1
00:00:02,934 --> 00:00:04,467
(crickets)
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00:00:04,600 --> 00:00:09,166
(owl hoot)
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00:00:18,600 --> 00:00:21,467
TYSON: John Goodricke was a
man who was permitted only the
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00:00:21,600 --> 00:00:23,467
briefest glimpse of the stars.
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00:00:24,266 --> 00:00:26,667
And yet, it could be
said that he made one of the
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00:00:26,800 --> 00:00:28,667
greatest discoveries of all.
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00:00:32,166 --> 00:00:35,100
He had been left completely
deaf by a childhood illness.
8
00:00:35,967 --> 00:00:38,667
And maybe that's why
he looked so carefully.
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00:00:42,467 --> 00:00:44,867
On a clear
summer night in 1784,
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00:00:45,767 --> 00:00:49,533
he went outside to see if a
particular star was still
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00:00:49,667 --> 00:00:52,600
doing something
that mystified him.
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00:00:53,400 --> 00:00:57,100
Something that no
other astronomer had
ever reported before.
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00:00:59,033 --> 00:01:01,667
Goodricke couldn't
believe his own eyes.
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00:01:02,166 --> 00:01:04,100
The star, called Beta Lyrae,
15
00:01:04,233 --> 00:01:08,266
changed regularly in
brightness over a
very brief period of time.
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00:01:08,734 --> 00:01:10,934
Only days.
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00:01:11,066 --> 00:01:13,800
What could possibly
make a star do that?
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00:01:17,066 --> 00:01:19,700
Even more surprising,
Goodricke found that he could
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00:01:19,834 --> 00:01:22,033
predict its variations
with high accuracy.
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00:01:24,367 --> 00:01:26,533
What could cause such a
change in a star's brightness?
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00:01:28,633 --> 00:01:31,033
None of the scenarios that
came to mind explained the
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00:01:31,166 --> 00:01:33,333
evidence before him.
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00:01:35,066 --> 00:01:37,500
And then, he thought
of another possibility.
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00:01:42,834 --> 00:01:45,734
Suppose there was something
orbiting Beta Lyrae
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00:01:45,867 --> 00:01:48,333
that eclipsed the star
on a regular basis.
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00:01:53,667 --> 00:01:55,600
But what could it be?
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00:02:07,133 --> 00:02:09,533
"A world perhaps?"
28
00:02:21,266 --> 00:02:23,734
How about a trillion?
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00:02:30,433 --> 00:02:35,934
(theme music plays)
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00:02:56,166 --> 00:03:02,400
♪ ♪
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00:03:21,934 --> 00:03:27,633
♪ ♪
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00:03:33,533 --> 00:03:35,533
TYSON: When John Goodricke's
discovery came to the attention
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00:03:35,667 --> 00:03:38,734
of the prestigious
British Royal Society in 1786,
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00:03:39,700 --> 00:03:41,767
he was immediately
made a member.
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00:03:45,166 --> 00:03:48,100
Word of this honor
never reached him,
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00:03:48,667 --> 00:03:51,867
days later he was
dead of pneumonia.
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00:03:54,200 --> 00:03:56,967
He was only 21.
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00:04:01,600 --> 00:04:04,633
It would be 150 years
before another astronomer
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00:04:04,767 --> 00:04:06,934
would solve Goodricke's mystery.
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00:04:07,400 --> 00:04:11,533
And in the process,
change our cosmos forever.
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00:04:12,400 --> 00:04:15,400
Even as a child,
Gerard Peter Kuiper could
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00:04:15,533 --> 00:04:17,166
see farther than anyone else.
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00:04:18,967 --> 00:04:22,000
He saw stars too distant
and too faint for others
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00:04:22,133 --> 00:04:24,200
to find without a telescope.
45
00:04:25,700 --> 00:04:28,667
This was in the Netherlands
more than a century ago.
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00:04:29,533 --> 00:04:31,900
Back then, the son of
a poor tailor could not
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00:04:32,033 --> 00:04:34,300
hope to become an astronomer.
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00:04:34,433 --> 00:04:37,333
But the boy would
not be stopped.
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00:04:37,767 --> 00:04:40,800
Back then, astronomers thought
that the cosmos consisted of
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00:04:40,934 --> 00:04:44,300
only a handful of planets,
those of our own solar system.
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00:04:45,867 --> 00:04:49,433
The great multitude of other
stars were just barren points
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00:04:49,567 --> 00:04:52,633
of light that had never
given birth to worlds.
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00:04:54,166 --> 00:04:58,567
We on Earth could
still feel special.
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00:04:59,300 --> 00:05:01,433
Our star system,
the scientists told us,
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00:05:01,567 --> 00:05:05,900
was the rarest of all, one
blessed by worlds and moons.
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00:05:13,600 --> 00:05:16,834
Kuiper yearned to know
how our Sun and its planets
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00:05:16,967 --> 00:05:19,233
came to be.
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00:05:21,000 --> 00:05:23,700
And made his way to the
University of Leiden,
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00:05:23,834 --> 00:05:25,700
where he quickly
distinguished himself.
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00:05:27,900 --> 00:05:30,600
He was invited to join the
dynamic astronomical community
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00:05:30,734 --> 00:05:34,066
in the United States,
but Kuiper had rough edges,
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00:05:35,266 --> 00:05:37,934
he was argumentative and
easily drawn into conflict
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00:05:38,066 --> 00:05:39,800
with his colleagues.
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00:05:39,934 --> 00:05:43,266
The prospect of directing a
remote observatory far away
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00:05:43,400 --> 00:05:45,767
from the capitals of
scientific culture must have
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00:05:45,900 --> 00:05:47,533
appealed to him.
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00:05:47,667 --> 00:05:50,900
And besides, you could
see the stars better there
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00:05:51,100 --> 00:05:53,567
than just about anywhere else.
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00:05:54,400 --> 00:05:58,033
Kuiper was given
an appointment at the
McDonald Observatory,
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00:05:58,166 --> 00:06:01,166
situated in
a corner of West Texas.
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00:06:02,333 --> 00:06:05,200
At the turn of the century, it
had been discovered that half
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00:06:05,333 --> 00:06:09,033
the visible stars were
really gravitational pairs.
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00:06:10,667 --> 00:06:13,033
Most binary stars
are like twins,
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00:06:13,166 --> 00:06:16,033
forming from the same
womb of gas and dust.
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00:06:17,233 --> 00:06:19,867
Others come of age separately
and become gravitationally
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00:06:20,000 --> 00:06:22,867
involved with each other
later in their development.
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00:06:23,700 --> 00:06:27,333
And the other half remain
single throughout their lives.
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00:06:28,100 --> 00:06:31,033
Kuiper chose to concentrate
on the binary stars.
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00:06:32,000 --> 00:06:34,100
He wondered if they could
shed light on the way that the
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00:06:34,233 --> 00:06:37,233
planets in our solar
system formed and came to be
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00:06:37,367 --> 00:06:39,734
gravitationally
bound to our Sun.
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00:06:40,233 --> 00:06:42,700
KUIPER: Bright ascension.
18 hours, 50 minutes.
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00:06:43,033 --> 00:06:45,600
Declination plus 33 degrees.
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00:06:45,734 --> 00:06:47,667
2175 minutes.
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00:06:48,133 --> 00:06:49,500
ASSISTANT: Mm-hmm.
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00:06:49,934 --> 00:06:52,166
TYSON: Kuiper looked at
the very same star that
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00:06:52,300 --> 00:06:54,900
had baffled John Goodricke
150 years before,
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00:06:55,734 --> 00:06:59,433
but Kuiper was looking at it
with a much bigger telescope.
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00:07:01,000 --> 00:07:03,834
And Kuiper was armed with
an awesome power that didn't
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00:07:03,967 --> 00:07:07,266
exist in Goodricke's time,
spectroscopy.
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00:07:08,066 --> 00:07:10,533
Spectroscopy is a way to
dissect the light of any
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00:07:10,667 --> 00:07:13,834
single star to find its
particular atomic and
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00:07:13,967 --> 00:07:15,633
molecular composition.
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00:07:16,400 --> 00:07:18,934
Kuiper looked at the
spectrum of the light produced
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00:07:19,066 --> 00:07:22,100
by Beta Lyrae and saw that,
as with all stars,
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00:07:22,633 --> 00:07:24,934
there was plenty of
hydrogen and helium,
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00:07:25,066 --> 00:07:29,000
but there was also
iron sodium and silicon.
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00:07:29,600 --> 00:07:31,333
So far, no surprises there.
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00:07:31,467 --> 00:07:33,567
Now, here comes the twist.
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00:07:34,266 --> 00:07:35,567
Bright lines?
101
00:07:35,700 --> 00:07:38,133
Where were those
bright lines coming from?
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00:07:38,266 --> 00:07:41,600
At that time, no astronomer
understood why bright lines
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00:07:41,734 --> 00:07:43,400
would appear in the
spectrum of a star.
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00:07:44,567 --> 00:07:47,400
Kuiper leapt to the
conclusion that the two stars
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00:07:47,533 --> 00:07:50,100
were so close that they
were exchanging matter,
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00:07:51,400 --> 00:07:54,400
super-hot gases that would
produce such a signature.
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00:07:55,734 --> 00:07:58,333
In trying to understand
what he had seen that night,
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00:07:59,100 --> 00:08:02,300
Kuiper discovered and
named the most interstellar
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00:08:02,433 --> 00:08:04,934
relationship in the cosmos.
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00:08:05,233 --> 00:08:08,867
Stars that are physically
locked in everlasting oneness,
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00:08:09,000 --> 00:08:12,133
bound together by
gravity and a bridge of fire
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00:08:13,033 --> 00:08:15,033
made of star stuff.
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00:08:17,600 --> 00:08:21,233
A bridge eight
million miles long,
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00:08:22,500 --> 00:08:24,400
connecting two stars,
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00:08:24,533 --> 00:08:27,233
one three times more
massive than our Sun,
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00:08:27,367 --> 00:08:31,066
the other 13 times
greater still.
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00:08:33,367 --> 00:08:36,667
A contact binary star system.
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00:08:37,100 --> 00:08:39,834
Why aren't they
round like our own star?
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00:08:40,233 --> 00:08:42,166
They are so
closed to one another,
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00:08:42,300 --> 00:08:45,734
tidal forces of gravity pull
them together and stretch them
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00:08:45,867 --> 00:08:48,433
into flaming teardrops.
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00:08:49,867 --> 00:08:54,333
The Beta Lyrae system is about
1,000 light-years from earth.
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00:08:54,934 --> 00:08:57,867
The largest telescopes of the
mid-20th century were just not
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00:08:58,000 --> 00:09:01,166
powerful enough to resolve
them as individual stars.
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00:09:02,400 --> 00:09:04,867
You needed that new
power of spectroscopy
126
00:09:05,200 --> 00:09:07,533
to disentangle them.
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00:09:07,667 --> 00:09:10,133
Kuiper imagined how the
formation of the contact
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00:09:10,266 --> 00:09:13,166
binary star system
could have happened.
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00:09:13,734 --> 00:09:16,567
He deduced that they were
formed when a vast cloud of
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00:09:16,700 --> 00:09:21,500
gas and dust become so
dense that gravitational
whirlpools formed.
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00:09:26,700 --> 00:09:29,400
In thinking about
these contact binaries,
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00:09:29,533 --> 00:09:32,166
Kuiper couldn't help but
wonder if any of these stellar
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00:09:32,300 --> 00:09:34,800
courtships ever
failed to catch on fire.
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00:09:37,100 --> 00:09:41,033
Kuiper asked himself,
was our world,
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00:09:41,166 --> 00:09:44,533
our Moon and all the planets
of our solar system nothing
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00:09:44,667 --> 00:09:47,166
more than a failed
binary star system?
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00:09:48,734 --> 00:09:52,600
And if that's how our
solar system was created,
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00:09:52,967 --> 00:09:56,400
had the same thing
happened around other
stars throughout the cosmos?
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00:10:02,834 --> 00:10:05,400
Gerard Kuiper had
a special power,
140
00:10:05,533 --> 00:10:08,133
he could see
farther than anyone else.
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00:10:08,667 --> 00:10:11,767
He was the first to envision
the universe we now live in.
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00:10:12,533 --> 00:10:16,266
Not a barren vastness meagerly
dotted by childless stars,
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00:10:17,033 --> 00:10:19,567
but one overflowing
with possible worlds,
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00:10:19,700 --> 00:10:22,200
countless planets and moons.
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00:10:24,600 --> 00:10:28,467
In 1949, Kuiper astonished
the world by declaring that
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00:10:28,600 --> 00:10:31,867
our solar system was
not so special after all,
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00:10:32,533 --> 00:10:36,066
that every other star had
its own family of worlds.
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00:10:38,767 --> 00:10:41,266
A world perhaps?
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00:10:42,734 --> 00:10:46,500
But science wasn't
ready for that universe,
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00:10:47,000 --> 00:10:50,934
it wasn't even ready
to take its first
baby steps off the planet.
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00:10:51,133 --> 00:10:52,533
Why not?
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00:10:52,667 --> 00:10:55,400
Science was carved up
into little kingdoms,
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00:10:55,533 --> 00:10:58,200
the various scientific
disciplines and scientists of
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00:10:58,333 --> 00:11:01,033
one discipline
didn't collaborate with
anyone from another.
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00:11:02,500 --> 00:11:05,600
But this had to change for
us to venture beyond Earth.
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00:11:06,233 --> 00:11:09,800
It all came to a head in
a feud between Kuiper and
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00:11:09,934 --> 00:11:12,033
another great scientist.
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00:11:13,000 --> 00:11:15,633
Like two stars of a
contact binary system,
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00:11:15,767 --> 00:11:17,500
they could not disengage.
160
00:11:17,633 --> 00:11:19,667
But despite their
loathing for each other,
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00:11:19,800 --> 00:11:22,934
they managed to create a
new kind of science and they
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00:11:23,066 --> 00:11:25,400
pioneered the Space Age,
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00:11:25,767 --> 00:11:28,900
mentoring its
greatest visionary and voice.
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00:11:35,133 --> 00:11:38,000
♪ ♪
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00:11:43,700 --> 00:11:49,133
♪ ♪
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00:11:49,467 --> 00:11:51,967
TYSON: Sometimes, the
cosmos just barges right in
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00:11:52,100 --> 00:11:54,233
and breaks down
your door, like tonight.
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00:11:56,633 --> 00:11:58,133
What's going on here?
169
00:11:58,266 --> 00:12:02,033
Our planet is passing through
the epic remnants of a comet,
170
00:12:02,433 --> 00:12:05,000
a debris field
millions of miles long.
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00:12:05,633 --> 00:12:08,700
That's why it looks like
it's raining stars tonight.
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00:12:09,233 --> 00:12:10,767
But they're not stars at all,
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00:12:10,900 --> 00:12:13,834
just bits of rock
and ice burning up
in Earth's atmosphere.
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00:12:15,033 --> 00:12:17,033
It's called a meteor shower.
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00:12:17,166 --> 00:12:19,767
And this one happens at
the same time every year.
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00:12:20,934 --> 00:12:22,266
Why?
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00:12:22,400 --> 00:12:24,500
Because it takes a year for
Earth to orbit the Sun and
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00:12:24,633 --> 00:12:26,533
return to that same
place where the comets
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00:12:26,667 --> 00:12:29,100
streaked by so long ago.
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00:12:29,233 --> 00:12:31,266
That's what a year is.
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00:12:32,166 --> 00:12:36,533
This could be a piece
of that comet or possibly
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00:12:36,667 --> 00:12:38,500
a fragment of an asteroid.
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00:12:39,100 --> 00:12:40,834
It came from another world,
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00:12:40,967 --> 00:12:44,000
a leftover from the
creation of our solar system.
185
00:12:44,133 --> 00:12:46,800
But how to understand it?
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00:12:47,300 --> 00:12:49,100
Well, back in
Gerard Kuiper's time,
187
00:12:49,233 --> 00:12:50,867
during the middle
of the 20th century,
188
00:12:51,066 --> 00:12:53,934
it depended on what kind
of a scientist you were.
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00:12:54,667 --> 00:12:57,367
The geologists would bring
their hammers and break this
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00:12:57,500 --> 00:13:00,433
sucker apart and look at its
dust under a microscope to
191
00:13:00,567 --> 00:13:03,467
study its
crystalline structure.
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00:13:03,800 --> 00:13:06,200
It was their way of finding
out which missing piece in
193
00:13:06,333 --> 00:13:08,834
this puzzle of Earth the
meteorite could provide.
194
00:13:10,200 --> 00:13:12,800
The chemists were searching
for the same answers,
195
00:13:12,934 --> 00:13:15,200
but they would drop it in
acid to see if it could be
196
00:13:15,333 --> 00:13:17,600
transformed from one
compound into another,
197
00:13:18,633 --> 00:13:20,667
torturing it to see
if it would give up
198
00:13:20,800 --> 00:13:22,800
its secrets about nature.
199
00:13:28,867 --> 00:13:32,900
The physicists would want
to see it at its most naked.
200
00:13:35,200 --> 00:13:38,467
Stripped down to its mass,
its density, its hardness.
201
00:13:39,200 --> 00:13:42,166
Its resistance to heat.
202
00:13:42,767 --> 00:13:46,166
The biologist wouldn't
even stop to pick it up.
203
00:13:46,533 --> 00:13:49,266
Back then, they would've
walked right by it because
204
00:13:49,400 --> 00:13:52,266
they didn't think there was
any chance that a meteorite
205
00:13:52,400 --> 00:13:55,800
from space had
anything to do with them.
206
00:13:56,200 --> 00:14:01,367
Life could only be from
one place, right here, Earth.
207
00:14:07,166 --> 00:14:09,367
And you want to know
the craziest thing?
208
00:14:09,867 --> 00:14:11,033
Back then,
209
00:14:11,166 --> 00:14:13,934
the astronomers would've
walked right by it, too.
210
00:14:14,066 --> 00:14:17,100
Their sights were focused
on the distance and we can't
211
00:14:17,233 --> 00:14:18,834
really blame them.
212
00:14:18,967 --> 00:14:21,266
What was happening in
astronomy back then?
213
00:14:21,400 --> 00:14:24,667
Big ideas about things far
beyond our solar system,
214
00:14:25,266 --> 00:14:27,567
Einstein's theory of relativity,
215
00:14:27,700 --> 00:14:30,667
with its vision of riding a
light beam across the cosmos
216
00:14:31,233 --> 00:14:34,567
and Edwin Hubble's discovery
that the universe was expanding,
217
00:14:35,533 --> 00:14:38,567
that distant
galaxies were flying
away from one another.
218
00:14:38,700 --> 00:14:42,133
That's what raised goosebumps,
not looking at a dumb rock
219
00:14:42,266 --> 00:14:44,367
lying in your own backyard.
220
00:14:44,700 --> 00:14:47,100
Studying the planets, moons,
comets and meteors of our own
221
00:14:47,233 --> 00:14:50,133
tiny solar system
seemed like little league.
222
00:14:52,266 --> 00:14:54,934
Until Kuiper dared to
venture into territories
223
00:14:55,066 --> 00:14:57,467
off-limits to astronomy.
224
00:14:57,800 --> 00:15:00,166
Night after night,
he would stay up here...
225
00:15:00,300 --> 00:15:04,600
A virtuoso playing the 45-ton
instrument like a violin.
226
00:15:04,967 --> 00:15:08,133
Searching the solar system
for clues to its origin.
227
00:15:08,567 --> 00:15:12,000
A mystery that he alone
recognized was insoluble
228
00:15:12,133 --> 00:15:16,233
without the cooperative
enterprise of all the
scientific disciplines.
229
00:15:17,300 --> 00:15:20,333
But the scientists didn't
know they needed one another.
230
00:15:20,767 --> 00:15:23,266
There wasn't a single
university department where
231
00:15:23,400 --> 00:15:27,100
scientists of multiple
disciplines could study
planetary astronomy.
232
00:15:27,867 --> 00:15:31,100
So here, in the
middle of nowhere,
233
00:15:32,000 --> 00:15:36,066
in a corner of West Texas,
Kuiper conducted his one-man
234
00:15:36,200 --> 00:15:38,467
exploration of
the solar system.
235
00:15:52,000 --> 00:15:55,033
He looked at Titan,
one of Saturn's moons,
236
00:15:55,166 --> 00:15:57,500
and discovered that
it had an atmosphere,
237
00:15:58,133 --> 00:16:00,667
it was thick with methane.
238
00:16:01,000 --> 00:16:04,633
A point of light in
the sky had suddenly
become a real place.
239
00:16:05,700 --> 00:16:08,967
Kuiper used the spectroscope
to probe the acrid clouds in
240
00:16:09,100 --> 00:16:12,934
the upper atmosphere
of Jupiter to see
what they were made of,
241
00:16:13,066 --> 00:16:15,433
their chemical
and atomic structures.
242
00:16:15,567 --> 00:16:17,800
And when he looked
at the red planet, Mars,
243
00:16:17,934 --> 00:16:21,166
he found carbon dioxide in
its atmosphere and he wondered,
244
00:16:22,033 --> 00:16:26,533
"Am I looking at my
planet's future or its past?"
245
00:16:27,400 --> 00:16:31,367
But to some people,
Kuiper was doing
nothing more than trespassing.
246
00:16:32,166 --> 00:16:34,500
Butting into chemical matters
where an astronomer
247
00:16:34,633 --> 00:16:36,800
had no business.
248
00:16:36,934 --> 00:16:39,633
Harold Urey was a chemist.
249
00:16:39,967 --> 00:16:41,400
Like Gerard Kuiper,
250
00:16:41,533 --> 00:16:44,533
he also had to fight
his way into science.
251
00:16:44,900 --> 00:16:47,433
Urey's family was
poor like Kuiper's.
252
00:16:47,567 --> 00:16:50,834
So he took a job teaching
grammar school in a
253
00:16:50,967 --> 00:16:53,367
mining camp in Montana.
254
00:16:54,900 --> 00:16:56,800
The parents of one of
his students urged him to
255
00:16:56,934 --> 00:16:59,367
find a way to get to college.
256
00:17:00,934 --> 00:17:03,233
Harold Urey took that
advice all the way to a
257
00:17:03,367 --> 00:17:05,767
Nobel Prize in chemistry.
258
00:17:07,800 --> 00:17:10,700
By 1949, he was riding high,
259
00:17:11,300 --> 00:17:14,533
a distinguished professor
at the University of Chicago.
260
00:17:14,900 --> 00:17:16,433
Then, and now,
261
00:17:16,567 --> 00:17:19,400
one of the world's
great capitals of science.
262
00:17:19,767 --> 00:17:21,600
But when Urey read
his morning paper,
263
00:17:21,734 --> 00:17:24,200
something began to
curdle inside him,
264
00:17:24,333 --> 00:17:26,934
a rising resentment.
265
00:17:27,066 --> 00:17:30,867
First, a pang at a
fellow scientist's
heightened celebrity.
266
00:17:31,200 --> 00:17:33,367
Well, that was normal.
267
00:17:33,734 --> 00:17:37,834
Then he got to the part about
the origin of the planets.
268
00:17:38,133 --> 00:17:40,667
He was offended that an
astronomer was making
269
00:17:40,800 --> 00:17:44,100
pronouncements
about the chemical nature
of the solar system.
270
00:17:44,467 --> 00:17:46,867
That was his turf.
271
00:17:49,367 --> 00:17:51,567
Scientists are human.
272
00:17:51,700 --> 00:17:53,166
We're primates.
273
00:17:53,533 --> 00:17:56,767
We carry the same evolutionary
baggage as everyone else.
274
00:17:57,967 --> 00:18:01,000
Kuiper and Urey were
two alpha males who chose
275
00:18:01,133 --> 00:18:03,567
scientific argument as
their weapon of combat.
276
00:18:05,633 --> 00:18:08,967
And the two men fought
over a single hostage,
277
00:18:09,333 --> 00:18:11,166
a young student.
278
00:18:15,467 --> 00:18:17,166
When Carl Sagan was a kid,
279
00:18:17,300 --> 00:18:20,300
he lived here, in
a small apartment in Brooklyn.
280
00:18:25,100 --> 00:18:28,266
(ticking)
281
00:18:30,700 --> 00:18:33,800
(street sounds)
282
00:18:38,433 --> 00:18:41,567
In the mid-1940s,
he made this drawing,
283
00:18:41,700 --> 00:18:43,734
filled with predictions,
284
00:18:43,867 --> 00:18:47,100
that is now in the
US Library of Congress.
285
00:18:57,400 --> 00:19:01,200
♪ ♪
286
00:19:06,834 --> 00:19:11,867
MAN (over PA): 3, 2, 1, 0.
All engine running.
287
00:19:13,166 --> 00:19:15,667
Liftoff, we have a liftoff!
288
00:19:17,367 --> 00:19:19,433
TYSON: In an era where life
here was in the last seconds
289
00:19:19,567 --> 00:19:22,166
of its four billion
captivity on Earth,
290
00:19:23,100 --> 00:19:27,000
he dreamed of going to the
planets and even to the stars.
291
00:19:29,200 --> 00:19:31,934
But he didn't want to
just go in his imagination,
292
00:19:32,066 --> 00:19:33,867
he wanted to really go.
293
00:19:34,300 --> 00:19:37,200
He wanted to know what
those worlds were really like.
294
00:19:38,233 --> 00:19:42,133
And he knew that the
only way to do that was to
become a scientist.
295
00:19:44,100 --> 00:19:47,300
The boy would come
under the wings of
the two warring giants.
296
00:19:48,233 --> 00:19:50,133
As much as they
hated each other,
297
00:19:50,266 --> 00:19:52,633
he loved them both.
298
00:19:52,934 --> 00:19:55,467
Together, the three of them
would tear down the walls
299
00:19:55,600 --> 00:19:57,700
between the scientists.
300
00:19:57,834 --> 00:20:00,467
And the boy would tear
down the tallest wall,
301
00:20:00,600 --> 00:20:04,266
the one between
science and everyone else.
302
00:20:12,667 --> 00:20:14,400
TYSON: Do something for me.
303
00:20:14,533 --> 00:20:17,633
I need you to pretend that
we live in a time before any
304
00:20:17,767 --> 00:20:21,233
spacecraft or human
had ever left Earth,
305
00:20:21,633 --> 00:20:24,734
no one had ever seen
our world from space.
306
00:20:25,700 --> 00:20:28,467
The most extravagant fantasies
of the greatest artists were
307
00:20:28,600 --> 00:20:31,033
no match for what was coming.
308
00:20:31,700 --> 00:20:34,500
This is how one of
them imagined Earth
must look from space.
309
00:20:36,066 --> 00:20:38,600
And then, in one
instant on a single day,
310
00:20:39,767 --> 00:20:42,066
everything changed.
311
00:20:43,667 --> 00:20:47,567
This is how Mother Earth
looked when she was naked,
312
00:20:47,700 --> 00:20:50,600
before nearly 5,000 satellites
were in orbit around her,
313
00:20:52,400 --> 00:20:55,800
before anyone had ever
counted backwards from ten.
314
00:20:58,333 --> 00:21:04,300
(counting down
from ten in Russian)
315
00:21:10,734 --> 00:21:14,233
(counting down
from ten in Russian)
316
00:21:44,867 --> 00:21:47,166
TYSON: On October 4, 1957,
317
00:21:47,300 --> 00:21:50,500
the Soviet Union became
the first nation to dip its
318
00:21:50,633 --> 00:21:54,333
toe into the
shallows of the cosmic ocean.
319
00:21:55,900 --> 00:21:58,367
It launched Sputnik 1,
320
00:21:58,934 --> 00:22:03,333
a simple radio
transmitter that
circled Earth every 96 minutes.
321
00:22:10,934 --> 00:22:13,700
All over the planet,
people came outside to find
322
00:22:13,834 --> 00:22:17,967
this new light in the sky,
a man-made moon.
323
00:22:19,800 --> 00:22:21,734
Nothing could stop us
from achieving our
324
00:22:21,867 --> 00:22:25,266
most daring dreams.
325
00:22:25,400 --> 00:22:30,333
Think of it, something
we made was a new light
in the night sky.
326
00:22:31,233 --> 00:22:34,500
Something like a star.
327
00:22:34,834 --> 00:22:36,433
As this was happening,
328
00:22:36,567 --> 00:22:39,233
the boy was
becoming a scientist,
329
00:22:39,667 --> 00:22:43,600
and this new knowledge moved
him as nothing before had.
330
00:22:44,567 --> 00:22:47,033
All he could think was that
he wanted to share it with
331
00:22:47,166 --> 00:22:49,333
everyone on Earth,
332
00:22:49,700 --> 00:22:52,667
but that kind of thing was
frowned upon by scientists,
333
00:22:53,000 --> 00:22:56,133
they saw themselves as
being members of an elite club.
334
00:22:57,433 --> 00:23:01,033
In 1950, when Carl Sagan
was just a high school student,
335
00:23:01,166 --> 00:23:03,967
he wrote a paper that earned
him an invitation to work in
336
00:23:04,100 --> 00:23:06,533
the lab of H.J. Muller,
337
00:23:06,667 --> 00:23:09,800
who had won the Nobel Prize
for his discovery that radiation
338
00:23:09,934 --> 00:23:12,400
causes mutations in genes.
339
00:23:13,934 --> 00:23:16,633
By the time Carl got to
the University of Chicago,
340
00:23:16,767 --> 00:23:19,633
he was beginning to
make a name for himself,
341
00:23:19,767 --> 00:23:22,333
and Harold Urey
chose to mentor him.
342
00:23:22,800 --> 00:23:24,166
Urey, the chemist,
343
00:23:24,300 --> 00:23:27,166
was now doing the thing that
he had resented Kuiper for,
344
00:23:27,300 --> 00:23:30,367
trespassing on the turf of
another scientific discipline.
345
00:23:31,333 --> 00:23:33,533
This time it was biology.
346
00:23:33,667 --> 00:23:36,633
Urey and his team wanted
to know how life could have
347
00:23:36,767 --> 00:23:38,934
originated from lifeless matter.
348
00:23:41,266 --> 00:23:43,433
Working with
another student of his,
349
00:23:44,166 --> 00:23:47,667
Stanley Miller, Urey designed
an experiment to simulate the
350
00:23:47,800 --> 00:23:51,066
chemical conditions of the
atmosphere on the early Earth.
351
00:23:51,834 --> 00:23:54,400
They wanted to see whether
those basic chemicals could
352
00:23:54,533 --> 00:23:58,333
have led to amino acids,
the building blocks of life.
353
00:24:00,834 --> 00:24:04,867
Could lightning have
provided the spark that
awakened matter into life?
354
00:24:06,734 --> 00:24:09,934
"And if it could
happen here on Earth,
355
00:24:10,400 --> 00:24:13,467
where else could it have
happened?" Carl wondered.
356
00:24:15,867 --> 00:24:18,533
When he wrote a paper
speculating on that possibility,
357
00:24:18,667 --> 00:24:20,934
Urey responded harshly.
358
00:24:21,834 --> 00:24:24,867
He scolded his
apprentice for
venturing beyond his expertise.
359
00:24:26,066 --> 00:24:29,066
But still, Carl loved Urey
because he knew that this
360
00:24:29,200 --> 00:24:31,967
toughness would make
him a better scientist.
361
00:24:33,567 --> 00:24:36,567
In the summer, Carl
traveled to the enemy camp,
362
00:24:36,700 --> 00:24:38,266
to McDonald Observatory,
363
00:24:38,400 --> 00:24:41,133
to observe Mars
with Gerard Kuiper,
364
00:24:41,433 --> 00:24:44,867
the only planetary
astronomer on Earth.
365
00:24:45,000 --> 00:24:48,033
That year, Mars was in a
favorable opposition to Earth.
366
00:24:49,400 --> 00:24:53,200
The two worlds would be the
closest they'd been in 30 years.
367
00:24:54,000 --> 00:24:56,633
But the weather
didn't cooperate,
368
00:24:56,767 --> 00:24:59,033
not in Texas, but on Mars.
369
00:24:59,834 --> 00:25:03,166
A global windblown dust
storm there prevented Kuiper
370
00:25:03,300 --> 00:25:05,767
and Sagan from
seeing anything new.
371
00:25:06,600 --> 00:25:08,633
Instead, they spent
those summer nights talking
372
00:25:08,767 --> 00:25:10,467
of many things.
373
00:25:10,600 --> 00:25:12,800
The older man taught
the young scientist the
374
00:25:12,934 --> 00:25:16,367
most efficient ways to
test his bold new ideas.
375
00:25:16,900 --> 00:25:19,834
They fantasized about what
those possible worlds circling
376
00:25:19,967 --> 00:25:22,400
other stars might be like.
377
00:25:22,734 --> 00:25:25,600
These two fearless scientific
imaginations ventured
378
00:25:25,734 --> 00:25:28,467
throughout the
galaxy all that summer.
379
00:25:28,834 --> 00:25:32,433
The gates to the wonderworld
were swinging open for Carl.
380
00:25:32,867 --> 00:25:34,967
And all of this was
happening as we were reaching
381
00:25:35,100 --> 00:25:38,767
beyond the planet for the
very first time.
382
00:25:39,700 --> 00:25:43,900
(Sputnik radio signal)
383
00:25:46,734 --> 00:25:49,100
Soviet Union's Sputnik
scared the hell out of
384
00:25:49,233 --> 00:25:50,967
the United States.
385
00:25:51,166 --> 00:25:54,200
The Cold War was a contest
between dueling ideologies
386
00:25:54,333 --> 00:25:56,600
about property and freedom.
387
00:25:57,166 --> 00:25:58,967
When the Russians
got there first,
388
00:25:59,100 --> 00:26:02,000
it seemed to reflect
badly on our world view.
389
00:26:02,600 --> 00:26:05,967
And if they could send an object
into orbit above our heads,
390
00:26:06,100 --> 00:26:09,066
we could no
longer protect our skies.
391
00:26:09,467 --> 00:26:11,500
Suddenly, there was
a new delivery system
392
00:26:11,633 --> 00:26:13,000
for nuclear weapons.
393
00:26:13,133 --> 00:26:14,800
Nowhere on Earth could
be safeguarded against
394
00:26:14,934 --> 00:26:17,066
espionage or attack.
395
00:26:17,200 --> 00:26:19,834
We needed a space
program of our own.
396
00:26:20,467 --> 00:26:23,166
The National Aeronautics
and Space Administration was
397
00:26:23,300 --> 00:26:25,967
founded a year
after Sputnik in 1958.
398
00:26:27,133 --> 00:26:30,233
Science was at last
ready to see Earth as Kuiper
399
00:26:30,367 --> 00:26:33,033
had been seeing it for years,
as a planet.
400
00:26:34,333 --> 00:26:35,867
What a concept.
401
00:26:36,300 --> 00:26:39,233
It may seem obvious to us now,
but in a time of fanatical,
402
00:26:39,367 --> 00:26:42,633
fight to the death nationalism,
it was a thunderbolt.
403
00:26:44,567 --> 00:26:47,367
But Kuiper's feud
with Urey still raged,
404
00:26:47,500 --> 00:26:49,133
even as they both took
leadership roles in the
405
00:26:49,266 --> 00:26:51,433
fledgling space program.
406
00:26:52,033 --> 00:26:54,934
Carl continued ferrying
between their warring labs.
407
00:26:55,433 --> 00:26:59,266
The enmity between the two men
was emotionally so corrosive
408
00:26:59,400 --> 00:27:01,333
that he said at the time he,
409
00:27:01,467 --> 00:27:03,900
"Felt like the child
of divorced parents and he was
410
00:27:04,033 --> 00:27:07,166
the only bridge
left between them."
411
00:27:07,533 --> 00:27:10,400
Urey fought for NASA
to go to the Moon.
412
00:27:10,533 --> 00:27:14,200
Among his reasons was a
desire to know, at last,
413
00:27:15,166 --> 00:27:17,867
how the solar system formed.
414
00:27:23,266 --> 00:27:26,233
Kuiper predicted what it would
be like when we got there.
415
00:27:26,367 --> 00:27:29,767
That when we stepped
down on the lunar
surface for the first time,
416
00:27:29,900 --> 00:27:32,834
it would feel
like walking on crunchy snow.
417
00:27:35,066 --> 00:27:38,200
The Moon is a silent world
because it has no atmosphere
418
00:27:38,333 --> 00:27:40,266
to carry sound waves.
419
00:27:40,400 --> 00:27:43,834
But Neil Armstrong later said
that he felt Kuiper's crunchy
420
00:27:43,967 --> 00:27:46,500
snow when he stepped
down onto the surface for the
421
00:27:46,633 --> 00:27:49,066
very first time.
422
00:27:49,767 --> 00:27:52,867
Some of the things the
wanderers left behind.
423
00:28:00,100 --> 00:28:01,900
Thanks to Urey and Kuiper,
424
00:28:02,033 --> 00:28:04,600
Carl Sagan was part
of this great adventure.
425
00:28:05,467 --> 00:28:08,700
He was living his most
extravagant childhood fantasies.
426
00:28:09,433 --> 00:28:11,467
He briefed the Apollo
astronauts before they left
427
00:28:11,600 --> 00:28:12,967
for the Moon.
428
00:28:13,100 --> 00:28:15,300
And he was there when
scientists first met to
429
00:28:15,433 --> 00:28:18,033
evaluate the information
gained from the dawn
430
00:28:18,166 --> 00:28:20,166
of space exploration.
431
00:28:20,800 --> 00:28:24,300
For the first time ever,
the biologist, the geologist,
432
00:28:24,934 --> 00:28:26,133
the astronomers,
433
00:28:26,266 --> 00:28:28,867
the physicists, the
chemists were all talking
434
00:28:29,000 --> 00:28:30,533
to one another.
435
00:28:30,667 --> 00:28:32,633
Actually, mostly shouting.
436
00:28:33,433 --> 00:28:35,600
The young Carl Sagan
stood up at one of their
437
00:28:35,734 --> 00:28:38,200
joint scientific
meetings and said,
438
00:28:38,333 --> 00:28:42,867
"Hey, guys, we're the
first generation of scientists
to receive these riches.
439
00:28:44,133 --> 00:28:46,600
We're in this together."
440
00:28:46,934 --> 00:28:50,567
He set a tone for planetary
science that still holds today.
441
00:28:52,500 --> 00:28:55,700
He edited the first modern
interdisciplinary journal for
442
00:28:55,834 --> 00:28:58,367
researchers studying
the world of the cosmos,
443
00:28:59,500 --> 00:29:02,300
Icarus, which
continues to this day.
444
00:29:02,900 --> 00:29:04,467
And he did something else.
445
00:29:04,600 --> 00:29:07,567
He started a lifelong campaign
to bring the revelations of
446
00:29:07,700 --> 00:29:11,934
science to everyone, and
he was one of a handful of
447
00:29:12,367 --> 00:29:15,066
scientists who made the
search for possible worlds,
448
00:29:15,200 --> 00:29:18,600
for extra-terrestrial life and
for intelligence respectable
449
00:29:18,734 --> 00:29:20,700
scientific pursuits.
450
00:29:21,767 --> 00:29:25,100
We've only been hunting for
new worlds for a few decades,
451
00:29:25,233 --> 00:29:28,200
but we've already discovered
many thousands of them.
452
00:29:30,333 --> 00:29:32,900
We think some of them are
hospitable to life and at
453
00:29:33,033 --> 00:29:36,133
least a dozen of
them are earth-like.
454
00:29:39,700 --> 00:29:42,633
What will they be like?
455
00:29:43,867 --> 00:29:45,900
Come with me.
456
00:30:00,333 --> 00:30:02,900
TYSON: Carl Sagan wanted
to liberate a scientific
457
00:30:03,033 --> 00:30:06,333
imagination from the single
example of life that we know,
458
00:30:07,500 --> 00:30:08,867
Earth life.
459
00:30:09,000 --> 00:30:11,667
He envisioned what the
life of another very different
460
00:30:11,800 --> 00:30:13,567
world would be like.
461
00:30:13,700 --> 00:30:17,000
Sagan collaborated with fellow
astrophysicist Ed Salpeter in
462
00:30:17,133 --> 00:30:20,967
the design of plausible
ecological systems for life in
463
00:30:21,100 --> 00:30:23,166
the roiling clouds of Jupiter.
464
00:30:24,967 --> 00:30:28,100
The challenge was to imagine
such life-forms without
465
00:30:28,233 --> 00:30:31,467
violating the laws of physics,
chemistry or biology.
466
00:30:33,633 --> 00:30:39,066
Is life so tenacious that
it could even make a home
in this storm of hydrogen,
467
00:30:39,667 --> 00:30:42,600
helium, water,
ammonia and methane?
468
00:30:43,867 --> 00:30:46,400
There's no
accessible solid surface.
469
00:30:46,533 --> 00:30:49,834
It's just this thick cloudy
atmosphere in which organic
470
00:30:49,967 --> 00:30:53,033
molecules are falling
like manna from heaven,
471
00:30:54,133 --> 00:30:58,734
like the products of Harold Urey
and Stanley Miller's laboratory
experiment on life's origin.
472
00:30:59,266 --> 00:31:02,300
However, this environment
poses a problem for life.
473
00:31:02,900 --> 00:31:07,200
The atmosphere is turbulent
and deep down it's very hot.
474
00:31:08,033 --> 00:31:10,800
An organism must be careful
that it's not carried downward
475
00:31:10,934 --> 00:31:13,300
to the hell below.
476
00:31:14,734 --> 00:31:16,767
One way to make a living
under these conditions is to
477
00:31:16,900 --> 00:31:19,400
reproduce before
you sink and get fried.
478
00:31:20,800 --> 00:31:23,567
Your only hope is that
convection will carry some of
479
00:31:23,700 --> 00:31:26,133
your offspring to the
higher and cooler layers
480
00:31:26,266 --> 00:31:28,667
of the atmosphere.
481
00:31:30,367 --> 00:31:33,000
Such organisms
could be very small.
482
00:31:33,667 --> 00:31:36,133
Sagan and Salpeter
call them "sinkers."
483
00:31:39,100 --> 00:31:41,266
But you could
also be a "floater,"
484
00:31:41,400 --> 00:31:45,734
a vast hydrogen blimp pumping
helium and heavier gases out
of your interior and
485
00:31:45,867 --> 00:31:48,834
retaining only the
lightest gas, hydrogen.
486
00:31:50,734 --> 00:31:53,800
Sagan and Salpeter reasoned
that like a hot air balloon
487
00:31:53,934 --> 00:31:57,200
you'd stay buoyant by keeping
your interior warm using
488
00:31:57,333 --> 00:32:00,133
energy acquired from
the foods you eat.
489
00:32:00,734 --> 00:32:04,200
A floater must eat organic
molecules or make its own food
490
00:32:04,333 --> 00:32:07,200
from sunlight and air,
as plants do on Earth.
491
00:32:09,533 --> 00:32:13,000
The bigger a floater is,
the more efficient it will be,
492
00:32:13,133 --> 00:32:15,300
up to a point.
493
00:32:15,934 --> 00:32:18,934
Floaters would be immense,
several kilometers across,
494
00:32:20,800 --> 00:32:24,133
enormously larger than the
greatest whale that ever was,
495
00:32:24,700 --> 00:32:27,367
beings the size of cities.
496
00:32:27,500 --> 00:32:29,367
The floaters may propel
themselves through the
497
00:32:29,500 --> 00:32:32,200
planetary atmosphere
with gusts of gas,
498
00:32:32,333 --> 00:32:34,300
like a ramjet or a rocket.
499
00:32:36,133 --> 00:32:39,066
Sagan and Salpeter imagined
them arranged in great lazy
500
00:32:39,200 --> 00:32:41,700
herds for as far as
the eye could see.
501
00:32:43,467 --> 00:32:46,533
The patterns on their skin
are adaptive camouflage,
502
00:32:46,667 --> 00:32:49,367
implying that
they have problems, too,
503
00:32:49,667 --> 00:32:53,767
because there's at
least one other ecological
niche in such an environment...
504
00:33:02,033 --> 00:33:04,100
Hunters.
505
00:33:04,233 --> 00:33:06,633
Hunters are fast, maneuverable.
506
00:33:11,433 --> 00:33:13,100
Hunters eat the floaters,
507
00:33:13,233 --> 00:33:15,433
both for their
organic molecules and for their
508
00:33:15,567 --> 00:33:17,700
store of pure hydrogen.
509
00:33:42,133 --> 00:33:46,100
There cannot be very
many hunters because if
they consume all the floaters,
510
00:33:46,934 --> 00:33:49,333
the hunters
themselves will parish.
511
00:34:03,166 --> 00:34:05,967
When scientists of the
21st century tested Sagan's
512
00:34:06,100 --> 00:34:08,867
imaginary life-forms against
what they knew of life,
513
00:34:09,767 --> 00:34:13,333
they realized that the
concept of a habitable zone
514
00:34:13,467 --> 00:34:15,500
had to be expanded.
515
00:34:15,633 --> 00:34:18,467
It moved into the
cloud tops of gas giants and
516
00:34:18,600 --> 00:34:20,834
the subsurface
oceans of ice worlds,
517
00:34:21,333 --> 00:34:24,200
and places we've
yet to imagine.
518
00:34:24,900 --> 00:34:27,800
Of all those worlds,
of all those stars,
519
00:34:29,400 --> 00:34:32,266
one must have been first.
520
00:34:35,433 --> 00:34:38,467
Come with me to the
oldest world we know.
521
00:34:46,700 --> 00:34:49,166
TYSON: We're in a
globular cluster,
522
00:34:49,300 --> 00:34:53,633
a densely packed ball
of a million stars, called M4,
523
00:34:54,033 --> 00:34:56,867
on the outskirts
of the Milky Way galaxy.
524
00:34:57,200 --> 00:34:59,900
When pulsars, rapidly
rotating neutron stars,
525
00:35:00,033 --> 00:35:03,533
were first discovered,
scientists wondered if they
526
00:35:03,667 --> 00:35:06,900
were a sign of intelligent
life because of the regularity
527
00:35:07,033 --> 00:35:08,834
of their radio signals.
528
00:35:09,934 --> 00:35:12,900
Once upon a time, this
star was a blue supergiant,
529
00:35:13,033 --> 00:35:15,934
but after a few million
years, it ran out of fuel,
530
00:35:16,533 --> 00:35:19,934
went supernova, then collapsed
into this ball of neutrons,
531
00:35:20,734 --> 00:35:23,233
no larger than a small town.
532
00:35:23,367 --> 00:35:25,867
It's nearby companion,
a white dwarf star,
533
00:35:26,000 --> 00:35:28,133
another burnt-out
stellar corpse,
534
00:35:28,266 --> 00:35:30,934
orbits only a few
million miles away.
535
00:35:31,066 --> 00:35:32,667
That's not why
we've come here.
536
00:35:32,800 --> 00:35:36,700
We've come in search
of the oldest known
planet in the cosmos.
537
00:35:39,667 --> 00:35:41,667
The cosmos was
young when this star,
538
00:35:41,800 --> 00:35:45,333
a white dwarf, was born,
12.7 billion years ago.
539
00:35:46,767 --> 00:35:49,667
The star was single then,
long before it was captured
540
00:35:49,800 --> 00:35:52,667
by the pulsar that
gave birth to a world.
541
00:35:53,400 --> 00:35:55,700
That world is out
here somewhere,
542
00:35:55,834 --> 00:35:58,867
taking 100 Earth years to
orbit these two shrunken stars.
543
00:36:01,000 --> 00:36:04,100
The fact that it exists bodes
well for those who dream of
544
00:36:04,233 --> 00:36:06,433
virtually infinite
possible worlds.
545
00:36:07,867 --> 00:36:11,767
If it formed less than a billion
years after the cosmos itself,
546
00:36:11,900 --> 00:36:14,967
then stars started
fostering planets soon after
547
00:36:15,100 --> 00:36:17,633
the beginning of time.
548
00:36:18,133 --> 00:36:21,633
Nurturing worlds
is what stars do.
549
00:36:23,200 --> 00:36:26,700
And what will the fate of
this oldest of planets be?
550
00:36:27,500 --> 00:36:30,166
Sorry to say,
it's a lonely one.
551
00:36:30,300 --> 00:36:32,567
Sometime in the
next billion years,
552
00:36:32,700 --> 00:36:36,400
the two stars will
be gravitationally
ambushed by a third.
553
00:36:44,233 --> 00:36:47,934
A red dwarf star will come
barreling into their vicinity.
554
00:36:48,066 --> 00:36:51,567
It's gravity will send this
ancient world careening out of
555
00:36:51,700 --> 00:36:56,600
its system and into the
lonely dark between the stars.
556
00:36:57,400 --> 00:37:02,266
A rogue planet
doomed to wander a
never-ending oblivion.
557
00:37:03,433 --> 00:37:06,967
But there are also homes away
from home that call to us,
558
00:37:07,100 --> 00:37:09,633
illuminated in
warmth not by one star,
559
00:37:09,767 --> 00:37:11,000
but three.
560
00:37:11,433 --> 00:37:14,700
I want to take you
to Gliese 667,
561
00:37:15,000 --> 00:37:17,333
a triple-star
system with six worlds,
562
00:37:17,467 --> 00:37:21,934
three of them enough
like earth to hold the
promise of life as we know it.
563
00:37:37,633 --> 00:37:42,300
Stars A and B are both a
little smaller than our Sun.
564
00:37:44,166 --> 00:37:47,533
This pair of orange
dwarfs orbit each other.
565
00:37:48,567 --> 00:37:52,233
Star C orbits them both,
it's a red dwarf.
566
00:37:53,667 --> 00:37:56,500
They're the most common
kind of star in the galaxy.
567
00:37:57,033 --> 00:38:00,100
As many as 80% of all
the stars in the cosmos may
568
00:38:00,233 --> 00:38:02,567
be red dwarfs.
569
00:38:02,967 --> 00:38:05,533
They consume their
hydrogen fuel slowly,
570
00:38:05,667 --> 00:38:07,633
so they last longer.
571
00:38:07,767 --> 00:38:10,000
More massive stars,
like blue giants,
572
00:38:10,133 --> 00:38:13,667
maintain such high pressures
that they burn out quickly.
573
00:38:27,200 --> 00:38:30,867
This outermost world of
the Gliese 667 system is
574
00:38:31,000 --> 00:38:34,367
four times the size of earth,
but it's too far from
575
00:38:34,500 --> 00:38:37,667
its stars to have
liquid water on its surface.
576
00:38:38,100 --> 00:38:40,033
That doesn't
mean it's lifeless.
577
00:38:40,166 --> 00:38:42,433
We don't yet know enough
about life to say what
578
00:38:42,567 --> 00:38:45,600
might be going on
beneath its frozen shell.
579
00:38:46,066 --> 00:38:47,934
We haven't yet
reached the habitable zone of
580
00:38:48,066 --> 00:38:49,734
this star system.
581
00:38:49,867 --> 00:38:52,600
Getting closer,
but not there yet,
582
00:38:53,200 --> 00:38:55,266
this even larger
world is impressive,
583
00:38:56,100 --> 00:38:58,834
but still just outside
that region considered to be
584
00:38:58,967 --> 00:39:03,400
hospitable to life and to the
human scientific imagination.
585
00:39:07,834 --> 00:39:10,233
Now, this is more like it.
586
00:39:10,734 --> 00:39:14,033
The kind of atmosphere
that promises life is here.
587
00:39:33,667 --> 00:39:39,433
♪ ♪
588
00:39:59,333 --> 00:40:01,367
♪ ♪
589
00:40:02,734 --> 00:40:05,900
(animal call)
590
00:40:36,767 --> 00:40:42,667
(waves and wind)
591
00:40:43,400 --> 00:40:48,033
(distant animal calls)
592
00:41:07,033 --> 00:41:11,433
(waves and wind)
593
00:41:29,200 --> 00:41:31,867
This isn't the stuff
of distant worlds,
594
00:41:32,000 --> 00:41:34,133
this little guy
is one of our own.
595
00:41:34,533 --> 00:41:38,467
All the other
life-forms we've just
seen were actually homegrown,
596
00:41:38,600 --> 00:41:40,500
right here on Earth.
597
00:41:40,867 --> 00:41:42,800
We haven't even begun
to get to know all the
598
00:41:42,934 --> 00:41:45,433
living things on
this tiny world.
599
00:41:46,000 --> 00:41:47,700
Think of all the possibilities,
600
00:41:47,834 --> 00:41:50,400
the different kinds of
life there must have been,
601
00:41:50,533 --> 00:41:53,700
and are, and will
be in the cosmos.
602
00:41:54,133 --> 00:41:55,567
Thanks to Gerard Kuiper,
603
00:41:55,700 --> 00:41:58,066
Harold Urey and so
many other scientists,
604
00:41:58,200 --> 00:42:02,667
we now know that it
takes just a few million
years for stars to evolve,
605
00:42:03,200 --> 00:42:06,633
and planets and moons to
coalesce out of gas and dust.
606
00:42:07,600 --> 00:42:10,500
In other words,
a solar system.
607
00:42:20,700 --> 00:42:22,633
It's a long
period of gestation,
608
00:42:22,767 --> 00:42:24,300
but far from rare.
609
00:42:24,433 --> 00:42:27,667
In our own galaxy, it happens
about once every month.
610
00:42:28,233 --> 00:42:29,967
In the observable universe,
611
00:42:30,100 --> 00:42:31,867
which we now think
contains as many as
612
00:42:32,000 --> 00:42:34,467
a trillion galaxies,
containing some
613
00:42:34,600 --> 00:42:38,000
200 million trillion stars,
614
00:42:39,266 --> 00:42:43,967
a cosmos of
200 million trillion stars,
615
00:42:45,233 --> 00:42:49,133
1,000 solar systems may be
forming every single second.
616
00:42:50,367 --> 00:42:53,367
That's 1,000 new solar
systems right there.
617
00:42:55,233 --> 00:42:56,800
1,000 new solar systems.
618
00:42:57,834 --> 00:42:59,233
1,000 new solar systems.
619
00:43:00,033 --> 00:43:01,433
1,000 new solar systems.
620
00:43:02,333 --> 00:43:04,367
1,000 new solar systems.
621
00:43:04,934 --> 00:43:06,867
1,000 new solar systems.
622
00:43:07,767 --> 00:43:09,800
1,000 new solar systems.
623
00:43:10,333 --> 00:43:11,467
(finger snap)
624
00:43:12,200 --> 00:43:13,400
(finger snap)
625
00:43:52,200 --> 00:43:54,166
Captioned by Cotter
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