1
00:00:02,200 --> 00:00:06,367
ROWE: A small black star
floats through space.

2
00:00:06,467 --> 00:00:10,800
This is the Sun, billions of
years in the future.

3
00:00:10,867 --> 00:00:13,800
It's all that remains
of our solar system,

4
00:00:14,967 --> 00:00:18,567
the sole survivor of
a dramatic history

5
00:00:18,567 --> 00:00:21,467
of elegant beauty
and extreme violence.

6
00:00:23,567 --> 00:00:26,000
Just because things look
really nice and serene

7
00:00:26,066 --> 00:00:28,467
now doesn't mean
it's always been that way.

8
00:00:30,266 --> 00:00:33,100
There are a lot of planets
that could have made it

9
00:00:33,166 --> 00:00:35,867
but didn't,
and we just happen to be

10
00:00:35,967 --> 00:00:37,266
one of the lucky ones that did.

11
00:00:38,900 --> 00:00:41,100
ROWE: The players in
our solar system's story

12
00:00:41,166 --> 00:00:44,367
are more tangled up
than we ever imagined.

13
00:00:44,367 --> 00:00:46,367
The more we look at
this stuff,

14
00:00:46,367 --> 00:00:48,967
the more we realize that
everything affects everything

15
00:00:48,967 --> 00:00:50,600
else, including us.

16
00:00:50,667 --> 00:00:54,400
ROWE: How did we go from
a vibrant family of planets

17
00:00:54,467 --> 00:00:57,100
orbiting the yellow sun
to a lone,

18
00:00:57,166 --> 00:00:59,166
dead zombie star?

19
00:01:16,467 --> 00:01:18,100
It's an old familiar story.

20
00:01:20,567 --> 00:01:23,567
A bunch of planets orbit
a yellow star

21
00:01:23,567 --> 00:01:26,300
in a quiet suburb of
the Milky Way galaxy.

22
00:01:28,567 --> 00:01:30,000
But it's not the whole story.

23
00:01:30,000 --> 00:01:30,266
But it's not the whole story.

24
00:01:31,567 --> 00:01:35,000
Over the past decade,
our vision of

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00:01:35,066 --> 00:01:38,100
our solar system has been
completely revamped.

26
00:01:39,266 --> 00:01:41,000
ROWE:
Think of the solar system as

27
00:01:41,066 --> 00:01:44,367
an old-fashioned mafia
crime family.

28
00:01:44,367 --> 00:01:47,867
The sun is the Don,
his quarreling children,

29
00:01:47,967 --> 00:01:49,600
the planets.

30
00:01:49,667 --> 00:01:52,166
Their story,
like any good mob movie,

31
00:01:52,166 --> 00:01:54,667
is an epic tale of empire
building,

32
00:01:54,667 --> 00:01:58,767
sibling rivalry, greed,
and ultra violence.

33
00:02:00,567 --> 00:02:02,667
THALLER: The origin of
the solar system was chaotic

34
00:02:02,667 --> 00:02:05,367
and violent --
planets colliding,

35
00:02:05,367 --> 00:02:08,600
planets
even changing places.

36
00:02:08,667 --> 00:02:12,166
ROWE: Now, a shift
in our understanding reveals

37
00:02:12,166 --> 00:02:17,467
a tale of tangled alliances
between family members.

38
00:02:17,567 --> 00:02:19,400
Just think about
how much our view

39
00:02:19,467 --> 00:02:21,166
of the solar system
has changed.

40
00:02:21,266 --> 00:02:23,967
The planets used to be
so far away from each other,

41
00:02:23,967 --> 00:02:25,900
and of course, they had nothing
to do with each other.

42
00:02:26,000 --> 00:02:28,767
And now, the history is all
about the interaction.

43
00:02:28,767 --> 00:02:30,000
So the idea that everything
is just

44
00:02:30,000 --> 00:02:31,567
So the idea that everything
is just

45
00:02:31,567 --> 00:02:35,300
its own world and doesn't
interact is completely wrong.

46
00:02:35,367 --> 00:02:37,667
We like to think of astronomy
as looking up,

47
00:02:37,767 --> 00:02:40,166
looking outward,
away from ourselves.

48
00:02:40,266 --> 00:02:42,700
But the more we do that,
the more we realize how

49
00:02:42,767 --> 00:02:45,567
connected we are
to everything out there.

50
00:02:45,667 --> 00:02:48,667
You probably have some
material in your body from

51
00:02:48,667 --> 00:02:50,000
pretty much every world that

52
00:02:50,066 --> 00:02:52,066
ever existed
in the solar system.

53
00:02:52,066 --> 00:02:54,567
ROWE:
Like any good mobster movie,

54
00:02:54,667 --> 00:02:58,967
our story starts with the humble
rise of the Godfather.

55
00:02:58,967 --> 00:03:00,000
in this tale,
that's the birth of the Sun.

56
00:03:00,000 --> 00:03:02,000
in this tale,
that's the birth of the Sun.

57
00:03:03,367 --> 00:03:06,767
But exactly how that happens
is a mystery.

58
00:03:08,166 --> 00:03:10,867
When we're trying to figure out
how the solar system began,

59
00:03:10,967 --> 00:03:12,567
you know, we don't have
a time machine.

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00:03:12,567 --> 00:03:17,100
So what can we use to find out
about how it formed?

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00:03:19,166 --> 00:03:22,100
ROWE: The solar system
has the answer,

62
00:03:22,166 --> 00:03:25,467
its own time machines --
meteorites.

63
00:03:30,367 --> 00:03:32,367
Meteorites are pieces of
the solar system from

64
00:03:32,467 --> 00:03:35,467
the distant past, and they've
remained unchanged since then.

65
00:03:35,567 --> 00:03:37,400
So they're like little
time capsules.

66
00:03:41,266 --> 00:03:43,266
They're like fossils
from before

67
00:03:43,367 --> 00:03:45,000
our solar system even formed.

68
00:03:45,066 --> 00:03:46,266
By studying them,

69
00:03:46,300 --> 00:03:48,767
we can really study what was
happening and what was going

70
00:03:48,867 --> 00:03:51,767
on in the very early days of
our own solar system.

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00:03:54,667 --> 00:03:56,567
ROWE: 2020 --

72
00:03:56,667 --> 00:03:59,767
scientists study ancient
material trapped inside

73
00:03:59,767 --> 00:04:00,000
a meteorite found in
Murchison, Australia.

74
00:04:00,000 --> 00:04:04,200
a meteorite found in
Murchison, Australia.

75
00:04:04,266 --> 00:04:07,967
The Murchison meteorite
contains tiny crystals called

76
00:04:07,967 --> 00:04:11,567
presolar grains
that predate our sun.

77
00:04:15,100 --> 00:04:18,166
OLUSEYI: And trapped
within them is evidence of

78
00:04:18,166 --> 00:04:20,600
the history of the formation
of our solar system.

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00:04:22,100 --> 00:04:23,867
ROWE: The presolar grains
are made up of

80
00:04:23,867 --> 00:04:28,600
elements like silicon that
form inside giant stars.

81
00:04:33,266 --> 00:04:35,467
When these stars die,
they blow out

82
00:04:35,567 --> 00:04:39,166
huge clouds of gas
and grains of dust.

83
00:04:39,166 --> 00:04:42,700
The term presolar grain
doesn't sound very romantic,

84
00:04:42,767 --> 00:04:45,667
but actually,
we might call those stardust,

85
00:04:45,667 --> 00:04:47,266
because these materials
are things that were

86
00:04:47,367 --> 00:04:49,667
made in stars
that no longer exist.

87
00:04:51,467 --> 00:04:53,767
ROWE: The Murchison meteorite
contains grains

88
00:04:53,767 --> 00:04:56,867
from at least
46 different stars.

89
00:04:58,367 --> 00:05:00,000
What the Murchison
meteorite tells us is that

90
00:05:00,000 --> 00:05:00,900
What the Murchison
meteorite tells us is that

91
00:05:01,000 --> 00:05:03,000
the material that came together

92
00:05:03,100 --> 00:05:06,967
that formed our solar system
had its origination in

93
00:05:06,967 --> 00:05:09,066
dozens of different stars.

94
00:05:09,066 --> 00:05:13,600
These stars died and blew out
all of these materials.

95
00:05:13,667 --> 00:05:16,900
And then created this huge
cloud of gas and dust

96
00:05:17,000 --> 00:05:18,066
called a nebula.

97
00:05:19,100 --> 00:05:21,066
OLUSEYI: The sources of
the material in that cloud

98
00:05:21,066 --> 00:05:23,300
could come from one of
a number of places.

99
00:05:23,367 --> 00:05:25,700
The material
from lots of stars'

100
00:05:25,767 --> 00:05:28,900
atmospheres
could be mixed in there.

101
00:05:29,000 --> 00:05:30,000
ROWE: In the mix were
the ingredients to build

102
00:05:30,000 --> 00:05:31,600
ROWE: In the mix were
the ingredients to build

103
00:05:31,667 --> 00:05:33,400
the solar system,

104
00:05:33,467 --> 00:05:35,367
but we don't know
what triggered

105
00:05:35,467 --> 00:05:37,900
the gas and dust
to form the Sun.

106
00:05:39,266 --> 00:05:42,000
A 2020 study
may have the answer.

107
00:05:44,066 --> 00:05:45,767
BULLOCK: One of the coolest
things we've discovered

108
00:05:45,867 --> 00:05:48,567
in the last couple of decades
about the Milky Way

109
00:05:48,567 --> 00:05:50,467
is there's a giant stream
of stars that's

110
00:05:50,467 --> 00:05:52,900
stretching across virtually
the whole sky.

111
00:05:56,266 --> 00:05:58,867
These stars were not
born in the galaxy.

112
00:05:58,967 --> 00:06:00,000
They're not from here.

113
00:06:00,000 --> 00:06:00,166
They're not from here.

114
00:06:02,100 --> 00:06:03,500
ROWE:
If not from our galaxy,

115
00:06:03,567 --> 00:06:05,667
then from where?

116
00:06:06,700 --> 00:06:10,200
We think these stars actually
came from

117
00:06:10,266 --> 00:06:14,166
the Sagittarius Dwarf galaxy,
which orbits the Milky Way.

118
00:06:16,166 --> 00:06:18,166
ROWE:
Over five billion years ago,

119
00:06:18,266 --> 00:06:21,400
the Sagittarius Dwarf
galaxy wanders

120
00:06:21,467 --> 00:06:23,300
too close to the Milky Way.

121
00:06:25,266 --> 00:06:30,000
Our galaxy's powerful gravity
drags Sagittarius towards it.

122
00:06:30,000 --> 00:06:30,100
Our galaxy's powerful gravity
drags Sagittarius towards it.

123
00:06:30,166 --> 00:06:31,800
The galaxies collide.

124
00:06:33,266 --> 00:06:34,500
As this is happening,

125
00:06:34,567 --> 00:06:37,266
the Milky Way is tearing
Sagittarius apart,

126
00:06:37,266 --> 00:06:38,967
ripping stars out of it.

127
00:06:41,166 --> 00:06:46,300
This is truly intergalactic
cosmological drama at play.

128
00:06:48,066 --> 00:06:51,166
This collision shakes up
the Milky Way.

129
00:06:51,166 --> 00:06:54,100
When a body passes

130
00:06:54,166 --> 00:06:56,367
through the disc
of our galaxy, it's

131
00:06:56,467 --> 00:06:58,767
gonna set off ripples,
and that's going to compress

132
00:06:58,767 --> 00:07:00,000
the gas clouds, and that's gonna
create star formation.

133
00:07:00,000 --> 00:07:02,467
the gas clouds, and that's gonna
create star formation.

134
00:07:02,567 --> 00:07:06,166
The Sagittarius Dwarf smashing
into the Milky Way

135
00:07:06,166 --> 00:07:09,767
is like dropping a boulder
into a pond.

136
00:07:15,700 --> 00:07:18,567
It sets out ripples
of density,

137
00:07:18,667 --> 00:07:21,500
and it disturbs
everything in the galaxy,

138
00:07:21,567 --> 00:07:23,967
but it doesn't disturb
everything equally.

139
00:07:23,967 --> 00:07:26,500
It causes some clumps of dust

140
00:07:26,567 --> 00:07:29,467
and gas to start
accumulating together.

141
00:07:33,100 --> 00:07:36,567
ROWE: The disruption in
one galactic zip code leads

142
00:07:36,567 --> 00:07:39,700
to new activity in others
across the Milky Way.

143
00:07:41,367 --> 00:07:43,867
The ripples trigger gas
and dust left over

144
00:07:43,967 --> 00:07:47,567
from the dying stars
to split into clumps,

145
00:07:47,667 --> 00:07:50,600
sparking a frenzy of
star formation.

146
00:07:51,767 --> 00:07:53,867
LANZA: Look, if you were
an observer,

147
00:07:53,967 --> 00:07:57,066
suddenly, out of
these little clumps of gas

148
00:07:57,066 --> 00:08:00,000
come bright ignition sparks
all at once.

149
00:08:00,000 --> 00:08:00,166
come bright ignition sparks
all at once.

150
00:08:04,900 --> 00:08:07,000
If you were to stand there
long enough,

151
00:08:07,066 --> 00:08:08,667
watching this stellar nursery,

152
00:08:08,767 --> 00:08:11,000
it might look kind of like
a field at night

153
00:08:11,066 --> 00:08:13,100
with fireflies blinking on.

154
00:08:14,600 --> 00:08:17,767
ROWE: Perhaps the Sun formed in
this starburst.

155
00:08:18,800 --> 00:08:21,367
OLUSEYI: The passage
of the Sagittarius Dwarf

156
00:08:21,467 --> 00:08:23,500
through our galaxy correlates

157
00:08:23,567 --> 00:08:26,467
in time to the formation and
birth of our sun.

158
00:08:26,467 --> 00:08:30,000
So maybe our solar system came
about as a result of

159
00:08:30,000 --> 00:08:31,367
So maybe our solar system came
about as a result of

160
00:08:31,367 --> 00:08:34,567
the Sagittarius Dwarf passing
through our galaxy

161
00:08:34,667 --> 00:08:36,300
over five million years ago.

162
00:08:36,367 --> 00:08:39,400
Of course, we don't know for
sure if this is what triggered

163
00:08:39,467 --> 00:08:42,467
the formation of our sun,
but the timing does fit.

164
00:08:45,567 --> 00:08:48,900
ROWE:
4.6 billion years ago,

165
00:08:49,000 --> 00:08:50,467
part of the cloud
seeded with

166
00:08:50,567 --> 00:08:54,700
material from dying stars
grows denser,

167
00:08:54,767 --> 00:08:58,100
until it gets so massive,
it collapses.

168
00:09:00,100 --> 00:09:03,000
NANCE:
As the gas cloud collapses,

169
00:09:03,066 --> 00:09:07,266
it gets hotter and hotter
and spins faster and faster,

170
00:09:07,266 --> 00:09:10,400
forming a dense core
at its center.

171
00:09:10,467 --> 00:09:16,367
The core is the protostar
that will later become our sun.

172
00:09:16,467 --> 00:09:20,767
ROWE: The protostar drags in
more and more gas and dust,

173
00:09:20,767 --> 00:09:24,367
creating a region of materials
spinning around it

174
00:09:24,467 --> 00:09:26,867
called the protoplanetary disk.

175
00:09:26,967 --> 00:09:30,000
OLUSEYI: As the Sun
builds up more mass,

176
00:09:30,000 --> 00:09:31,100
OLUSEYI: As the Sun
builds up more mass,

177
00:09:31,166 --> 00:09:33,900
it's getting compressed
gravitationally, and so the core

178
00:09:34,000 --> 00:09:35,767
is getting hotter
and hotter and hotter.

179
00:09:35,867 --> 00:09:37,367
The densities are increasing.

180
00:09:40,367 --> 00:09:43,567
ROWE: The new Don, the head
of our solar mobster family,

181
00:09:43,567 --> 00:09:47,300
immediately reveals
a ferocious nature,

182
00:09:47,367 --> 00:09:51,200
blasting out supercharged jets
of radiation.

183
00:09:52,266 --> 00:09:57,467
The early sun was not
the calm, glowing orb

184
00:09:57,467 --> 00:10:00,000
that we see in our sky today --
it was far more chaotic.

185
00:10:00,000 --> 00:10:00,900
that we see in our sky today --
it was far more chaotic.

186
00:10:03,166 --> 00:10:05,800
It's sort of like
in its toddler phase.

187
00:10:05,867 --> 00:10:07,900
It was acting up
all the time.

188
00:10:10,066 --> 00:10:13,100
It has all of this energy that
pushes material off of

189
00:10:13,166 --> 00:10:15,000
the surface
and launches it into

190
00:10:15,066 --> 00:10:16,266
what we call the solar wind.

191
00:10:18,567 --> 00:10:21,200
ROWE: The blizzard of
particles races out

192
00:10:21,266 --> 00:10:23,867
at over a million miles
an hour.

193
00:10:23,967 --> 00:10:27,000
It smashes into
the protoplanetary disk

194
00:10:27,066 --> 00:10:28,767
and blows the gas away.

195
00:10:31,066 --> 00:10:35,100
At the same time, the Sun's
core heats up to 18 million

196
00:10:35,166 --> 00:10:37,066
degrees Fahrenheit,

197
00:10:37,066 --> 00:10:41,367
triggering the fusion of
hydrogen into helium.

198
00:10:41,367 --> 00:10:43,667
And that releases
a tremendous amount of

199
00:10:43,767 --> 00:10:46,400
energy that eventually works
its way back to the surface of

200
00:10:46,467 --> 00:10:48,367
the star
and comes out as light.

201
00:10:50,100 --> 00:10:53,867
Finally, the Sun
becomes the recognizable

202
00:10:53,867 --> 00:10:56,066
sun that we see
in our sky today.

203
00:10:58,100 --> 00:11:00,000
ROWE: The sun is now
the Godfather,

204
00:11:00,000 --> 00:11:00,867
ROWE: The sun is now
the Godfather,

205
00:11:00,867 --> 00:11:03,100
pulling the strings on
the solar system.

206
00:11:04,567 --> 00:11:06,767
The young Don's
rise to the top

207
00:11:06,867 --> 00:11:09,967
triggers a power struggle
with its willful children,

208
00:11:09,967 --> 00:11:11,767
the planets.

209
00:11:11,867 --> 00:11:14,100
It's a brutal fight
for survival.

210
00:11:26,500 --> 00:11:29,200
ROWE:
4.6 billion years ago,

211
00:11:30,367 --> 00:11:34,700
our mob family rises in
a quiet suburb of the Milky Way.

212
00:11:35,767 --> 00:11:39,767
Its Godfather, the Sun,
forms from a collapsed

213
00:11:39,867 --> 00:11:41,100
stellar nebula.

214
00:11:44,867 --> 00:11:48,110
The greedy star scarfs down
most of the cloud of gas

215
00:11:48,110 --> 00:11:48,266
The greedy star scarfs down
most of the cloud of gas

216
00:11:48,266 --> 00:11:50,200
and dust,
but just enough

217
00:11:50,266 --> 00:11:53,166
is left over
to build the planets.

218
00:11:53,266 --> 00:11:56,567
We're standing here on a big
planet, and we look up in

219
00:11:56,667 --> 00:11:58,967
the sky, and we see other
planets going around the Sun,

220
00:11:58,967 --> 00:12:02,266
and it's an obvious
and challenging question to ask,

221
00:12:02,266 --> 00:12:03,767
where did these planets
come from?

222
00:12:05,700 --> 00:12:09,367
ROWE: How did the leftover gas
and dust build the planets?

223
00:12:10,900 --> 00:12:13,767
To solve the mystery,

224
00:12:13,767 --> 00:12:16,100
scientists study
other star systems

225
00:12:16,166 --> 00:12:18,110
across the Milky Way.

226
00:12:18,110 --> 00:12:18,300
across the Milky Way.

227
00:12:18,367 --> 00:12:19,867
HOPKINS:
We can't go back in time

228
00:12:19,867 --> 00:12:22,066
and watch our own
solar system forming.

229
00:12:22,066 --> 00:12:25,567
But we can look at other,
new solar systems as they're

230
00:12:25,667 --> 00:12:28,800
forming and use that to
understand how our own

231
00:12:28,867 --> 00:12:30,100
might have formed.

232
00:12:34,000 --> 00:12:40,900
ROWE: Star system PDS 70
is one such system.

233
00:12:41,000 --> 00:12:44,900
It's young,
just 5.4 million years old.

234
00:12:47,266 --> 00:12:48,110
And nestled inside
the protoplanetary disk are

235
00:12:48,110 --> 00:12:50,600
And nestled inside
the protoplanetary disk are

236
00:12:50,667 --> 00:12:54,800
two infant planets
feeding on gas and dust.

237
00:12:58,000 --> 00:13:00,967
We can see these baby
exoplanets pulling in

238
00:13:00,967 --> 00:13:03,567
material and creating
these gaps in the disk.

239
00:13:03,667 --> 00:13:05,867
It's an amazing discovery --
it's kind of mind-blowing

240
00:13:05,967 --> 00:13:09,667
that we can see a new
solar system being born.

241
00:13:11,600 --> 00:13:14,266
CHRISTIANSEN: These snapshots,
these systems like PDS 70,

242
00:13:14,367 --> 00:13:17,967
are so valuable, because they
let us test our theories.

243
00:13:17,967 --> 00:13:18,110
We thought planets formed from
these discs of dust and gas,

244
00:13:18,110 --> 00:13:21,000
We thought planets formed from
these discs of dust and gas,

245
00:13:21,100 --> 00:13:23,500
but we hadn't seen it
until now.

246
00:13:23,567 --> 00:13:25,767
ROWE: What we couldn't see
was how gas

247
00:13:25,867 --> 00:13:29,200
and dust bind together
to grow into planets.

248
00:13:35,567 --> 00:13:37,166
That took an astronaut on

249
00:13:37,166 --> 00:13:40,367
the space station messing
around with breakfast.

250
00:13:42,767 --> 00:13:44,200
Ah.

251
00:13:44,266 --> 00:13:45,567
Don Pettit,
this one astronaut,

252
00:13:45,567 --> 00:13:47,767
took a bag
full of salt and sugar

253
00:13:47,867 --> 00:13:48,110
and coffee grounds and just
shook it to see what would

254
00:13:48,110 --> 00:13:50,066
and coffee grounds and just
shook it to see what would

255
00:13:50,066 --> 00:13:51,900
happen in 0G.

256
00:13:52,000 --> 00:13:53,600
And to his astonishment,

257
00:13:53,667 --> 00:13:57,467
he saw that they immediately
clumped up.

258
00:13:57,467 --> 00:14:01,200
It's effectively electrostatic
forces that are causing

259
00:14:01,266 --> 00:14:03,400
those clumps to form --
the salt grains

260
00:14:03,467 --> 00:14:05,867
rub around with each other,
and they develop a charge,

261
00:14:05,867 --> 00:14:07,500
an electrical charge.

262
00:14:07,567 --> 00:14:10,367
And so those clumps
very naturally form.

263
00:14:12,100 --> 00:14:14,667
ROWE:
These clumps were strong.

264
00:14:14,667 --> 00:14:18,110
They didn't fall apart when
they hit the sides of the bag.

265
00:14:18,110 --> 00:14:19,367
They didn't fall apart when
they hit the sides of the bag.

266
00:14:19,367 --> 00:14:21,567
DURDA: And sitting down
on the ground,

267
00:14:21,667 --> 00:14:24,600
down at mission control,
was astronaut Stan Love,

268
00:14:24,667 --> 00:14:26,700
going, "Oh, my God,
Don, you've solved the first

269
00:14:26,767 --> 00:14:28,567
steps of planetary formation."

270
00:14:30,266 --> 00:14:34,100
A very similar
process went on

271
00:14:34,166 --> 00:14:36,266
in the early
protoplanetary disk.

272
00:14:36,367 --> 00:14:38,567
Instead of salt,
it's mineral grains.

273
00:14:42,567 --> 00:14:46,600
So the dust grains that you
start with stick to each other

274
00:14:46,667 --> 00:14:48,110
because of
electrostatic forces,

275
00:14:48,110 --> 00:14:48,367
because of
electrostatic forces,

276
00:14:48,467 --> 00:14:49,667
basically static cling,

277
00:14:49,767 --> 00:14:51,800
and it's almost exactly
identical to how

278
00:14:51,867 --> 00:14:54,100
a dust bunny forms
in your room.

279
00:14:54,166 --> 00:14:56,767
SUTTER: These are cosmic dust
bunnies that

280
00:14:56,867 --> 00:15:01,367
will some day grow up
into giant planets.

281
00:15:01,367 --> 00:15:06,100
ROWE: Astronomers call these
cosmic dust bunnies pebbles.

282
00:15:08,000 --> 00:15:11,700
We think clumping dust
particles formed trillions

283
00:15:11,767 --> 00:15:15,066
of pebbles each around
an inch in diameter.

284
00:15:15,066 --> 00:15:18,110
It's the first step in
planet construction.

285
00:15:18,110 --> 00:15:18,667
It's the first step in
planet construction.

286
00:15:18,667 --> 00:15:20,967
The next step in
forming a planet

287
00:15:20,967 --> 00:15:23,500
involves planetesimals
and these are objects that are

288
00:15:23,567 --> 00:15:26,600
roughly half a mile
to 100 miles in size.

289
00:15:28,700 --> 00:15:31,567
ROWE: But how pebbles build
planetesimals was

290
00:15:31,667 --> 00:15:36,066
a mystery, because pebbles
don't play well together.

291
00:15:38,266 --> 00:15:40,166
Grains of protoplanetary
material stick

292
00:15:40,166 --> 00:15:42,066
together because
of static charge.

293
00:15:42,066 --> 00:15:44,100
The problem is,
once they get too big,

294
00:15:44,166 --> 00:15:46,066
that force isn't enough,
and they'll just

295
00:15:46,066 --> 00:15:47,567
bounce off each other.

296
00:15:53,667 --> 00:15:57,000
Yet we know that we have to
get all the way up to hundreds

297
00:15:57,066 --> 00:15:58,867
of miles across to build
our planetesimals.

298
00:15:58,867 --> 00:16:02,567
How do you build a bigger
structure when the particles

299
00:16:02,667 --> 00:16:04,166
that you're trying
to lump together

300
00:16:04,166 --> 00:16:05,667
are bouncing off of
each other?

301
00:16:07,300 --> 00:16:10,467
WALSH: So a new idea
came forward about how to make

302
00:16:10,467 --> 00:16:12,667
this big jump from
pebble-sized things

303
00:16:12,767 --> 00:16:14,567
all the way up to
planetesimals,

304
00:16:14,667 --> 00:16:17,100
and this relies on
the interaction of a huge number

305
00:16:17,166 --> 00:16:18,110
of pebbles moving together
through the gas

306
00:16:18,110 --> 00:16:19,600
of pebbles moving together
through the gas

307
00:16:19,667 --> 00:16:21,567
around the star.

308
00:16:21,567 --> 00:16:25,266
BATYGIN: In the disk
of gas and dust that encircles

309
00:16:25,367 --> 00:16:26,500
the young sun,

310
00:16:26,500 --> 00:16:30,800
pebbles will begin to coalesce
into these big clouds,

311
00:16:30,867 --> 00:16:35,700
much in the same way that
individual fish will form

312
00:16:35,767 --> 00:16:36,900
schools of fish.

313
00:16:37,000 --> 00:16:41,467
ROWE: More and more pebbles
join the cloud.

314
00:16:41,467 --> 00:16:44,200
Eventually,
you get enough of them

315
00:16:44,266 --> 00:16:46,800
together that they collapse
under their own gravity

316
00:16:46,867 --> 00:16:48,110
and make one big
planetesimal.

317
00:16:48,110 --> 00:16:48,200
and make one big
planetesimal.

318
00:16:59,667 --> 00:17:01,700
ROWE: The planetesimals
face a race

319
00:17:01,767 --> 00:17:05,567
against time to grow
into planets.

320
00:17:05,567 --> 00:17:07,567
They must grab enough
building material

321
00:17:07,667 --> 00:17:11,266
from the protoplanetary disk
before their Don,

322
00:17:11,367 --> 00:17:13,867
the Sun,
blasts it all away.

323
00:17:26,166 --> 00:17:28,467
ROWE:
4.6 billion years ago,

324
00:17:28,567 --> 00:17:32,166
a fierce battle erupts between
the head of the family,

325
00:17:32,166 --> 00:17:35,100
the Sun, and his children,
the growing planets.

326
00:17:35,166 --> 00:17:40,367
The Godfather is armed and
dangerous and threatening to

327
00:17:40,467 --> 00:17:42,867
destroy the planet's
food source

328
00:17:42,967 --> 00:17:45,567
with his weapon of choice,
the solar wind.

329
00:17:46,567 --> 00:17:48,270
There's this strong wind
of high-energy particles

330
00:17:48,270 --> 00:17:49,367
There's this strong wind
of high-energy particles

331
00:17:49,367 --> 00:17:51,000
coming out of the Sun.

332
00:17:51,066 --> 00:17:53,266
That blows away the disk
of gas.

333
00:17:54,867 --> 00:17:57,400
ROWE: The planets must fight
to grab hold of

334
00:17:57,467 --> 00:18:01,200
the remaining resources before
the Sun drives them away.

335
00:18:01,266 --> 00:18:06,700
So it's a race against time --
Jupiter is racing

336
00:18:06,767 --> 00:18:09,200
the Sun to capture
as much material as

337
00:18:09,266 --> 00:18:12,200
it can before the Sun
blows it all away.

338
00:18:12,266 --> 00:18:15,300
And what we see from studying
other solar systems is

339
00:18:15,367 --> 00:18:18,270
that those disks only last for
about five million years.

340
00:18:18,270 --> 00:18:19,166
that those disks only last for
about five million years.

341
00:18:19,266 --> 00:18:21,300
ROWE: We used to think
of the solar system's

342
00:18:21,367 --> 00:18:24,367
protoplanetary disk
like an old-school diner

343
00:18:24,467 --> 00:18:27,100
where the mob family
came to eat.

344
00:18:27,166 --> 00:18:31,166
The firstborn child, Jupiter,
grows by wolfing down

345
00:18:31,166 --> 00:18:34,467
planetesimals, followed by
a second course of gas.

346
00:18:35,667 --> 00:18:38,667
HOPKINS: The old model of planet
formation is the idea that

347
00:18:38,667 --> 00:18:42,700
these large-ish planetesimals
that are miles across

348
00:18:42,767 --> 00:18:44,100
collide and stick to
each other,

349
00:18:44,166 --> 00:18:46,467
kind of like modeling clay,
until you get a bigger

350
00:18:46,467 --> 00:18:47,700
and bigger object that can

351
00:18:47,767 --> 00:18:48,270
eventually get so massive that
it starts to then pull in

352
00:18:48,270 --> 00:18:50,667
eventually get so massive that
it starts to then pull in

353
00:18:50,667 --> 00:18:55,400
the more diffuse gas around it
to form a gaseous atmosphere.

354
00:18:55,467 --> 00:18:59,400
ROWE: It's a simple idea,
but with a big problem --

355
00:18:59,467 --> 00:19:01,000
time.

356
00:19:01,100 --> 00:19:03,400
By that old model,
it would take upwards of

357
00:19:03,467 --> 00:19:06,900
100 million years to accumulate
enough planetesimals to do that.

358
00:19:08,000 --> 00:19:10,100
ROWE: Way too long
for Jupiter to grow

359
00:19:10,166 --> 00:19:13,000
before the Sun blows all
the gas away.

360
00:19:14,767 --> 00:19:16,767
We found
a clue to how Jupiter

361
00:19:16,867 --> 00:19:18,270
beat the problem of
the disappearing gas

362
00:19:18,270 --> 00:19:19,767
beat the problem of
the disappearing gas

363
00:19:19,767 --> 00:19:24,000
in 2017, when the Juno
spacecraft investigated

364
00:19:24,100 --> 00:19:25,767
the gas giant's core.

365
00:19:25,867 --> 00:19:28,867
HOPKINS: The traditional
theories predict that

366
00:19:28,867 --> 00:19:30,900
Jupiter's core would be
kind of like a big ball

367
00:19:31,000 --> 00:19:34,300
of solid iron or rock,
surrounded by

368
00:19:34,367 --> 00:19:36,967
a giant gaseous atmosphere.

369
00:19:40,667 --> 00:19:44,867
SUTTER: Juno instead found
that Jupiter's core is fuzzy.

370
00:19:44,967 --> 00:19:47,900
There's no boundary
between hard rock

371
00:19:48,000 --> 00:19:48,270
and then
gaseous atmosphere.

372
00:19:48,270 --> 00:19:49,567
and then
gaseous atmosphere.

373
00:19:49,667 --> 00:19:52,467
There's just a gradual
transition as you move

374
00:19:52,567 --> 00:19:56,667
outwards from mostly rock
and icy to mostly gassy.

375
00:19:58,400 --> 00:20:02,000
ROWE: This fuzzy transition from
rock ice core to gas

376
00:20:02,066 --> 00:20:03,367
suggests that young Jupiter

377
00:20:03,367 --> 00:20:06,867
didn't eat a la carte with
separate courses of

378
00:20:06,967 --> 00:20:08,600
planetesimals and then gas.

379
00:20:11,300 --> 00:20:16,166
Instead, it devoured the whole
buffet in one sitting.

380
00:20:16,166 --> 00:20:18,270
HOPKINS: These fuzzy cores
suggest that,

381
00:20:18,270 --> 00:20:18,900
HOPKINS: These fuzzy cores
suggest that,

382
00:20:19,000 --> 00:20:21,266
as Jupiter's core
was forming,

383
00:20:21,266 --> 00:20:24,667
it was actually incorporating
a mixture of gas and ice

384
00:20:24,667 --> 00:20:28,200
and rocks all together
in its formation.

385
00:20:28,266 --> 00:20:30,667
ROWE: This was possible
because there was still

386
00:20:30,667 --> 00:20:33,900
lots of gas in
the protoplanetary disk.

387
00:20:36,367 --> 00:20:37,900
Everything was moving through

388
00:20:38,000 --> 00:20:40,400
this very thick disk
of dust and gas.

389
00:20:40,467 --> 00:20:41,867
That means that everything
was actually

390
00:20:41,967 --> 00:20:44,300
being slowed down by the drag.

391
00:20:44,367 --> 00:20:46,000
Things were the size
of pebbles,

392
00:20:46,100 --> 00:20:47,967
they were feeling
the drag, too.

393
00:20:47,967 --> 00:20:48,270
That meant they lost energy
and made it easier for Jupiter

394
00:20:48,270 --> 00:20:51,300
That meant they lost energy
and made it easier for Jupiter

395
00:20:51,367 --> 00:20:52,767
to pull them in.

396
00:20:54,066 --> 00:20:56,700
ROWE: The young planetesimals
grab millions

397
00:20:56,767 --> 00:20:59,600
of pebbles along with
lots of gas.

398
00:20:59,667 --> 00:21:03,767
They're drawing in gas
as well as these pebbles.

399
00:21:03,867 --> 00:21:06,867
The pebbles basically run out,
and they keep drawing

400
00:21:06,967 --> 00:21:08,867
this gas in and get bigger
and bigger and bigger.

401
00:21:10,200 --> 00:21:13,700
HOPKINS: This formation model
allows you to grow a planet like

402
00:21:13,767 --> 00:21:15,266
Jupiter much more quickly,

403
00:21:15,367 --> 00:21:17,367
because it's gobbling up
everything at once at

404
00:21:17,467 --> 00:21:18,270
a very rapid pace, and that
allows it to potentially beat

405
00:21:18,270 --> 00:21:20,967
a very rapid pace, and that
allows it to potentially beat

406
00:21:20,967 --> 00:21:22,700
the Sun and grow within a few

407
00:21:22,767 --> 00:21:25,967
million years before the Sun
blows everything away.

408
00:21:27,900 --> 00:21:29,700
ROWE: Both Jupiter
and Saturn

409
00:21:29,767 --> 00:21:33,266
won their race against the Sun
and grew large.

410
00:21:34,767 --> 00:21:38,000
But the inner planets
were not so lucky.

411
00:21:40,200 --> 00:21:44,767
The Godfather ruthlessly
limited the food on their menu.

412
00:21:44,767 --> 00:21:47,300
HOWETT:
And so the planets that formed

413
00:21:47,367 --> 00:21:48,270
depend upon what you have to
begin with -- if you're making

414
00:21:48,270 --> 00:21:50,467
depend upon what you have to
begin with -- if you're making

415
00:21:50,467 --> 00:21:52,667
a cake, and you only have
certain ingredients,

416
00:21:52,767 --> 00:21:54,867
you can only make a cake out
of those ingredients,

417
00:21:54,967 --> 00:21:56,567
and the planets
are the same way.

418
00:21:56,667 --> 00:21:58,166
They could only be made out

419
00:21:58,166 --> 00:22:00,166
of things that are in
their vicinity.

420
00:22:00,266 --> 00:22:03,000
In the inner solar system,
where it's much warmer,

421
00:22:03,100 --> 00:22:05,667
volatiles like water
and ammonia

422
00:22:05,767 --> 00:22:07,967
had evaporated
and get blown away.

423
00:22:07,967 --> 00:22:11,700
So the only materials found
here for building planets

424
00:22:11,767 --> 00:22:15,000
were rocky,
metallic materials.

425
00:22:15,066 --> 00:22:16,767
So the planets
that formed in this

426
00:22:16,767 --> 00:22:18,270
inner region are rocky planets
with metallic cores.

427
00:22:18,270 --> 00:22:20,667
inner region are rocky planets
with metallic cores.

428
00:22:23,200 --> 00:22:25,867
ROWE: The ice giants feasted
on materials that

429
00:22:25,967 --> 00:22:29,700
only survive far from
the Sun's harmful influence.

430
00:22:31,000 --> 00:22:32,367
HOPKINS:
When you get further out,

431
00:22:32,467 --> 00:22:35,767
the distances that Uranus
and Neptune are at, ammonia

432
00:22:35,867 --> 00:22:39,266
and methane start to turn into
their own frozen ices.

433
00:22:39,266 --> 00:22:40,867
That's why we call them
ice giants, because

434
00:22:40,867 --> 00:22:44,367
they're formed primarily
out of these solid ices.

435
00:22:44,367 --> 00:22:47,967
ROWE: And there were plenty
of these ices to gorge on.

436
00:22:49,767 --> 00:22:51,400
HOWETT: The further you are
from the Sun,

437
00:22:51,467 --> 00:22:53,767
the less the effect
the solar wind has.

438
00:22:53,867 --> 00:22:55,867
It's a bit like if you're
standing next to a fan, where if

439
00:22:55,967 --> 00:22:57,400
you're right next to it,
you're really gonna feel it.

440
00:22:57,467 --> 00:22:58,700
You step back a few paces,

441
00:22:58,767 --> 00:23:00,467
it's not as blowy,
and so it's

442
00:23:00,567 --> 00:23:02,600
the same thing happening in
the outer solar system.

443
00:23:02,667 --> 00:23:04,100
It's not able to strip away

444
00:23:04,166 --> 00:23:06,867
the gasses and the rock quite
as much.

445
00:23:06,867 --> 00:23:08,767
ROWE: The ice giants
grew to over

446
00:23:08,867 --> 00:23:11,967
14 times the mass of Earth.

447
00:23:11,967 --> 00:23:14,767
The Godfather, the Sun,

448
00:23:14,767 --> 00:23:16,867
ruthlessly controls the family.

449
00:23:16,967 --> 00:23:18,270
But firstborn Jupiter has
grown large.

450
00:23:18,270 --> 00:23:20,800
But firstborn Jupiter has
grown large.

451
00:23:20,867 --> 00:23:22,900
He craves power

452
00:23:23,000 --> 00:23:26,867
and attempts a hostile takeover
of the inner solar system,

453
00:23:26,867 --> 00:23:29,667
triggering mass murder
and mayhem.

454
00:23:41,000 --> 00:23:42,967
ROWE: We used to think
that all star systems

455
00:23:42,967 --> 00:23:45,000
were similar to our own.

456
00:23:45,066 --> 00:23:49,266
That's because our solar system
was the only one we knew.

457
00:23:49,266 --> 00:23:51,867
OLUSEYI: It's hard to get
a perspective on

458
00:23:51,867 --> 00:23:53,800
your home if you've not been
anywhere else.

459
00:23:53,867 --> 00:23:57,266
We thought it was typical,
but now that we've discovered

460
00:23:57,367 --> 00:24:00,266
hundreds of others,
it's the weird one.

461
00:24:00,266 --> 00:24:02,266
It may surprise you to learn
that we've never found

462
00:24:02,266 --> 00:24:03,445
a solar system
around another star

463
00:24:03,445 --> 00:24:04,367
a solar system
around another star

464
00:24:04,367 --> 00:24:06,100
that really resembles our own,

465
00:24:06,166 --> 00:24:08,266
with all of these small, rocky
planets in the middle of

466
00:24:08,266 --> 00:24:10,567
the solar system
and these big gas giants

467
00:24:10,567 --> 00:24:12,367
farther out.

468
00:24:12,467 --> 00:24:17,667
ROWE: We've found star systems
with super puff planets,

469
00:24:17,767 --> 00:24:21,467
rocky worlds orbiting
tiny red stars,

470
00:24:21,467 --> 00:24:24,667
giant stars
with superheated planets

471
00:24:24,767 --> 00:24:26,767
that rain liquid iron,

472
00:24:26,867 --> 00:24:30,000
water worlds,
and planets orbiting zombie

473
00:24:30,066 --> 00:24:31,500
white dwarf stars,

474
00:24:31,567 --> 00:24:33,445
but none that look like
our home system.

475
00:24:33,445 --> 00:24:34,667
but none that look like
our home system.

476
00:24:34,767 --> 00:24:37,500
Every solar system
we look at, ours

477
00:24:37,567 --> 00:24:41,000
just look like it's standing
off in a corner all by itself.

478
00:24:42,767 --> 00:24:46,467
ROWE: The other systems may be
very different from our own,

479
00:24:46,567 --> 00:24:50,467
but they can still show us how
the solar system developed.

480
00:24:52,867 --> 00:24:54,900
2021.

481
00:24:55,000 --> 00:24:57,200
Scientists discover
six planets orbiting

482
00:24:57,266 --> 00:24:58,967
a small orange star

483
00:24:58,967 --> 00:25:01,567
called TOI-178.

484
00:25:02,567 --> 00:25:03,445
And they range from just
a little bit more massive than

485
00:25:03,445 --> 00:25:04,800
And they range from just
a little bit more massive than

486
00:25:04,867 --> 00:25:06,767
the Earth,
about 1.5 times,

487
00:25:06,867 --> 00:25:09,800
to a bit more than seven times
the mass of the Earth.

488
00:25:09,867 --> 00:25:13,000
These are called
super-Earths, and it turns out,

489
00:25:13,100 --> 00:25:15,700
these are really abundant
out in the universe.

490
00:25:16,767 --> 00:25:20,166
ROWE: Around 40 percent
of the star systems we've found

491
00:25:20,266 --> 00:25:24,266
contain at least one
super-Earth.

492
00:25:24,266 --> 00:25:27,567
One of the most peculiar
aspects about our solar system

493
00:25:27,667 --> 00:25:29,700
is that we don't have
any super-Earths.

494
00:25:29,767 --> 00:25:31,600
We see these
things everywhere.

495
00:25:31,667 --> 00:25:32,967
Not here.

496
00:25:36,567 --> 00:25:38,467
ROWE: The first clue to
solving the mystery of

497
00:25:38,467 --> 00:25:43,266
the missing super-Earths comes
from an asteroid called Psyche.

498
00:25:43,266 --> 00:25:45,767
It orbits
in the asteroid belt,

499
00:25:45,767 --> 00:25:50,467
a band of rocky objects
between Mars and Jupiter.

500
00:25:50,567 --> 00:25:53,967
The asteroid Psyche appears
to be a fascinating world

501
00:25:53,967 --> 00:25:57,000
made almost entirely of metal,
of iron and nickel.

502
00:25:59,867 --> 00:26:03,445
LANZA: We think it's the core
of a now destroyed planet.

503
00:26:03,445 --> 00:26:04,200
LANZA: We think it's the core
of a now destroyed planet.

504
00:26:04,266 --> 00:26:07,500
You can think of Psyche
as a metallic kernel of

505
00:26:07,567 --> 00:26:11,066
a nut whose shell was smashed
off in a huge collision.

506
00:26:16,767 --> 00:26:20,200
ROWE: The asteroid belt
is full of similar debris,

507
00:26:20,266 --> 00:26:23,700
like blood splatter
at a mafia murder scene.

508
00:26:28,567 --> 00:26:30,700
It points to serious
felonies taking

509
00:26:30,767 --> 00:26:33,000
place in the early
solar system.

510
00:26:33,066 --> 00:26:33,445
We think that there were
once dozens of

511
00:26:33,445 --> 00:26:37,700
We think that there were
once dozens of

512
00:26:37,767 --> 00:26:40,900
rocky protoplanets orbiting
around the young sun.

513
00:26:43,467 --> 00:26:45,066
Now we only have four.

514
00:26:47,700 --> 00:26:49,967
We find clues to what caused

515
00:26:49,967 --> 00:26:53,667
this planetary homicide in
distant star systems.

516
00:26:55,100 --> 00:26:57,867
PLAIT: The first exoplanets
that we found orbiting stars

517
00:26:57,867 --> 00:27:00,166
like the Sun are what we call
hot Jupiters.

518
00:27:00,166 --> 00:27:02,100
Nobody expected these.

519
00:27:02,166 --> 00:27:03,445
These are planets
as big or bigger

520
00:27:03,445 --> 00:27:05,000
These are planets
as big or bigger

521
00:27:05,100 --> 00:27:06,567
than Jupiter,
but orbiting

522
00:27:06,667 --> 00:27:09,000
super close in to their star.

523
00:27:09,066 --> 00:27:11,467
When the young star is forming,

524
00:27:11,467 --> 00:27:13,400
it blows out all of
the material

525
00:27:13,467 --> 00:27:14,367
that's very close to it,

526
00:27:14,367 --> 00:27:16,667
the sheer force
of the solar winds, so

527
00:27:16,767 --> 00:27:18,567
there's nothing that could
have formed right there.

528
00:27:18,567 --> 00:27:19,600
How the heck did you get

529
00:27:19,667 --> 00:27:23,000
a planet that big,
that close to a star?

530
00:27:23,100 --> 00:27:26,200
ROWE:
Hot Jupiters forced scientists

531
00:27:26,266 --> 00:27:28,567
to consider a radical idea.

532
00:27:28,667 --> 00:27:31,300
We always assumed
that planets were

533
00:27:31,367 --> 00:27:33,367
formed where
we see them today.

534
00:27:33,467 --> 00:27:35,767
But these hot Jupiters couldn't
have been formed there.

535
00:27:35,767 --> 00:27:39,767
They must have migrated in
from further out.

536
00:27:39,867 --> 00:27:41,700
WALSH: That made us look
at our solar system

537
00:27:41,767 --> 00:27:43,567
through a different lens.

538
00:27:43,567 --> 00:27:47,867
And all of a sudden, we started
seeing signs that, oh, maybe --

539
00:27:47,867 --> 00:27:49,867
yeah, maybe this happened here.

540
00:27:49,967 --> 00:27:53,367
ROWE: One million years after

541
00:27:53,367 --> 00:27:56,700
the birth of the mafia
family-like solar system,

542
00:27:56,767 --> 00:27:59,000
many small rocky planets
grow in

543
00:27:59,100 --> 00:28:02,367
the inner part of
the protoplanetary disk.

544
00:28:02,367 --> 00:28:03,445
Underboss Jupiter makes
a move to take control of

545
00:28:03,445 --> 00:28:06,700
Underboss Jupiter makes
a move to take control of

546
00:28:06,767 --> 00:28:08,066
the family.

547
00:28:08,066 --> 00:28:12,567
The giant planet's gravity
creates spiraling waves in

548
00:28:12,567 --> 00:28:16,467
the protoplanetary disk,
which drag on Jupiter,

549
00:28:16,567 --> 00:28:17,767
slowing it down.

550
00:28:22,767 --> 00:28:25,567
So Jupiter slows down just
a little bit in its orbit around

551
00:28:25,567 --> 00:28:27,667
the Sun,
and as it slows down,

552
00:28:27,667 --> 00:28:32,000
it falls inwards towards
the Sun and migrates closer

553
00:28:32,100 --> 00:28:33,445
and closer.

554
00:28:33,445 --> 00:28:33,467
and closer.

555
00:28:33,567 --> 00:28:35,567
ROWE:
Jupiter crashes into

556
00:28:35,667 --> 00:28:39,367
the inner solar system --
in its path,

557
00:28:39,467 --> 00:28:41,300
the infant rocky planets.

558
00:28:43,166 --> 00:28:46,700
You can't take something with
300 times the mass of the Earth

559
00:28:46,767 --> 00:28:48,967
and let it roam around
the inner solar system

560
00:28:48,967 --> 00:28:51,567
and hope it's not gonna
do anything -- Jupiter is like

561
00:28:51,667 --> 00:28:54,467
a monster truck at a stock car
rally race, right?

562
00:28:54,467 --> 00:28:56,367
It's just plowing through
everything,

563
00:28:56,367 --> 00:28:57,567
just chaos everywhere.

564
00:29:02,400 --> 00:29:03,445
So here we are, forming
our lovely young solar system,

565
00:29:03,445 --> 00:29:04,867
So here we are, forming
our lovely young solar system,

566
00:29:04,967 --> 00:29:06,500
and there are
all kinds of new planets

567
00:29:06,567 --> 00:29:09,567
forming, and they're settling
into nice orderly orbits.

568
00:29:09,567 --> 00:29:11,467
And here comes Jupiter,

569
00:29:11,467 --> 00:29:12,767
the big bully on the block.

570
00:29:14,367 --> 00:29:18,800
ROWE: Enforcer Jupiter pushes
its smaller siblings around.

571
00:29:18,867 --> 00:29:22,800
Gravitationally, it starts to
destabilize the inner planets,

572
00:29:22,867 --> 00:29:25,867
so nice circular orbits
start to go all haywire,

573
00:29:26,867 --> 00:29:28,100
and things begin to
actually play

574
00:29:28,166 --> 00:29:30,367
pinball in the early
solar system.

575
00:29:31,467 --> 00:29:33,445
ROWE: The growing inner planets
fly off in all directions.

576
00:29:33,445 --> 00:29:35,867
ROWE: The growing inner planets
fly off in all directions.

577
00:29:35,867 --> 00:29:38,000
Some collide violently.

578
00:29:39,000 --> 00:29:40,300
Many die in the melee.

579
00:29:43,767 --> 00:29:46,600
DURDA: This is like
solar system demolition derby

580
00:29:46,667 --> 00:29:48,700
in the early days
of the formation of the planets,

581
00:29:48,767 --> 00:29:50,300
where things are
smashing into each other

582
00:29:50,367 --> 00:29:53,000
and destroying little planets
right and left.

583
00:29:55,867 --> 00:29:58,367
ROWE: This cosmic carnage
could explain why

584
00:29:58,467 --> 00:30:00,700
we don't have any
super-Earths.

585
00:30:06,300 --> 00:30:09,967
Perhaps our solar system once
had large, rocky planets,

586
00:30:11,166 --> 00:30:12,767
but debris from the colliding

587
00:30:12,867 --> 00:30:15,367
inner planets slowed down
their orbits,

588
00:30:16,867 --> 00:30:21,500
dragging the young
super-Earths into the Sun.

589
00:30:21,567 --> 00:30:24,767
These primordial super-Earths
get pushed

590
00:30:24,767 --> 00:30:27,000
onto the Sun
and destroyed altogether.

591
00:30:32,600 --> 00:30:33,445
It only takes 100,000
years to destroy

592
00:30:33,445 --> 00:30:36,300
It only takes 100,000
years to destroy

593
00:30:36,367 --> 00:30:38,867
the primordial group
of super-Earths that

594
00:30:38,867 --> 00:30:41,100
would have formed
in the inner solar system.

595
00:30:41,166 --> 00:30:45,266
ROWE: But not everyone agrees
with this version of events.

596
00:30:45,266 --> 00:30:49,266
This is a pretty cool idea,
but I'm not convinced by it.

597
00:30:49,367 --> 00:30:52,100
We have a lot of ideas of why
we are the way we are today.

598
00:30:52,166 --> 00:30:54,500
What we need is more evidence
to be able to separate

599
00:30:54,567 --> 00:30:55,600
these ideas out.

600
00:30:57,166 --> 00:30:59,066
ROWE: An alternative theory
suggests that

601
00:30:59,066 --> 00:31:02,567
Jupiter stole everyone
else's lunch,

602
00:31:02,667 --> 00:31:03,445
starving the inner solar
system of food

603
00:31:03,445 --> 00:31:06,467
starving the inner solar
system of food

604
00:31:06,567 --> 00:31:10,200
so the planets couldn't
grow into super-Earths.

605
00:31:11,767 --> 00:31:14,266
WALSH: Without Jupiter, Earth
and Venus and Mars might

606
00:31:14,266 --> 00:31:16,266
have just kept on growing
and growing and growing.

607
00:31:16,266 --> 00:31:17,467
We might have ended up with
a bunch

608
00:31:17,567 --> 00:31:19,166
of super-Earths
in the inner solar system.

609
00:31:20,567 --> 00:31:23,567
ROWE: Mob underboss
Jupiter's unprovoked assault

610
00:31:23,667 --> 00:31:27,166
on his smaller siblings in the
inner solar system continued.

611
00:31:28,266 --> 00:31:31,767
The attack caused many
casualties and nearly put

612
00:31:31,867 --> 00:31:33,445
our planet
in an early grave.

613
00:31:33,445 --> 00:31:34,667
our planet
in an early grave.

614
00:31:45,500 --> 00:31:49,266
ROWE: For thousands of years,
people have looked up at

615
00:31:49,266 --> 00:31:54,066
the sky and seen the planets
orbiting the Sun in harmony.

616
00:31:54,066 --> 00:31:57,367
THALLER: They've seen all
of this wonderful order.

617
00:31:57,367 --> 00:31:59,000
And that's what we thought.

618
00:31:59,100 --> 00:32:01,200
Everything formed together,
the Sun,

619
00:32:01,266 --> 00:32:04,200
the planets, almost like this
beautiful clockwork set up in

620
00:32:04,266 --> 00:32:05,400
the heavens.

621
00:32:05,467 --> 00:32:07,662
Now we know that actually that
was far from the truth.

622
00:32:07,662 --> 00:32:08,667
Now we know that actually that
was far from the truth.

623
00:32:13,367 --> 00:32:15,467
ROWE: Around two million
years after the birth

624
00:32:15,467 --> 00:32:18,667
of the Godfather, the Sun,
the underboss,

625
00:32:18,767 --> 00:32:22,200
Jupiter, makes a power grab
and crashes

626
00:32:22,266 --> 00:32:23,700
into the inner solar system.

627
00:32:33,266 --> 00:32:35,567
PLAIT: If Jupiter had continued
its journey toward the Sun,

628
00:32:35,667 --> 00:32:37,662
it would have ejected a lot
of the stuff that was left.

629
00:32:37,662 --> 00:32:38,166
it would have ejected a lot
of the stuff that was left.

630
00:32:38,166 --> 00:32:40,166
There would be
no inner rocky planets.

631
00:32:40,266 --> 00:32:41,600
It would just be Jupiter.

632
00:32:43,000 --> 00:32:46,667
ROWE: Fortunately,
we avoid complete slaughter.

633
00:32:46,767 --> 00:32:50,867
Something stops Jupiter's
murderous attack.

634
00:32:50,867 --> 00:32:53,467
Lucky for us,
we had an ace in the hole.

635
00:32:53,467 --> 00:32:55,767
We had a friend,
and that friend is so

636
00:32:55,767 --> 00:32:59,100
beautiful in the sky today,
and we call that friend Saturn.

637
00:33:03,000 --> 00:33:07,000
Saturn is also migrating
inward toward the Sun,

638
00:33:07,100 --> 00:33:07,662
but the rate it's moving in
depends on the mass of

639
00:33:07,662 --> 00:33:10,367
but the rate it's moving in
depends on the mass of

640
00:33:10,367 --> 00:33:12,867
the planet -- Saturn is
less massive than Jupiter,

641
00:33:12,867 --> 00:33:14,667
so it's moving in
more rapidly.

642
00:33:16,100 --> 00:33:19,867
ROWE: Peace-making consigliere,
Saturn, catches up

643
00:33:19,967 --> 00:33:22,700
with Jupiter
and brokers a deal.

644
00:33:22,767 --> 00:33:25,266
When they reach each other,
they don't collide.

645
00:33:25,367 --> 00:33:28,900
They get stuck in a complicated
orbital dance with each other.

646
00:33:29,000 --> 00:33:32,567
ROWE: Their cosmic tango
strips out gas from the disc,

647
00:33:32,567 --> 00:33:37,662
clearing a path for Saturn and
Jupiter to move back outwards.

648
00:33:37,662 --> 00:33:38,000
clearing a path for Saturn and
Jupiter to move back outwards.

649
00:33:38,100 --> 00:33:39,767
So this can actually reverse

650
00:33:39,767 --> 00:33:42,100
their migration, and all of
a sudden, we have

651
00:33:42,166 --> 00:33:44,300
the two planets moving outward
in the solar system.

652
00:33:44,367 --> 00:33:47,100
So it's like Saturn has
a trailer hitch, and it's towing

653
00:33:47,166 --> 00:33:49,266
Jupiter back to the outer
solar system,

654
00:33:49,266 --> 00:33:50,266
where we find them today.

655
00:33:53,500 --> 00:33:56,867
PLAIT: Saturn saved
the earth, basically.

656
00:33:56,867 --> 00:33:59,367
If it hadn't have been there
to pull Jupiter back out from

657
00:33:59,367 --> 00:34:00,567
the inner solar system,

658
00:34:00,600 --> 00:34:02,900
Jupiter would have thrown all
the inner planets out.

659
00:34:03,000 --> 00:34:07,266
So no Mercury, no Venus,
no Mars, no Earth.

660
00:34:07,266 --> 00:34:07,662
ROWE: Three million years after
the birth of the Sun,

661
00:34:07,662 --> 00:34:11,066
ROWE: Three million years after
the birth of the Sun,

662
00:34:11,066 --> 00:34:14,200
around 20 baby planets
survive Jupiter's

663
00:34:14,266 --> 00:34:16,800
ransacking of
the inner solar system,

664
00:34:16,867 --> 00:34:19,367
but the carnage isn't over.

665
00:34:21,867 --> 00:34:24,400
WALSH: The inner solar system's
kind of in turmoil.

666
00:34:24,467 --> 00:34:26,967
The gravitational interaction
from Jupiter was severe.

667
00:34:28,667 --> 00:34:31,066
Everything is excited,
orbits are out of control

668
00:34:31,066 --> 00:34:33,266
and crazy, and things are
interacting and having big,

669
00:34:33,367 --> 00:34:34,567
violent collisions.

670
00:34:38,100 --> 00:34:41,166
ROWE: The inner solar system
is like a congested highway.

671
00:34:44,000 --> 00:34:47,600
Planets cross lanes,
collisions are frequent.

672
00:34:50,600 --> 00:34:52,567
As the bloodshed continues,

673
00:34:52,667 --> 00:34:56,567
the young Earth wanders into
the path of a smaller planet.

674
00:34:58,100 --> 00:35:00,066
PLAIT: There's a theory,
and it's a pretty good one,

675
00:35:00,066 --> 00:35:02,000
that the Earth,
a long time ago,

676
00:35:02,100 --> 00:35:04,767
was hit by another
relatively big planet,

677
00:35:04,867 --> 00:35:06,000
and we call that planet Theia.

678
00:35:08,900 --> 00:35:12,767
ROWE: Theia hit Earth at over
25,000 miles an hour.

679
00:35:14,800 --> 00:35:16,700
The impact destroyed Theia

680
00:35:18,100 --> 00:35:19,467
and nearly wiped out Earth.

681
00:35:21,100 --> 00:35:23,800
OLUSEYI: When Earth
was struck by Theia,

682
00:35:23,867 --> 00:35:27,367
it was unlike any event
before or since.

683
00:35:27,367 --> 00:35:29,367
We think about the event
that wiped

684
00:35:29,367 --> 00:35:31,300
out the dinosaurs
as a huge collision.

685
00:35:31,367 --> 00:35:34,100
Oh, this one dwarfs that one.

686
00:35:37,667 --> 00:35:40,867
The Earth was completely
turned inside out.

687
00:35:40,967 --> 00:35:45,800
The surface was new, it was
molten, and it was raining fire,

688
00:35:45,867 --> 00:35:49,867
literally -- lava rock was
raining down from the heavens.

689
00:35:53,467 --> 00:35:55,767
ROWE: Earth was badly
wounded but survived.

690
00:36:00,066 --> 00:36:03,066
Material from Theia
mixed with Earth rock,

691
00:36:03,066 --> 00:36:07,100
building a bigger planet
and a new companion.

692
00:36:08,500 --> 00:36:10,000
This collision was so huge,

693
00:36:10,100 --> 00:36:12,266
it blasted off a tremendous
amount of material off

694
00:36:12,266 --> 00:36:15,400
the Earth's surface, and this
coalesced to form the Moon.

695
00:36:19,867 --> 00:36:22,066
ROWE: That theory
may now become fact.

696
00:36:24,266 --> 00:36:26,300
We found
two massive chunks of

697
00:36:26,367 --> 00:36:29,166
rock buried deep beneath
Earth's surface.

698
00:36:30,367 --> 00:36:33,767
These massive lumps of rock
have a different density,

699
00:36:33,767 --> 00:36:35,400
a different composition,

700
00:36:35,467 --> 00:36:37,367
than the rest of
the mantle rock around them.

701
00:36:38,667 --> 00:36:41,967
ROWE:
A new study in 2021 suggests

702
00:36:41,967 --> 00:36:43,367
they don't come from Earth.

703
00:36:46,066 --> 00:36:47,867
It could be that
these dense blobs of

704
00:36:47,867 --> 00:36:50,700
material deep in our mantle
are remnants of Theia.

705
00:36:53,367 --> 00:36:54,900
ROWE: Throughout
the inner solar system

706
00:36:55,000 --> 00:36:57,467
protoplanet
hit protoplanet.

707
00:37:00,600 --> 00:37:04,400
Some high speed crashes
ended in catastrophe.

708
00:37:05,900 --> 00:37:07,662
There was drama,
a lot of drama.

709
00:37:07,662 --> 00:37:08,400
There was drama,
a lot of drama.

710
00:37:08,467 --> 00:37:10,266
It's as much
a story of destruction

711
00:37:10,266 --> 00:37:11,600
as it is of creation.

712
00:37:11,667 --> 00:37:14,100
There are a lot of planets
that could have made it

713
00:37:14,166 --> 00:37:15,400
but didn't.

714
00:37:15,467 --> 00:37:17,967
And we just happened to be one
of the lucky ones that did.

715
00:37:20,300 --> 00:37:24,700
Slower impacts glued
the colliding worlds together,

716
00:37:24,767 --> 00:37:27,700
building hybrid planets
from the wreckage.

717
00:37:30,767 --> 00:37:34,200
The four terrestrial planets --
Mercury, Venus,

718
00:37:34,266 --> 00:37:37,300
Earth, and Mars --
emerged from the ashes

719
00:37:37,367 --> 00:37:37,662
of the 20 protoplanets
and joined the mob family.

720
00:37:37,662 --> 00:37:41,000
of the 20 protoplanets
and joined the mob family.

721
00:37:41,066 --> 00:37:43,300
The planets are connected.

722
00:37:43,367 --> 00:37:45,600
You probably have some
material in your body

723
00:37:45,667 --> 00:37:47,166
from pretty much every world

724
00:37:47,266 --> 00:37:48,667
that ever existed
in the solar system.

725
00:37:48,667 --> 00:37:50,800
Everything mixed around.

726
00:37:50,867 --> 00:37:53,367
That mixing made Earth

727
00:37:53,467 --> 00:37:56,266
larger and better
equipped to survive.

728
00:37:57,600 --> 00:37:59,967
The bloodbath also
left its mark

729
00:37:59,967 --> 00:38:01,600
on the other
surviving planets.

730
00:38:03,300 --> 00:38:04,867
RADEBAUGH: What's strange
about Venus is that

731
00:38:04,867 --> 00:38:07,467
it actually spins in
the opposite direction.

732
00:38:07,467 --> 00:38:07,662
All the other planets spin
sort of with --

733
00:38:07,662 --> 00:38:09,467
All the other planets spin
sort of with --

734
00:38:09,467 --> 00:38:12,400
with a righthand spin,
from the west to the east,

735
00:38:12,467 --> 00:38:15,667
and Venus spins from the east
to the west.

736
00:38:15,767 --> 00:38:18,867
LANZA: And also
Venus's spin is very slow.

737
00:38:18,867 --> 00:38:22,400
It's 243 times slower
than that of Earth's.

738
00:38:22,467 --> 00:38:26,000
You can imagine a big
protoplanetary embryo,

739
00:38:26,066 --> 00:38:27,900
almost the size of Venus
itself, smashing

740
00:38:28,000 --> 00:38:29,467
almost head-on to Venus,

741
00:38:30,767 --> 00:38:34,600
just in the right angle to
stop the rotation,

742
00:38:34,667 --> 00:38:37,662
slow it down, even actually
reverse it slightly.

743
00:38:37,662 --> 00:38:37,900
slow it down, even actually
reverse it slightly.

744
00:38:38,000 --> 00:38:41,000
And now, it's still spinning
like that today.

745
00:38:43,667 --> 00:38:46,900
ROWE: Mercury carries horrific
scars from Jupiter's

746
00:38:47,000 --> 00:38:49,567
assault on the inner
solar system.

747
00:38:51,066 --> 00:38:53,867
THALLER: Mercury has always
seemed to be a bit of

748
00:38:53,967 --> 00:38:55,900
an odd planet, because it really
is sort of a cannonball.

749
00:38:56,000 --> 00:38:58,800
It has a giant core compared
to the rest of the planet.

750
00:38:58,867 --> 00:39:01,100
So the question is,
how do you get

751
00:39:01,166 --> 00:39:03,700
this large core,
but very little rock,

752
00:39:03,767 --> 00:39:05,367
very little mantle
and crust around it?

753
00:39:06,600 --> 00:39:07,662
ROWE: We think Mercury
hit another planet, hard.

754
00:39:07,662 --> 00:39:10,166
ROWE: We think Mercury
hit another planet, hard.

755
00:39:11,300 --> 00:39:15,467
DARTNELL: The outer layers of
Mercury, its rocky mantle,

756
00:39:15,567 --> 00:39:18,166
was blasted off,
leaving behind

757
00:39:18,166 --> 00:39:22,800
just the dense iron cannonball
core of this planet,

758
00:39:22,867 --> 00:39:26,567
which ricocheted off and then
settled in Mercury's

759
00:39:26,667 --> 00:39:28,800
current orbit,
close to the Sun.

760
00:39:33,367 --> 00:39:35,767
ROWE: That leaves
one last rocky planet

761
00:39:35,767 --> 00:39:37,662
member of the mafia
family -- Mars.

762
00:39:37,662 --> 00:39:39,767
member of the mafia
family -- Mars.

763
00:39:42,567 --> 00:39:45,567
It's older and much smaller
than its neighbors,

764
00:39:45,667 --> 00:39:46,900
Venus and Earth.

765
00:39:49,467 --> 00:39:52,066
One way to interpret
Mars in this scenario is that

766
00:39:52,066 --> 00:39:53,567
Mars was one of
those original

767
00:39:53,667 --> 00:39:56,166
20 or 30 planetary embryos,
or protoplanets,

768
00:39:56,166 --> 00:39:58,400
and it just survived.

769
00:39:58,467 --> 00:40:00,867
It avoided
this big violent end game

770
00:40:00,867 --> 00:40:03,200
of the giant impact stage of
planet formation.

771
00:40:04,367 --> 00:40:06,767
ROWE:
Mars sat on the sidelines,

772
00:40:06,767 --> 00:40:07,662
far enough away
from the action to

773
00:40:07,662 --> 00:40:08,400
far enough away
from the action to

774
00:40:08,467 --> 00:40:10,767
be safe from physical harm,

775
00:40:10,867 --> 00:40:15,000
but enforcer Jupiter's violent
raid on the inner solar system

776
00:40:15,066 --> 00:40:20,000
still prevented Mars from
reaching its full potential.

777
00:40:20,066 --> 00:40:22,700
One big effect
of Jupiter's incursion

778
00:40:22,767 --> 00:40:23,700
into the inner solar system is

779
00:40:23,767 --> 00:40:26,000
to blast away
a bunch of material,

780
00:40:26,066 --> 00:40:28,266
around where we find Mars today.

781
00:40:28,367 --> 00:40:30,700
THALLER: In some ways,
Jupiter kinda ate Mars's lunch.

782
00:40:30,767 --> 00:40:32,667
So Mars just didn't have as
much stuff to

783
00:40:32,667 --> 00:40:35,100
work with, and it never became
a very big planet.

784
00:40:36,200 --> 00:40:37,662
ROWE: After 60 million years of
family feuding,

785
00:40:37,662 --> 00:40:39,667
ROWE: After 60 million years of
family feuding,

786
00:40:39,767 --> 00:40:43,500
the battle of the planets is
finally over.

787
00:40:43,567 --> 00:40:46,200
OLUSEYI: Out of all the mayhem
and chaos of the early

788
00:40:46,266 --> 00:40:49,467
solar system, four
terrestrial planets remained.

789
00:40:49,467 --> 00:40:52,100
One of them was Earth.

790
00:40:52,166 --> 00:40:54,467
THALLER: Given everything we've
now learned about how violent

791
00:40:54,567 --> 00:40:57,467
it was, we understand just
how vulnerable we've been

792
00:40:57,467 --> 00:41:00,166
all the way along --
planets colliding, planets

793
00:41:00,266 --> 00:41:03,567
even changing places --
in some ways now, it's amazing

794
00:41:03,567 --> 00:41:06,000
the Earth even survived.

795
00:41:06,066 --> 00:41:07,662
ROWE: Our planet emerged as one
of the winners from underboss

796
00:41:07,662 --> 00:41:09,367
ROWE: Our planet emerged as one
of the winners from underboss

797
00:41:09,367 --> 00:41:12,667
Jupiter's homicidal assault
on the inner planets.

798
00:41:12,767 --> 00:41:16,767
But Jupiter's return to
the outer solar system soon

799
00:41:16,867 --> 00:41:18,467
triggered more mayhem,

800
00:41:18,567 --> 00:41:21,567
mayhem that would threaten
Earth with the biggest

801
00:41:21,667 --> 00:41:24,266
bombardment in its history.

802
00:41:38,300 --> 00:41:41,767
ROWE: The mafia family
we call the solar system has

803
00:41:41,767 --> 00:41:45,500
survived underboss Jupiter's
attack on the inner planets

804
00:41:46,700 --> 00:41:50,500
but faces more disruption from
its enforcer

805
00:41:50,567 --> 00:41:52,500
when the giant gas
planet heads

806
00:41:52,567 --> 00:41:56,100
out towards
where Uranus and Neptune grow,

807
00:41:56,166 --> 00:41:58,853
a journey that may help
explain several mysteries about

808
00:41:58,853 --> 00:41:59,166
a journey that may help
explain several mysteries about

809
00:41:59,166 --> 00:42:00,300
the solar system,

810
00:42:00,367 --> 00:42:03,467
including the size
of the ice giants.

811
00:42:04,667 --> 00:42:06,867
PLAIT: The biggest problem with
the outer solar system is

812
00:42:06,967 --> 00:42:08,266
literally bigness.

813
00:42:08,367 --> 00:42:11,867
Uranus and Neptune are too big
for where they are.

814
00:42:11,967 --> 00:42:14,367
ROWE: The problem is
the availability of

815
00:42:14,367 --> 00:42:16,000
building materials.

816
00:42:16,100 --> 00:42:17,900
This far out from the Sun,

817
00:42:18,000 --> 00:42:21,700
there wasn't enough gas and
dust in the protoplanetary disk

818
00:42:21,767 --> 00:42:24,867
to construct such
large planets.

819
00:42:24,967 --> 00:42:28,853
One way of solving the riddle
of how Uranus and Neptune

820
00:42:28,853 --> 00:42:28,867
One way of solving the riddle
of how Uranus and Neptune

821
00:42:28,867 --> 00:42:32,100
are so big is that they didn't
form where they are now.

822
00:42:32,166 --> 00:42:33,200
So we think that they formed

823
00:42:33,266 --> 00:42:36,066
further in
and then maybe moved out.

824
00:42:37,600 --> 00:42:39,767
ROWE:
This is what we think happened.

825
00:42:40,800 --> 00:42:43,767
Five million years after
the birth of the Sun,

826
00:42:43,867 --> 00:42:47,767
Jupiter and Saturn reached
the same region of space as

827
00:42:47,867 --> 00:42:49,767
Uranus and Neptune.

828
00:42:49,767 --> 00:42:54,600
The four quarreling children
call a truce and orbit together.

829
00:42:54,667 --> 00:42:57,600
OLUSEYI: Orbits are on
the razor's edge of stability

830
00:42:57,667 --> 00:42:58,853
as it is, and so one thing that
helped to stabilize

831
00:42:58,853 --> 00:43:00,667
as it is, and so one thing that
helped to stabilize

832
00:43:00,767 --> 00:43:02,667
our solar system
in the early days

833
00:43:02,667 --> 00:43:06,500
was that it was in
this cloud of gas and dust

834
00:43:06,567 --> 00:43:09,500
that was this
protoplanetary disk.

835
00:43:09,567 --> 00:43:12,367
ROWE: Gas in
the protoplanetary disk can

836
00:43:12,467 --> 00:43:14,867
slow down planets
so they migrate.

837
00:43:14,867 --> 00:43:19,300
But it can also stabilize
their orbits.

838
00:43:20,567 --> 00:43:23,400
Like sand on
the side of a racing track

839
00:43:23,467 --> 00:43:26,100
that's there to slow
down the cars and help them get

840
00:43:26,166 --> 00:43:27,300
back on track,

841
00:43:27,367 --> 00:43:28,853
the gas allows the planets to
not veer off too much

842
00:43:28,853 --> 00:43:31,900
the gas allows the planets to
not veer off too much

843
00:43:32,000 --> 00:43:35,867
away from their stable
compact configuration.

844
00:43:37,200 --> 00:43:40,700
ROWE: The ceasefire between
the gas planets is short-lived.

845
00:43:43,800 --> 00:43:48,166
Once the Godfather Sun blows
away the last of the gas,

846
00:43:48,166 --> 00:43:52,667
the largest Mafioso children
set off on another crime spree.

847
00:43:54,467 --> 00:43:56,400
So when the gas goes away,

848
00:43:56,467 --> 00:43:58,767
you no longer have this
dampening effect on the orbits

849
00:43:58,767 --> 00:43:58,853
of the giant planets,
and they can start

850
00:43:58,853 --> 00:44:01,667
of the giant planets,
and they can start

851
00:44:01,767 --> 00:44:03,066
interacting with each other.

852
00:44:03,066 --> 00:44:06,066
And Jupiter is free to be
a bully again, only this time,

853
00:44:06,066 --> 00:44:07,600
he's got a big
sidekick -- Saturn.

854
00:44:09,166 --> 00:44:12,400
ROWE: Former peacekeeper,
Saturn, joins forces

855
00:44:12,467 --> 00:44:14,600
with Jupiter,
and they start

856
00:44:14,667 --> 00:44:16,367
messing with
Uranus and Neptune.

857
00:44:18,166 --> 00:44:21,367
So the two largest kids team
up together and start pushing

858
00:44:21,467 --> 00:44:23,000
everyone else around.

859
00:44:23,066 --> 00:44:25,600
When you put really big planets
that are really massive,

860
00:44:25,667 --> 00:44:26,767
really close to each other,

861
00:44:26,867 --> 00:44:28,567
over time,
they start to push on each

862
00:44:28,567 --> 00:44:28,853
other's orbits, and their
orbits start to get excited.

863
00:44:28,853 --> 00:44:30,567
other's orbits, and their
orbits start to get excited.

864
00:44:30,667 --> 00:44:32,867
The whole thing starts
to unravel

865
00:44:32,967 --> 00:44:35,867
and eventually culminates in
a violent

866
00:44:35,867 --> 00:44:37,767
and beautiful instability.

867
00:44:41,900 --> 00:44:44,000
ROWE: Gravitational shoves
from Jupiter

868
00:44:44,100 --> 00:44:47,100
and Saturn pushed
the ice giants outwards.

869
00:44:50,200 --> 00:44:53,467
Uranus still bears the scars
from this power move.

870
00:44:58,567 --> 00:44:58,853
For one thing, it's orbiting
the Sun on its side.

871
00:44:58,853 --> 00:45:02,000
For one thing, it's orbiting
the Sun on its side.

872
00:45:02,100 --> 00:45:03,667
Instead of having
its rotation axis

873
00:45:03,667 --> 00:45:04,967
sort of straight up and down,

874
00:45:04,967 --> 00:45:08,467
more or less, it's tipped
way over, so its pole is

875
00:45:08,467 --> 00:45:11,266
pointing more or less towards
the Sun instead of up and down.

876
00:45:11,367 --> 00:45:12,667
That's really weird.

877
00:45:14,166 --> 00:45:19,000
ROWE: Recent studies suggest
a giant impact caused

878
00:45:19,066 --> 00:45:22,300
Uranus's strange orientation.

879
00:45:23,367 --> 00:45:25,066
Over four billion years ago,

880
00:45:25,066 --> 00:45:28,266
a large icy object hits
the ice giant

881
00:45:28,367 --> 00:45:28,853
with a glancing blow.

882
00:45:28,853 --> 00:45:29,700
with a glancing blow.

883
00:45:31,667 --> 00:45:34,767
The planet starts to tip over.

884
00:45:34,767 --> 00:45:37,500
Then,
the attacker comes around

885
00:45:37,567 --> 00:45:40,166
and smashes into Uranus
a second time.

886
00:45:43,800 --> 00:45:48,767
This 1-2 punch knocks
the ice giant onto its side.

887
00:45:53,200 --> 00:45:54,367
A clue to the cause of

888
00:45:54,467 --> 00:45:58,166
the collision comes from
Neptune's moon, Triton.

889
00:45:59,767 --> 00:46:02,200
RADEBAUGH: What's odd about
Triton is that it orbits

890
00:46:02,266 --> 00:46:04,000
the wrong way around Neptune,
and that's

891
00:46:04,100 --> 00:46:05,600
the wrong way for
the whole solar system,

892
00:46:05,667 --> 00:46:08,100
so everything is going in this
direction, Triton is going

893
00:46:08,166 --> 00:46:09,467
the other way.

894
00:46:09,467 --> 00:46:11,400
The other thing is that Triton
is made of slightly different

895
00:46:11,467 --> 00:46:14,100
things than it should be
at the orbit of Neptune.

896
00:46:14,166 --> 00:46:17,600
Its color, its density,
are just a little bit off.

897
00:46:17,667 --> 00:46:20,100
What we think
that means is that

898
00:46:20,166 --> 00:46:22,767
it probably didn't form there.

899
00:46:25,867 --> 00:46:28,100
ROWE: We find pointers to
Triton's origin

900
00:46:28,166 --> 00:46:28,853
on the dwarf planet Pluto.

901
00:46:28,853 --> 00:46:30,367
on the dwarf planet Pluto.

902
00:46:34,867 --> 00:46:37,100
Pluto sits in the Kuiper belt,

903
00:46:37,166 --> 00:46:42,000
a band of millions of icy
objects beyond Neptune.

904
00:46:45,266 --> 00:46:46,967
RADEBAUGH: When we looked
at Triton and compared it

905
00:46:46,967 --> 00:46:49,166
with Pluto from
telescopes from Earth,

906
00:46:49,166 --> 00:46:52,266
we recognize these two are
very similar to each other.

907
00:46:52,367 --> 00:46:54,166
On Triton,
there's nitrogen ice,

908
00:46:54,266 --> 00:46:56,767
carbon monoxide ice,
there's carbon dioxide ice.

909
00:46:56,767 --> 00:46:58,853
These are the same types of
ices that we see on Pluto.

910
00:46:58,853 --> 00:46:59,667
These are the same types of
ices that we see on Pluto.

911
00:47:00,800 --> 00:47:04,667
ROWE: This similarity in
chemical composition suggests

912
00:47:04,667 --> 00:47:08,266
that Pluto and Triton
formed in the same place,

913
00:47:10,100 --> 00:47:12,767
an ancient band of icy objects

914
00:47:12,767 --> 00:47:16,066
called
the trans-Neptunian belt.

915
00:47:18,867 --> 00:47:21,967
When the giant planet orbits
go berserk, Uranus and Neptune

916
00:47:21,967 --> 00:47:24,767
get tossed into this
trans-Neptunian disk.

917
00:47:24,867 --> 00:47:28,853
it's like a big bowling bowl
coming in and knocking off

918
00:47:28,853 --> 00:47:29,266
it's like a big bowling bowl
coming in and knocking off

919
00:47:29,367 --> 00:47:31,900
bowling pins left and right.

920
00:47:34,767 --> 00:47:36,400
THALLER:
Chaos ensues,

921
00:47:36,467 --> 00:47:38,600
and as the two outer
planets get pushed through

922
00:47:38,667 --> 00:47:39,867
all of this stuff,

923
00:47:39,867 --> 00:47:42,300
throwing things left,
right, and center, all kinds of

924
00:47:42,367 --> 00:47:44,066
collisions are inevitable.

925
00:47:44,066 --> 00:47:47,467
ROWE: One of these collisions
knocks Uranus over.

926
00:47:54,166 --> 00:47:57,266
Another small planet
heads towards Neptune.

927
00:47:59,500 --> 00:48:04,867
The ice giant grabs it,
creating the moon, Triton.

928
00:48:06,100 --> 00:48:08,500
The other
trans-Neptunian objects

929
00:48:08,567 --> 00:48:12,266
scatter outwards,
forming the Kuiper belt.

930
00:48:15,367 --> 00:48:18,567
Tremors from this planetary
bowling match spread far

931
00:48:18,667 --> 00:48:19,667
and wide,

932
00:48:19,667 --> 00:48:22,867
sparking a cataclysmic
onslaught of the inner

933
00:48:22,967 --> 00:48:25,700
solar system billions
of miles away.

934
00:48:27,467 --> 00:48:28,467
THALLER: The Kuiper belt --

935
00:48:28,467 --> 00:48:28,853
this very, very distant
collection of small,

936
00:48:28,853 --> 00:48:31,100
this very, very distant
collection of small,

937
00:48:31,166 --> 00:48:32,867
rocky bodies in the outer
solar system --

938
00:48:32,967 --> 00:48:35,266
you would think that we have
no connection to that at all.

939
00:48:35,367 --> 00:48:38,000
But instead, it may be
responsible for helping life

940
00:48:38,100 --> 00:48:39,100
get started on Earth.

941
00:48:50,867 --> 00:48:53,066
ROWE:
4.6 billion years ago,

942
00:48:54,066 --> 00:48:58,567
a cloud of gas collapses in
a quiet suburb of the Milky Way.

943
00:49:00,066 --> 00:49:03,767
It's the birth of our mobster
family solar system.

944
00:49:03,767 --> 00:49:08,266
The Godfather, the Sun,
ignites and takes control.

945
00:49:08,266 --> 00:49:12,100
His children, the planets,
grow from the disk of gas

946
00:49:12,166 --> 00:49:13,020
and dust left over from
the birth of the star.

947
00:49:13,020 --> 00:49:16,066
and dust left over from
the birth of the star.

948
00:49:17,500 --> 00:49:21,066
Gas planets form in
the cold outer suburbs,

949
00:49:21,066 --> 00:49:24,266
rocky ones in the warm
inner real estate.

950
00:49:25,266 --> 00:49:28,000
But the Sun's
fearsome nature

951
00:49:28,066 --> 00:49:30,467
threatens the young Earth.

952
00:49:30,567 --> 00:49:34,200
The early Earth,
right after its formation,

953
00:49:34,266 --> 00:49:36,367
was not a great place to
be alive.

954
00:49:36,367 --> 00:49:37,867
In fact, it would not have
been possible

955
00:49:37,967 --> 00:49:39,967
to be alive,
because it was so hot.

956
00:49:39,967 --> 00:49:42,767
It had no atmosphere.
It had been blown away.

957
00:49:42,767 --> 00:49:43,020
It wasn't even fully solid, and
it had no water to speak of.

958
00:49:43,020 --> 00:49:47,400
It wasn't even fully solid, and
it had no water to speak of.

959
00:49:48,567 --> 00:49:50,867
The Earth is too close
to the Sun to have

960
00:49:50,967 --> 00:49:53,467
formed with the amount of
water that we see today.

961
00:49:53,567 --> 00:49:55,800
The protoplanetary disk was
just too hot for water

962
00:49:55,867 --> 00:49:56,867
to condense,

963
00:49:58,000 --> 00:50:00,000
and water vapor would have
been blown away by

964
00:50:00,100 --> 00:50:02,400
the stellar wind --
for the same reason,

965
00:50:02,467 --> 00:50:06,100
it was also lacking in carbon
and volatile organic materials.

966
00:50:07,266 --> 00:50:09,367
DURDA: This raises a big
mystery -- where did all that

967
00:50:09,367 --> 00:50:11,066
material ultimately
come from

968
00:50:11,066 --> 00:50:13,020
that we now obviously have
in abundance on planet Earth?

969
00:50:13,020 --> 00:50:14,600
that we now obviously have
in abundance on planet Earth?

970
00:50:18,967 --> 00:50:22,500
ROWE: NASA's Dawn mission to
the dwarf planet, Ceres,

971
00:50:22,567 --> 00:50:24,867
provided a clue.

972
00:50:24,867 --> 00:50:28,200
Ceres sits
in the asteroid belt,

973
00:50:28,266 --> 00:50:31,967
a band of rocky debris left
over from Jupiter's attack on

974
00:50:31,967 --> 00:50:33,066
the inner planets.

975
00:50:34,166 --> 00:50:36,100
The Dawn mission
showed us that

976
00:50:36,166 --> 00:50:39,100
Ceres is actually
a really wet world.

977
00:50:39,166 --> 00:50:40,967
We thought it was just rock,

978
00:50:40,967 --> 00:50:43,020
but instead, Ceres is rich in
water, ammonia, and carbon.

979
00:50:43,020 --> 00:50:46,200
but instead, Ceres is rich in
water, ammonia, and carbon.

980
00:50:50,367 --> 00:50:53,100
ROWE: These chemicals
are essential for life.

981
00:50:53,166 --> 00:50:57,100
Analysis of other asteroids

982
00:50:57,166 --> 00:51:01,000
found lots of
this volatile material.

983
00:51:01,100 --> 00:51:04,600
This is surprising,
because this close in,

984
00:51:04,667 --> 00:51:07,300
the Sun should have
vaporized them.

985
00:51:09,066 --> 00:51:11,266
They could not have formed in
the asteroid belt, because

986
00:51:11,266 --> 00:51:13,020
temperatures were way too high
for those materials --

987
00:51:13,020 --> 00:51:13,767
temperatures were way too high
for those materials --

988
00:51:13,767 --> 00:51:16,100
water, ammonia --
to be able to condense.

989
00:51:16,166 --> 00:51:19,266
They must have formed in
the outer solar system and then

990
00:51:19,367 --> 00:51:22,166
been transported
to the inner solar system.

991
00:51:24,800 --> 00:51:28,467
ROWE: A 2019 study discovered
evidence of a storm of

992
00:51:28,567 --> 00:51:34,567
icy objects raining inwards
around 4.48 billion years ago.

993
00:51:34,667 --> 00:51:37,200
At the same time,
the giant gas

994
00:51:37,266 --> 00:51:40,400
planets were tearing
through the outer solar system.

995
00:51:41,567 --> 00:51:43,020
As Jupiter and Saturn,
Uranus and Neptune,

996
00:51:43,020 --> 00:51:44,567
As Jupiter and Saturn,
Uranus and Neptune,

997
00:51:44,667 --> 00:51:47,266
are migrating back outwards in
the solar system,

998
00:51:47,367 --> 00:51:51,166
they're excavating a whole
slew of icy planetesimals,

999
00:51:51,166 --> 00:51:54,200
like a like a snowplow bursting
through a snowdrift,

1000
00:51:54,266 --> 00:51:56,400
scattering these things all
through the solar system.

1001
00:51:59,667 --> 00:52:01,600
The outer planets
hurl millions of

1002
00:52:01,667 --> 00:52:06,300
icy objects in towards
their Don, the Sun.

1003
00:52:07,967 --> 00:52:13,000
Some, like Ceres,
stop in the asteroid belt.

1004
00:52:15,066 --> 00:52:18,967
Others continue and smash
into the inner planets,

1005
00:52:22,100 --> 00:52:23,400
including Earth.

1006
00:52:25,967 --> 00:52:30,600
We are being rained down on by
giant asteroids, comets.

1007
00:52:30,667 --> 00:52:33,100
The entire surface of
the Earth is molten again.

1008
00:52:33,166 --> 00:52:35,100
I mean, it is a rain of
the largest

1009
00:52:35,166 --> 00:52:38,767
objects you can imagine onto
the surface of the Earth.

1010
00:52:38,767 --> 00:52:41,100
Everything just would have
been completely smashed

1011
00:52:41,166 --> 00:52:42,266
to pieces.

1012
00:52:42,367 --> 00:52:43,020
Imagine something like
the dinosaur-killing impact

1013
00:52:43,020 --> 00:52:45,300
Imagine something like
the dinosaur-killing impact

1014
00:52:45,367 --> 00:52:46,767
happening once a month.

1015
00:52:48,100 --> 00:52:51,567
ROWE: The onslaught lasts
for 30 million years.

1016
00:52:54,567 --> 00:52:56,867
It pulverizes
the Earth's surface

1017
00:52:59,266 --> 00:53:02,000
but brings fresh chemicals
to replace

1018
00:53:02,100 --> 00:53:04,500
material blasted away
by the Sun.

1019
00:53:06,266 --> 00:53:09,066
All of these asteroids and
comets raining down on Earth

1020
00:53:09,066 --> 00:53:11,667
of course are causing massive
amounts of destruction

1021
00:53:11,767 --> 00:53:12,767
but they're bringing

1022
00:53:12,767 --> 00:53:13,020
the building blocks
of life, as well.

1023
00:53:13,020 --> 00:53:14,667
the building blocks
of life, as well.

1024
00:53:14,767 --> 00:53:17,667
The carbon-based molecules
that make us up, the water that

1025
00:53:17,767 --> 00:53:19,567
every bit of life
on Earth needs,

1026
00:53:19,667 --> 00:53:22,166
all of the conditions
necessary for life

1027
00:53:22,266 --> 00:53:24,367
were brought by
the bombardment.

1028
00:53:24,467 --> 00:53:28,567
If that chaotic bombardment
hadn't happened, it's just

1029
00:53:28,667 --> 00:53:31,100
possible that we wouldn't be
here today.

1030
00:53:31,166 --> 00:53:34,567
ROWE: Even though some of our
mob family now live in

1031
00:53:34,567 --> 00:53:36,500
the outer reaches
of the solar system,

1032
00:53:36,567 --> 00:53:38,467
the family ties to the planets

1033
00:53:38,467 --> 00:53:41,600
in the inner regions are
still strong.

1034
00:53:41,667 --> 00:53:43,020
HOWETT: The distances
between all of

1035
00:53:43,020 --> 00:53:44,000
HOWETT: The distances
between all of

1036
00:53:44,100 --> 00:53:46,367
the planets in our solar
system are large.

1037
00:53:46,467 --> 00:53:47,867
You get a sense of that

1038
00:53:47,867 --> 00:53:50,000
if you go into the night sky,
and Jupiter and Saturn

1039
00:53:50,100 --> 00:53:51,300
are pinpricks of light,

1040
00:53:51,367 --> 00:53:54,500
but really, they're all
interconnected in a very

1041
00:53:54,567 --> 00:53:56,400
complex way --
gravity has this

1042
00:53:56,467 --> 00:54:00,867
huge effect and can go over
long distances.

1043
00:54:02,100 --> 00:54:04,734
The solar system
has this huge, violent past

1044
00:54:04,734 --> 00:54:07,734
as these giants have
moved and interacted.

1045
00:54:08,967 --> 00:54:11,567
It's really remarkable how
interconnected

1046
00:54:11,567 --> 00:54:13,020
all these planetary
bodies really are,

1047
00:54:13,020 --> 00:54:14,166
all these planetary
bodies really are,

1048
00:54:14,266 --> 00:54:16,367
even though we think of them
as very separate.

1049
00:54:19,467 --> 00:54:21,734
ROWE: This interaction
between planets,

1050
00:54:21,734 --> 00:54:23,667
billions of miles apart,

1051
00:54:23,767 --> 00:54:26,300
transformed
the inner solar system

1052
00:54:26,367 --> 00:54:28,166
and primed Earth for life.

1053
00:54:29,967 --> 00:54:33,667
But our planet was
still uninhabitable.

1054
00:54:36,166 --> 00:54:37,867
RADEBAUGH: The early Earth,
right after the bombardment,

1055
00:54:37,967 --> 00:54:40,367
would have been
a complete hellscape,

1056
00:54:40,467 --> 00:54:43,020
and it would have been
really hot magma everywhere.

1057
00:54:43,020 --> 00:54:43,667
and it would have been
really hot magma everywhere.

1058
00:54:43,767 --> 00:54:47,900
Big impact craters with impact
melt all across the floors --

1059
00:54:48,000 --> 00:54:49,734
it would have
been unrecognizable.

1060
00:54:50,767 --> 00:54:52,800
Not only was it
incredibly hot,

1061
00:54:52,867 --> 00:54:55,900
but it also didn't have
an atmosphere, and at that time,

1062
00:54:56,000 --> 00:54:58,567
there was no liquid water
on the surface yet.

1063
00:54:58,567 --> 00:55:02,000
Early Earth could not
have supported life.

1064
00:55:02,066 --> 00:55:03,867
ROWE: For life to start,

1065
00:55:03,967 --> 00:55:09,100
Earth must cool down
and build a new atmosphere.

1066
00:55:09,166 --> 00:55:12,100
The Earth developed its second
atmosphere using materials

1067
00:55:12,166 --> 00:55:13,020
delivered by
the great bombardment.

1068
00:55:13,020 --> 00:55:14,100
delivered by
the great bombardment.

1069
00:55:14,166 --> 00:55:16,367
All of these volatiles,
like water

1070
00:55:16,467 --> 00:55:19,600
and carbon organic materials
were incorporated

1071
00:55:19,667 --> 00:55:22,066
into the Earth's crust,
and then,

1072
00:55:22,066 --> 00:55:23,567
volcanoes were able to outgas

1073
00:55:23,567 --> 00:55:26,967
all of these materials, forming
a very thick layer of gas.

1074
00:55:26,967 --> 00:55:30,100
This new atmosphere had
a composition that was mostly

1075
00:55:30,166 --> 00:55:33,800
water vapor, carbon dioxide,
and nitrogen.

1076
00:55:33,867 --> 00:55:36,367
ROWE: Over the next
30 million years,

1077
00:55:36,367 --> 00:55:40,367
Earth cools --
a solid surface forms.

1078
00:55:42,166 --> 00:55:43,020
DURDA: As the planet is cooling,
the water vapor

1079
00:55:43,020 --> 00:55:44,467
DURDA: As the planet is cooling,
the water vapor

1080
00:55:44,467 --> 00:55:46,800
in the atmosphere
is going to be raining out.

1081
00:55:46,867 --> 00:55:50,100
That's gonna form
pools of liquid water

1082
00:55:50,166 --> 00:55:51,266
on the surface of
the Earth.

1083
00:55:53,567 --> 00:55:55,100
RADEBAUGH: The earliest
evidence for liquid water

1084
00:55:55,166 --> 00:55:57,867
on Earth was
4.3 billion years ago.

1085
00:55:57,967 --> 00:56:00,467
Remember, that's just
200 million years after

1086
00:56:00,467 --> 00:56:02,734
its formation,
which is really fast.

1087
00:56:04,266 --> 00:56:07,600
ROWE: Trillions of gallons
of water rain down.

1088
00:56:08,767 --> 00:56:12,000
Torrential rains for, I mean,
you know, imagine monsoon rains

1089
00:56:12,100 --> 00:56:13,020
for, you know, tens and tens
of thousands of years.

1090
00:56:13,020 --> 00:56:15,200
for, you know, tens and tens
of thousands of years.

1091
00:56:19,066 --> 00:56:20,667
RADEBAUGH: All this water
would have rained

1092
00:56:20,767 --> 00:56:21,767
onto the surface, rained,

1093
00:56:21,767 --> 00:56:25,000
rained, and eventually
filled up our oceans.

1094
00:56:27,467 --> 00:56:30,166
ROWE: The oceans pull
life-forming chemicals from

1095
00:56:30,266 --> 00:56:35,066
the rocks and the atmosphere,
creating the primordial soup.

1096
00:56:36,500 --> 00:56:38,467
Life can begin.

1097
00:56:39,734 --> 00:56:42,266
THALLER: We used to be so
disconnected from each other,

1098
00:56:42,266 --> 00:56:43,020
each planet just living
entirely separately.

1099
00:56:43,020 --> 00:56:44,567
each planet just living
entirely separately.

1100
00:56:44,667 --> 00:56:46,667
Now, we know things
mix around.

1101
00:56:46,767 --> 00:56:49,500
Now we know that probably
the building blocks of

1102
00:56:49,567 --> 00:56:51,667
life itself
and the water in my body

1103
00:56:51,767 --> 00:56:53,600
actually came from
the outer solar system.

1104
00:56:53,667 --> 00:56:55,500
I like that.

1105
00:56:56,667 --> 00:56:59,400
ROWE: A series of
interconnecting and often

1106
00:56:59,467 --> 00:57:01,467
violent incidents
going right back

1107
00:57:01,467 --> 00:57:05,266
to the start of the solar
system led to our existence.

1108
00:57:05,367 --> 00:57:09,734
HOWETT: If you look at what the
solar system has been through,

1109
00:57:09,734 --> 00:57:13,020
what has to happen for life
to happen.

1110
00:57:13,020 --> 00:57:13,100
what has to happen for life
to happen.

1111
00:57:13,166 --> 00:57:16,000
When you add all of those
things up, we shouldn't exist.

1112
00:57:16,066 --> 00:57:19,100
We just shouldn't be here.
The chances are so, so slim.

1113
00:57:19,166 --> 00:57:21,000
And yet here we are.

1114
00:57:22,266 --> 00:57:24,667
PLAIT: The Earth has managed to
survive a lot of the nonsense

1115
00:57:24,767 --> 00:57:26,500
the solar system
has thrown at it,

1116
00:57:26,567 --> 00:57:29,166
and some of that is probably
just luck of the draw.

1117
00:57:29,266 --> 00:57:31,467
So I think even
on our worst days,

1118
00:57:31,467 --> 00:57:34,266
we should remember that we're
pretty lucky just to be here.

1119
00:57:34,266 --> 00:57:38,367
Earth won the cosmic
game of chance,

1120
00:57:39,667 --> 00:57:43,020
but were the other
Mafioso children as lucky?

1121
00:57:43,020 --> 00:57:43,100
but were the other
Mafioso children as lucky?

1122
00:57:43,166 --> 00:57:44,900
Did Mars and Venus

1123
00:57:45,000 --> 00:57:49,367
also develop environments
capable of supporting life?

1124
00:57:59,500 --> 00:58:03,066
ROWE: 200 million years
after the birth of the Sun,

1125
00:58:03,066 --> 00:58:05,066
the mafia family prospers.

1126
00:58:07,000 --> 00:58:09,500
The inner planets have
the building blocks of

1127
00:58:09,567 --> 00:58:12,266
life thrown in from
the outer solar system.

1128
00:58:15,166 --> 00:58:18,100
So, in theory,
they could be habitable.

1129
00:58:23,367 --> 00:58:28,600
But when the Russian probe
Venera landed on Venus in 1970,

1130
00:58:28,667 --> 00:58:31,300
it found a scorching,
hostile world.

1131
00:58:32,967 --> 00:58:35,166
RADEBAUGH: The conditions
on Venus are crazy.

1132
00:58:35,266 --> 00:58:38,900
The temperature on the surface
is over 800 degrees Fahrenheit,

1133
00:58:39,000 --> 00:58:41,166
so it's hot enough
to melt lead.

1134
00:58:41,166 --> 00:58:43,900
The first probes that
landed on Venus functioned for

1135
00:58:44,000 --> 00:58:45,367
a little while,
and then they were

1136
00:58:45,467 --> 00:58:46,967
crushed like a tin can
and melted.

1137
00:58:48,734 --> 00:58:52,767
LANZA: It has a huge, crushing
atmospheric pressure,

1138
00:58:52,867 --> 00:58:53,203
which is 90 times that on
the Earth's surface,

1139
00:58:53,203 --> 00:58:55,600
which is 90 times that on
the Earth's surface,

1140
00:58:55,667 --> 00:58:58,266
and that's entirely
carbon dioxide.

1141
00:59:00,900 --> 00:59:03,367
DURDA: And it gets worse still,
because gasses in

1142
00:59:03,467 --> 00:59:05,166
the atmosphere have combined

1143
00:59:05,266 --> 00:59:08,367
to make really this concentrated
solution of gasses.

1144
00:59:08,367 --> 00:59:10,367
So you've got this noxious,

1145
00:59:10,367 --> 00:59:14,266
acidic, corrosive environment
coupled with very, very

1146
00:59:14,367 --> 00:59:16,100
high temperatures.

1147
00:59:16,166 --> 00:59:18,200
Life as we know it
could not survive

1148
00:59:18,266 --> 00:59:20,467
on the surface of Venus
as it is today.

1149
00:59:25,266 --> 00:59:29,200
ROWE: New climate models suggest
that four billion years ago,

1150
00:59:29,266 --> 00:59:34,000
Venus was a very different
planet to the one we see today.

1151
00:59:34,100 --> 00:59:38,500
These models suggest that, in
the past, Venus had actually

1152
00:59:38,567 --> 00:59:42,000
a cooler surface temperature
and had a better composition

1153
00:59:42,066 --> 00:59:43,300
for habitability.

1154
00:59:45,567 --> 00:59:49,000
We think it once had a much
thinner atmosphere, much more

1155
00:59:49,066 --> 00:59:51,000
like Earth's atmosphere today.

1156
00:59:51,100 --> 00:59:53,203
It would have had a climate,
which was much, much cooler,

1157
00:59:53,203 --> 00:59:55,266
It would have had a climate,
which was much, much cooler,

1158
00:59:55,367 --> 00:59:59,266
and therefore, even
the possibility of liquid water

1159
00:59:59,266 --> 01:00:02,767
on the surface --
maybe Venus had oceans

1160
01:00:02,834 --> 01:00:05,567
in the way that we find
on Earth still today.

1161
01:00:07,367 --> 01:00:09,867
It even makes sense that Venus
would be similar to Earth,

1162
01:00:09,867 --> 01:00:11,967
because it formed out
of basically

1163
01:00:11,967 --> 01:00:14,900
the same materials, close to
the same location from the Sun,

1164
01:00:15,000 --> 01:00:17,567
and ended up being even
almost the same size.

1165
01:00:19,200 --> 01:00:22,367
Really,
we are twin planets.

1166
01:00:22,367 --> 01:00:23,203
The barrage of icy objects

1167
01:00:23,203 --> 01:00:26,100
The barrage of icy objects

1168
01:00:26,166 --> 01:00:30,100
from the outer solar system that
struck Earth also hit Venus.

1169
01:00:31,266 --> 01:00:34,467
LANZA: Just like Earth,
Venus got a whole bunch

1170
01:00:34,567 --> 01:00:37,734
of volatiles from bombardments,
and those in turn were

1171
01:00:37,734 --> 01:00:41,166
recycled and produced a very
nice atmosphere

1172
01:00:41,166 --> 01:00:44,100
and allowed water to exist
on the surface as a liquid.

1173
01:00:47,000 --> 01:00:51,200
These early conditions on
Venus could have provided

1174
01:00:51,266 --> 01:00:53,166
a habitat,

1175
01:00:53,266 --> 01:00:56,767
the right sort of conditions
for life to have got started.

1176
01:00:56,867 --> 01:00:59,066
What about Mars?

1177
01:00:59,066 --> 01:01:01,667
Was it also habitable?

1178
01:01:01,767 --> 01:01:03,834
Looking at it today,
all we see

1179
01:01:03,834 --> 01:01:06,467
is a frozen,
barren wasteland.

1180
01:01:06,467 --> 01:01:09,400
Part of the reason it's so
cold is it's further away

1181
01:01:09,467 --> 01:01:12,066
from the Sun, and it doesn't
have a very thick atmosphere.

1182
01:01:12,066 --> 01:01:14,367
So it's very hard
for it to retain heat.

1183
01:01:14,467 --> 01:01:17,667
It also has extremely
low atmospheric pressure,

1184
01:01:17,767 --> 01:01:20,467
which means that any liquid
water on the surface would just

1185
01:01:20,467 --> 01:01:23,203
boil away,
and any current water

1186
01:01:23,203 --> 01:01:23,400
boil away,
and any current water

1187
01:01:23,467 --> 01:01:26,467
that's on the planet
is locked up in ice.

1188
01:01:27,467 --> 01:01:30,767
ROWE: However, recent surveys
of Mars reveal

1189
01:01:30,834 --> 01:01:35,834
a very different planet, once
capable of supporting life.

1190
01:01:35,834 --> 01:01:37,900
COOPER: As you look across
the landscape of Mars,

1191
01:01:38,000 --> 01:01:41,166
you can see these physical
features that give us hints

1192
01:01:41,266 --> 01:01:42,767
that water used to exist there,

1193
01:01:42,867 --> 01:01:46,266
like dried lake beds
and riverbeds.

1194
01:01:46,367 --> 01:01:49,467
RADEBAUGH: We see abundant
evidence of river channels,

1195
01:01:49,567 --> 01:01:52,166
drainages all across
the landscape.

1196
01:01:52,266 --> 01:01:53,203
The best way, I think the only
way to form these is

1197
01:01:53,203 --> 01:01:55,100
The best way, I think the only
way to form these is

1198
01:01:55,166 --> 01:01:56,300
by rainfall.

1199
01:01:56,367 --> 01:01:59,400
There had to have been clouds
and rain in Mars's past.

1200
01:01:59,467 --> 01:02:02,767
And there's also sediments
and mineral deposits that could

1201
01:02:02,867 --> 01:02:05,867
only form in the presence of
liquid water.

1202
01:02:08,066 --> 01:02:11,467
ROWE: We calculate that Mars
once had five million

1203
01:02:11,467 --> 01:02:14,367
cubic miles of liquid water
on the surface.

1204
01:02:14,367 --> 01:02:17,834
That's enough for an ocean

1205
01:02:17,834 --> 01:02:19,900
bigger than the Earth's
Arctic Ocean.

1206
01:02:20,000 --> 01:02:22,567
So we think that Mars had
an ocean

1207
01:02:22,567 --> 01:02:23,203
in its northern hemisphere.

1208
01:02:23,203 --> 01:02:24,667
in its northern hemisphere.

1209
01:02:27,066 --> 01:02:29,567
ROWE: To have oceans,

1210
01:02:29,567 --> 01:02:32,467
Mars must have had
a thick atmosphere.

1211
01:02:34,367 --> 01:02:36,266
And recently,
a space probe

1212
01:02:36,367 --> 01:02:39,834
orbiting the red planet
found evidence.

1213
01:02:42,000 --> 01:02:43,667
RADEBAUGH: The MAVEN mission
revealed that

1214
01:02:43,734 --> 01:02:46,567
Mars is losing its
atmosphere rapidly.

1215
01:02:46,567 --> 01:02:48,266
I mean, this is
something like a quarter pound

1216
01:02:48,367 --> 01:02:51,200
a second of atmosphere
being stripped away

1217
01:02:51,266 --> 01:02:52,467
by the solar wind.

1218
01:02:52,567 --> 01:02:53,203
We can take those MAVEN loss
rates for Mars's atmosphere

1219
01:02:53,203 --> 01:02:55,667
We can take those MAVEN loss
rates for Mars's atmosphere

1220
01:02:55,734 --> 01:02:57,000
and extrapolate back in time,

1221
01:02:57,100 --> 01:02:59,967
and we can see that Mars had
an atmosphere as thick as

1222
01:02:59,967 --> 01:03:01,967
Earth's in the past.

1223
01:03:01,967 --> 01:03:03,667
With a thicker atmosphere,
Mars would

1224
01:03:03,734 --> 01:03:07,166
have been able to retain heat
much more effectively

1225
01:03:07,266 --> 01:03:09,166
and would have had increased
atmospheric pressure,

1226
01:03:09,266 --> 01:03:11,600
which would have allowed
liquid water to persist on

1227
01:03:11,667 --> 01:03:12,567
the surface.

1228
01:03:12,667 --> 01:03:14,367
In the past,
Mars would have been just

1229
01:03:14,467 --> 01:03:18,467
a beautiful landscape filled
with running rivers and lakes,

1230
01:03:18,467 --> 01:03:21,066
and that water could have
potentially sustained

1231
01:03:21,066 --> 01:03:22,367
ancient life.

1232
01:03:25,100 --> 01:03:28,200
All of the observations that
we have of Mars to date

1233
01:03:28,266 --> 01:03:31,600
just tell us that it was
absolutely a habitable world.

1234
01:03:31,667 --> 01:03:35,867
RADEBAUGH: So now we have
an Earth that had kind of

1235
01:03:35,867 --> 01:03:38,166
settled down after the heavy
bombardment of Venus

1236
01:03:38,266 --> 01:03:39,900
that might have
water on the surface

1237
01:03:40,000 --> 01:03:41,767
and a thinner atmosphere
and Mars, with

1238
01:03:41,834 --> 01:03:43,600
a thicker atmosphere
and water on the surface,

1239
01:03:43,667 --> 01:03:47,467
water on all three surfaces --
maybe all three were right

1240
01:03:47,467 --> 01:03:48,667
for life.

1241
01:03:48,734 --> 01:03:51,667
It's actually remarkable to
think that all three of

1242
01:03:51,734 --> 01:03:53,203
these planets could have been
habitable at the same time.

1243
01:03:53,203 --> 01:03:54,900
these planets could have been
habitable at the same time.

1244
01:03:56,066 --> 01:03:59,100
ROWE: But this golden age
of habitability

1245
01:03:59,166 --> 01:04:00,200
is short-lived.

1246
01:04:02,367 --> 01:04:05,000
Another battle erupts
between the planets

1247
01:04:05,066 --> 01:04:08,066
and their Don, the Sun.

1248
01:04:08,066 --> 01:04:12,367
Venus and Mars suffers
serious collateral damage.

1249
01:04:24,600 --> 01:04:26,367
ROWE:
Four billion years ago,

1250
01:04:26,467 --> 01:04:29,967
the mob family,
the solar system, is thriving.

1251
01:04:32,500 --> 01:04:35,300
The children, Earth, Mars
and Venus,

1252
01:04:35,367 --> 01:04:38,166
have the conditions to
sustain life.

1253
01:04:44,300 --> 01:04:47,100
2020 --
scientists investigate

1254
01:04:47,166 --> 01:04:47,453
how Mars became uninhabitable.

1255
01:04:47,453 --> 01:04:49,567
how Mars became uninhabitable.

1256
01:04:51,767 --> 01:04:55,266
They detect faint magnetic
traces coming from

1257
01:04:55,367 --> 01:04:58,834
lava spewed out by ancient
volcanic eruptions.

1258
01:05:02,000 --> 01:05:06,967
The magnetic lava on Mars
tells us that when that lava

1259
01:05:07,033 --> 01:05:11,967
was molten, there was a strong
global magnetic field

1260
01:05:12,033 --> 01:05:13,300
on that planet.

1261
01:05:15,066 --> 01:05:17,453
ROWE: Dating the rocks
tells us that Mars's

1262
01:05:17,453 --> 01:05:18,166
ROWE: Dating the rocks
tells us that Mars's

1263
01:05:18,166 --> 01:05:23,934
magnetic field was active
4.5 billion years ago.

1264
01:05:24,000 --> 01:05:28,000
Having a magnetic field really
helps a planet retain

1265
01:05:28,066 --> 01:05:30,266
its atmosphere, and that's just
because a magnetic field

1266
01:05:30,266 --> 01:05:33,500
protects the planet's atmosphere
from incoming radiation.

1267
01:05:33,567 --> 01:05:36,266
Solar wind, cosmic rays,
you name it.

1268
01:05:43,166 --> 01:05:46,000
ROWE: On Earth, liquid iron
churning around

1269
01:05:46,066 --> 01:05:47,453
the hot molten core generates
a magnetic field.

1270
01:05:47,453 --> 01:05:49,667
the hot molten core generates
a magnetic field.

1271
01:05:51,266 --> 01:05:56,033
The younger Mars
would have still had a much

1272
01:05:56,100 --> 01:05:59,767
hotter core, with churning
convection currents in

1273
01:05:59,867 --> 01:06:01,133
its interior,

1274
01:06:01,166 --> 01:06:05,600
and these would have generated
a global magnetic field in

1275
01:06:05,667 --> 01:06:09,266
exactly the same way the Earth
creates its magnetic field.

1276
01:06:09,266 --> 01:06:15,100
ROWE: Mars couldn't maintain
its magnetic field,

1277
01:06:15,166 --> 01:06:17,453
because Jupiter's violent
assault on the inner

1278
01:06:17,453 --> 01:06:17,734
because Jupiter's violent
assault on the inner

1279
01:06:17,734 --> 01:06:20,867
solar system stole
the red planet's lunch,

1280
01:06:22,300 --> 01:06:25,467
THALLER: Jupiter migrated in
about where Mars is today.

1281
01:06:25,567 --> 01:06:27,767
So that means that most of
the material

1282
01:06:27,834 --> 01:06:30,266
was actually swallowed up by
the gravity of Jupiter.

1283
01:06:30,266 --> 01:06:33,166
So Mars just got unlucky.

1284
01:06:33,166 --> 01:06:36,667
ROWE: Small planets
lose heat faster.

1285
01:06:36,734 --> 01:06:39,367
Tiny Mars cooled down.

1286
01:06:39,467 --> 01:06:42,166
And so as Mars's core cooled,

1287
01:06:42,166 --> 01:06:45,200
the convection in that core
would have slowed down, to

1288
01:06:45,266 --> 01:06:47,453
the point where no magnetic
field would be generated.

1289
01:06:47,453 --> 01:06:47,834
the point where no magnetic
field would be generated.

1290
01:06:47,834 --> 01:06:50,400
Once the magnetic field
at Mars is shut off,

1291
01:06:50,467 --> 01:06:53,266
well, that's the end of the
protection for the atmosphere.

1292
01:06:55,867 --> 01:06:58,600
ROWE:
3.7 billion years ago,

1293
01:06:58,667 --> 01:07:01,867
the Sun attacks
the defenseless Mars.

1294
01:07:01,967 --> 01:07:06,767
The solar wind just
bombards it and strips it

1295
01:07:06,834 --> 01:07:09,200
away of the atmosphere
very quickly over time.

1296
01:07:10,367 --> 01:07:11,934
ROWE:
Without its thermal blanket,

1297
01:07:12,000 --> 01:07:15,767
Mars's surface freezes,
and the atmospheric

1298
01:07:15,867 --> 01:07:17,453
pressure plummets.

1299
01:07:17,453 --> 01:07:18,467
pressure plummets.

1300
01:07:18,567 --> 01:07:23,200
As the atmospheric pressure
drops, surface water

1301
01:07:23,266 --> 01:07:26,467
gradually evaporates
or even boils away.

1302
01:07:32,600 --> 01:07:35,667
ROWE: Venus also suffered
a climate catastrophe.

1303
01:07:37,734 --> 01:07:40,000
We find clues on its surface.

1304
01:07:43,500 --> 01:07:46,934
Like all planetary-sized
bodies in the solar system,

1305
01:07:47,000 --> 01:07:47,453
Venus has impact craters on it

1306
01:07:47,453 --> 01:07:48,967
Venus has impact craters on it

1307
01:07:49,033 --> 01:07:50,967
from asteroids
smacking into it,

1308
01:07:51,033 --> 01:07:54,834
but there aren't that many,
which is a little odd.

1309
01:07:54,834 --> 01:07:56,066
ROWE:
They're not damaged

1310
01:07:56,066 --> 01:07:58,667
like the craters we see
on other worlds.

1311
01:07:58,767 --> 01:08:02,767
LANZA: They look pristine,
as if nothing has modified them,

1312
01:08:02,867 --> 01:08:04,367
as if they happened yesterday.

1313
01:08:04,367 --> 01:08:07,266
So that suggests
these craters and the surface

1314
01:08:07,266 --> 01:08:09,400
on which they reside
are both very young.

1315
01:08:11,000 --> 01:08:13,266
ROWE: There are several
theories suggesting that

1316
01:08:13,367 --> 01:08:14,767
volcanic eruptions

1317
01:08:14,867 --> 01:08:17,453
resurfaced the planet around
500 million years ago.

1318
01:08:17,453 --> 01:08:18,100
resurfaced the planet around
500 million years ago.

1319
01:08:20,667 --> 01:08:23,567
One idea is that Venus has
a very thick crust,

1320
01:08:23,567 --> 01:08:26,300
and it doesn't move around in
plates like Earth's does.

1321
01:08:26,367 --> 01:08:29,367
So it's just a lid over
the planet, and eventually,

1322
01:08:29,367 --> 01:08:31,166
the pressure builds up
and builds up

1323
01:08:31,266 --> 01:08:33,667
and builds up until it --
boom, lets out all at once.

1324
01:08:39,667 --> 01:08:43,200
RADEBAUGH: A catastrophic event
that overturned

1325
01:08:43,266 --> 01:08:46,867
the entire crust of Venus
and resurfaced it.

1326
01:08:48,300 --> 01:08:50,066
ROWE:
An alternate theory suggests

1327
01:08:50,066 --> 01:08:53,300
the resurfacing happened over
millions of years.

1328
01:08:54,567 --> 01:08:57,100
RADEBAUGH: A series of large
volcanic eruptions

1329
01:08:57,166 --> 01:08:59,266
that would have completely
resurfaced the planet.

1330
01:09:02,767 --> 01:09:05,300
Imagine watching
this event on Venus -- I mean,

1331
01:09:05,367 --> 01:09:08,400
the overturn of
an entire crust?

1332
01:09:08,467 --> 01:09:10,266
That's just completely
awe-inspiring.

1333
01:09:11,867 --> 01:09:15,166
ROWE: Volcanic events
release huge amounts of gas.

1334
01:09:18,967 --> 01:09:21,467
Icelandic volcano,
Eyjafjallajokull,

1335
01:09:21,567 --> 01:09:26,767
blasts out up to 300,000 tons
of carbon dioxide every day.

1336
01:09:29,166 --> 01:09:33,100
Venus's planet-wide volcanism
would have been off the charts.

1337
01:09:35,367 --> 01:09:41,734
Such a huge worldwide bout of
volcanic activity would release

1338
01:09:41,734 --> 01:09:46,867
huge amounts of carbon dioxide
in the Venusian atmosphere.

1339
01:09:46,934 --> 01:09:47,453
ROWE: Scientists think
this enormous release of gas

1340
01:09:47,453 --> 01:09:50,667
ROWE: Scientists think
this enormous release of gas

1341
01:09:50,734 --> 01:09:54,667
may have triggered
the Venusian climate change.

1342
01:09:54,734 --> 01:09:57,166
Carbon dioxide
built up in Venus's

1343
01:09:57,166 --> 01:10:01,200
atmosphere, trapping
heat from the Sun.

1344
01:10:01,266 --> 01:10:04,100
DARTNELL: As soon as the climate
on Venus started to warm up

1345
01:10:04,166 --> 01:10:06,934
a little,
there's greater evaporation

1346
01:10:07,000 --> 01:10:10,567
coming off the oceans,
and that water vapor

1347
01:10:10,567 --> 01:10:14,033
in the atmosphere
is itself a greenhouse gas.

1348
01:10:14,100 --> 01:10:16,266
The climate gets even warmer.

1349
01:10:18,200 --> 01:10:21,767
ROWE: Venus reaches
880 degrees Fahrenheit.

1350
01:10:25,266 --> 01:10:28,834
Any chance
for life broils away.

1351
01:10:33,667 --> 01:10:36,834
The Earth also faces
a searing hot future

1352
01:10:36,834 --> 01:10:39,200
when the aging Godfather,

1353
01:10:39,266 --> 01:10:44,166
the Sun, bloats up and attacks
his family once again,

1354
01:10:44,266 --> 01:10:47,453
transforming into a lethal
weapon of mass destruction.

1355
01:10:47,453 --> 01:10:49,266
transforming into a lethal
weapon of mass destruction.

1356
01:11:02,066 --> 01:11:05,000
ROWE: For the last four billion
years, our mob family,

1357
01:11:05,066 --> 01:11:07,667
the solar system,
lived in harmony,

1358
01:11:07,734 --> 01:11:11,133
but nothing lasts forever.

1359
01:11:11,133 --> 01:11:14,133
The godfather, the Sun,

1360
01:11:14,133 --> 01:11:17,367
will grow old, fat, and mean.

1361
01:11:17,367 --> 01:11:21,266
Stars like the Sun
only have enough

1362
01:11:21,266 --> 01:11:24,266
hydrogen to fuse for about
10 billion years.

1363
01:11:24,266 --> 01:11:26,619
So that means that
in about five billion years,

1364
01:11:26,619 --> 01:11:27,467
So that means that
in about five billion years,

1365
01:11:27,567 --> 01:11:31,567
the Sun will actually
run out of hydrogen.

1366
01:11:33,767 --> 01:11:37,000
ROWE: With no hydrogen
fuel left, fusion stops.

1367
01:11:38,100 --> 01:11:42,400
The core collapses
and reignites, fusing helium.

1368
01:11:52,867 --> 01:11:55,934
NANCE: The energy released by
all of this fusion causes

1369
01:11:56,000 --> 01:11:56,619
the star to balloon outwards
and become a red giant.

1370
01:11:56,619 --> 01:11:59,934
the star to balloon outwards
and become a red giant.

1371
01:12:02,367 --> 01:12:05,600
ROWE: The red giant is like
a bitter old gangster.

1372
01:12:07,166 --> 01:12:10,667
Bloated and aggressive,
it attacks the inner planets.

1373
01:12:14,567 --> 01:12:16,300
Mercury and Venus
are gonna be engulfed

1374
01:12:16,367 --> 01:12:18,500
by the Sun as it becomes
a red giant.

1375
01:12:19,934 --> 01:12:21,667
It burns up both planets.

1376
01:12:23,000 --> 01:12:25,066
Next in line, Earth.

1377
01:12:26,667 --> 01:12:30,400
Then the universe
throws us a lifeline.

1378
01:12:30,467 --> 01:12:35,367
As the Sun expands outward, as
it enters its red giant phase,

1379
01:12:35,367 --> 01:12:38,266
it's actually going to be
losing mass.

1380
01:12:41,967 --> 01:12:44,066
The red giant blows off gas.

1381
01:12:45,600 --> 01:12:48,834
And as it loses mass,
its gravity is weakening.

1382
01:12:48,834 --> 01:12:51,500
OLUSEYI: So this means that
the Sun's grip on

1383
01:12:51,567 --> 01:12:54,266
the planets that orbit it
is gonna be weakening.

1384
01:12:54,266 --> 01:12:56,619
And so they sort of start
moving away from the Sun.

1385
01:12:56,619 --> 01:12:57,567
And so they sort of start
moving away from the Sun.

1386
01:12:57,567 --> 01:13:00,166
It's almost like they're
running away from the heat.

1387
01:13:00,166 --> 01:13:03,300
If you can't stand the heat,
get out of the solar system.

1388
01:13:05,266 --> 01:13:08,767
ROWE: Can Earth and Mars outrun
the expanding red giant?

1389
01:13:09,967 --> 01:13:12,367
So it's a race, right?
Who is going to get

1390
01:13:12,467 --> 01:13:16,467
far enough from the Sun to
escape being engulfed by it?

1391
01:13:18,767 --> 01:13:21,266
MINGARELLI: The eventual fate
of the Earth is not clear.

1392
01:13:23,000 --> 01:13:26,100
It's possible that the Earth
will be completely swallowed up

1393
01:13:26,166 --> 01:13:26,619
by the Sun's atmosphere,

1394
01:13:26,619 --> 01:13:27,767
by the Sun's atmosphere,

1395
01:13:27,834 --> 01:13:31,367
its new, bloated,
red atmosphere.

1396
01:13:36,467 --> 01:13:40,166
Even if the Earth escapes
being directly

1397
01:13:40,166 --> 01:13:41,467
engulfed by the Sun,

1398
01:13:41,567 --> 01:13:45,066
it's still not a good day for
our planet, because the Sun is

1399
01:13:45,133 --> 01:13:47,500
gonna be really,
really close.

1400
01:13:47,567 --> 01:13:50,734
PLAIT: So imagine basically
something red-hot, glowing,

1401
01:13:50,734 --> 01:13:52,000
covering the sky.

1402
01:13:52,066 --> 01:13:54,133
The earth will be molten,
and in fact, a lot of it

1403
01:13:54,133 --> 01:13:55,567
will vaporize.

1404
01:13:55,667 --> 01:13:56,619
So it's not like you're gonna
want to be here anyway.

1405
01:13:56,619 --> 01:13:58,033
So it's not like you're gonna
want to be here anyway.

1406
01:13:59,166 --> 01:14:00,667
OLUSEYI:
As I look at this scenario,

1407
01:14:00,734 --> 01:14:04,133
what's clear is that life
isn't gonna make it on Earth.

1408
01:14:08,967 --> 01:14:12,934
ROWE: Mars had a head start and
escapes complete destruction.

1409
01:14:14,066 --> 01:14:16,100
It'll be cooked, I mean,
it'll be a molten planet,

1410
01:14:16,166 --> 01:14:17,467
but it'll still be there.

1411
01:14:21,734 --> 01:14:24,266
The aging Don
wipes out life in

1412
01:14:24,266 --> 01:14:26,619
the inner solar system but may
help it survive elsewhere.

1413
01:14:26,619 --> 01:14:30,767
the inner solar system but may
help it survive elsewhere.

1414
01:14:31,867 --> 01:14:34,100
The sun's red giant phase
may initially bring

1415
01:14:34,166 --> 01:14:36,567
new opportunities for life in
the outer solar system.

1416
01:14:38,467 --> 01:14:42,266
SUTTER: Right now, the outer
solar system is locked in ice,

1417
01:14:42,266 --> 01:14:43,567
it's way too cold,

1418
01:14:43,567 --> 01:14:46,734
but when our sun becomes a red
giant, it will become much,

1419
01:14:46,734 --> 01:14:47,567
much brighter.

1420
01:14:47,667 --> 01:14:50,467
It will warm up
the outer system.

1421
01:14:53,367 --> 01:14:56,619
ROWE: And transform the gas
giant's icy moons.

1422
01:14:56,619 --> 01:14:57,600
ROWE: And transform the gas
giant's icy moons.

1423
01:14:59,567 --> 01:15:01,767
Europa and Enceladus,
that orbit Jupiter

1424
01:15:01,834 --> 01:15:04,934
and Saturn respectively, are
currently frozen worlds.

1425
01:15:05,000 --> 01:15:07,367
They have icy crusts
and are believed

1426
01:15:07,467 --> 01:15:09,867
to have liquid oceans
below those crusts.

1427
01:15:18,467 --> 01:15:21,266
ROWE: Scientists believe
that these subsurface oceans

1428
01:15:21,266 --> 01:15:23,734
may harbor life.

1429
01:15:23,734 --> 01:15:26,367
As the temperature increases,

1430
01:15:26,467 --> 01:15:26,619
their frozen exteriors are
gonna be thawed,

1431
01:15:26,619 --> 01:15:28,767
their frozen exteriors are
gonna be thawed,

1432
01:15:28,867 --> 01:15:30,867
and they'll become
entirely ocean worlds.

1433
01:15:35,767 --> 01:15:38,266
CHRISTIANSEN: Any life forms
already evolving in their oceans

1434
01:15:38,266 --> 01:15:40,734
will have a whole new world of
possibility open to them.

1435
01:15:42,467 --> 01:15:44,033
Or if life isn't there yet,

1436
01:15:44,100 --> 01:15:46,266
then it would certainly have
a chance to evolve.

1437
01:15:46,367 --> 01:15:48,667
We may have explosions of life

1438
01:15:48,767 --> 01:15:51,300
on these other outer
solar system bodies.

1439
01:15:53,867 --> 01:15:56,619
ROWE: But this burst of
new life may be short-lived.

1440
01:15:56,619 --> 01:15:57,133
ROWE: But this burst of
new life may be short-lived.

1441
01:15:58,467 --> 01:16:01,066
Even though these ocean worlds
may seem like a great

1442
01:16:01,133 --> 01:16:03,967
place to move to after
the inner solar system

1443
01:16:04,033 --> 01:16:06,600
is engulfed,
I would not start packing yet.

1444
01:16:12,567 --> 01:16:17,600
ROWE: The red giant will grow to
over 250 times its current size.

1445
01:16:18,834 --> 01:16:21,200
As the Sun continues
to expand,

1446
01:16:21,266 --> 01:16:24,400
these new ocean worlds
will start getting hotter

1447
01:16:24,467 --> 01:16:26,619
and hotter, and eventually,
all of the water will

1448
01:16:26,619 --> 01:16:26,867
and hotter, and eventually,
all of the water will

1449
01:16:26,934 --> 01:16:27,967
evaporate away.

1450
01:16:32,000 --> 01:16:33,967
ROWE:
Any new life dies out,

1451
01:16:36,967 --> 01:16:39,400
but bodies
in the furthest reaches

1452
01:16:39,467 --> 01:16:42,867
of the solar system
fare better.

1453
01:16:42,967 --> 01:16:44,967
PLAIT: The key to surviving
the Sun turning

1454
01:16:45,033 --> 01:16:47,100
into a red giant is
basically distance.

1455
01:16:47,166 --> 01:16:49,734
So the farther out
you are from the Sun now,

1456
01:16:49,734 --> 01:16:51,300
the better off you
are then.

1457
01:16:53,867 --> 01:16:56,619
ROWE: The best bet might be
the distant dwarf planets,

1458
01:16:56,619 --> 01:16:57,400
ROWE: The best bet might be
the distant dwarf planets,

1459
01:16:57,467 --> 01:16:58,867
like Pluto.

1460
01:17:01,266 --> 01:17:03,867
So now we have these objects
that might actually

1461
01:17:03,967 --> 01:17:07,033
become the most Earth-like
bodies in the solar system.

1462
01:17:07,100 --> 01:17:09,133
These may be our lifeboats.

1463
01:17:13,867 --> 01:17:16,300
PLAIT: I mean, they won't have
breathable atmospheres,

1464
01:17:16,367 --> 01:17:18,367
and it's not like they're gonna
be great places to live,

1465
01:17:18,467 --> 01:17:21,166
but, you know, the Earth is
gonna be basically toast at

1466
01:17:21,266 --> 01:17:23,934
that point, so, you know,
what choice do you have?

1467
01:17:24,000 --> 01:17:26,619
ROWE: Humanity may use the warm
outer bodies as stepping stones

1468
01:17:26,619 --> 01:17:28,200
ROWE: Humanity may use the warm
outer bodies as stepping stones

1469
01:17:28,266 --> 01:17:30,667
to a new home,
because when

1470
01:17:30,734 --> 01:17:33,166
the Godfather's sun
gets very old,

1471
01:17:33,166 --> 01:17:38,266
he becomes frail and unable to
stop other more powerful Dons

1472
01:17:38,367 --> 01:17:41,767
from destroying
the solar system forever.

1473
01:17:55,467 --> 01:17:58,567
ROWE: Six billion years
in the future.

1474
01:17:59,767 --> 01:18:03,867
The aging Godfather's attack
on his children ends.

1475
01:18:06,867 --> 01:18:10,667
The bloated red giant dies,
releasing a burst of energy,

1476
01:18:10,767 --> 01:18:12,867
which blasts the outer regions

1477
01:18:12,967 --> 01:18:16,000
of the star, plus the remains
of the vaporized

1478
01:18:16,066 --> 01:18:17,796
planets, out into space...

1479
01:18:17,796 --> 01:18:18,033
planets, out into space...

1480
01:18:21,266 --> 01:18:24,367
...ready to build new stars
and new planets.

1481
01:18:25,834 --> 01:18:28,567
What's left are veils of

1482
01:18:28,667 --> 01:18:32,166
beautiful colored gas called
a planetary nebula,

1483
01:18:33,233 --> 01:18:35,567
the surviving planets,

1484
01:18:35,567 --> 01:18:40,066
and, at the heart,
the remains of the Sun,

1485
01:18:40,133 --> 01:18:45,000
now nothing
but a burnt-out core.

1486
01:18:46,300 --> 01:18:47,796
We call those leftover cores
from small stars

1487
01:18:47,796 --> 01:18:49,567
We call those leftover cores
from small stars

1488
01:18:49,567 --> 01:18:53,567
white dwarf stars, and they're
much smaller than the Sun.

1489
01:18:54,767 --> 01:18:57,767
The white dwarf will be
about half the Sun's original

1490
01:18:57,834 --> 01:19:02,233
mass and all contained into
the size of the Earth.

1491
01:19:02,233 --> 01:19:05,400
ROWE: The dense white dwarf
doesn't burn fuel,

1492
01:19:05,467 --> 01:19:07,667
so it can't
generate energy.

1493
01:19:09,667 --> 01:19:11,934
The solar system cools.

1494
01:19:13,100 --> 01:19:15,767
We'll start seeing freezing
from the outer solar system

1495
01:19:15,834 --> 01:19:17,796
to the inner solar system --
we'll start with Pluto.

1496
01:19:17,796 --> 01:19:18,934
to the inner solar system --
we'll start with Pluto.

1497
01:19:20,266 --> 01:19:22,600
Then Enceladus around Saturn.

1498
01:19:23,767 --> 01:19:26,033
And then Europa
around Jupiter,

1499
01:19:26,100 --> 01:19:27,834
and then finally Mars.

1500
01:19:27,834 --> 01:19:32,600
So, you know, they've already
had any volatiles sent away.

1501
01:19:32,667 --> 01:19:35,367
Their surfaces are now gonna
be metallic and rocky,

1502
01:19:35,367 --> 01:19:39,133
and you're gonna end up with
these very frozen, rocky,

1503
01:19:39,133 --> 01:19:41,266
metallic worlds.

1504
01:19:41,266 --> 01:19:44,233
ROWE:
The near-dead Godfather

1505
01:19:44,233 --> 01:19:46,867
is now a shadow
of his former self.

1506
01:19:47,967 --> 01:19:49,467
And the solar system is at

1507
01:19:49,467 --> 01:19:52,867
the mercy of more powerful
mobster stars.

1508
01:19:52,967 --> 01:19:56,400
The white dwarf of the Sun has
about half the mass

1509
01:19:56,467 --> 01:19:57,467
of the Sun today,

1510
01:19:57,467 --> 01:19:59,600
which means gravity
is half as strong.

1511
01:19:59,667 --> 01:20:02,867
So the planets in their orbits
will move further out.

1512
01:20:05,166 --> 01:20:07,400
These outer planets,
which survived

1513
01:20:07,467 --> 01:20:09,266
the Sun turning
into a red giant,

1514
01:20:09,266 --> 01:20:12,033
their orbits are now much, much
larger than they were before,

1515
01:20:12,100 --> 01:20:15,066
up to about a factor of two.

1516
01:20:15,133 --> 01:20:17,796
That's an issue, because there
are other stars in the galaxy.

1517
01:20:17,796 --> 01:20:18,400
That's an issue, because there
are other stars in the galaxy.

1518
01:20:19,567 --> 01:20:23,100
We're part of the Milky Way
Galaxy, and our best estimate

1519
01:20:23,166 --> 01:20:26,867
is that there is something like
100 billion other suns like ours

1520
01:20:26,967 --> 01:20:28,233
orbiting our galaxy.

1521
01:20:29,767 --> 01:20:32,667
PLAIT: Every 20 million years,
something like that,

1522
01:20:32,767 --> 01:20:36,066
one of them will pass by close
enough to affect the orbits

1523
01:20:36,133 --> 01:20:37,367
of these planets.

1524
01:20:40,367 --> 01:20:44,400
So in this distant future,
where our sun is a white dwarf,

1525
01:20:44,467 --> 01:20:47,033
as our orbits are larger
and things are moving slower,

1526
01:20:47,100 --> 01:20:47,796
we're way more susceptible to
the effects of passing stars.

1527
01:20:47,796 --> 01:20:50,266
we're way more susceptible to
the effects of passing stars.

1528
01:20:53,033 --> 01:20:55,500
You can imagine this like
ships passing each other in

1529
01:20:55,567 --> 01:20:58,667
the ocean, where there's one
whizzes by another,

1530
01:20:58,734 --> 01:21:02,567
it creates waves that knock
the other one around.

1531
01:21:02,567 --> 01:21:07,000
BATYGIN: Passing stars will give
the planets little nudges,

1532
01:21:07,066 --> 01:21:08,033
little kicks.

1533
01:21:08,100 --> 01:21:13,066
The giant planets will enter
a chaotic phase

1534
01:21:13,133 --> 01:21:15,300
where everything
except for Jupiter will be

1535
01:21:15,367 --> 01:21:16,934
scattered out of
the solar system.

1536
01:21:21,367 --> 01:21:22,600
ROWE: 50 billion years in
the future,

1537
01:21:22,667 --> 01:21:27,133
the solar system faces another
ruthless gangster

1538
01:21:27,133 --> 01:21:28,767
out on the make.

1539
01:21:28,867 --> 01:21:31,834
Its gravity is gonna
yank Jupiter away from the Sun

1540
01:21:31,834 --> 01:21:33,867
and fling it out into
interstellar space,

1541
01:21:33,967 --> 01:21:35,600
and Jupiter will become
a rogue planet.

1542
01:21:37,667 --> 01:21:41,033
ROWE: All that's left
of our once strong mafia family,

1543
01:21:41,100 --> 01:21:44,667
the Sun, eight planets,
and countless moons,

1544
01:21:44,734 --> 01:21:47,667
is the small,
weak white dwarf.

1545
01:21:47,767 --> 01:21:47,796
Eventually, a white dwarf cools
so much that it no longer

1546
01:21:47,796 --> 01:21:51,667
Eventually, a white dwarf cools
so much that it no longer

1547
01:21:51,734 --> 01:21:56,166
emits radiation, and it becomes
what we call a black dwarf.

1548
01:21:58,367 --> 01:22:01,166
And this is basically
just a burnt-out shell

1549
01:22:01,266 --> 01:22:04,767
of a star composed of
oxygen and carbon.

1550
01:22:06,300 --> 01:22:08,166
OLUSEYI:
It can form a carbon crystal,

1551
01:22:08,266 --> 01:22:10,233
which we happen
to call diamonds.

1552
01:22:10,233 --> 01:22:14,567
So think of a black dwarf as
a diamond in the sky.

1553
01:22:17,867 --> 01:22:22,500
ROWE: A cosmic gem destined to
wander the galaxy for eternity.

1554
01:22:28,367 --> 01:22:31,834
Our solar system formed
from chaos but grew

1555
01:22:31,834 --> 01:22:36,100
from collaboration between
the planets and the Sun.

1556
01:22:36,166 --> 01:22:37,600
PLAIT:
We know the planets affect us.

1557
01:22:37,667 --> 01:22:40,166
We know the Sun affects us --
in a few billion years,

1558
01:22:40,266 --> 01:22:42,066
the Sun is really gonna
affect us.

1559
01:22:42,133 --> 01:22:43,934
The more we look at
this stuff,

1560
01:22:44,000 --> 01:22:46,500
the more we realize that
everything affects everything

1561
01:22:46,567 --> 01:22:47,796
else, including us.

1562
01:22:47,796 --> 01:22:48,300
else, including us.

1563
01:22:49,367 --> 01:22:52,400
HOWETT: Without all of
these things interplaying,

1564
01:22:52,467 --> 01:22:54,967
the Earth wouldn't have
the stable environment

1565
01:22:55,033 --> 01:22:56,867
that we have today,
and life wouldn't be

1566
01:22:56,967 --> 01:22:58,233
able to exist.

1567
01:22:58,266 --> 01:23:00,867
And so the chances are small,
but it's worked out well for us.

1568
01:23:03,600 --> 01:23:06,734
WALSH: As we piece together
the events that have

1569
01:23:06,734 --> 01:23:08,600
we think shaped
our solar system,

1570
01:23:08,667 --> 01:23:11,266
we step back and think about
all the moving parts,

1571
01:23:11,367 --> 01:23:14,934
all of the chance encounters,
all of the chaos.

1572
01:23:15,000 --> 01:23:17,166
And it's hard not to think
that we're really

1573
01:23:17,266 --> 01:23:17,796
lucky to be sitting here
on this planet Earth.

1574
01:23:17,796 --> 01:23:19,600
lucky to be sitting here
on this planet Earth.

1575
01:23:19,667 --> 01:23:21,934
ROWE: In the future,

1576
01:23:22,000 --> 01:23:24,600
our mafia family
will be gone.

1577
01:23:24,667 --> 01:23:27,667
But somewhere
out in the Milky Way,

1578
01:23:27,767 --> 01:23:33,066
a new mobster star system may
rise from the ashes of our own.

1579
01:23:34,066 --> 01:23:35,367
OLUSEYI: One of the trends
that we see in

1580
01:23:35,367 --> 01:23:38,233
our universe is that
destruction leads to creation.

1581
01:23:38,233 --> 01:23:42,367
The fact that our star is
gonna one day die

1582
01:23:42,367 --> 01:23:44,767
doesn't mean that it's
the end of anything.

1583
01:23:44,867 --> 01:23:47,100
It's the beginning of
something new.

1584
01:23:47,166 --> 01:23:47,796
So I think in the future,
it's only going to get

1585
01:23:47,796 --> 01:23:49,400
So I think in the future,
it's only going to get

1586
01:23:49,467 --> 01:23:50,767
more complicated,

1587
01:23:50,834 --> 01:23:53,467
more interesting, and we're
gonna find out just how dynamic

1588
01:23:53,467 --> 01:23:55,100
a place the universe really is.