570 --> 00:13:46,386
We've been looking at the sky
for tens of years,
268
00:13:46,410 --> 00:13:47,656
something like that.
269
00:13:47,680 --> 00:13:50,056
What is the likelihood
that at that exact moment
270
00:13:50,080 --> 00:13:54,196
someone is gonna be beaming
a signal toward us?
271
00:13:54,220 --> 00:13:56,426
Perhaps the universe prevents
272
00:13:56,450 --> 00:14:01,366
intelligent civilizations
from surviving for very long,
273
00:14:01,390 --> 00:14:04,436
making our chances
for first contact
274
00:14:04,460 --> 00:14:06,536
even more unlikely.
275
00:14:06,560 --> 00:14:07,776
Maybe there is
something out there
276
00:14:07,800 --> 00:14:10,776
that is filtering us
from seeing them.
277
00:14:10,800 --> 00:14:12,746
We actually call this
the great filter.
278
00:14:12,770 --> 00:14:14,016
Maybe there is something
that says,
279
00:14:14,040 --> 00:14:16,186
"yeah, you're not getting
past here."
280
00:14:16,210 --> 00:14:19,956
Rocky planets like ours
are ideal for hosting life,
281
00:14:19,980 --> 00:14:22,926
but they're fragile.
282
00:14:22,950 --> 00:14:25,996
And this fragility means
the universe
283
00:14:26,020 --> 00:14:29,226
could filter out
intelligent life quickly.
284
00:14:34,320 --> 00:14:37,006
We've discovered
very violent star explosions
285
00:14:37,030 --> 00:14:39,206
like gamma-ray bursts.
286
00:14:39,230 --> 00:14:41,876
These are powerful enough,
they may sterilize planets
287
00:14:41,900 --> 00:14:44,000
even across an entire galaxy.
288
00:14:47,670 --> 00:14:49,646
And even if intelligent species
289
00:14:49,670 --> 00:14:52,086
survive natural phenomenon,
290
00:14:52,110 --> 00:14:54,786
they may still be filtered out
291
00:14:54,810 --> 00:14:58,356
by hitting
the self-destruct button.
292
00:14:58,380 --> 00:15:00,696
As we can tell from
our own experience,
293
00:15:00,720 --> 00:15:03,726
the moment that we started
developing technology,
294
00:15:03,750 --> 00:15:06,736
we also developed the means
for our own destruction
295
00:15:06,760 --> 00:15:09,266
by changing the climate
on our planet,
296
00:15:09,290 --> 00:15:11,936
by developing weapons
of mass destruction.
297
00:15:11,960 --> 00:15:13,906
And so it's quite possible
that civilizations
298
00:15:13,930 --> 00:15:17,076
that are advanced enough
are short-lived.
299
00:15:17,100 --> 00:15:18,806
And if they're short-lived,
300
00:15:18,830 --> 00:15:21,146
that would explain why,
at this point in time,
301
00:15:21,170 --> 00:15:23,716
there are very few of them
that might be around
302
00:15:23,740 --> 00:15:25,540
to communicate with us.
303
00:15:27,780 --> 00:15:31,826
Finding the relics
of an extinct alien civilization
304
00:15:31,850 --> 00:15:36,166
could be the ultimate cosmic
warning for the human race.
305
00:15:36,190 --> 00:15:38,226
If we were to find
a civilization out there
306
00:15:38,250 --> 00:15:40,796
that may have destroyed
themselves by pollution
307
00:15:40,820 --> 00:15:42,136
or conflict,
308
00:15:42,160 --> 00:15:45,636
it would be almost like
staring into a mirror,
309
00:15:45,660 --> 00:15:48,106
and it would be
a very grim foreshadowing
310
00:15:48,130 --> 00:15:52,176
and maybe a lessons-learned
for us humans here on earth.
311
00:15:52,200 --> 00:15:55,686
We can only hope
that some advanced alien species
312
00:15:55,710 --> 00:15:58,410
escaped the universe's
deadly filter.
313
00:16:01,810 --> 00:16:04,686
But even if E.T.s still exist
out there,
314
00:16:04,710 --> 00:16:08,326
the odds are still stacked
against first contact.
315
00:16:13,520 --> 00:16:17,636
One other way that we've got
this alien-contact story
316
00:16:17,660 --> 00:16:22,306
a bit wrong is just down to
the laws of physics.
317
00:16:22,330 --> 00:16:25,576
Every day,
the physics of the cosmos
318
00:16:25,600 --> 00:16:28,246
makes our chances
of contact worse
319
00:16:28,270 --> 00:16:31,346
because our universe
is expanding,
320
00:16:31,370 --> 00:16:34,510
and it's expanding fast.
321
00:16:49,430 --> 00:16:52,376
February 2018...
322
00:16:52,400 --> 00:16:55,476
astrophysicists
at the university of Oklahoma
323
00:16:55,500 --> 00:16:58,676
find a potential series
of rogue planets
324
00:16:58,700 --> 00:17:01,540
3.8 billion light-years away.
325
00:17:04,140 --> 00:17:08,086
Ranging between the size
of our moon and Jupiter,
326
00:17:08,110 --> 00:17:10,786
these would be
the first alien worlds
327
00:17:10,810 --> 00:17:13,410
ever discovered
outside our galaxy...
328
00:17:16,450 --> 00:17:19,836
...and maybe the first of many.
329
00:17:19,860 --> 00:17:22,666
Our galaxy alone
has trillions of planets.
330
00:17:22,690 --> 00:17:25,466
The observable universe
has trillions of galaxies...
331
00:17:25,490 --> 00:17:27,436
it's estimated about 2 trillion.
332
00:17:27,460 --> 00:17:30,376
So trillions of trillions?
333
00:17:30,400 --> 00:17:33,046
Come on.
334
00:17:33,070 --> 00:17:35,216
But finding
exoplanets is no guarantee
335
00:17:35,240 --> 00:17:37,786
of finding alien life.
336
00:17:37,810 --> 00:17:41,016
And when it comes to contacting
extraterrestrials,
337
00:17:41,040 --> 00:17:44,686
our efforts
have met with silence.
338
00:17:44,710 --> 00:17:46,896
Our search for life
has come up empty.
339
00:17:46,920 --> 00:17:48,356
Do we need
to change our tactics?
340
00:17:48,380 --> 00:17:50,020
Are we doing something wrong?
341
00:17:52,660 --> 00:17:53,996
I think it's gonna be
very, very hard
342
00:17:54,020 --> 00:17:56,236
to find
extraterrestrial intelligence
343
00:17:56,260 --> 00:17:57,666
the way that
we're looking for it.
344
00:17:57,690 --> 00:18:00,876
We would have to get
really, really lucky.
345
00:18:00,900 --> 00:18:02,236
But I don't think
we're gonna get lucky.
346
00:18:02,260 --> 00:18:03,446
I think that if we want to know
347
00:18:03,470 --> 00:18:05,006
whether there's life out there
in the cosmos,
348
00:18:05,030 --> 00:18:06,700
we have to go visit it.
349
00:18:08,870 --> 00:18:10,546
We've sent
the new horizons probe
350
00:18:10,570 --> 00:18:15,286
billions of miles across
the solar system to Pluto.
351
00:18:15,310 --> 00:18:18,926
Perhaps one day we'll be able
to send spacecraft
352
00:18:18,950 --> 00:18:20,396
across the universe
353
00:18:20,420 --> 00:18:24,026
to search for alien life
on distant rogue planets.
354
00:18:30,630 --> 00:18:35,136
But if a craft left our galaxy
to visit these new worlds,
355
00:18:35,160 --> 00:18:37,346
its mission would be tough
356
00:18:37,370 --> 00:18:40,716
thanks to the physics
of the cosmos.
357
00:18:40,740 --> 00:18:44,316
From our perspective
here in the milky way,
358
00:18:44,340 --> 00:18:49,116
every galaxy is, on average,
receding away from us.
359
00:18:49,140 --> 00:18:51,426
It looks like nobody likes us
360
00:18:51,450 --> 00:18:55,926
and is trying to get as far away
from us as possible.
361
00:18:55,950 --> 00:19:01,896
This is because
our giant universe is expanding.
362
00:19:01,920 --> 00:19:04,136
When we talk about
the expanding universe,
363
00:19:04,160 --> 00:19:06,906
we don't mean that galaxies
are doing something active
364
00:19:06,930 --> 00:19:09,746
to run away from one another.
365
00:19:09,770 --> 00:19:13,046
Actually, it's the underlying
space that's expanding,
366
00:19:13,070 --> 00:19:14,616
and the galaxies
are embedded in that,
367
00:19:14,640 --> 00:19:16,816
and that's what causes
everything to move apart
368
00:19:16,840 --> 00:19:19,586
from everything else.
369
00:19:19,610 --> 00:19:21,056
The regions of the universe
370
00:19:21,080 --> 00:19:23,656
within 3 million light-years
of us
371
00:19:23,680 --> 00:19:27,626
are expanding
at around 45 miles a second.
372
00:19:27,650 --> 00:19:31,966
That's over 160,000 miles
an hour.
373
00:19:31,990 --> 00:19:33,796
So with our current technology,
374
00:19:33,820 --> 00:19:35,596
do we have any chance
of actually seeing
375
00:19:35,620 --> 00:19:37,666
what these other planets
are like?
376
00:19:37,690 --> 00:19:39,776
Well, think about the fastest
and farthest things
377
00:19:39,800 --> 00:19:42,236
we have right now,
like the voyager spacecraft.
378
00:19:42,260 --> 00:19:44,206
They've been in space
for more than 30 years
379
00:19:44,230 --> 00:19:48,446
going incredibly fast...
38,000 miles an hour.
380
00:19:48,470 --> 00:19:52,856
38,000 miles an hour is fast.
381
00:19:52,880 --> 00:19:55,086
But the closest galaxies to us
382
00:19:55,110 --> 00:19:59,556
are moving away at over
four times that speed.
383
00:19:59,580 --> 00:20:02,256
And the further away a probe
is sent to travel,
384
00:20:02,280 --> 00:20:04,926
the tougher its task.
385
00:20:04,950 --> 00:20:06,436
The thing about the expansion
of the universe
386
00:20:06,460 --> 00:20:08,596
is that the farther away
something is,
387
00:20:08,620 --> 00:20:11,536
the faster it's moving
away from you.
388
00:20:11,560 --> 00:20:14,806
The more distant two objects
are away from each other,
389
00:20:14,830 --> 00:20:17,406
the more space there is
between them,
390
00:20:17,430 --> 00:20:19,176
and the more space
there is between them,
391
00:20:19,200 --> 00:20:23,846
the more space there is
to expand.
392
00:20:23,870 --> 00:20:25,346
The rate at which
they're moving away
393
00:20:25,370 --> 00:20:27,016
is proportional
to their distance.
394
00:20:27,040 --> 00:20:30,426
If it's twice as far away,
it moves away twice as fast.
395
00:20:30,450 --> 00:20:31,826
It is three times farther away,
396
00:20:31,850 --> 00:20:34,896
and moves away
three times as fast.
397
00:20:34,920 --> 00:20:37,026
Scale it up to
the planets we've discovered
398
00:20:37,050 --> 00:20:39,996
3.8 billion light-years away,
399
00:20:40,020 --> 00:20:42,536
and thanks to the expansion
of the universe,
400
00:20:42,560 --> 00:20:46,336
those extra-galactic worlds
are moving away from us
401
00:20:46,360 --> 00:20:51,746
at over 49,000 miles per second.
402
00:20:51,770 --> 00:20:54,016
Imagine that you're a runner,
and you see the finish line.
403
00:20:54,040 --> 00:20:55,876
You're getting
a bit closer to it,
404
00:20:55,900 --> 00:20:58,846
but now, actually,
the track itself is expanding.
405
00:20:58,870 --> 00:21:01,286
And as the track expands
faster and faster,
406
00:21:01,310 --> 00:21:04,256
it's expanding faster
than you can possibly run.
407
00:21:04,280 --> 00:21:06,526
All of a sudden, that
finish line starts receding,
408
00:21:06,550 --> 00:21:08,920
and you're never, ever
gonna reach it.
409
00:21:12,520 --> 00:21:15,366
Say one day
we're able to build probes
410
00:21:15,390 --> 00:21:19,676
that travel at the fastest speed
physics allows...
411
00:21:19,700 --> 00:21:21,300
the speed of light.
412
00:21:23,870 --> 00:21:26,016
Even that might not be enough
413
00:21:26,040 --> 00:21:29,616
because sometimes
the universe itself
414
00:21:29,640 --> 00:21:31,716
doesn't play by the rules.
415
00:21:31,740 --> 00:21:34,916
It's not possible for things
to travel through space
416
00:21:34,940 --> 00:21:38,456
faster than the speed of light,
but it is possible for space
417
00:21:38,480 --> 00:21:40,896
to expand faster
than the speed of light.
418
00:21:40,920 --> 00:21:43,626
Everywhere we look,
we see very distant galaxies
419
00:21:43,650 --> 00:21:46,236
that are apparently receding,
or moving away from earth,
420
00:21:46,260 --> 00:21:48,436
at greater than
the speed of light.
421
00:21:48,460 --> 00:21:50,636
There are distant galaxies
we can see in the sky that,
422
00:21:50,660 --> 00:21:53,606
even if we were to build the
most advanced spaceship possible
423
00:21:53,630 --> 00:21:55,236
that could even move
at the speed of light,
424
00:21:55,260 --> 00:21:57,346
we could never get there.
425
00:21:57,370 --> 00:22:01,316
97% of the galaxies that we can
see in the distant sky
426
00:22:01,340 --> 00:22:05,186
are actually unreachable to us.
427
00:22:05,210 --> 00:22:07,516
So for all
the galaxies out there
428
00:22:07,540 --> 00:22:10,386
and all the planets
that could harbor life,
429
00:22:10,410 --> 00:22:12,980
most of them
are out of our reach.
430
00:22:15,720 --> 00:22:18,626
The physics of the universe
has dealt an immense blow
431
00:22:18,650 --> 00:22:20,596
to first contact.
432
00:22:20,620 --> 00:22:23,966
The true reality of the universe
will always be hidden from us
433
00:22:23,990 --> 00:22:27,806
because of this,
because of this expansion.
434
00:22:27,830 --> 00:22:29,976
The further we look
out into the universe,
435
00:22:30,000 --> 00:22:35,076
the more unlikely
first contact becomes.
436
00:22:35,100 --> 00:22:37,886
We might need
an advanced alien race
437
00:22:37,910 --> 00:22:41,316
to come and visit us instead.
438
00:22:41,340 --> 00:22:43,256
Suppose we get that lucky.
439
00:22:43,280 --> 00:22:48,426
Even then, would first contact
actually be feasible?
440
00:22:48,450 --> 00:22:49,926
We think aliens are like us.
441
00:22:49,950 --> 00:22:51,096
They're not.
442
00:22:51,120 --> 00:22:53,166
We're assuming that
the life is like us
443
00:22:53,190 --> 00:22:56,266
and that their planetary
environment is like ours.
444
00:22:56,290 --> 00:22:58,236
I don't think
that's gonna be the case
445
00:22:58,260 --> 00:23:00,976
for most of the life
in the universe.
446
00:23:01,000 --> 00:23:03,576
So, could extraterrestrials
447
00:23:03,600 --> 00:23:08,030
even survive first contact
with us and our planet?
448
00:23:22,650 --> 00:23:26,026
July 2019...
449
00:23:26,050 --> 00:23:29,706
the test satellite
discovered a new alien world
450
00:23:29,730 --> 00:23:32,266
31 light-years from us
451
00:23:32,290 --> 00:23:36,006
named GJ 357 d.
452
00:23:36,030 --> 00:23:38,906
At over six times the mass
of our home planet,
453
00:23:38,930 --> 00:23:41,376
it's thought to be
a super earth.
454
00:23:41,400 --> 00:23:43,446
And from our observations,
455
00:23:43,470 --> 00:23:47,286
super earths appear to be
prime real estate.
456
00:23:47,310 --> 00:23:48,916
What we see is that
the most common type
457
00:23:48,940 --> 00:23:52,256
of terrestrial planet
is what we call a super earth.
458
00:23:52,280 --> 00:23:54,296
So that means
it's a terrestrial planet,
459
00:23:54,320 --> 00:23:57,526
but much more massive.
460
00:23:57,550 --> 00:24:00,496
More massive can mean
more gravity,
461
00:24:00,520 --> 00:24:04,936
creating a planetary environment
completely unlike our own
462
00:24:04,960 --> 00:24:08,706
and life completely unlike ours.
463
00:24:08,730 --> 00:24:10,746
If they're on
the surface of a super earth,
464
00:24:10,770 --> 00:24:14,446
it could be that gravity
is gonna be way stronger.
465
00:24:14,470 --> 00:24:17,316
So these aliens
aren't gonna be very tall,
466
00:24:17,340 --> 00:24:21,086
but they are gonna be
very strong.
467
00:24:21,110 --> 00:24:23,656
Super earths are just
one of the many avenues
468
00:24:23,680 --> 00:24:25,756
the universe creates.
469
00:24:25,780 --> 00:24:29,196
There are other exoplanets
orbiting red stars
470
00:24:29,220 --> 00:24:31,596
10 times smaller than our sun
471
00:24:31,620 --> 00:24:34,396
and others making binary systems
472
00:24:34,420 --> 00:24:38,506
comprising two stars
instead of one.
473
00:24:38,530 --> 00:24:42,736
We see planets of all shapes
and sizes around stars
474
00:24:42,760 --> 00:24:46,846
of all shapes and sizes,
of all sorts of configurations.
475
00:24:46,870 --> 00:24:52,316
The potential for life
is much more rich and varied
476
00:24:52,340 --> 00:24:54,416
than we ever thought before.
477
00:24:54,440 --> 00:24:59,156
Retro rockets
five and six fired.
478
00:24:59,180 --> 00:25:00,596
Images of science fiction
479
00:25:00,620 --> 00:25:03,826
have fueled numerous fantasies
of first contact,
480
00:25:03,850 --> 00:25:06,236
but our knowledge
of the universe suggests
481
00:25:06,260 --> 00:25:09,436
reality could be
far, far stranger.
482
00:25:09,460 --> 00:25:10,836
If anything,
Hollywood has kind of
483
00:25:10,860 --> 00:25:12,706
constrained our imagination
484
00:25:12,730 --> 00:25:15,206
in terms of presenting
so many aliens
485
00:25:15,230 --> 00:25:17,206
that basically look like,
you know,
486
00:25:17,230 --> 00:25:19,546
humans wearing a rubber suit
or something.
487
00:25:19,570 --> 00:25:20,870
Lower landing legs.
488
00:25:23,040 --> 00:25:26,586
We have to, have to,
let go of this obsession
489
00:25:26,610 --> 00:25:28,916
that they're gonna be
anything like us.
490
00:25:28,940 --> 00:25:32,556
So if we're looking for
two-legged dudes, forget it.
491
00:25:39,450 --> 00:25:42,136
Say an intelligent
alien species lives
492
00:25:42,160 --> 00:25:44,136
in our stellar neighborhood
493
00:25:44,160 --> 00:25:46,776
and wants to make
first contact with us.
494
00:25:46,800 --> 00:25:49,506
If that alien evolved
on a super earth
495
00:25:49,530 --> 00:25:53,246
or orbited a red star
instead of a yellow one,
496
00:25:53,270 --> 00:25:55,446
it's wildly different biology
497
00:25:55,470 --> 00:25:58,086
may prevent it
from ever setting foot,
498
00:25:58,110 --> 00:26:00,770
or tentacle, on planet earth.
499
00:26:04,480 --> 00:26:06,596
When you look at life
here on earth,
500
00:26:06,620 --> 00:26:08,526
it's almost as if it was
custom-made
501
00:26:08,550 --> 00:26:10,326
for this temperature,
for these elements,
502
00:26:10,350 --> 00:26:11,726
for this environment.
503
00:26:11,750 --> 00:26:14,366
An exoplanet with conditions
to support life
504
00:26:14,390 --> 00:26:16,166
could still be
completely different
505
00:26:16,190 --> 00:26:18,566
than life here on earth.
506
00:26:18,590 --> 00:26:20,576
What are things gonna be
like on an alien world
507
00:26:20,600 --> 00:26:23,376
which has a little bit
more potassium
508
00:26:23,400 --> 00:26:25,176
or is warmer than average
on earth
509
00:26:25,200 --> 00:26:27,346
or has a thicker atmosphere?
510
00:26:27,370 --> 00:26:29,416
Each one of these
small variations
511
00:26:29,440 --> 00:26:34,386
can mean a completely different
ecosystem.
512
00:26:34,410 --> 00:26:36,756
So could an alien organism
513
00:26:36,780 --> 00:26:40,810
really adapt to our ecosystem
when it lands on earth?
514
00:26:43,090 --> 00:26:44,896
Maybe we haven't made
first contact
515
00:26:44,920 --> 00:26:48,366
because they can't
actually visit us.
516
00:26:48,390 --> 00:26:50,236
They could step
through the airlock
517
00:26:50,260 --> 00:26:52,466
of their spaceship
and onto the earth
518
00:26:52,490 --> 00:26:55,536
and just find something toxic
with our environment,
519
00:26:55,560 --> 00:26:57,446
some some reason
they're not compatible
520
00:26:57,470 --> 00:26:59,346
with the surface of the earth.
521
00:26:59,370 --> 00:27:03,246
It's almost as if
the universe is out there
522
00:27:03,270 --> 00:27:07,316
deliberately trying to stop us
meeting any aliens.
523
00:27:07,340 --> 00:27:09,056
Biology creates another obstacle
524
00:27:09,080 --> 00:27:11,086
for making first contact,
525
00:27:11,110 --> 00:27:14,296
but as planetary scientist
Jani Radebough finds,
526
00:27:14,320 --> 00:27:17,126
even life on earth
can get pretty weird,
527
00:27:17,150 --> 00:27:18,966
taking extreme measures to adapt
528
00:27:18,990 --> 00:27:21,796
to a potentially hostile
environment.
529
00:27:21,820 --> 00:27:23,336
This is the great salt lake.
530
00:27:23,360 --> 00:27:25,106
It is the remains
of what used to be
531
00:27:25,130 --> 00:27:27,236
a much larger lake in the past.
532
00:27:27,260 --> 00:27:32,906
And when it evaporated away,
it left behind all of the salt.
533
00:27:32,930 --> 00:27:35,916
The great salt lake
is nearly 10 times saltier
534
00:27:35,940 --> 00:27:38,146
than earth's oceans.
535
00:27:38,170 --> 00:27:39,856
The extreme salt content
536
00:27:39,880 --> 00:27:44,426
should make it an inhospitable
place for life.
537
00:27:44,450 --> 00:27:48,680
Despite this, there are
organisms thriving in the water.
538
00:27:50,590 --> 00:27:52,896
As we look at life
in this vast lake
539
00:27:52,920 --> 00:27:55,396
and find that there are billions
of microbes living here
540
00:27:55,420 --> 00:27:58,606
in this unexpected environment,
then we start to realize,
541
00:27:58,630 --> 00:28:01,806
well, life forms in ways
that we just don't expect,
542
00:28:01,830 --> 00:28:03,776
in places we don't expect.
543
00:28:03,800 --> 00:28:07,716
Microbial life
known as extremophiles
544
00:28:07,740 --> 00:28:11,416
have developed an ingenious way
to survive in the lake.
545
00:28:11,440 --> 00:28:13,516
Well, they actually use
these solar-powered pumps
546
00:28:13,540 --> 00:28:15,816
to pull the salt
out of their cells
547
00:28:15,840 --> 00:28:18,126
so that they can operate
more normally.
548
00:28:18,150 --> 00:28:19,526
But in order to do that,
they have to live
549
00:28:19,550 --> 00:28:20,826
very close to the surface,
550
00:28:20,850 --> 00:28:23,726
which means they get
a huge amount of U.V. radiation.
551
00:28:23,750 --> 00:28:26,836
So all this pink color
that you see behind me
552
00:28:26,860 --> 00:28:29,136
is actually the pink
of the organisms,
553
00:28:29,160 --> 00:28:31,206
and it's sort of like
a built-in sunscreen
554
00:28:31,230 --> 00:28:34,606
that helps protect them against
the U.V. radiation.
555
00:28:34,630 --> 00:28:38,476
Extremophiles are
rewriting our expectations
556
00:28:38,500 --> 00:28:41,216
of where life can survive
on earth.
557
00:28:41,240 --> 00:28:45,946
Could alien biology be much
more resilient than we think?
558
00:28:45,970 --> 00:28:48,716
These extremophiles
should be a little reminder
559
00:28:48,740 --> 00:28:52,426
that we haven't been
thinking big enough.
560
00:28:52,450 --> 00:28:56,666
Maybe E.T. Could readily
adapt to our environment,
561
00:28:56,690 --> 00:28:59,626
or perhaps they've got
other ideas,
562
00:28:59,650 --> 00:29:04,436
using technology to overcome
any biological barriers.
563
00:29:04,460 --> 00:29:09,136
Maybe the first aliens we meet
will be robots.
564
00:29:09,160 --> 00:29:11,306
They can build
much more powerful life
565
00:29:11,330 --> 00:29:14,016
if they don't limit themselves
to meat bags.
566
00:29:14,040 --> 00:29:15,776
Advanced aliens could have left
567
00:29:15,800 --> 00:29:18,916
their biological brains
and bodies behind,
568
00:29:18,940 --> 00:29:24,486
traveling instead as
mobile artificial intelligence.
569
00:29:24,510 --> 00:29:27,056
We tend to think of
intelligence and consciousness
570
00:29:27,080 --> 00:29:29,296
as something mysterious
that can only exist
571
00:29:29,320 --> 00:29:31,966
inside of biological organisms
like us
572
00:29:31,990 --> 00:29:35,996
and somehow therefore
can't be copied.
573
00:29:36,020 --> 00:29:39,066
But what's given us the whole
a.I. Revolution, right...
574
00:29:39,090 --> 00:29:40,276
the idea that, no,
575
00:29:40,300 --> 00:29:42,436
intelligence and probably
consciousness, too,
576
00:29:42,460 --> 00:29:44,376
is just information processing,
577
00:29:44,400 --> 00:29:47,016
and it's just the information
processing that really matters.
578
00:29:47,040 --> 00:29:50,086
Perhaps an alien would be
able to download
579
00:29:50,110 --> 00:29:53,186
its consciousness
into some sort of computer
580
00:29:53,210 --> 00:29:58,386
and travel as
a disembodied consciousness.
581
00:29:58,410 --> 00:30:01,510
In this state,
you'd be essentially immortal.
582
00:30:06,020 --> 00:30:09,096
So it's possible an
advanced species could find ways
583
00:30:09,120 --> 00:30:13,536
to face the challenges
of first contact.
584
00:30:13,560 --> 00:30:16,776
But if an alien civilization
is out there
585
00:30:16,800 --> 00:30:18,506
and more advanced than us,
586
00:30:18,530 --> 00:30:22,476
could there be
an even bigger issue at play?
587
00:30:22,500 --> 00:30:25,486
Maybe the reason
that intelligent aliens
588
00:30:25,510 --> 00:30:28,386
haven't ever come to the earth
to visit us
589
00:30:28,410 --> 00:30:32,126
is maybe we're just
not that interesting.
590
00:30:32,150 --> 00:30:35,126
So maybe the biggest
barrier for first contact
591
00:30:35,150 --> 00:30:39,190
is the fact that aliens
don't actually want to meet us.
592
00:30:55,800 --> 00:30:58,616
In the movies,
first contact usually leads
593
00:30:58,640 --> 00:31:01,316
to an alien invasion.
594
00:31:01,340 --> 00:31:03,380
Cities get zapped.
595
00:31:09,080 --> 00:31:12,050
Humanity faces annihilation.
596
00:31:12,950 --> 00:31:15,336
Maybe a visit from E.T.
597
00:31:15,360 --> 00:31:18,236
Isn't such a good thing,
after all.
598
00:31:18,260 --> 00:31:21,976
Imagine if we if we got
an intergalactic e-mail,
599
00:31:22,000 --> 00:31:25,976
so from, you know,
superioraliencivilization. Org,
600
00:31:26,000 --> 00:31:29,216
saying, "hey, we're gonna
show up in 30 years."
601
00:31:29,240 --> 00:31:30,616
Would we just be like,
"oh, all right,
602
00:31:30,640 --> 00:31:33,386
let's get back to
watching our reality TV shows
603
00:31:33,410 --> 00:31:34,956
and worry about that
when they get here"?
604
00:31:34,980 --> 00:31:37,626
No, we would seriously
freak out.
605
00:31:37,650 --> 00:31:41,256
People might freak out,
606
00:31:41,280 --> 00:31:44,526
but the truth is we've been
sign-posting our location
607
00:31:44,550 --> 00:31:47,036
into the cosmos for decades.
608
00:31:47,060 --> 00:31:51,066
The earth has been
a detectably technological world
609
00:31:51,090 --> 00:31:52,566
for about 100 years.
610
00:31:52,590 --> 00:31:55,006
We've been broadcasting signals,
611
00:31:55,030 --> 00:32:00,246
and yet, that apparently hasn't
attracted anyone's attention.
612
00:32:00,270 --> 00:32:01,976
It's pretty noteworthy
613
00:32:02,000 --> 00:32:04,516
that none of them
has shown any interest,
614
00:32:04,540 --> 00:32:06,956
when they could have
turned earth into a parking lot
615
00:32:06,980 --> 00:32:09,386
if they wanted, right?
616
00:32:09,410 --> 00:32:12,356
Perhaps no one
has redeveloped planet earth
617
00:32:12,380 --> 00:32:15,026
because an advanced civilization
618
00:32:15,050 --> 00:32:18,666
simply doesn't want to
make first contact.
619
00:32:18,690 --> 00:32:20,196
Frankly, if they're
that intelligent,
620
00:32:20,220 --> 00:32:23,096
they're not gonna be
very interested in us.
621
00:32:23,120 --> 00:32:26,206
So maybe that's why they haven't
bothered to make contact.
622
00:32:26,230 --> 00:32:28,406
And if the alien
is that advanced,
623
00:32:28,430 --> 00:32:31,546
we're probably not
very interesting to it.
624
00:32:31,570 --> 00:32:33,716
It's a little bit like,
you know,
625
00:32:33,740 --> 00:32:38,040
wandering around outside
and seeing ants on the sidewalk.
626
00:32:40,080 --> 00:32:43,686
Alien invasion makes
for great science fiction,
627
00:32:43,710 --> 00:32:45,826
but what do we actually
have on earth
628
00:32:45,850 --> 00:32:49,296
that's worth
all that alien effort?
629
00:32:49,320 --> 00:32:50,996
How realistic really are
630
00:32:51,020 --> 00:32:53,966
these depictions from Hollywood?
631
00:32:53,990 --> 00:32:59,666
One common trope is the aliens
coming to devour the human race.
632
00:32:59,690 --> 00:33:03,106
But the science doesn't really
support this being possible.
633
00:33:03,130 --> 00:33:09,016
Would an alien even be able
to digest the human body?
634
00:33:09,040 --> 00:33:12,286
When eating,
enzymes in our digestive system
635
00:33:12,310 --> 00:33:15,386
break down molecules
in our food.
636
00:33:15,410 --> 00:33:19,656
The food we can eat, and these
enzymes are very specific
637
00:33:19,680 --> 00:33:23,596
to the molecules
they can attack and break down.
638
00:33:23,620 --> 00:33:27,396
The same rules would apply
to a hungry alien.
639
00:33:27,420 --> 00:33:29,066
To be able to digest us
640
00:33:29,090 --> 00:33:31,066
and for us to be nutritious
for them,
641
00:33:31,090 --> 00:33:33,936
we'd have to have a very, very
similar biochemistry
642
00:33:33,960 --> 00:33:36,676
to what exists
on the alien's home world,
643
00:33:36,700 --> 00:33:39,846
what their bodies
have adapted to.
644
00:33:39,870 --> 00:33:42,046
So it seems highly unlikely
645
00:33:42,070 --> 00:33:44,616
that aliens would come
looking for food.
646
00:33:44,640 --> 00:33:47,256
But how about a drink?
647
00:33:47,280 --> 00:33:50,226
In order for life as we know it
to exist,
648
00:33:50,250 --> 00:33:52,586
one needs liquid water.
649
00:33:52,610 --> 00:33:55,856
If aliens live
on a barren desert planet,
650
00:33:55,880 --> 00:34:00,536
a water world like ours
could be highly attractive.
651
00:34:00,560 --> 00:34:03,196
While we call ourselves
the blue planet,
652
00:34:03,220 --> 00:34:05,836
our oceans are not unique.
653
00:34:05,860 --> 00:34:10,606
The universe offers
far greater water resources.
654
00:34:10,630 --> 00:34:12,276
In our solar system,
we're finding that
655
00:34:12,300 --> 00:34:18,546
most of the liquid water exists
in moons around the gas giants.
656
00:34:18,570 --> 00:34:20,956
We believe Jupiter's moon Europa
657
00:34:20,980 --> 00:34:25,456
has a layer of water ice
around 15 miles thick
658
00:34:25,480 --> 00:34:29,526
floating on an ocean
up to 100 miles deep.
659
00:34:29,550 --> 00:34:32,866
This single moon may have
twice as much water
660
00:34:32,890 --> 00:34:36,196
as all earth's oceans combined.
661
00:34:36,220 --> 00:34:39,536
Europa is the water world
of our solar system
662
00:34:39,560 --> 00:34:41,176
and not the earth.
663
00:34:41,200 --> 00:34:44,576
So if you were an alien
looking for water,
664
00:34:44,600 --> 00:34:47,946
you wouldn't bother going to
a big planet like the earth
665
00:34:47,970 --> 00:34:50,716
to suck it up through
some kind of giant straw.
666
00:34:50,740 --> 00:34:52,846
You'd go to
the outer solar system.
667
00:34:52,870 --> 00:34:56,956
You might harvest icy moons.
668
00:34:56,980 --> 00:34:58,626
Instead of working against
669
00:34:58,650 --> 00:35:01,856
the powerful gravitational pull
of earth,
670
00:35:01,880 --> 00:35:05,466
an alien race could draw water
from Europa,
671
00:35:05,490 --> 00:35:09,466
where gravity is almost
10 times weaker.
672
00:35:09,490 --> 00:35:13,406
So what other resources
have we got to offer?
673
00:35:13,430 --> 00:35:17,946
Maybe aliens come to strip mine
the earth's crust
674
00:35:17,970 --> 00:35:22,646
for metals... iron or titanium
or platinum.
675
00:35:22,670 --> 00:35:24,116
Aliens might use these metals
676
00:35:24,140 --> 00:35:26,346
for exactly the same things
that we do...
677
00:35:26,370 --> 00:35:30,010
for building spaceships,
for building their technology.
678
00:35:32,480 --> 00:35:34,296
Such materials could be useful
679
00:35:34,320 --> 00:35:38,796
for any alien civilization
short on mineral resources.
680
00:35:38,820 --> 00:35:41,496
Problem is,
a lot of our planet's metals
681
00:35:41,520 --> 00:35:45,006
are buried deep
in the earth's interior.
682
00:35:45,030 --> 00:35:48,536
When the earth formed,
the great deal of its iron
683
00:35:48,560 --> 00:35:50,946
sunk down into the core
of our planet
684
00:35:50,970 --> 00:35:52,476
and took a lot of metals
with it.
685
00:35:52,500 --> 00:35:56,446
So they're actually quite hard
to mine on the earth.
686
00:35:56,470 --> 00:35:58,986
An alien race would be
better off prospecting
687
00:35:59,010 --> 00:36:04,686
for more accessible minerals
situated in the asteroid belt.
688
00:36:04,710 --> 00:36:07,596
In the asteroid belt, there's
an asteroid called psyche,
689
00:36:07,620 --> 00:36:09,996
which is made up
of pure iron nickel,
690
00:36:10,020 --> 00:36:12,796
just like the core of the earth.
691
00:36:12,820 --> 00:36:16,036
Psyche provides a near-150-mile
692
00:36:16,060 --> 00:36:19,366
exposed strip of iron nickel,
693
00:36:19,390 --> 00:36:24,446
yet another reason E.T.
Wouldn't need to bother with us.
694
00:36:24,470 --> 00:36:26,876
For my money,
none of those reasons
695
00:36:26,900 --> 00:36:29,546
would draw aliens to earth.
696
00:36:29,570 --> 00:36:32,886
All these things can be found
far more easily elsewhere.
697
00:36:32,910 --> 00:36:34,816
The possibility of first contact
698
00:36:34,840 --> 00:36:37,926
is beginning to sound
increasingly remote.
699
00:36:37,950 --> 00:36:40,426
The universe throws up
massive barriers
700
00:36:40,450 --> 00:36:44,796
stopping us from communicating
with an intelligent alien race,
701
00:36:44,820 --> 00:36:48,196
a race that might very well
have absolutely no interest
702
00:36:48,220 --> 00:36:50,096
in contacting us,
703
00:36:50,120 --> 00:36:53,266
unless, of course,
they already have.
704
00:36:53,290 --> 00:36:55,306
Is it possible that
there have been alien signals
705
00:36:55,330 --> 00:36:58,776
that we've already detected but
we didn't realize what they are?
706
00:36:58,800 --> 00:37:00,346
Scientists have discovered
707
00:37:00,370 --> 00:37:05,146
a powerful cosmic signal
that they cannot explain.
708
00:37:05,170 --> 00:37:08,840
Could this finally be
first contact?
709
00:37:23,290 --> 00:37:26,706
July 2018...
710
00:37:26,730 --> 00:37:29,176
the chime telescope
in British Columbia
711
00:37:29,200 --> 00:37:32,246
detected a short flash
of radio energy
712
00:37:32,270 --> 00:37:34,446
quicker than a blinking eye.
713
00:37:34,470 --> 00:37:38,216
It's called a fast radio burst.
714
00:37:38,240 --> 00:37:41,056
These are intensely powerful,
very, very short
715
00:37:41,080 --> 00:37:43,786
lived radio bursts
that can be 1,000 times brighter
716
00:37:43,810 --> 00:37:45,856
than the sun
at radio wavelengths,
717
00:37:45,880 --> 00:37:49,480
that arrive and disappear
in an instant.
718
00:37:52,190 --> 00:37:54,866
Most fast radio bursts
are one-offs,
719
00:37:54,890 --> 00:37:59,236
blinking into existence,
then disappearing forever.
720
00:37:59,260 --> 00:38:01,076
But not this one.
721
00:38:01,100 --> 00:38:05,746
A few days later, scientists
caught the flash again.
722
00:38:05,770 --> 00:38:07,976
The amount of energy
that it takes to produce
723
00:38:08,000 --> 00:38:09,176
a burst like this,
724
00:38:09,200 --> 00:38:10,986
for us to detect it
here on earth
725
00:38:11,010 --> 00:38:14,256
from billions of light-years,
is immense.
726
00:38:14,280 --> 00:38:17,056
And we've run across
things like this before...
727
00:38:17,080 --> 00:38:19,356
exploding stars,
gamma-ray bursts.
728
00:38:19,380 --> 00:38:21,756
These are all
very strange objects,
729
00:38:21,780 --> 00:38:23,696
but that does not explain these
730
00:38:23,720 --> 00:38:26,896
because some of these
fast radio bursts repeat.
731
00:38:26,920 --> 00:38:29,666
So whatever it is that can
generate this kind of energy,
732
00:38:29,690 --> 00:38:31,460
it can do it more than once.
733
00:38:36,130 --> 00:38:39,146
Light comes in
many different wavelengths.
734
00:38:39,170 --> 00:38:41,946
Radio waves are the longest,
making them good
735
00:38:41,970 --> 00:38:44,100
for long-distance communication.
736
00:38:46,370 --> 00:38:49,156
We've used radio waves
for over 100 years,
737
00:38:49,180 --> 00:38:52,926
from wireless radio to TV,
738
00:38:52,950 --> 00:38:55,556
from cellphone calls
to communications
739
00:38:55,580 --> 00:38:58,096
with space probes.
740
00:38:58,120 --> 00:39:01,296
Could alien civilizations
be using radio waves,
741
00:39:01,320 --> 00:39:04,566
but on a much larger scale?
742
00:39:04,590 --> 00:39:07,336
What if we already intercepted
alien communications,
743
00:39:07,360 --> 00:39:10,476
but we just don't know it?
744
00:39:10,500 --> 00:39:12,346
Our radio and television signals
745
00:39:12,370 --> 00:39:17,216
only use a very narrow band
of the radio spectrum.
746
00:39:17,240 --> 00:39:19,916
Fast radio bursts are different,
747
00:39:19,940 --> 00:39:22,186
and that's a problem.
748
00:39:22,210 --> 00:39:24,156
Here's the thing
about fast radio bursts...
749
00:39:24,180 --> 00:39:26,626
they are emitting
a broad range of wavelengths,
750
00:39:26,650 --> 00:39:28,756
so it's not the best way
to communicate.
751
00:39:28,780 --> 00:39:33,626
If these are aliens,
they're not very smart aliens.
752
00:39:33,650 --> 00:39:36,596
It turns out
that broad-range wavelengths
753
00:39:36,620 --> 00:39:38,466
are easy to distort.
754
00:39:38,490 --> 00:39:42,436
There is a very thin gas
out there between the stars,
755
00:39:42,460 --> 00:39:44,176
and when you emit radio waves,
756
00:39:44,200 --> 00:39:46,606
the radio waves interact
with this gas.
757
00:39:46,630 --> 00:39:47,946
And the way they interact
758
00:39:47,970 --> 00:39:51,546
depends on the wavelength
you're talking about.
759
00:39:51,570 --> 00:39:53,756
If you use a broad range
of wavelengths
760
00:39:53,780 --> 00:39:56,256
to send a signal
across interstellar space,
761
00:39:56,280 --> 00:39:57,726
by the time
somebody receives it,
762
00:39:57,750 --> 00:39:59,950
it can be a little distorted
and weird.
763
00:40:02,820 --> 00:40:05,396
If aliens are
sending out radio bursts,
764
00:40:05,420 --> 00:40:09,836
the signal would get so degraded
that by the time it reaches us,
765
00:40:09,860 --> 00:40:13,876
we wouldn't be able
to decipher it.
766
00:40:13,900 --> 00:40:18,076
As a calling card,
not incredibly useful.
767
00:40:18,100 --> 00:40:20,276
Whether these
mysterious bursts really are
768
00:40:20,300 --> 00:40:24,686
aliens trying to say hello
or just a natural phenomenon,
769
00:40:24,710 --> 00:40:27,156
this is not first contact,
770
00:40:27,180 --> 00:40:29,116
at least not yet.
771
00:40:29,140 --> 00:40:30,726
I want to be careful here,
right?
772
00:40:30,750 --> 00:40:33,726
I'm not a naysayer.
I'm not gonna pooh-pooh aliens.
773
00:40:33,750 --> 00:40:35,596
But, you know, let's go through
the other things first
774
00:40:35,620 --> 00:40:38,266
because the universe is filled
with weird stuff,
775
00:40:38,290 --> 00:40:39,826
and let's see what that is.
776
00:40:39,850 --> 00:40:42,996
And if we eliminate all those,
and all that's left is aliens,
777
00:40:43,020 --> 00:40:45,466
yeah, let's talk.
778
00:40:45,490 --> 00:40:49,206
If extraterrestrial
species are out there,
779
00:40:49,230 --> 00:40:51,746
our universe makes it
extremely difficult
780
00:40:51,770 --> 00:40:54,776
to contact them.
781
00:40:54,800 --> 00:40:57,116
But in spite
of all the obstacles,
782
00:40:57,140 --> 00:40:59,100
maybe there's still hope.
783
00:41:01,410 --> 00:41:03,886
We once thought that
there could be 10,000
784
00:41:03,910 --> 00:41:07,956
intelligent civilizations
in the milky way alone.
785
00:41:07,980 --> 00:41:11,466
Now we know that our cosmos
is filled with planets
786
00:41:11,490 --> 00:41:14,066
just waiting to be found.
787
00:41:14,090 --> 00:41:16,166
Our technology is evolving.
788
00:41:16,190 --> 00:41:18,406
Searches are expanding.
789
00:41:18,430 --> 00:41:22,236
The truth about our mission
to make first contact is this...
790
00:41:22,260 --> 00:41:27,576
we are only
just getting started.
791
00:41:27,600 --> 00:41:32,186
I'd love for tomorrow morning
some sort of interstellar tweet
792
00:41:32,210 --> 00:41:33,886
to be beamed at the earth,
793
00:41:33,910 --> 00:41:35,386
and we would then realize
794
00:41:35,410 --> 00:41:38,686
that we are not alone
in this cosmos.
795
00:41:38,710 --> 00:41:39,926
I'm all ready to celebrate.
796
00:41:39,950 --> 00:41:42,656
Here we have already
a champagne on ice
797
00:41:42,680 --> 00:41:46,026
to pop when they find it.
798
00:41:46,050 --> 00:41:49,066
Scientists really do
hope we find evidence
799
00:41:49,090 --> 00:41:51,266
of extraterrestrial life
someday.
800
00:41:51,290 --> 00:41:54,636
We have observatories and
satellites that look at the sky.
801
00:41:54,660 --> 00:41:58,476
All day, all night, every day.
802
00:41:58,500 --> 00:42:01,946
The discovery of alien life
would simultaneously be,
803
00:42:01,970 --> 00:42:03,776
in a way, unsurprising
804
00:42:03,800 --> 00:42:07,256
and yet the greatest discovery
in all of human history.
805
00:42:07,280 --> 00:42:09,116
Even if life
is really, really rare,
806
00:42:09,140 --> 00:42:11,056
the universe
is really, really big,
807
00:42:11,080 --> 00:42:14,396
and so there could be countless
alien civilizations out there.
808
00:42:14,420 --> 00:42:17,196
But the actual discovery
or confirmation of that...
809
00:42:17,220 --> 00:42:19,966
I can think of no greater
scientific discovery.
810
00:42:19,990 --> 00:42:23,136
It would quite literally change
our entire civilization.