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Across the universe,
there are stellar systems
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completely unlike our own
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containing two stars
instead of one.
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00:00:11,070 --> 00:00:16,232
Our sun isn't so
typical after all.
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00:00:16,232 --> 00:00:20,348
Even the most fantastical
imaginings of Sci-Fi writers,
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00:00:20,348 --> 00:00:24,304
it doesn't even come close
to what nature can produce.
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These are binary stars,
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and they create
some of the deadliest
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places in the universe.
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Any planet that's close by
is gonna get cooked.
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00:00:38,668 --> 00:00:41,621
But some binaries may
have an unexpected trick
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up their sleeve,
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one that transforms
our search for alien worlds.
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When it comes to the occurrence
of life on a planet,
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it may very well be
that having two stars
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could be a lot better
than having one.
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Imagine living in
the light of two suns.
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Are we missing out?
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Could two stars
be better than one?
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Look at our sky.
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You see the same
solitary sun rising
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and setting day after day.
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But throughout the galaxy,
alien civilizations
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could be enjoying twin
sunrises and twin sunsets
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because they orbit
two stars instead of one.
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Half the star systems
in our galaxy are binary stars.
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It appears to be a common root
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of stellar formation
and evolution.
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00:01:59,805 --> 00:02:02,918
So, we can't just focus
on the single-star systems
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and think we have
a complete picture.
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The complete picture
may include planets
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orbiting binary stars...
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Alien worlds rooted
in Sci-Fi fantasies
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00:02:17,254 --> 00:02:21,812
that have inspired
scientists for decades.
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If there is one single
event that can most link
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to why I became a scientist,
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it was going to see
the original "star wars" movie,
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"episode iv,"
when I was 7 years old.
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And I can remember that scene
of Luke Skywalker
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standing out on
the deserts of Tatooine,
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and there's a double sunset.
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The music swells up, and I
can remember my 7-year-old heart
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kind of leaping out of my chest.
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That's the moment
when I realized I wanted
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to be an astronomer.
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Could two stars
be even better than one?
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Living on a planet that orbits
a binary system
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could be really exciting.
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Imagine seeing two stars
in the sky every day.
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That's pretty cool.
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00:02:59,831 --> 00:03:01,006
But you know what?
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Sometimes it can get
too exciting.
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Some binary systems
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are not
places for Sci-Fi adventures.
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They're horror stories.
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In some cases,
the interactions between
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binary stars get deadly.
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The stars can actually
turn on each other.
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Binary stars are kind of
like siblings.
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00:03:23,284 --> 00:03:25,723
They're born together
and they grow up together.
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But sometimes one of
those siblings can be evil.
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This evil sibling is a pulsar.
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It starts life billions
of years ago
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as the big brother in a binary.
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But something transforms
it into a monster.
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When a large star dies,
it will end its life
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as a supernova
with a crazy big explosion.
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And a pulsar
is what's left behind.
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This big brother's
death triggers
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one of the biggest
bangs in the universe.
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In the midst of the explosion,
the star's core collapses,
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crushing material down
into a hyper-dense ball.
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Rapid rotation and intense
magnetic fields
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jump start twin beams
of deadly radiation,
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00:04:28,401 --> 00:04:30,708
and the pulsar comes to life.
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The pulsar has to be one of
the most amazing monsters
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that the universe
has ever thought of.
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They're only about
10 miles across,
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and yet they contain
the mass of at least the sun
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or even sometimes twice the sun.
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The pulsar's sibling
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is lucky
to live through the chaos
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of the nearby supernova.
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But it now orbits
a brother from hell
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in a cosmic no-man's land.
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00:05:02,303 --> 00:05:04,481
Orbiting a pulsar would be
a pretty rough experience
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00:05:04,481 --> 00:05:06,659
for any object in its vicinity.
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Pulsars are spitting out
tremendous amounts
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00:05:08,838 --> 00:05:11,147
of lethal radiation
from their poles.
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00:05:13,496 --> 00:05:16,508
It wouldn't be good to live
on a planetary system
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near a pulsar
because you are gonna be pointed
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00:05:19,120 --> 00:05:23,839
toward a laser
of planetary death.
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00:05:23,849 --> 00:05:28,095
But these death rays
can't last forever.
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Within a few million years,
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the pulsar spins itself
to death.
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With its evil sibling dead,
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can the other star
finally live in peace?
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Stars, as I tell students,
are a lot like people.
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As they age, they tend
to expand a bit.
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For a single star, it can expand
and be as big as it likes.
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But in a binary,
there's a problem.
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Now, this is where the story
gets really interesting.
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See, you've got your companion
star that's swelled up
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into a red giant.
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Some of that red giant material
now can get incorporated
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00:06:07,777 --> 00:06:09,191
back into the pulsar
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00:06:09,191 --> 00:06:12,463
and spin it up into something
called a millisecond pulsar.
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The bloated red giant
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00:06:17,192 --> 00:06:19,775
can't hold on to
its outer layers,
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and the pulsar begins to feed.
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Matter streams into it,
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transferring momentum
into the pulsar,
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spinning it faster and faster
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until it rotates hundreds
of times a second.
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The beams re-ignite.
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Our pulsar is back
from the dead once more.
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They're dying and resurrecting
over and over and over again.
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It's like a zombie
you just can't kill.
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The red giant extends
the life of its zombie brother
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00:06:55,163 --> 00:06:57,131
billions of years longer.
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00:07:00,904 --> 00:07:04,276
We know of hundreds of
millisecond pulsars
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scattered throughout the cosmos.
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A terrifying thought.
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But it gets even scarier.
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Some of them are alone.
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What's happened
to their sibling?
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Binary stars are
ultimately responsible
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for the existence
of millisecond pulsars.
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They only exist because
they've sucked the life
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out of their companion stars.
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The millisecond pulsars
that we see that are all alone
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may have just gotten
rid of the body.
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This is PSR j1311-3430,
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00:07:45,503 --> 00:07:49,728
a rare breed of millisecond
pulsar known as a black widow.
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00:07:52,814 --> 00:07:57,825
Like its spider namesake,
it's deadly,
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one of the most massive
fast-spinning pulsars
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00:08:00,547 --> 00:08:03,593
in the universe,
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spitting out 100 times more
radiation than a regular one.
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00:08:09,304 --> 00:08:11,928
A black widow pulsar is right
on the edge of physics.
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00:08:11,928 --> 00:08:13,924
Any larger and it
would be a black hole.
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00:08:13,934 --> 00:08:16,744
The intense radiation
is amazing.
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00:08:16,754 --> 00:08:19,663
It's hard to fathom
that these things exist.
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00:08:19,673 --> 00:08:21,932
But generally, the rule is
the following with the universe,
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00:08:21,932 --> 00:08:23,407
which is big and old.
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If it can happen,
it does happen.
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The black widow pulsar
is the stuff of nightmares.
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Its radiation heats
the companion star
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00:08:33,636 --> 00:08:37,372
to over
21,000 degrees Fahrenheit,
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00:08:37,372 --> 00:08:41,245
more than twice as hot
as the surface of our sun.
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00:08:46,000 --> 00:08:49,342
It is nothing less than
stellar annihilation.
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00:08:51,110 --> 00:08:55,110
Pulsars are already dramatic,
energetic events.
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Now you're adding in,
"hey, let's destroy a star."
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Black widow spiders
famously eat their mates,
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00:09:01,440 --> 00:09:04,525
and that's exactly what
a black widow pulsar does.
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00:09:04,525 --> 00:09:06,954
It actually uses the material
from its companion star
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00:09:06,954 --> 00:09:08,457
to spin itself up,
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00:09:08,457 --> 00:09:10,982
and then it obliterates
it completely.
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00:09:10,982 --> 00:09:14,755
The companion star vanishes,
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murdered by its zombie sibling.
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00:09:19,484 --> 00:09:21,507
It's the ultimate
cosmic ingratitude.
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Here you have a companion star
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that's brought the pulsar back
to life after it's died twice,
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and now its entire body
is eviscerated
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by the radiation of the pulsar
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without a speck of dust
to suggest it was ever there.
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These black widow pulsars
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are like the assassins
of the galaxy.
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Not only do they
destroy the star,
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they get rid of the evidence.
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When pulsars are involved,
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00:09:48,633 --> 00:09:51,649
two stars
are much worse than one.
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But could the opposite
also be true?
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Can two stars create an oasis
for habitable alien worlds?
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00:10:22,983 --> 00:10:26,554
Binary stars offer
an exciting possibility...
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Alien exoplanets orbiting
two stars instead of one.
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These binary stars
are everywhere,
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so the universe could
actually be something like
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what we see in Sci-Fi movies.
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The Tatooine sky
could be a real thing.
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00:10:48,747 --> 00:10:51,828
There could be a planet
with life and civilization,
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00:10:51,828 --> 00:10:55,988
and in the sky,
there could be two suns.
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What would it be like
to live on these worlds?
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00:11:00,724 --> 00:11:04,081
Could two stars
be even better for life?
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00:11:06,059 --> 00:11:09,417
Our home planet orbits
a solitary sun
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in a safe region
where life could evolve.
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00:11:14,093 --> 00:11:16,451
Today we're familiar
with a very stable,
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well-behaved star...
Our own sun.
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00:11:18,859 --> 00:11:20,687
And of course we know
there's some solar weather.
189
00:11:20,687 --> 00:11:22,755
Sometimes it throws out
high-energy particles
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00:11:22,755 --> 00:11:24,794
that create the northern
and Southern lights,
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00:11:24,794 --> 00:11:27,122
but it's a very reliable star.
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00:11:27,122 --> 00:11:29,190
It wasn't always that way.
193
00:11:29,190 --> 00:11:31,658
When the sun was much younger,
it was more active,
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00:11:31,658 --> 00:11:33,656
it was more violent.
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00:11:37,523 --> 00:11:41,330
Our young sun rotated
over 10 times faster
196
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than it does today,
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00:11:43,528 --> 00:11:46,755
causing its magnetic field
to twist and tangle,
198
00:11:46,765 --> 00:11:49,823
sending out huge solar flares.
199
00:11:52,530 --> 00:11:54,029
Solar flares can be very bad for
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the habitability of a planet,
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00:11:55,258 --> 00:11:57,326
particularly if you're
very close to the star,
202
00:11:57,326 --> 00:11:58,965
and the reason's
because solar flares
203
00:11:58,965 --> 00:12:01,123
essentially represent
high-energy radiation.
204
00:12:01,133 --> 00:12:03,031
For example,
high-energy protons.
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00:12:03,031 --> 00:12:05,229
They smash into the atmosphere
and they can strip away
206
00:12:05,229 --> 00:12:08,796
gas off the atmosphere.
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00:12:08,796 --> 00:12:12,833
Picture the early
solar system...
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00:12:12,833 --> 00:12:14,801
Flares and solar storms
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attack the atmospheres
of rocky planets.
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00:12:19,128 --> 00:12:24,193
Deadly charged particles can rip
them away molecule by molecule.
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Without an atmosphere,
liquid water cannot survive,
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00:12:30,868 --> 00:12:34,435
and no liquid water
means no life.
213
00:12:36,773 --> 00:12:40,729
In the very early stages, our
solar system was an awful place.
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00:12:40,739 --> 00:12:43,597
The sun was young
and highly irregular
215
00:12:43,607 --> 00:12:47,903
and emitting lots of energy
in our region.
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00:12:47,903 --> 00:12:50,931
It took a long time,
probably 500 million years or so
217
00:12:50,941 --> 00:12:52,540
before the solar system
218
00:12:52,540 --> 00:12:55,307
calmed down enough to imagine
219
00:12:55,307 --> 00:13:00,473
that anything like life
could evolve here on earth.
220
00:13:00,473 --> 00:13:02,641
This is a galaxy-wide problem
221
00:13:02,641 --> 00:13:05,109
for planets orbiting one star.
222
00:13:07,137 --> 00:13:11,444
Take Proxima Centauri,
the closest star to our sun.
223
00:13:11,444 --> 00:13:13,142
It's a red dwarf,
224
00:13:13,142 --> 00:13:16,369
the most common type of star
in the milky way.
225
00:13:18,777 --> 00:13:24,912
And it even has its own planet
named Proxima B.
226
00:13:24,912 --> 00:13:29,278
But Proxima Centauri has not
treated its planet gently.
227
00:13:31,746 --> 00:13:34,774
If Proxima B
has any liquid water,
228
00:13:34,774 --> 00:13:37,412
it would have
to be extremely lucky.
229
00:13:40,309 --> 00:13:42,248
Proxima Centauri
would have caused
230
00:13:42,248 --> 00:13:43,976
huge amounts of energy
to come out,
231
00:13:43,976 --> 00:13:45,675
and it would
effectively strip away
232
00:13:45,675 --> 00:13:49,641
Proxima B of any kind of
atmosphere or surface water,
233
00:13:49,651 --> 00:13:53,578
thereby removing any chance
of there being habitable world.
234
00:13:53,578 --> 00:13:55,616
The only hope we have left
for Proxima B
235
00:13:55,616 --> 00:13:58,014
is a strong magnetic field.
236
00:13:58,014 --> 00:14:00,682
This would surround
and protect the planet
237
00:14:00,682 --> 00:14:03,480
from the onslaught
of violent energy
238
00:14:03,480 --> 00:14:05,178
that comes out
of Proxima Centauri,
239
00:14:05,178 --> 00:14:07,117
and that way, there could
still be an ocean,
240
00:14:07,117 --> 00:14:09,185
there could be
an oxygen-rich atmosphere,
241
00:14:09,185 --> 00:14:11,083
and perhaps habitable
environment,
242
00:14:11,083 --> 00:14:13,281
somewhere where life
could have started.
243
00:14:13,281 --> 00:14:16,419
But right now for Proxima B,
odds are stacked against it.
244
00:14:21,854 --> 00:14:23,683
Earth's strong magnetic field
245
00:14:23,683 --> 00:14:26,920
protects us from the sun's
worst outbursts,
246
00:14:26,920 --> 00:14:29,288
allowing liquid water
to survive.
247
00:14:32,015 --> 00:14:34,413
But other planets,
like Mars and Mercury,
248
00:14:34,423 --> 00:14:37,021
have not been so lucky.
249
00:14:37,021 --> 00:14:40,548
Solar storms blasted
their young atmospheres...
250
00:14:42,826 --> 00:14:45,984
Until they became thin and weak,
251
00:14:45,994 --> 00:14:48,821
snuffing out any
chances for life.
252
00:14:53,857 --> 00:14:58,223
But could binary systems
actually make things easier,
253
00:14:58,223 --> 00:15:04,388
where planets orbit around
two stars instead of one?
254
00:15:04,388 --> 00:15:07,825
Young stars can be
very violent and chaotic,
255
00:15:07,825 --> 00:15:10,053
but in the system
where there are two stars,
256
00:15:10,063 --> 00:15:13,790
the interaction of those stars
can slow down their rotation,
257
00:15:13,790 --> 00:15:17,057
and that means that that
violence can be slowed down.
258
00:15:17,057 --> 00:15:19,425
These solar storms
can be tempered
259
00:15:19,425 --> 00:15:22,093
so they're not as violent,
they're not as frequent,
260
00:15:22,093 --> 00:15:26,290
and if any young planet
is formed with an atmosphere,
261
00:15:26,300 --> 00:15:28,298
it can keep it.
262
00:15:28,298 --> 00:15:31,625
So, when it comes to the
occurrence of life on a planet,
263
00:15:31,625 --> 00:15:34,123
it may very well be
that having two stars
264
00:15:34,133 --> 00:15:37,660
could be a lot better
than having one.
265
00:15:37,660 --> 00:15:40,223
Gravitational interactions
266
00:15:40,233 --> 00:15:43,614
can slow down the spin
of two close sun-like stars,
267
00:15:43,614 --> 00:15:48,315
giving life the chance
to develop.
268
00:15:48,315 --> 00:15:50,947
But not just on one world...
269
00:15:50,947 --> 00:15:55,817
On many planets
throughout the system.
270
00:15:55,817 --> 00:15:57,758
With two stars in the middle
of a solar system,
271
00:15:57,758 --> 00:15:59,207
you have twice
the amount of heat,
272
00:15:59,207 --> 00:16:00,587
twice the amount of light,
273
00:16:00,587 --> 00:16:02,165
and that extends
the habitable zone
274
00:16:02,165 --> 00:16:04,235
farther out
into the solar system.
275
00:16:07,330 --> 00:16:10,119
For planetary
scientist Jani Radebaugh,
276
00:16:10,129 --> 00:16:14,200
exploring systems like this
would be a dream come true.
277
00:16:17,620 --> 00:16:20,844
To me, it is so thrilling that
worlds like this could exist
278
00:16:20,844 --> 00:16:23,150
and that they might
even harbor life.
279
00:16:23,150 --> 00:16:25,812
I mean, there could be a Sci-Fi
desert planet like this one
280
00:16:25,812 --> 00:16:29,991
with twin suns, my
personal favorite and one
281
00:16:29,991 --> 00:16:32,031
that I can't wait to visit,
or if we wanted,
282
00:16:32,031 --> 00:16:34,860
we could just hop over
to another habitable planet
283
00:16:34,860 --> 00:16:36,960
and find something
completely different.
284
00:16:40,025 --> 00:16:41,829
Galactic backpackers
could explore
285
00:16:41,829 --> 00:16:44,530
a variety of Sci-Fi landscapes.
286
00:16:48,315 --> 00:16:52,386
Perhaps alien civilizations
are already out there,
287
00:16:52,386 --> 00:16:55,580
living on these
habitable worlds.
288
00:16:59,266 --> 00:17:03,672
Two suns could create
better star systems than one,
289
00:17:03,672 --> 00:17:06,659
but they could also
make things chaotic,
290
00:17:06,659 --> 00:17:11,499
shooting entire worlds
into space at hyper speed.
291
00:17:29,843 --> 00:17:32,573
what would life be like
292
00:17:32,573 --> 00:17:34,939
on a planet in a binary system?
293
00:17:34,939 --> 00:17:38,004
Could it be better?
294
00:17:38,004 --> 00:17:43,593
Or is planet earth really
as good as it gets?
295
00:17:43,593 --> 00:17:45,890
If you're looking for an
abode for life in the galaxy,
296
00:17:45,900 --> 00:17:48,621
we tend to, you know, look for a
rather cozy existence out there,
297
00:17:48,621 --> 00:17:50,730
but, you know, it's possible
that stars can take you
298
00:17:50,730 --> 00:17:52,435
on a bit of a wild ride
sometimes.
299
00:17:55,560 --> 00:17:56,940
Over the past decade,
300
00:17:56,950 --> 00:17:59,345
we've observed
mysterious objects
301
00:17:59,345 --> 00:18:01,947
hurtling through the galaxy.
302
00:18:01,947 --> 00:18:05,594
Scientists call them
hypervelocity stars.
303
00:18:08,394 --> 00:18:10,661
When we say hypervelocity stars,
304
00:18:10,661 --> 00:18:13,352
we're talking some
hyper velocities.
305
00:18:13,362 --> 00:18:17,265
They've been observed moving up
to 620 miles per second.
306
00:18:17,275 --> 00:18:20,262
You're talking about something
the size of a star, the sun,
307
00:18:20,262 --> 00:18:23,416
an octillion tons of mass or
something like that
308
00:18:23,426 --> 00:18:27,635
getting flung away way
faster than a rifle bullet.
309
00:18:29,537 --> 00:18:31,775
These hypervelocity stars
310
00:18:31,775 --> 00:18:34,239
start off in a binary system,
311
00:18:34,239 --> 00:18:38,744
but something tears them apart...
Something big.
312
00:18:40,823 --> 00:18:42,992
In order to create
a hypervelocity star,
313
00:18:42,992 --> 00:18:46,412
you need a very intense source
of gravitational power.
314
00:18:46,412 --> 00:18:48,285
Well, the most intense
source we know of
315
00:18:48,285 --> 00:18:50,523
is the black hole
at the center of the galaxy.
316
00:18:57,630 --> 00:19:01,050
This black hole
is Sagittarius a-star.
317
00:19:05,486 --> 00:19:07,625
It is supermassive...
318
00:19:07,625 --> 00:19:12,425
Four million times
the mass of our sun.
319
00:19:12,425 --> 00:19:15,422
Two stars stray
a little too close,
320
00:19:15,422 --> 00:19:18,901
and the enormous gravity
of the black hole pulls at them.
321
00:19:20,843 --> 00:19:24,796
But the star closest feels
a much stronger tug,
322
00:19:24,796 --> 00:19:28,048
and this binary system
gets ripped apart.
323
00:19:31,212 --> 00:19:33,608
It's a little bit like
the Olympic hammer throw,
324
00:19:33,608 --> 00:19:36,959
where the hammer is
one star in the binary system
325
00:19:36,959 --> 00:19:39,985
and the Olympian
is the other star,
326
00:19:39,985 --> 00:19:41,237
with the cord
connecting the hammer
327
00:19:41,237 --> 00:19:42,489
being the gravitational tie
328
00:19:42,489 --> 00:19:44,234
between the binary stars.
329
00:19:44,234 --> 00:19:46,925
If you cut that cord,
the other star can go flying off
330
00:19:46,925 --> 00:19:49,428
at very, very high speed.
331
00:19:51,400 --> 00:19:53,046
Once the cord is cut,
332
00:19:53,046 --> 00:19:55,382
the binary stars
separate forever.
333
00:19:57,688 --> 00:19:59,985
One is trapped
in the gravitational grip
334
00:19:59,985 --> 00:20:03,337
of the black hole.
335
00:20:03,337 --> 00:20:06,235
The other is flung
out of the galaxy,
336
00:20:06,235 --> 00:20:10,769
becoming
a literal shooting star.
337
00:20:10,779 --> 00:20:15,766
But the star may not be alone.
338
00:20:15,776 --> 00:20:19,157
If a planet is gravitationally
bound to a star
339
00:20:19,157 --> 00:20:22,548
and that star gets ejected
from the system,
340
00:20:22,548 --> 00:20:24,352
if conditions are right,
341
00:20:24,362 --> 00:20:27,447
that planet can hitch a ride
with that star.
342
00:20:27,447 --> 00:20:30,079
Where the star goes,
the planet goes.
343
00:20:34,751 --> 00:20:37,245
If you're on planet
around a hypervelocity star,
344
00:20:37,255 --> 00:20:40,113
you would be the envy of poets
and scientists everywhere
345
00:20:40,113 --> 00:20:43,859
because you would have the most
breathtaking view imaginable.
346
00:20:43,859 --> 00:20:45,968
You would start at the very
center of the galaxy,
347
00:20:45,968 --> 00:20:49,349
you'll have this beautiful view
of the supermassive black hole.
348
00:20:52,868 --> 00:20:55,372
Generation after generation
349
00:20:55,372 --> 00:20:57,176
on this hypervelocity planet
350
00:20:57,186 --> 00:21:00,862
would be treated to thrilling
new views of the galaxy.
351
00:21:04,943 --> 00:21:06,809
By the time you're done
as you're ejected,
352
00:21:06,809 --> 00:21:10,216
you would see
the entire milky way galaxy,
353
00:21:10,216 --> 00:21:14,183
everything, and it would recede
away from you
354
00:21:14,183 --> 00:21:18,081
as you moved off into space
to who knows where.
355
00:21:22,303 --> 00:21:25,514
Hypervelocity planets
just go to show
356
00:21:25,514 --> 00:21:29,746
that the universe is way
stranger than fiction.
357
00:21:29,746 --> 00:21:32,819
As we learn more about
stars and stellar systems,
358
00:21:32,829 --> 00:21:36,953
even the most fantastical
imaginings of Sci-Fi writers,
359
00:21:36,953 --> 00:21:39,928
it doesn't even come close
to what nature can produce.
360
00:21:43,276 --> 00:21:46,222
This hypervelocity
star and planet
361
00:21:46,222 --> 00:21:48,579
go on the journey of a lifetime,
362
00:21:48,579 --> 00:21:51,269
but what about the stranded
companion star,
363
00:21:51,269 --> 00:21:53,557
stuck in the center
of the galaxy
364
00:21:53,567 --> 00:21:57,760
next to a supermassive
black hole?
365
00:21:57,760 --> 00:22:01,717
It, too, could have
a planet orbiting it,
366
00:22:01,717 --> 00:22:04,574
but it's a world
living on borrowed time.
367
00:22:06,930 --> 00:22:10,200
If there's a planet orbiting
the star that gets left behind
368
00:22:10,210 --> 00:22:11,977
by the hypervelocity star,
369
00:22:11,977 --> 00:22:13,352
so the planet is now orbiting
370
00:22:13,352 --> 00:22:15,610
the star that's orbiting
the black hole,
371
00:22:15,610 --> 00:22:18,694
that's not probably
gonna last very long.
372
00:22:18,694 --> 00:22:22,297
Typically, the little guy...
Pew! Gets shot away.
373
00:22:25,734 --> 00:22:28,454
So it's entirely possible
that we have hypervelocity
374
00:22:28,454 --> 00:22:32,283
rogue planets, planets
without a star
375
00:22:32,293 --> 00:22:33,628
that are shooting
out of the galaxy
376
00:22:33,628 --> 00:22:37,203
at high speed, as well.
377
00:22:37,203 --> 00:22:39,755
But it's not a trip
you'd want to take.
378
00:22:44,213 --> 00:22:46,737
Because this world is
destined to wander
379
00:22:46,737 --> 00:22:50,144
the emptiness of space
forever and alone.
380
00:22:52,078 --> 00:22:53,188
The problem with the planet
381
00:22:53,188 --> 00:22:55,515
is that it's no longer
bound to a star,
382
00:22:55,515 --> 00:22:58,726
so the outer surface
would most likely freeze.
383
00:23:00,788 --> 00:23:02,035
Binary stars
384
00:23:02,035 --> 00:23:06,159
can create weird environments
for planets.
385
00:23:06,169 --> 00:23:10,715
You could get an exhilarating
view of the galaxy,
386
00:23:10,715 --> 00:23:13,670
or freeze on an icy wasteland.
387
00:23:21,859 --> 00:23:26,052
But astronomers are finding
bizarre new systems
388
00:23:26,052 --> 00:23:29,332
where stars are not
being torn apart,
389
00:23:29,332 --> 00:23:33,524
they're being driven together,
390
00:23:33,524 --> 00:23:38,758
creating a cosmic event
coming soon to our galaxy.
391
00:23:55,568 --> 00:23:58,249
are two stars better than one?
392
00:24:00,576 --> 00:24:04,965
Binary systems are certainly
very dramatic.
393
00:24:04,965 --> 00:24:08,470
There's even one that has
two stars so close,
394
00:24:08,470 --> 00:24:11,976
they're touching.
395
00:24:11,976 --> 00:24:17,091
KIC 9832227 is a very
interesting binary system.
396
00:24:17,091 --> 00:24:19,379
It's what we call
a contact binary.
397
00:24:19,389 --> 00:24:23,179
So this means that the two stars
are basically in contact,
398
00:24:23,189 --> 00:24:24,662
but they're separate stars.
399
00:24:24,662 --> 00:24:28,521
They share a common
atmosphere or envelope.
400
00:24:28,521 --> 00:24:30,327
One's about a third the mass
of the sun,
401
00:24:30,327 --> 00:24:32,880
one about 1.4 times
the mass of the sun,
402
00:24:32,880 --> 00:24:37,171
and they're rotating around
each other every 11 hours.
403
00:24:37,171 --> 00:24:40,814
2017...
Scientists from Calvin college
404
00:24:40,814 --> 00:24:44,545
reveal an exciting discovery.
405
00:24:44,545 --> 00:24:50,015
These binary stars are
moving even closer together.
406
00:24:50,015 --> 00:24:53,353
They do the math
and make a bold prediction.
407
00:24:55,886 --> 00:24:59,284
So, this star is different from
all other contact binary stars
408
00:24:59,294 --> 00:25:01,945
we've studied
because this one, we believe,
409
00:25:01,945 --> 00:25:04,989
in the next five years
is going to merge,
410
00:25:04,989 --> 00:25:07,875
spiral in together, and explode.
411
00:25:10,654 --> 00:25:13,207
But it's a star
close enough to us...
412
00:25:13,217 --> 00:25:15,574
Only 1,800 light years away...
413
00:25:15,574 --> 00:25:17,665
That when it explodes,
it'd be bright enough
414
00:25:17,665 --> 00:25:19,894
to see with your naked eye.
415
00:25:19,894 --> 00:25:22,781
Two stars crashing together...
416
00:25:22,781 --> 00:25:26,846
An event known as a red Nova.
417
00:25:26,846 --> 00:25:28,544
If this is true,
if you really see it,
418
00:25:28,544 --> 00:25:30,017
it would be fabulous,
419
00:25:30,017 --> 00:25:31,853
because not only
would it validate
420
00:25:31,853 --> 00:25:33,425
this amazing prediction,
421
00:25:33,425 --> 00:25:35,919
but we have something new to
look at in the night sky.
422
00:25:35,919 --> 00:25:39,424
If this comes through,
this would just be
423
00:25:39,424 --> 00:25:41,614
the event of my lifetime.
424
00:25:44,245 --> 00:25:47,682
We don't get to predict
too many things in astronomy
425
00:25:47,682 --> 00:25:48,889
except, you know,
426
00:25:48,889 --> 00:25:51,285
"a billion years from now,
this thing will happen."
427
00:25:51,285 --> 00:25:55,282
So you have to appreciate
what this thing is.
428
00:25:55,282 --> 00:25:58,915
These stars are probably
billions of years old.
429
00:25:58,915 --> 00:26:02,459
We're just so lucky to be able
to see this right at the end
430
00:26:02,459 --> 00:26:04,580
where we just have
a few years left...
431
00:26:04,590 --> 00:26:07,958
A few years out of
a billion-year life span.
432
00:26:11,699 --> 00:26:14,871
It's an amazing
cosmic coincidence
433
00:26:14,871 --> 00:26:18,445
brought to you
by the number three.
434
00:26:18,445 --> 00:26:21,656
Before these stars
came into close contact,
435
00:26:21,656 --> 00:26:23,845
they may have had a neighbor...
436
00:26:23,855 --> 00:26:29,601
A distant third star
that set this all in motion.
437
00:26:29,601 --> 00:26:31,020
Whenever you have three objects,
438
00:26:31,020 --> 00:26:34,400
the gravitational dynamics
becomes incredibly complicated.
439
00:26:36,046 --> 00:26:38,845
The third star pulls
on the binary
440
00:26:38,845 --> 00:26:40,619
as the two orbit each other,
441
00:26:40,619 --> 00:26:44,995
stretching them out basically
into an elongated orbit.
442
00:26:44,995 --> 00:26:46,769
The two stars resist that,
443
00:26:46,769 --> 00:26:49,725
trying to circularize
their orbit again.
444
00:26:49,735 --> 00:26:52,356
That back and forth interaction
445
00:26:52,356 --> 00:26:54,692
pushes the third star
further away,
446
00:26:54,692 --> 00:26:58,309
pulls the two stars closer.
447
00:26:58,309 --> 00:27:01,167
The stars have been
shoved together,
448
00:27:01,177 --> 00:27:04,656
but their story is about
to get even weirder.
449
00:27:07,681 --> 00:27:10,244
Matter will stream off
the smaller star
450
00:27:10,254 --> 00:27:14,353
until it is too gravitationally
weak to hold its position...
451
00:27:16,502 --> 00:27:19,518
Driving their orbits
even tighter together,
452
00:27:19,527 --> 00:27:22,149
moving them faster and faster.
453
00:27:24,288 --> 00:27:29,057
Finally, the smaller star
will plunge into the larger one,
454
00:27:29,057 --> 00:27:32,773
tearing through it...
455
00:27:32,773 --> 00:27:36,291
And blasting hundreds of
trillions of tons of debris
456
00:27:36,291 --> 00:27:39,120
in every direction.
457
00:27:39,120 --> 00:27:41,357
This would be an enormous
amount of energy.
458
00:27:41,357 --> 00:27:43,555
Explosion at its peak
will be 10,000 times
459
00:27:43,564 --> 00:27:47,635
brighter than the star is today.
460
00:27:47,635 --> 00:27:52,276
This collision will
also be an act of creation.
461
00:27:52,276 --> 00:27:57,993
The cores of the two stars
will collide and become one,
462
00:27:57,993 --> 00:28:01,580
creating a super hot
blue ball of gas,
463
00:28:01,580 --> 00:28:05,522
a newborn star.
464
00:28:05,532 --> 00:28:07,434
Just think about
how cool that is.
465
00:28:07,434 --> 00:28:10,657
In the constellation Cygnus,
in about five years' time,
466
00:28:10,657 --> 00:28:14,894
a new star is gonna turn on
created from two older stars...
467
00:28:14,894 --> 00:28:18,255
An entirely new way of
seeing a star being born.
468
00:28:21,310 --> 00:28:22,660
Around the star,
469
00:28:22,660 --> 00:28:25,548
searing-hot gas
will expand outwards,
470
00:28:25,558 --> 00:28:29,795
turning red as it cools,
becoming the red Nova.
471
00:28:35,620 --> 00:28:38,931
The explosion will create
a brand-new light
472
00:28:38,941 --> 00:28:42,548
as bright as the north star
in our night sky.
473
00:28:44,825 --> 00:28:47,712
It's just phenomenal
that we get this opportunity.
474
00:28:47,712 --> 00:28:51,201
This is what every
astronomer wants to do.
475
00:28:53,212 --> 00:28:54,887
We are at a safe distance
476
00:28:54,887 --> 00:28:57,183
from this colliding star duo.
477
00:28:59,125 --> 00:29:02,968
But would we feel the same way
if we were on a planet
478
00:29:02,978 --> 00:29:05,639
orbiting this binary system.
479
00:29:05,639 --> 00:29:08,566
This is a very,
very energetic event.
480
00:29:08,566 --> 00:29:11,946
Could life survive
such an event?
481
00:29:11,956 --> 00:29:14,913
I wouldn't want to be there
as the test Guinea pig.
482
00:29:18,500 --> 00:29:20,471
All this energy
comes pouring in,
483
00:29:20,471 --> 00:29:23,950
and your atmosphere
is likely to be stripped away.
484
00:29:23,950 --> 00:29:26,187
If there are oceans
on this world,
485
00:29:26,187 --> 00:29:28,296
they're likely to be vaporized,
486
00:29:28,296 --> 00:29:32,268
and there may be very little
left other than rock.
487
00:29:32,278 --> 00:29:34,505
A Nova is nothing you want
to fool around with.
488
00:29:34,515 --> 00:29:37,334
Any planet that's close by
is gonna get cooked.
489
00:29:37,334 --> 00:29:41,187
It's gonna get sandblasted,
and then, you know, there it is.
490
00:29:41,187 --> 00:29:43,030
If that's the kind of place
you want to be,
491
00:29:43,030 --> 00:29:46,016
hey, more power to you,
but I like earth.
492
00:29:50,067 --> 00:29:52,698
Earth has a good thing
going these days
493
00:29:52,698 --> 00:29:54,965
with our single star.
494
00:29:54,965 --> 00:30:01,144
No collisions,
no explosions, no drama.
495
00:30:01,144 --> 00:30:03,677
For two stars to be
better than one,
496
00:30:03,677 --> 00:30:07,323
we need to find rocky planets
in a binary system.
497
00:30:10,053 --> 00:30:14,656
But so far, we haven't,
raising the question...
498
00:30:14,665 --> 00:30:17,878
Can they really exist at all?
499
00:30:35,835 --> 00:30:38,367
The Kepler space telescope
500
00:30:38,367 --> 00:30:41,590
has blown the search for alien
worlds wide open,
501
00:30:41,590 --> 00:30:44,576
discovering
thousands of exoplanets
502
00:30:44,576 --> 00:30:46,784
orbiting single stars.
503
00:30:50,499 --> 00:30:53,751
But finding rocky planets
in binary systems
504
00:30:53,751 --> 00:30:55,663
is proving difficult.
505
00:30:59,083 --> 00:31:01,872
We have found planets
orbiting binary star systems,
506
00:31:01,882 --> 00:31:04,208
and that's a big leap forward
in our understanding
507
00:31:04,208 --> 00:31:05,726
of how the universe works.
508
00:31:05,726 --> 00:31:08,978
Unfortunately, those planets
have all been gas giants,
509
00:31:08,978 --> 00:31:12,890
and they're not really
good for forming life.
510
00:31:12,890 --> 00:31:16,773
For alien civilizations
to exist around two suns,
511
00:31:16,773 --> 00:31:18,843
they need solid ground.
512
00:31:18,843 --> 00:31:22,430
The hunt for the world
of our Sci-Fi dreams
513
00:31:22,430 --> 00:31:25,613
has so far been fruitless.
514
00:31:25,623 --> 00:31:28,639
We always have to consider
that maybe rocky planets
515
00:31:28,649 --> 00:31:30,226
around binary stars
516
00:31:30,226 --> 00:31:33,379
just don't exist for some reason
that we currently don't know.
517
00:31:33,379 --> 00:31:38,051
And that would mean
there would be no Tatooine.
518
00:31:38,051 --> 00:31:40,978
Could paired stars
make it impossible
519
00:31:40,978 --> 00:31:43,047
for a rocky planet to form.
520
00:31:45,777 --> 00:31:48,507
If you're a planet trying to
form around a binary system,
521
00:31:48,507 --> 00:31:51,070
the gravity in the middle
is always changing.
522
00:31:51,070 --> 00:31:53,139
Instead of a single star,
you have two stars
523
00:31:53,139 --> 00:31:56,697
orbiting each other.
524
00:31:56,697 --> 00:31:59,669
These two infant stars
525
00:31:59,669 --> 00:32:03,070
start a gravitational
tug-of-war.
526
00:32:03,070 --> 00:32:07,143
The material between them is
pulled in different directions,
527
00:32:07,143 --> 00:32:11,445
making it harder for bits of
rock and dust to stick together.
528
00:32:11,455 --> 00:32:17,829
The system seems too chaotic
for rocky planets to form.
529
00:32:17,829 --> 00:32:20,660
The complex
gravitational interactions
530
00:32:20,670 --> 00:32:24,472
at play destabilize
a lot of potential orbits.
531
00:32:24,472 --> 00:32:28,144
There aren't a lot of
opportunities for a young planet
532
00:32:28,144 --> 00:32:32,347
that might want to form to find
a stable, long-term home
533
00:32:32,347 --> 00:32:35,918
that lasts for billions of years
around that binary system.
534
00:32:35,918 --> 00:32:40,431
It's relatively easy to get
ejected or consumed
535
00:32:40,431 --> 00:32:42,632
by the stars themselves.
536
00:32:44,703 --> 00:32:47,405
So, why can't
rocky planets survive
537
00:32:47,405 --> 00:32:50,206
when gas giants can?
538
00:32:50,206 --> 00:32:54,148
As any good realtor will tell
you, it's all about
539
00:32:54,148 --> 00:32:58,391
location, location, location.
540
00:32:58,391 --> 00:33:02,263
We think that rocky planets tend
to form close in around stars
541
00:33:02,263 --> 00:33:04,664
where it's nice and warm, but
further out where it's colder,
542
00:33:04,664 --> 00:33:06,805
you have the gas giant
planets forming.
543
00:33:06,805 --> 00:33:08,766
So, if you have
a binary star system,
544
00:33:08,776 --> 00:33:11,278
it's like a gravitational
tornado whipping out
545
00:33:11,278 --> 00:33:13,009
all of that rocky material
546
00:33:13,009 --> 00:33:15,150
so that you're only left
with the cold stuff,
547
00:33:15,150 --> 00:33:17,921
which can form
gas giants further out.
548
00:33:17,921 --> 00:33:20,593
If a two-star system
were a city,
549
00:33:20,593 --> 00:33:24,025
the gas giants are out
in the suburbs.
550
00:33:24,035 --> 00:33:28,097
A nice, peaceful spot away from
the competing gravity
551
00:33:28,107 --> 00:33:31,509
of the two stars.
552
00:33:31,509 --> 00:33:36,382
Perhaps one-star systems
are better than two.
553
00:33:36,382 --> 00:33:38,983
Gas giants aren't great
for life,
554
00:33:38,983 --> 00:33:45,026
and those are the planets we're
finding in these binary systems.
555
00:33:45,026 --> 00:33:47,198
The very reason that we're here
could be down to the fact
556
00:33:47,198 --> 00:33:49,229
that we have one star
rather than two.
557
00:33:52,540 --> 00:33:54,341
But in 2017,
558
00:33:54,341 --> 00:33:58,184
a discovery
around 2,000 light years away
559
00:33:58,184 --> 00:34:01,385
gives us new hope.
560
00:34:01,385 --> 00:34:04,187
So, as we discover
new things in the universe,
561
00:34:04,197 --> 00:34:06,598
we tend to give them
catalogue names,
562
00:34:06,598 --> 00:34:08,259
which can be very boring
563
00:34:08,269 --> 00:34:10,830
and very difficult
to keep track of.
564
00:34:10,840 --> 00:34:14,973
But SDSS 1557
is worth remembering.
565
00:34:17,374 --> 00:34:20,186
We've seen a binary system
that is a white dwarf...
566
00:34:20,186 --> 00:34:22,487
Which is the core
of a star like the sun
567
00:34:22,487 --> 00:34:24,018
after it's gotten very old,
568
00:34:24,018 --> 00:34:27,490
blown off its outer layers...
That's orbited by a brown dwarf,
569
00:34:27,500 --> 00:34:28,890
an object which is
sort of on the border
570
00:34:28,900 --> 00:34:31,432
between a planet and a star.
571
00:34:31,432 --> 00:34:36,905
What's most exciting
about the SDSS 1557 system
572
00:34:36,905 --> 00:34:41,317
is that we've found
rocky debris.
573
00:34:41,317 --> 00:34:42,918
We see the basic materials,
574
00:34:42,918 --> 00:34:46,360
the basic ingredients are there
for forming planets.
575
00:34:46,360 --> 00:34:47,861
This is a really
exciting discovery
576
00:34:47,861 --> 00:34:49,962
because we've seen
the remnants of asteroids
577
00:34:49,962 --> 00:34:53,434
and rocks orbiting about
this ancient binary system,
578
00:34:53,434 --> 00:34:56,806
systems that we thought
could've never had surviving
579
00:34:56,806 --> 00:34:59,207
rocky-type things
around it before.
580
00:35:01,278 --> 00:35:05,320
This binary system
is billions of years old,
581
00:35:05,320 --> 00:35:07,291
and through all that time,
582
00:35:07,291 --> 00:35:11,994
the rocky material
hasn't been wiped out.
583
00:35:11,994 --> 00:35:14,235
It has survived.
584
00:35:14,235 --> 00:35:18,908
This is a huge stepping stone
to finding our rocky planet
585
00:35:18,908 --> 00:35:22,380
with two suns.
586
00:35:22,380 --> 00:35:24,711
The system provides evidence
there's rocky material
587
00:35:24,721 --> 00:35:27,583
close in around
a binary star system,
588
00:35:27,593 --> 00:35:30,554
so it's a signpost
that rocky planet formation
589
00:35:30,554 --> 00:35:33,926
can occur around
binary star systems.
590
00:35:33,926 --> 00:35:38,268
The odds might be longer,
but it's still possible.
591
00:35:38,268 --> 00:35:43,111
Could there even still
be a planet in this system?
592
00:35:43,111 --> 00:35:47,914
There may still be planetary
objects around SDS 1557.
593
00:35:47,924 --> 00:35:50,825
We just haven't seen them yet,
but they may still be there.
594
00:35:57,429 --> 00:36:00,901
The search is still on.
595
00:36:00,911 --> 00:36:05,543
A rocky planet orbiting
two stars could really exist.
596
00:36:07,584 --> 00:36:10,186
So, for those of us hoping
for that Tatooine out there,
597
00:36:10,186 --> 00:36:12,357
that planet
with the double sunset,
598
00:36:12,357 --> 00:36:14,688
these debris fields
actually give us hope.
599
00:36:14,698 --> 00:36:17,730
Maybe the conditions, at least,
are right for the formation
600
00:36:17,730 --> 00:36:20,902
of rocky planets
around binary stars.
601
00:36:20,902 --> 00:36:22,272
I think it's out there.
602
00:36:22,272 --> 00:36:25,344
I think finding it is more
a question of when than if.
603
00:36:25,344 --> 00:36:29,076
As an astronomer, this is
a fantastic time to be alive
604
00:36:29,086 --> 00:36:30,717
at the cusp of discovery.
605
00:36:30,717 --> 00:36:34,319
As a science fiction fan, this
is a fantastic time to be alive
606
00:36:34,329 --> 00:36:37,061
because the stuff I read
as a kid is coming true.
607
00:36:39,662 --> 00:36:43,310
But perhaps
the biggest Sci-Fi fantasy
608
00:36:43,310 --> 00:36:46,486
is much closer to home,
609
00:36:46,486 --> 00:36:51,048
because new research is
suggesting something stunning...
610
00:36:51,048 --> 00:36:54,922
Our own sun could have a twin.
611
00:37:13,555 --> 00:37:17,685
A new study in 2017
throws into question
612
00:37:17,685 --> 00:37:20,074
our understanding of the sun.
613
00:37:24,086 --> 00:37:26,544
For the first time now,
astronomers are able to peer
614
00:37:26,544 --> 00:37:29,229
inside the clouds
that form stars,
615
00:37:29,238 --> 00:37:32,090
and the amazing thing is that
the evidence is suggesting
616
00:37:32,090 --> 00:37:36,053
that every single sun-like star
forms as part of a binary pair.
617
00:37:37,862 --> 00:37:42,286
The scientists study
the Perseus molecular cloud,
618
00:37:42,296 --> 00:37:46,131
a stellar nursery around
750 light years from us,
619
00:37:46,131 --> 00:37:49,012
packed with stars
just like our sun.
620
00:37:51,677 --> 00:37:54,725
Many of them are in wide
binary systems,
621
00:37:54,725 --> 00:37:57,448
traveling in huge orbits
around each other
622
00:37:57,448 --> 00:38:01,814
that span centuries or more.
623
00:38:01,814 --> 00:38:05,226
And all of these binaries
are babies,
624
00:38:05,226 --> 00:38:09,484
less than 500,000 years old.
625
00:38:09,494 --> 00:38:12,699
The only way to explain
these young systems
626
00:38:12,709 --> 00:38:18,481
is that they formed this way...
Not alone, but in a pair.
627
00:38:22,453 --> 00:38:25,206
Just based on statistics
and our understanding
628
00:38:25,206 --> 00:38:27,763
of what's going on inside
these star-forming clouds,
629
00:38:27,763 --> 00:38:30,752
it is highly likely that
the sun formed with a twin.
630
00:38:33,338 --> 00:38:36,494
Perhaps 4.5 billion years ago,
631
00:38:36,494 --> 00:38:39,601
our sun burst into life
with a sibling.
632
00:38:41,804 --> 00:38:44,232
Could this twin
still be out there
633
00:38:44,232 --> 00:38:47,546
in a distant orbit
that we haven't seen?
634
00:38:49,778 --> 00:38:53,092
There was an idea that
the sun could have a companion,
635
00:38:53,092 --> 00:38:54,930
which was nicknamed Nemesis,
636
00:38:54,930 --> 00:38:57,782
and this thing would've
orbited way far out,
637
00:38:57,782 --> 00:39:01,656
way past Neptune
in the solar system.
638
00:39:01,656 --> 00:39:05,324
Scientists searched
for this Nemesis star,
639
00:39:05,333 --> 00:39:08,706
but they came back empty handed.
640
00:39:08,706 --> 00:39:11,990
We've looked... we've had
telescopic surveys of the sky,
641
00:39:11,990 --> 00:39:15,038
including infrared surveys
where these types of objects
642
00:39:15,038 --> 00:39:16,779
would be very bright,
643
00:39:16,779 --> 00:39:20,584
and we've swept the entire
sky multiple times
644
00:39:20,584 --> 00:39:22,619
and we've seen nothing.
645
00:39:26,356 --> 00:39:31,508
What happened to our
sun's sibling is a mystery.
646
00:39:31,508 --> 00:39:35,382
How do we end up with one star
as opposed to binary?
647
00:39:35,382 --> 00:39:38,460
We really don't
quite understand.
648
00:39:38,470 --> 00:39:40,367
If it doesn't orbit us now,
649
00:39:40,367 --> 00:39:44,733
it may have left
our system long ago.
650
00:39:44,733 --> 00:39:46,926
Over time, some of
these binary stars
651
00:39:46,936 --> 00:39:49,099
get closer together
and stay together,
652
00:39:49,099 --> 00:39:52,117
and others get ripped apart
and lose each other entirely.
653
00:39:52,117 --> 00:39:55,755
It's very possible that our sun,
at some point,
654
00:39:55,755 --> 00:39:59,728
had a twin that got ejected.
655
00:39:59,728 --> 00:40:01,822
We don't know exactly when
656
00:40:01,822 --> 00:40:03,592
our sister star was torn away.
657
00:40:03,602 --> 00:40:05,824
It could be clear on the other
side of the galaxy
658
00:40:05,824 --> 00:40:09,039
from us by now.
659
00:40:09,039 --> 00:40:12,982
But after everything
we've seen in binary systems,
660
00:40:12,982 --> 00:40:15,608
we may be much
better off without it.
661
00:40:17,604 --> 00:40:19,413
I'm pretty happy
with having just one sun,
662
00:40:19,413 --> 00:40:23,474
so I'm fine to live
in this solar system.
663
00:40:23,484 --> 00:40:26,198
A binary sunset would be
more beautiful,
664
00:40:26,207 --> 00:40:29,806
but only more beautiful
if you were alive.
665
00:40:29,816 --> 00:40:32,009
And yet binary stars
666
00:40:32,009 --> 00:40:35,057
don't just
bring death and destruction.
667
00:40:35,057 --> 00:40:37,387
They could also create systems
668
00:40:37,387 --> 00:40:41,851
with a series
of habitable worlds.
669
00:40:41,851 --> 00:40:44,309
There's so much we don't know
about our own environment
670
00:40:44,309 --> 00:40:46,905
and how it compares to
other places in the universe.
671
00:40:46,905 --> 00:40:49,000
It seems like we're in
a very lucky place.
672
00:40:49,000 --> 00:40:51,723
The sun is very stable,
it's a single star,
673
00:40:51,723 --> 00:40:53,562
we're in a nice orbit around it,
674
00:40:53,562 --> 00:40:56,118
but maybe there are places out
there that are even better.
675
00:40:56,128 --> 00:40:57,928
We just didn't even know to ask.
676
00:41:00,091 --> 00:41:02,588
It's certainly possible
677
00:41:02,588 --> 00:41:05,764
that two stars are better
for life than one,
678
00:41:05,774 --> 00:41:09,540
but until we find
these alien worlds,
679
00:41:09,540 --> 00:41:12,559
it remains an open question.
680
00:41:15,056 --> 00:41:17,446
It's hard to say whether
we're lucky or unlucky
681
00:41:17,446 --> 00:41:19,451
to be on a planet
orbiting a single star.
682
00:41:19,451 --> 00:41:21,644
It's probably a little
boring here
683
00:41:21,644 --> 00:41:23,974
compared to what
it would seem like
684
00:41:23,974 --> 00:41:26,138
in these binary star systems.
685
00:41:28,773 --> 00:41:31,624
You know, from a romantic,
visual perspective,
686
00:41:31,624 --> 00:41:35,528
I kind of wish we did live
in a binary star system.
687
00:41:35,528 --> 00:41:38,743
Can you imagine somebody
living on a circum-binary planet
688
00:41:38,743 --> 00:41:41,958
and finding an earthlike planet
orbiting a solitary star.
689
00:41:41,958 --> 00:41:43,758
Would they think, "oh, how
interesting that would be.
690
00:41:43,758 --> 00:41:46,383
Can you imagine
having one sunset?
691
00:41:46,383 --> 00:41:47,563
What would that look like?"
692
00:41:47,563 --> 00:41:49,628
I can imagine them
asking themselves
693
00:41:49,638 --> 00:41:51,830
the questions we ask ourselves.
694
00:41:51,830 --> 00:41:54,092
So it's just a matter
of perspective, you know?
695
00:41:54,092 --> 00:41:57,012
Grass is always greener on the
other side of the binary system.
55734
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