1
00:00:03,167 --> 00:00:05,033
Narrator: OUR WORLD FORMED

2
00:00:05,033 --> 00:00:08,267
THROUGH A SERIES
OF DEVASTATING CATACLYSMS...

3
00:00:09,900 --> 00:00:12,200
IT COULD HAVE LITERALLY
BLOWN THE EARTH TO BITS,

4
00:00:12,200 --> 00:00:14,400
AND THEN WE WOULDN'T EVEN HAVE
A PLANET TODAY.

5
00:00:14,400 --> 00:00:19,300
Narrator: ...AN APOCALYPTIC
PLANETARY COLLISION,

6
00:00:19,300 --> 00:00:22,767
MILLIONS
OF BRUTAL COSMIC STRIKES,

7
00:00:22,767 --> 00:00:26,767
AND THE MOST POWERFUL BLAST
IN THE UNIVERSE,

8
00:00:26,767 --> 00:00:28,133
A SUPERNOVA.

9
00:00:28,133 --> 00:00:32,433
OUR ATOMS WOULD HAVE BEEN
SCATTERED INTO OUTER SPACE.

10
00:00:32,433 --> 00:00:39,267
Narrator: YET, THESE CATASTROPHES
CREATED THE PLANET WE KNOW TODAY.

11
00:00:39,267 --> 00:00:41,233
THE EARTH IS
AN INCREDIBLY SPECIAL PLACE.

12
00:00:41,233 --> 00:00:43,733
IT SEEMS LIKE EVERYTHING HAS
WORKED OUT JUST PERFECTLY.

13
00:00:43,733 --> 00:00:49,167
Narrator: COULD OTHER PLANETS
HAVE FORMED THE SAME WAY?

14
00:00:49,167 --> 00:00:54,033
IF SO, THE UNIVERSE COULD BE
FULL OF EARTHS...

15
00:00:54,033 --> 00:00:56,467
AND FULL OF LIFE.

16
00:00:56,467 --> 00:00:58,467
-- Captions by VITAC --
www.vitac.com

17
00:00:58,467 --> 00:01:00,533
CAPTIONS PAID FOR BY
DISCOVERY COMMUNICATIONS

18
00:01:12,833 --> 00:01:14,900
OUR PLANET IS EXTRAORDINARY.

19
00:01:17,267 --> 00:01:20,633
IT PROVIDES
EVERYTHING LIFE NEEDS --

20
00:01:20,633 --> 00:01:26,300
TRILLIONS OF CREATURES, PLANTS,

21
00:01:26,300 --> 00:01:29,667
AND US.

22
00:01:29,667 --> 00:01:32,133
Schweickart: WELL, YOU LOOK DOWN
AT THE EARTH FROM SPACE

23
00:01:32,133 --> 00:01:34,733
AND EVERYTHING
THAT WE KNOW OF THAT'S LIFE

24
00:01:34,733 --> 00:01:38,633
IS DOWN THERE ON THAT PLANET,
THAT BEAUTIFUL PLANET

25
00:01:38,633 --> 00:01:42,600
THAT YOU NOW ARE GOING AROUND
EVERY HOUR AND A HALF,

26
00:01:42,600 --> 00:01:45,333
AND THAT'S
ALMOST OVERWHELMING --

27
00:01:45,333 --> 00:01:48,133
JUST THE BEAUTY OF THE EARTH.

28
00:01:48,133 --> 00:01:52,067
Narrator:
IT'S UNIQUE IN OUR SOLAR SYSTEM,

29
00:01:52,067 --> 00:01:56,300
BUT IS IT UNIQUE
IN THE UNIVERSE?

30
00:01:56,300 --> 00:01:57,667
Dr. Sykes: IT'S IMPORTANT
FOR US TO UNDERSTAND

31
00:01:57,667 --> 00:02:00,967
THE CONDITIONS THAT LED
TO THE FORMATION OF THE EARTH

32
00:02:00,967 --> 00:02:02,300
BECAUSE THEN WE CAN
LOOK FOR THOSE CONDITIONS

33
00:02:02,300 --> 00:02:03,967
AROUND OTHER STARS.

34
00:02:03,967 --> 00:02:05,967
AND IF WE FIND
THOSE CONDITIONS THERE,

35
00:02:05,967 --> 00:02:07,133
THEN THAT WOULD SUGGEST

36
00:02:07,133 --> 00:02:08,967
THAT OTHER EARTHS COULD BE
FORMING

37
00:02:08,967 --> 00:02:10,267
ELSEWHERE IN THE UNIVERSE.

38
00:02:13,500 --> 00:02:17,333
Narrator: COULD THERE BE OTHER
PLANETS LIKE OURS AMONG THE STARS?

39
00:02:20,300 --> 00:02:24,433
TO FIND OUT,
WE MUST TRAVEL BACK IN TIME...

40
00:02:26,433 --> 00:02:30,067
...AND DISCOVER
HOW THE EARTH WAS MADE.

41
00:02:36,300 --> 00:02:40,700
REWIND THE CLOCK
4 1/2 BILLION YEARS,

42
00:02:40,700 --> 00:02:42,667
AND THIS IS WHAT YOU SEE.

43
00:02:44,867 --> 00:02:50,933
THIS SPECK OF DUST WILL
BECOME THE EARTH

44
00:02:50,933 --> 00:02:54,900
BY COMBINING
WITH COUNTLESS OTHERS.

45
00:02:54,900 --> 00:02:58,233
THEY'RE ALL PART
OF A GIANT CLOUD

46
00:02:58,233 --> 00:03:01,400
CALLED A STELLAR NURSERY.

47
00:03:01,400 --> 00:03:03,967
THE FIRST STEP
OF PLANETARY FORMATION

48
00:03:03,967 --> 00:03:07,067
IS ABOUT TO START...

49
00:03:11,933 --> 00:03:15,367
...AN EVENT THAT WILL
TRANSFORM THE CLOUD

50
00:03:15,367 --> 00:03:20,900
INTO THOUSANDS
OF INFANT SOLAR SYSTEMS,

51
00:03:20,900 --> 00:03:23,100
INCLUDING OUR OWN.

52
00:03:29,067 --> 00:03:31,800
THE SAME PROCESS
IS HAPPENING TODAY,

53
00:03:31,800 --> 00:03:37,067
7,000 LIGHT-YEARS AWAY,
IN THE EAGLE NEBULA.

54
00:03:39,633 --> 00:03:42,633
OUR OWN SOLAR SYSTEM FORMED

55
00:03:42,633 --> 00:03:48,733
INSIDE CLOUDS OF GAS AND DUST
LIKE THESE.

56
00:03:48,733 --> 00:03:52,533
Dr. Plait: THERE ARE
THESE THREE TRUNKS OF GAS,

57
00:03:52,533 --> 00:03:54,733
AND THEY'RE NICKNAMED
THE "PILLARS OF CREATION,"

58
00:03:54,733 --> 00:03:56,900
AND THEY'RE
TRILLIONS OF MILES LONG.

59
00:03:56,900 --> 00:03:58,267
THESE ARE HUGE STRUCTURES.

60
00:03:58,267 --> 00:04:01,633
Narrator: THE CLOUDS LOOK DENSE,

61
00:04:01,633 --> 00:04:05,400
BUT THEY'RE
ACTUALLY VERY SPARSE.

62
00:04:05,400 --> 00:04:07,700
Plait: THESE GAS CLOUDS ARE
INCREDIBLY TENUOUS.

63
00:04:07,700 --> 00:04:09,067
YOU'D HAVE TO COMPRESS,

64
00:04:09,067 --> 00:04:13,067
BASICALLY, A MOUNTAIN'S VOLUME
WORTH OF THIS STUFF,

65
00:04:13,067 --> 00:04:16,067
SQUEEZE IT DOWN JUST TO MAKE
A LITTLE, TINY ROCK LIKE THIS.

66
00:04:16,067 --> 00:04:23,533
Narrator: TO COMPRESS THE GAS AND
DUST INTO DENSE STARS AND PLANETS

67
00:04:23,533 --> 00:04:28,400
TAKES
A SUPREMELY POWERFUL EVENT --

68
00:04:28,400 --> 00:04:33,700
ONE THAT CAN ONLY FOLLOW
THE DEATH OF A GIANT STAR.

69
00:04:33,700 --> 00:04:39,133
IN 2007,
THE SPITZER SPACE TELESCOPE

70
00:04:39,133 --> 00:04:40,567
CAPTURED THIS IMAGE --

71
00:04:40,567 --> 00:04:46,567
A BALL OF HOT GAS
BEHIND THE EAGLE NEBULA...

72
00:04:49,500 --> 00:04:54,067
...EVIDENCE
THAT A HUGE STAR HAS EXPLODED

73
00:04:54,067 --> 00:04:59,767
AND SENT A VAST WALL OF GAS
RACING TOWARD THE PILLARS.

74
00:04:59,767 --> 00:05:01,933
Dr. Thaller:
THERE'S A WAVE OF HOT MATERIAL

75
00:05:01,933 --> 00:05:03,700
APPROACHING
THE PILLARS OF CREATION,

76
00:05:03,700 --> 00:05:05,833
AND THIS MAY BE A SHOCK WAVE
FROM A SUPERNOVA,

77
00:05:05,833 --> 00:05:06,900
A DYING STAR.

78
00:05:11,333 --> 00:05:17,433
Narrator: SUPERNOVAS BRIEFLY
OUTSHINE ENTIRE GALAXIES.

79
00:05:17,433 --> 00:05:21,733
SUPERHEATED PLASMA BLASTS
INTO SPACE

80
00:05:21,733 --> 00:05:24,967
AT 70 MILLION MILES PER HOUR.

81
00:05:24,967 --> 00:05:31,833
A MIGHTY SHOCK WAVE SPEEDS
TOWARD THE PILLARS OF CREATION.

82
00:05:37,833 --> 00:05:42,300
WHEN IT HITS,
IT WILL DEMOLISH THEM.

83
00:05:42,300 --> 00:05:47,600
IT WILL ALSO CREATE NEW WORLDS.

84
00:05:47,600 --> 00:05:51,867
SUPERNOVA SHOCK WAVES SMASH
INTO THE PILLARS,

85
00:05:51,867 --> 00:05:55,167
COMPRESSING
THE THIN GAS AND DUST

86
00:05:55,167 --> 00:05:58,567
INTO DENSE CLUMPS.

87
00:05:58,567 --> 00:06:05,500
EACH IS A NEW STAR,
A NEW SOLAR SYSTEM.

88
00:06:05,500 --> 00:06:07,933
MOLECULAR CLOUD MINDING
ITS OWN BUSINESS

89
00:06:07,933 --> 00:06:10,633
GETS BLASTED
BY A SUPERNOVA EXPLOSION,

90
00:06:10,633 --> 00:06:16,067
CRUSHING THE CLOUD
DOWN INTO STARS AND PLANETS.

91
00:06:16,067 --> 00:06:19,900
Narrator:
WIND BACK 4 1/2 BILLION YEARS,

92
00:06:19,900 --> 00:06:25,100
AND OUR SOLAR SYSTEM STARTS
THE SAME WAY.

93
00:06:25,100 --> 00:06:29,067
A SUPERNOVA CRUSHES
A MASSIVE DUSTY CLOUD

94
00:06:29,067 --> 00:06:33,467
INTO A PROTOPLANETARY DISK.

95
00:06:33,467 --> 00:06:36,467
A THIN NEBULOUS CLOUD BECOMES

96
00:06:36,467 --> 00:06:40,433
A DENSE WHIRLPOOL
OF GAS AND DUST --

97
00:06:40,433 --> 00:06:46,067
A SOLAR SYSTEM IN THE MAKING.

98
00:06:46,067 --> 00:06:48,800
ONE STAR IS DESTROYED.

99
00:06:48,800 --> 00:06:52,167
A NEW STAR IS BORN --

100
00:06:52,167 --> 00:06:56,933
OUR SUN AND ITS PLANETS.

101
00:06:56,933 --> 00:06:58,767
THIS IS THE FIRST LINK

102
00:06:58,767 --> 00:07:02,167
IN THE LONG AND UNLIKELY
CHAIN OF EVENTS

103
00:07:02,167 --> 00:07:04,400
THAT MADE OUR WORLD.

104
00:07:06,833 --> 00:07:10,167
FOR EARTH TO EVEN BE HERE,

105
00:07:10,167 --> 00:07:14,900
WE HAD TO BEAT
ASTRONOMICAL ODDS.

106
00:07:14,900 --> 00:07:18,233
A HOST OF DIFFERENT FACTORS
HAVE TO LINE UP

107
00:07:18,233 --> 00:07:20,400
TO GET A PLANET
JUST LIKE THE EARTH.

108
00:07:20,400 --> 00:07:22,167
YOU HAVE TO HAVE
THE RIGHT DISTANCE,

109
00:07:22,167 --> 00:07:24,600
THE RIGHT SIZE,
THE RIGHT KIND OF MOON.

110
00:07:27,233 --> 00:07:32,433
Narrator: ON EARTH, ALL THE
CONDITIONS ARE JUST RIGHT FOR LIFE.

111
00:07:32,433 --> 00:07:35,633
Krauss: TO GET A WORLD LIKE
OURS, YOU NEED A LOT OF ACES.

112
00:07:35,633 --> 00:07:38,867
SOMEHOW, OUR SOLAR SYSTEM HIT
THE JACKPOT.

113
00:07:38,867 --> 00:07:42,700
BUT THE BIG QUESTION IS
DID IT HAPPEN ANYWHERE ELSE?

114
00:07:46,333 --> 00:07:50,700
Narrator: ONE OF THE UNIVERSE'S
MOST VIOLENT EVENTS

115
00:07:50,700 --> 00:07:55,800
TRIGGERED
THE BIRTH OF OUR PLANET.

116
00:07:55,800 --> 00:08:01,233
A SPARSE CLOUD CRUSHED
INTO A DENSE SWIRL OF DUST.

117
00:08:03,233 --> 00:08:08,733
SOME OF THIS DUST WILL BECOME
PLANET EARTH.

118
00:08:08,733 --> 00:08:14,733
BUT HOW DO TINY DUST GRAINS
CREATE ENTIRE WORLDS?

119
00:08:24,933 --> 00:08:29,400
Narrator: A SUPERNOVA EXPLOSION
TRIGGERS A CHAIN OF EVENTS

120
00:08:29,400 --> 00:08:32,300
THAT WILL EVENTUALLY CREATE
THE EARTH...

121
00:08:34,400 --> 00:08:37,467
...THE FORMATION
OF OUR SOLAR SYSTEM.

122
00:08:39,833 --> 00:08:44,733
A HOT BALL OF GAS GROWS
IN THE CENTER.

123
00:08:44,733 --> 00:08:50,600
THIS WILL BECOME OUR SUN.

124
00:08:50,600 --> 00:08:55,133
THE DUST THAT SWIRLS AROUND IT
WILL FORM THE PLANETS.

125
00:08:56,967 --> 00:09:01,767
BUT FIRST,
THE GRAINS MUST STICK TOGETHER.

126
00:09:01,767 --> 00:09:04,367
Dr. Levison: SO, WE HAVE THIS
INTERESTING CONUNDRUM, RIGHT?

127
00:09:04,367 --> 00:09:07,700
SO, THIS DISK CONSISTS
OF GAS AND DUST PARTICLES.

128
00:09:07,700 --> 00:09:09,900
THEY'RE ABOUT THE SIZE OF,
LET'S SAY,

129
00:09:09,900 --> 00:09:11,500
PARTICLES IN SMOKE, ALL RIGHT?

130
00:09:11,500 --> 00:09:13,400
WE'LL SAY CIGARETTE SMOKE,
RIGHT?

131
00:09:13,400 --> 00:09:14,833
SO, THESE ARE SMALL THINGS.

132
00:09:14,833 --> 00:09:19,233
AND, SOMEHOW, WE HAVE TO GET
FROM THOSE LITTLE GRAINS

133
00:09:19,233 --> 00:09:20,500
TO WHAT WE SEE ON THE EARTH.

134
00:09:20,500 --> 00:09:25,867
Narrator: GRAVITY IS
A POWERFUL ATTRACTIVE FORCE.

135
00:09:25,867 --> 00:09:30,767
IT SHAPES
GALAXIES AND SOLAR SYSTEMS,

136
00:09:30,767 --> 00:09:34,133
BUT SPECKS OF DUST ARE
FAR TOO SMALL

137
00:09:34,133 --> 00:09:37,233
TO PULL ON EACH OTHER.

138
00:09:37,233 --> 00:09:42,100
SOMEHOW, THEY CLUMP TOGETHER
TO FORM PLANETS.

139
00:09:42,100 --> 00:09:46,400
SO, IF GRAVITY DOESN'T
BIND THEM, WHAT DOES?

140
00:09:48,933 --> 00:09:52,067
IN GERMANY,
SCIENTISTS ARE ON THE CASE.

141
00:09:53,800 --> 00:09:54,867
OKAY.

142
00:09:54,867 --> 00:09:58,733
THEY CAN SIMULATE
HOW DUST BEHAVES IN SPACE

143
00:09:58,733 --> 00:10:03,067
INSIDE A HUGE TOWER.

144
00:10:03,067 --> 00:10:04,967
Blum: HERE, WE DO
FREE-FALL EXPERIMENTS.

145
00:10:04,967 --> 00:10:07,233
SO,
THE WHOLE EXPERIMENTAL SETUP,

146
00:10:07,233 --> 00:10:10,700
INCLUDING OUR DUST AGGREGATES,
ARE IN PERFECT FREE FALL.

147
00:10:10,700 --> 00:10:14,167
IT IS SIMULATION OF SPACE,
BUT A VERY GOOD ONE, INDEED.

148
00:10:14,167 --> 00:10:17,300
I THINK THIS IS THE CLOSEST
YOU CAN GET TO SPACE ON EARTH.

149
00:10:18,233 --> 00:10:22,467
Narrator: RESEARCHERS PLACE DUST
IN THE CONTAINER

150
00:10:22,467 --> 00:10:25,367
AND LOAD IT
INTO A LAUNCH CAPSULE.

151
00:10:27,433 --> 00:10:29,633
AT THE BASE OF THE TOWER,

152
00:10:29,633 --> 00:10:33,333
THEY LOWER IT
INTO A SUPER-POWERFUL CATAPULT.

153
00:10:33,333 --> 00:10:37,867
THIS LAUNCHES
THE HALF-TON CAPSULE

154
00:10:37,867 --> 00:10:41,700
FROM ZERO
TO OVER 100 MILES PER HOUR

155
00:10:41,700 --> 00:10:43,733
IN A QUARTER OF A SECOND.

156
00:10:47,033 --> 00:10:48,233
400 FEET UP,

157
00:10:48,233 --> 00:10:51,800
THE CAPSULE REACHES
THE TOP OF THE TOWER,

158
00:10:51,800 --> 00:10:55,300
THEN PLUNGES BACK DOWN.

159
00:10:55,300 --> 00:11:01,500
A DRUM OF POLYSTYRENE BALLS,
30 FEET DEEP, BREAKS ITS FALL.

160
00:11:04,067 --> 00:11:08,533
ALL THIS GIVES
JUST 10 SECONDS OF ZERO GRAVITY,

161
00:11:08,533 --> 00:11:13,233
JUST ENOUGH TIME, THEY HOPE,
FOR THE DUST TO STICK.

162
00:11:13,233 --> 00:11:16,600
THREE, TWO, ONE, AND GO.

163
00:11:19,333 --> 00:11:22,833
Narrator: MOMENTS AFTER
THE CAPSULE LAUNCHES,

164
00:11:22,833 --> 00:11:25,133
THE DUST INSIDE BECOMES
WEIGHTLESS.

165
00:11:27,767 --> 00:11:30,100
THE GRAINS CLUMP TOGETHER,

166
00:11:30,100 --> 00:11:33,267
JUST LIKE
THE EARLY SOLAR SYSTEM.

167
00:11:40,300 --> 00:11:42,433
THESE IMAGES REVEAL

168
00:11:42,433 --> 00:11:48,167
HOW DUST PARTICLES CAME TOGETHER
4 1/2 BILLION YEARS AGO

169
00:11:48,167 --> 00:11:51,067
TO FORM THE EARTH.

170
00:11:51,067 --> 00:11:52,900
Blum: THE FORCE THAT BINDS
THE AGGREGATES TOGETHER

171
00:11:52,900 --> 00:11:54,133
IS NOT GRAVITY.

172
00:11:54,133 --> 00:11:57,367
THEY ARE TOO SMALL
FOR GRAVITY TO BE EFFICIENT.

173
00:11:57,367 --> 00:12:02,333
WE THINK THE FORCE THAT BINDS
THE AGGREGATES TOGETHER

174
00:12:02,333 --> 00:12:04,533
IS ELECTROSTATIC FORCE.

175
00:12:04,533 --> 00:12:06,467
Marcy:
IT'S THE SAME REASON

176
00:12:06,467 --> 00:12:09,700
THAT WHEN YOU PULL
YOUR CLOTHES OUT OF THE DRYER --

177
00:12:09,700 --> 00:12:12,233
YOU KNOW HOW THE CLOTHES
SOMETIMES STICK TO YOU?

178
00:12:12,233 --> 00:12:14,800
THAT'S THE SAME EFFECT
THAT ALLOWS

179
00:12:14,800 --> 00:12:17,600
ONE DUST PARTICLE
TO STICK TO ANOTHER.

180
00:12:17,600 --> 00:12:22,067
Narrator: DUST PARTICLES JOIN
TO FORM BALLS OF FLUFF.

181
00:12:22,067 --> 00:12:24,600
Dr. Levison: THE LITTLE
STATIC CHARGES THAT THEY HAVE

182
00:12:24,600 --> 00:12:26,267
CAN MAKE THEM STICK
WHEN THEY HIT,

183
00:12:26,267 --> 00:12:28,467
AND YOU GET SOMETHING
SORT OF LIKE THE DUST BUNNIES

184
00:12:28,467 --> 00:12:30,233
THAT I HAVE A LOT OF
UNDERNEATH MY BED.

185
00:12:30,233 --> 00:12:37,167
Narrator: THESE COSMIC DUST BUNNIES
ARE PLANETS IN THE MAKING.

186
00:12:38,333 --> 00:12:41,867
THEY START OUT
SMALLER THAN A PINHEAD,

187
00:12:41,867 --> 00:12:43,767
THEN GROW.

188
00:12:43,767 --> 00:12:47,700
THE DUST IS NOW IN CLUMPS,

189
00:12:47,700 --> 00:12:53,633
BUT IT'S STILL
JUST BALLS OF DUST.

190
00:12:53,633 --> 00:12:58,700
TURNING DUST BALLS INTO ROCKS
TAKES A WHOLE NEW PROCESS...

191
00:13:00,833 --> 00:13:04,067
...A COSMIC ELECTRIC STORM.

192
00:13:07,067 --> 00:13:13,733
SPACE CLOUDS BUILD UP CHARGE
JUST LIKE CLOUDS HERE ON EARTH,

193
00:13:13,733 --> 00:13:16,733
GENERATING
HUGE BOLTS OF LIGHTNING.

194
00:13:19,733 --> 00:13:22,967
BALLS OF DUST CAN
TURN INTO SOLID ROCKS

195
00:13:22,967 --> 00:13:26,367
BY AN ENERGETIC EVENT,
LIKE LIGHTNING.

196
00:13:26,367 --> 00:13:30,767
Narrator: THE ELECTRIC BOLTS
SMASH THROUGH THE DUST BALLS

197
00:13:30,767 --> 00:13:34,367
AND HEAT THEM
TO 3,000 DEGREES FAHRENHEIT.

198
00:13:37,600 --> 00:13:43,300
IN MINUTES, THEY COOL AND FUSE
INTO SOLID ROCK.

199
00:13:43,300 --> 00:13:48,833
METEORITES TODAY STILL CARRY
THESE ANCIENT ROCK BALLS

200
00:13:48,833 --> 00:13:51,267
INSIDE THEM.

201
00:13:51,267 --> 00:13:53,400
THESE TINY GLOBULES

202
00:13:53,400 --> 00:13:57,800
WERE ONCE THE BUILDING BLOCKS
OF PLANETS.

203
00:13:57,800 --> 00:14:00,467
TO FORM THE EARTH,

204
00:14:00,467 --> 00:14:06,933
THESE TINY BALLS MUST COLLIDE,
STICK, AND GROW.

205
00:14:06,933 --> 00:14:09,533
ROCKS BEGIN TO BUILD UP
BY ACCIDENTAL COLLISIONS,

206
00:14:09,533 --> 00:14:11,067
WHICH CAN TAKE A LONG TIME.

207
00:14:11,067 --> 00:14:14,267
EVENTUALLY, THE PROTOPLANETS,
AS WE CALL THEM --

208
00:14:14,267 --> 00:14:15,467
THE BABY PLANETS --

209
00:14:15,467 --> 00:14:20,100
GET THE SIZE OF ASTEROIDS,
KILOMETERS ACROSS.

210
00:14:20,100 --> 00:14:25,200
Narrator: THE BABY EARTH IS NOW
THE SIZE OF A FEW CITY BLOCKS,

211
00:14:25,200 --> 00:14:28,767
BIG ENOUGH FOR A NEW FORCE
TO TAKE CHARGE --

212
00:14:28,767 --> 00:14:31,133
GRAVITY.

213
00:14:31,133 --> 00:14:32,500
Marcy: AT THAT POINT,

214
00:14:32,500 --> 00:14:35,933
A SINGLE ASTEROID WILL
GRAVITATIONALLY ATTRACT

215
00:14:35,933 --> 00:14:37,700
A NEIGHBORING ASTEROID.

216
00:14:37,700 --> 00:14:39,500
AND, SO, THOSE TWO ASTEROIDS

217
00:14:39,500 --> 00:14:41,867
THAT WOULD HAVE
PASSED IN THE NIGHT

218
00:14:41,867 --> 00:14:45,333
ARE GRAVITATIONALLY ATTRACTED,
AND THEY HIT EACH OTHER.

219
00:14:47,567 --> 00:14:49,833
Plait: ONCE GRAVITY STARTS
TO REAR ITS HEAD,

220
00:14:49,833 --> 00:14:51,100
THINGS REALLY SPEED UP

221
00:14:51,100 --> 00:14:54,200
BECAUSE INSTEAD OF JUST RANDOMLY
PLOWING THROUGH MATERIAL

222
00:14:54,200 --> 00:14:55,733
AND GETTING BIGGER THAT WAY,

223
00:14:55,733 --> 00:14:57,933
NOW IT'S STARTING
TO DRAW MATERIAL IN.

224
00:15:00,133 --> 00:15:06,233
Narrator: GRAVITY PULLS ROCKS
TOGETHER, THEN HOLDS THEM THERE

225
00:15:06,233 --> 00:15:11,867
TO PRODUCE BIGGER AND BIGGER
PILES OF RUBBLE.

226
00:15:11,867 --> 00:15:14,900
Plait: SO, THIS FORMATION PROCESS,
WHICH WAS TAKING A LONG TIME

227
00:15:14,900 --> 00:15:17,267
TO GET TO THE SIZE
WHERE GRAVITY KICKS IN,

228
00:15:17,267 --> 00:15:19,467
SUDDENLY GETS
KICKED INTO OVERDRIVE,

229
00:15:19,467 --> 00:15:21,800
AND THE PLANET GROWS
VERY RAPIDLY.

230
00:15:21,800 --> 00:15:29,900
Narrator: BUT PLANETS ARE MORE
THAN JUST OVERGROWN ROCK PILES.

231
00:15:29,900 --> 00:15:33,533
THESE ROCKS ARE LUMPY AND INERT.

232
00:15:33,533 --> 00:15:38,233
HOW DID THE EARTH BECOME
ROUND AND FULL OF LIFE?

233
00:15:47,567 --> 00:15:52,900
Narrator: THE EARLY SOLAR SYSTEM IS
A CONSTRUCTION SITE FOR PLANETS.

234
00:15:54,567 --> 00:15:57,367
DUST STICKS TOGETHER
TO FORM ROCKS.

235
00:15:57,367 --> 00:16:02,467
ROCKS JOIN TO FORM ASTEROIDS.

236
00:16:02,467 --> 00:16:08,467
BUT MOST ASTEROIDS
LOOK NOTHING LIKE EARTH.

237
00:16:08,467 --> 00:16:11,267
Marcy: AND WHEN YOU LOOK AT
A CLOSE-UP OF AN ASTEROID,

238
00:16:11,267 --> 00:16:14,100
IT LOOKS LIKE
SOME KIND OF DISTORTED PEANUT,

239
00:16:14,100 --> 00:16:16,533
LIKE A POTATO THAT'S BEEN
SORT OF BASHED.

240
00:16:16,533 --> 00:16:20,233
YOU CAN SEE
GIANT CRATERS AND OBLONG SHAPES.

241
00:16:20,233 --> 00:16:24,567
Narrator: THE YOUNG EARTH IS ONE
OF BILLIONS

242
00:16:24,567 --> 00:16:29,067
OF MISSHAPEN SPACE BOULDERS.

243
00:16:29,067 --> 00:16:32,733
TO BECOME A PLANET,
IT MUST FIRST BECOME ROUND.

244
00:16:32,733 --> 00:16:36,800
THAT PROCESS ONLY STARTS

245
00:16:36,800 --> 00:16:40,933
WHEN IT'S SEVERAL HUNDRED MILES
ACROSS,

246
00:16:40,933 --> 00:16:46,767
WHEN ITS OWN INTERNAL GRAVITY
BEGINS TO CHANGE ITS SHAPE.

247
00:16:49,900 --> 00:16:52,867
ONCE YOU GET ENOUGH MATERIAL,
ENOUGH MASS,

248
00:16:52,867 --> 00:16:55,200
THE GRAVITATIONAL FORCE BECOMES
STRONGER.

249
00:16:55,200 --> 00:16:57,867
ANY GIANT MOUNTAIN WILL BE
CRUSHED DOWN

250
00:16:57,867 --> 00:17:00,600
BY THE FORCE OF GRAVITY.

251
00:17:00,600 --> 00:17:02,700
Dr. Levison:
THE GRAVITY IS SO STRONG

252
00:17:02,700 --> 00:17:04,600
THAT IT CAN
ACTUALLY BREAK ROCKS,

253
00:17:04,600 --> 00:17:07,067
AND THE ROCKS, ITSELF,
CAN ACT LIKE A FLUID,

254
00:17:07,067 --> 00:17:08,467
MAKING AN OBJECT ROUND.

255
00:17:10,667 --> 00:17:16,467
Narrator: HUGE OUTCROPS OF ROCK
CRUMBLE AND FALL.

256
00:17:16,467 --> 00:17:19,967
THE IMMENSE SELF-GRAVITY
OF THE EARLY EARTH

257
00:17:19,967 --> 00:17:25,667
CRUSHES IT
INTO THE MOST EFFICIENT SHAPE --

258
00:17:25,667 --> 00:17:29,400
A VAST, ROUND BALL OF ROCK...

259
00:17:32,733 --> 00:17:35,533
...A LOPSIDED PILE OF RUBBLE

260
00:17:35,533 --> 00:17:39,367
TRANSFORMED
INTO A MINIATURE WORLD.

261
00:17:44,600 --> 00:17:47,100
THE EARTH HAS A NEW SHAPE,

262
00:17:47,100 --> 00:17:50,633
BUT IT'S STILL
JUST A BALL OF ROCK.

263
00:17:50,633 --> 00:17:55,067
ITS STRUCTURE WILL
ALSO SOON CHANGE.

264
00:17:55,067 --> 00:18:02,467
COSMIC ROCKS AND BOULDERS
STILL RAIN DOWN FROM SPACE.

265
00:18:02,467 --> 00:18:05,767
EACH COLLISION HEATS THE GROUND.

266
00:18:05,767 --> 00:18:07,800
Dr. Plait:
THERE'S A HUGE AMOUNT OF ENERGY

267
00:18:07,800 --> 00:18:09,867
STORED IN AN OBJECT
THAT'S MOVING RAPIDLY.

268
00:18:09,867 --> 00:18:11,067
AND WHEN THAT HITS THE EARTH,

269
00:18:11,067 --> 00:18:13,067
ALL THAT ENERGY IS DUMPED
INTO THE MATERIAL,

270
00:18:13,067 --> 00:18:14,667
AND THAT HEATS IT UP
AND MELTS IT.

271
00:18:14,667 --> 00:18:16,633
AND THE EARTH BECAME MOLTEN

272
00:18:16,633 --> 00:18:19,400
AND STAYED THAT WAY
FOR A LONG TIME.

273
00:18:19,400 --> 00:18:23,300
Narrator: THE YOUNG PLANET IS
NO LONGER SOLID ROCK.

274
00:18:23,300 --> 00:18:26,067
IT'S A SEETHING MOLTEN MASS...

275
00:18:29,067 --> 00:18:31,433
...JUST LIKE THIS BLAST FURNACE

276
00:18:31,433 --> 00:18:34,567
AT THE SEVERSTAL PLANT
IN DETROIT.

277
00:18:38,733 --> 00:18:40,067
Kaku: BELIEVE IT OR NOT,

278
00:18:40,067 --> 00:18:43,867
THIS PROCESS BEHIND ME MAKES
LIFE ON EARTH POSSIBLE.

279
00:18:46,100 --> 00:18:49,533
Narrator:
THEY FEED IN GROUND-UP IRON ORE,

280
00:18:49,533 --> 00:18:51,867
A MIXTURE OF ROCK AND METAL...

281
00:18:53,667 --> 00:18:57,300
...JUST LIKE THE EARLY EARTH.

282
00:19:01,833 --> 00:19:07,567
PUT IRON ORE IN A FURNACE,
AND THE HEAT MELTS EVERYTHING.

283
00:19:10,433 --> 00:19:16,200
Kaku: THIS MOLTEN IRON IS
AT 2,700 DEGREES FAHRENHEIT.

284
00:19:16,200 --> 00:19:19,133
THAT'S ABOUT THE TEMPERATURE
OF THE SURFACE OF THE EARTH

285
00:19:19,133 --> 00:19:21,800
4 1/2 BILLION YEARS AGO.

286
00:19:21,800 --> 00:19:25,767
IMAGINE AN ENTIRE PLANET MOLTEN.

287
00:19:25,767 --> 00:19:27,667
IN THE DISTANCE, YOU WOULD SEE

288
00:19:27,667 --> 00:19:31,100
THUNDERING VOLCANOES
SPEWING OUT LAVA.

289
00:19:31,100 --> 00:19:35,100
IT WOULD BE A SCENE
RIGHT OUT OF DANTE'S "INFERNO."

290
00:19:41,400 --> 00:19:43,633
Narrator:
IRON IS HEAVIER THAN ROCK.

291
00:19:43,633 --> 00:19:48,267
NOW MOLTEN, THEY SEPARATE.

292
00:19:48,267 --> 00:19:51,300
THIS IS AMAZING.

293
00:19:51,300 --> 00:19:52,800
WE'RE WITNESSING A PROCESS

294
00:19:52,800 --> 00:19:55,200
WHICH CREATED
THE VERY CRUST OF THE EARTH

295
00:19:55,200 --> 00:19:56,600
BILLIONS OF YEARS AGO --

296
00:19:56,600 --> 00:19:58,767
THE CRUST
THAT WE WALK ON EVERY DAY.

297
00:20:01,000 --> 00:20:07,900
Narrator: MOLTEN ROCK RISES TO THE
SURFACE AND COOLS TO FORM THE CRUST.

298
00:20:07,900 --> 00:20:12,233
MOLTEN IRON SINKS UNDERNEATH.

299
00:20:12,233 --> 00:20:13,833
INSIDE THE EARTH,

300
00:20:13,833 --> 00:20:17,733
IT SANK ALL THE WAY
TO THE PLANET'S CORE.

301
00:20:17,733 --> 00:20:22,167
THE ROCKY SURFACE IS
WHERE WE LIVE.

302
00:20:22,167 --> 00:20:26,367
BUT WITHOUT EARTH'S
MOLTEN IRON CORE,

303
00:20:26,367 --> 00:20:30,000
NONE OF US COULD SURVIVE.

304
00:20:30,000 --> 00:20:35,167
THIS PROCESS SEPARATED THE IRON
FROM THE ROCKY MINERALS.

305
00:20:35,167 --> 00:20:38,400
AS THE IRON DESCENDED
TO THE CENTER OF THE EARTH,

306
00:20:38,400 --> 00:20:41,033
IT EVENTUALLY CREATED
A MAGNETIC FIELD,

307
00:20:41,033 --> 00:20:43,100
AND THAT'S WHY WE'RE HERE TODAY.

308
00:20:43,100 --> 00:20:49,000
Narrator: THE MOLTEN IRON SWIRLS
INSIDE THE EARTH'S CORE

309
00:20:49,000 --> 00:20:53,500
AND GENERATES
A POWERFUL MAGNETIC FIELD

310
00:20:53,500 --> 00:20:55,833
AROUND THE PLANET --

311
00:20:55,833 --> 00:21:02,800
A COSMIC SHIELD AGAINST
DEADLY RADIATION FROM SPACE.

312
00:21:02,800 --> 00:21:08,867
BUT THE YOUNG EARTH IS
STILL SMALL --

313
00:21:08,867 --> 00:21:12,967
FAR SMALLER THAN THE MOON TODAY.

314
00:21:12,967 --> 00:21:17,967
THIS NEWLY-FORMED WORLD
MUST GROW.

315
00:21:20,667 --> 00:21:24,833
IT MUST ALSO AVOID
BEING BLOWN TO PIECES.

316
00:21:24,833 --> 00:21:28,633
THOUSANDS OF PROTOPLANETS

317
00:21:28,633 --> 00:21:32,333
ARE HURTLING
AROUND THE SOLAR SYSTEM,

318
00:21:32,333 --> 00:21:36,400
AND SOME ARE HEADING
STRAIGHT FOR EARTH.

319
00:21:45,233 --> 00:21:52,633
Narrator: IT'S 100,000 YEARS
SINCE OUR SOLAR SYSTEM FORMED.

320
00:21:52,633 --> 00:21:56,800
THE YOUNG EARTH
ALREADY LOOKS LIKE A PLANET.

321
00:21:56,800 --> 00:21:58,433
IT'S ROUND.

322
00:21:58,433 --> 00:22:03,500
IT HAS AN IRON CORE
AND A ROCKY SURFACE.

323
00:22:03,500 --> 00:22:10,300
YET, OUR BABY PLANET IS
JUST A FEW HUNDRED MILES ACROSS.

324
00:22:10,300 --> 00:22:13,900
IT HAS A LONG WAY TO GO.

325
00:22:13,900 --> 00:22:20,067
IT MUST GROW
4,000 TIMES MORE MASSIVE,

326
00:22:20,067 --> 00:22:23,500
AND IT HAS COMPETITION.

327
00:22:23,500 --> 00:22:29,633
THOUSANDS OF OTHER PROTOPLANETS
SHOOT THROUGH THE SOLAR SYSTEM,

328
00:22:29,633 --> 00:22:34,633
OFTEN COLLIDING
AT OVER 20,000 MILES PER HOUR.

329
00:22:37,067 --> 00:22:41,800
YOU CAN FIND PROOF
OF THIS ANCIENT DESTRUCTIVE ERA

330
00:22:41,800 --> 00:22:43,700
IN MODERN-DAY ARIZONA.

331
00:22:43,700 --> 00:22:51,667
NOT METEOR CRATER ITSELF --
THAT'S JUST 50,000 YEARS OLD --

332
00:22:51,667 --> 00:22:55,733
BUT THE ASTEROID
THAT GOUGED IT OUT.

333
00:22:55,733 --> 00:23:01,467
THAT WAS
4 1/2 BILLION YEARS OLD.

334
00:23:01,467 --> 00:23:04,467
MARK SYKES AND MARVIN KILLGORE

335
00:23:04,467 --> 00:23:09,067
THINK THE ASTEROID CAME
FROM A VIOLENT EVENT

336
00:23:09,067 --> 00:23:11,267
IN THE EARLY SOLAR SYSTEM.

337
00:23:13,500 --> 00:23:18,533
THE ASTEROID FLEW THROUGH SPACE
FOR BILLIONS OF YEARS,

338
00:23:18,533 --> 00:23:22,200
THEN IT HIT EARTH.

339
00:23:22,200 --> 00:23:27,233
THEY AIM TO FIND
A FRAGMENT OF THE ASTEROID,

340
00:23:27,233 --> 00:23:32,100
A REMNANT FROM THE PERIOD
OF PLANETARY FORMATION.

341
00:23:32,100 --> 00:23:34,167
Dr. Sykes: [ LAUGHS ]

342
00:23:34,167 --> 00:23:36,967
ABOUT SIX MILES FROM HERE IS
METEOR CRATER,

343
00:23:36,967 --> 00:23:41,267
AND THAT WAS AN IMPACT
50,000 YEARS OR SO AGO,

344
00:23:41,267 --> 00:23:44,767
AND IT SPEWED
A BUNCH OF PIECES OUT.

345
00:23:44,767 --> 00:23:46,267
Narrator: THEY'RE CONVINCED

346
00:23:46,267 --> 00:23:50,100
THE ORIGINAL ASTEROID WAS
RICH IN IRON,

347
00:23:50,100 --> 00:23:51,700
SO THEY'VE COME PREPARED

348
00:23:51,700 --> 00:23:55,133
WITH SOME
IMPRESSIVE METAL DETECTORS.

349
00:23:55,133 --> 00:23:56,300
DOES IT WORK?

350
00:23:56,300 --> 00:23:57,867
OH, YEAH.

351
00:23:57,867 --> 00:24:00,400
[ METAL DETECTOR CLICKING ]

352
00:24:00,400 --> 00:24:01,867
[ TONE WARBLES ]

353
00:24:01,867 --> 00:24:03,633
THAT'S THE SOUND
WE'RE LISTENING FOR.

354
00:24:07,967 --> 00:24:12,333
BUT EVEN WITH A QUAD-DRAWN
METAL DETECTOR,

355
00:24:12,333 --> 00:24:15,867
METEORITES ARE HARD TO FIND.

356
00:24:17,867 --> 00:24:21,300
YEAH, ARE YOU PRETTY CONVINCED
THERE'S NOTHING THERE?

357
00:24:21,300 --> 00:24:24,433
YEAH, I DON'T REALLY --
I'M NOT DETECTING ANYTHING.

358
00:24:28,333 --> 00:24:32,067
THEY FIND METAL
BUT NO METEORITES.

359
00:24:32,067 --> 00:24:34,600
Dr. Sykes: MY GREAT DISCOVERY
OF THE AFTERNOON

360
00:24:34,600 --> 00:24:39,067
HAS BEEN THIS BOLT...

361
00:24:39,067 --> 00:24:40,567
AND THIS PIECE OF WIRE.

362
00:24:40,567 --> 00:24:43,367
[ LAUGHS ]

363
00:24:47,067 --> 00:24:53,667
Narrator: IT TAKES HOURS OF
SEARCHING AND MANY FALSE ALARMS.

364
00:24:53,667 --> 00:24:58,533
THEN, WITH THE LIGHT FADING,
THE DETECTOR SOUNDS AGAIN.

365
00:24:58,533 --> 00:24:59,767
[ TONE WARBLES ]

366
00:25:04,233 --> 00:25:07,100
Dr. Sykes: HOW ABOUT THAT?
SUCCESS AT LAST.

367
00:25:07,100 --> 00:25:12,967
THIS METEORITE IS
OVER 90% IRON AND NICKLE.

368
00:25:12,967 --> 00:25:14,600
IT COULD ONLY FORM

369
00:25:14,600 --> 00:25:17,767
RIGHT IN THE CORE
OF A PROTOPLANET.

370
00:25:17,767 --> 00:25:20,500
THE PROTOPLANET IT CAME FROM

371
00:25:20,500 --> 00:25:25,100
MUST HAVE SMASHED APART
IN A BRUTAL COLLISION.

372
00:25:25,100 --> 00:25:30,433
Dr. Sykes: WELL, IN THE EARLY SOLAR
SYSTEM, IT WAS A PRETTY VIOLENT PLACE,

373
00:25:30,433 --> 00:25:34,700
AND THESE PROTOPLANETARY EMBRYOS
WOULD SMASH INTO EACH OTHER.

374
00:25:34,700 --> 00:25:36,867
THEY WOULD SHATTER EACH OTHER,

375
00:25:36,867 --> 00:25:39,767
EXPOSING
THE INTERIOR CORES LIKE THIS.

376
00:25:39,767 --> 00:25:41,867
IT WAS A VERY TUMULTUOUS TIME.

377
00:25:41,867 --> 00:25:49,267
Narrator: ENTIRE WORLDS REDUCED
TO CHUNKS OF ROCK AND METAL

378
00:25:49,267 --> 00:25:54,233
AND SCATTERED INTO OUTER SPACE.

379
00:25:54,233 --> 00:25:56,600
IN THE EARLY SOLAR SYSTEM,

380
00:25:56,600 --> 00:26:01,433
THESE VAST COLLISIONS
ARE COMMON.

381
00:26:01,433 --> 00:26:05,767
THE YOUNG EARTH IS IN DANGER.

382
00:26:05,767 --> 00:26:11,633
THE PERIOD'S NAME IS
THE "TITANOMACHIA" --

383
00:26:11,633 --> 00:26:15,633
LITERALLY
THE "WAR OF THE TITANS."

384
00:26:18,067 --> 00:26:21,067
ALL ROCKY PLANETS,
THE EARTH INCLUDED,

385
00:26:21,067 --> 00:26:26,500
GO THROUGH
THIS DESTRUCTIVE PHASE.

386
00:26:26,500 --> 00:26:30,100
SOMETIMES,
THEY SHATTER COMPLETELY.

387
00:26:30,100 --> 00:26:34,533
SOMETIMES,
ONE CONSUMES THE OTHER.

388
00:26:34,533 --> 00:26:37,533
Dr. Levison: ALL THE BIG GUYS ARE
SORT OF COMPETING WITH ONE ANOTHER

389
00:26:37,533 --> 00:26:39,833
IN A VERY VIOLENT WAY, ACTUALLY,

390
00:26:39,833 --> 00:26:44,067
TO SEE WHO COMES OUT ON TOP
BY EATING ALL THEIR NEIGHBORS.

391
00:26:44,067 --> 00:26:50,467
Narrator: THE BATTLE LASTS
OVER 30 MILLION YEARS.

392
00:26:50,467 --> 00:26:54,600
FINALLY, THOUSANDS
OF PROTOPLANETS HAVE COMBINED

393
00:26:54,600 --> 00:26:59,600
INTO A FEW FULL-SIZE PLANETS --

394
00:26:59,600 --> 00:27:08,467
MERCURY, VENUS, EARTH, MARS,
AND A FIFTH PLANET, THEA.

395
00:27:08,467 --> 00:27:14,400
IT'S RACING TOWARD EARTH --

396
00:27:14,400 --> 00:27:18,533
OUR PLANET'S LAST GIANT IMPACT.

397
00:27:20,533 --> 00:27:28,833
THEA IS THE SIZE OF MARS --
BIG ENOUGH TO DESTROY THE EARTH.

398
00:27:28,833 --> 00:27:30,633
IF THAT THING HAD
HIT US STRAIGHT ON,

399
00:27:30,633 --> 00:27:32,833
IT COULD HAVE LITERALLY
BLOWN THE EARTH TO BITS,

400
00:27:32,833 --> 00:27:35,067
AND THEN WE WOULDN'T EVEN HAVE
A PLANET TODAY.

401
00:27:35,067 --> 00:27:38,700
Kaku: IF THIS MARS-LIKE OBJECT
HAD A DIRECT HIT WITH THE EARTH,

402
00:27:38,700 --> 00:27:41,433
PERHAPS THERE WOULD HAVE BEEN
ANOTHER ASTEROID BELT

403
00:27:41,433 --> 00:27:42,800
WHERE THE EARTH IS TODAY.

404
00:27:42,800 --> 00:27:47,133
Narrator: BUT EARTH IS IN LUCK.

405
00:27:47,133 --> 00:27:53,433
INSTEAD OF A HEAD-ON CRASH,
THEA STRIKES A GLANCING BLOW.

406
00:27:57,600 --> 00:28:03,067
IT'S THE MOST VIOLENT EVENT
THE EARTH HAS EVER KNOWN.

407
00:28:06,500 --> 00:28:11,967
THE IMPACT TURNS THE EARTH
BACK TO A MOLTEN WORLD,

408
00:28:11,967 --> 00:28:17,533
A VAST MAGMA OCEAN
600 MILES DEEP.

409
00:28:20,633 --> 00:28:23,367
THE EARTH BARELY SURVIVES.

410
00:28:28,300 --> 00:28:32,867
AND THE ENCOUNTER CHANGES
OUR WORLD FOREVER.

411
00:28:35,267 --> 00:28:39,933
MATERIAL BLASTS
OUT INTO SPACE --

412
00:28:39,933 --> 00:28:46,500
ENOUGH ROCK TO BUILD
A MOUNTAIN AS WIDE AS AMERICA

413
00:28:46,500 --> 00:28:50,533
AND 10,000 MILES HIGH.

414
00:28:50,533 --> 00:28:52,067
THERE WOULD HAVE BEEN
SO MUCH ENERGY,

415
00:28:52,067 --> 00:28:53,067
SO MUCH CATASTROPHE.

416
00:28:53,067 --> 00:28:55,267
HUGE AMOUNTS OF MATERIAL
BLASTED OFF

417
00:28:55,267 --> 00:28:57,600
AND WENT INTO ORBIT
AROUND THE EARTH.

418
00:28:57,600 --> 00:29:02,933
THE DEBRIS FORMS
A HUGE RING AROUND THE EARTH.

419
00:29:02,933 --> 00:29:08,533
THIS GATHERS TOGETHER
TO FORM TWO ROCKY BODIES,

420
00:29:08,533 --> 00:29:12,833
BOTH ORBITING THE EARTH.

421
00:29:12,833 --> 00:29:14,833
Dr. Thaller: SOMETHING THE
SIZE OF MARS HIT THE EARTH

422
00:29:14,833 --> 00:29:16,200
ABOUT 4 BILLION YEARS AGO.

423
00:29:16,200 --> 00:29:18,567
LOTS OF MATERIAL WOULD HAVE BEEN
THROWN OFF.

424
00:29:18,567 --> 00:29:19,767
WE NOW THINK
THAT IT MAY HAVE FORMED

425
00:29:19,767 --> 00:29:22,300
NOT ONLY ONE MOON BUT TWO.

426
00:29:22,300 --> 00:29:26,067
Narrator: FOR MILLIONS OF YEARS,

427
00:29:26,067 --> 00:29:29,933
TWO MOONS DOMINATE
THE EARTH'S SKY.

428
00:29:32,500 --> 00:29:37,467
EVENTUALLY,
THEY DRIFT TOGETHER AND COLLIDE.

429
00:29:44,167 --> 00:29:50,667
TWO MOONS MERGE INTO ONE --

430
00:29:50,667 --> 00:29:55,400
THE MASSIVE MOON WE SEE TODAY.

431
00:29:55,400 --> 00:29:57,067
Dr. Thaller: THERE'S NO OTHER
PLANET THAT WE KNOW OF

432
00:29:57,067 --> 00:29:58,800
THAT HAS A MOON AS LARGE AS OURS

433
00:29:58,800 --> 00:30:01,100
IN COMPARISON
TO THE SIZE OF THE PLANET.

434
00:30:01,100 --> 00:30:02,600
WE'RE ALMOST A BINARY PLANET --

435
00:30:02,600 --> 00:30:04,467
TWO WORLDS GOING
AROUND EACH OTHER.

436
00:30:04,467 --> 00:30:11,100
Narrator: WITHOUT THIS LARGE
MOON, WE MIGHT NOT EVEN BE HERE.

437
00:30:13,100 --> 00:30:15,100
Marcy:
THE MOON PLAYS A KEY ROLE

438
00:30:15,100 --> 00:30:18,500
IN THE SURVIVAL OF LIFE
HERE ON THE EARTH.

439
00:30:18,500 --> 00:30:21,367
AND THE REASON IS THAT THE MOON,
IN ITS ORBIT,

440
00:30:21,367 --> 00:30:24,800
STABILIZES THE EARTH.

441
00:30:24,800 --> 00:30:30,000
Narrator: THE MOON KEEPS THE EARTH
SPINNING AT THE SAME ANGLE.

442
00:30:30,000 --> 00:30:33,467
THAT STEADIES OUR CLIMATE.

443
00:30:33,467 --> 00:30:36,567
THE FACT THAT THE EARTH'S AXIS
STAYS IN THE SAME DIRECTION

444
00:30:36,567 --> 00:30:39,133
AS IT GOES AROUND THE SUN
PRODUCES THE SEASONS,

445
00:30:39,133 --> 00:30:40,600
BUT REGULAR SEASONS --

446
00:30:40,600 --> 00:30:44,667
THINGS THAT LIFE CAN DEPEND UPON
AS IT EVOLVES.

447
00:30:44,667 --> 00:30:50,733
Narrator: EARTH IS NEITHER TOO
HOT NOR TOO COLD FOR LIFE

448
00:30:50,733 --> 00:30:52,733
THANKS TO OUR DISTANCE
FROM THE SUN

449
00:30:52,733 --> 00:30:56,233
AND OUR MASSIVE MOON.

450
00:31:00,767 --> 00:31:05,900
THE EARTH IS NOT COVERED
IN ICE OR STEAM

451
00:31:05,900 --> 00:31:07,500
BUT IN LIQUID WATER.

452
00:31:11,067 --> 00:31:16,633
YET, THAT WATER MUST COME
FROM SOMEWHERE.

453
00:31:16,633 --> 00:31:19,567
THE NEWLY FORMED EARTH IS DRY.

454
00:31:22,067 --> 00:31:28,233
TO GET WATER, OUR PLANET MUST,
ONCE AGAIN, FACE DISASTER.

455
00:31:38,267 --> 00:31:44,233
Narrator: IT'S HALF A BILLION YEARS
SINCE THE SUN FIRST IGNITED.

456
00:31:44,233 --> 00:31:46,567
FOUR BILLION YEARS FROM NOW,

457
00:31:46,567 --> 00:31:50,067
THE FIRST HUMANS WILL
SET FOOT ON EARTH.

458
00:31:52,400 --> 00:31:58,700
THE MOON HAS JUST FORMED,
AND THE EARTH IS A DESERT.

459
00:32:03,200 --> 00:32:05,367
ONE OF THE MORE AMAZING IDEAS
IN ASTRONOMY

460
00:32:05,367 --> 00:32:07,833
IS THAT THE EARTH STARTED OUT
HOT AND DRY.

461
00:32:07,833 --> 00:32:09,833
THERE WAS
NO WATER HERE ORIGINALLY.

462
00:32:09,833 --> 00:32:13,200
Narrator:
AS THE PLANETS FORMED,

463
00:32:13,200 --> 00:32:17,800
THE SUN'S INTENSE RADIATION
VAPORIZED THE WATER

464
00:32:17,800 --> 00:32:20,833
IN THE INNER SOLAR SYSTEM.

465
00:32:20,833 --> 00:32:25,467
FARTHER FROM THE SUN,
TEMPERATURES WERE COOLER.

466
00:32:25,467 --> 00:32:27,500
SO IN THE OUTER SOLAR SYSTEM,

467
00:32:27,500 --> 00:32:32,233
ICE AND WATER COLLECTED
ON COMETS AND ASTEROIDS.

468
00:32:34,233 --> 00:32:41,100
WHILE CLOSER TO THE SUN,
THE YOUNG EARTH WAS DRY.

469
00:32:41,100 --> 00:32:43,700
SO, THINGS CHANGED.
WHAT HAPPENED?

470
00:32:43,700 --> 00:32:47,067
HOW IS THAT NOW WE HAVE
THIS WONDERFUL WATER CYCLE?

471
00:32:47,067 --> 00:32:49,467
WELL, THE WATER PROBABLY CAME
FROM SOMEWHERE ELSE.

472
00:32:49,467 --> 00:32:51,333
Plait:
WELL, IF YOU WANT TO HAVE

473
00:32:51,333 --> 00:32:53,800
A SOLAR SYSTEM THAT HAS
A LOT OF WATER IN IT,

474
00:32:53,800 --> 00:32:56,367
YOU HAVE TO BRING IT
FROM THE OUTER PARTS

475
00:32:56,367 --> 00:32:57,933
DOWN INTO THE INNER PARTS,

476
00:32:57,933 --> 00:33:00,967
AND YOU CAN DO THAT
THROUGH COMETS AND ASTEROIDS.

477
00:33:00,967 --> 00:33:09,467
Narrator: COMETS AND ICY ASTEROIDS
CONTAIN HUGE RESERVES OF WATER,

478
00:33:09,467 --> 00:33:15,067
BUT THEY'RE HUNDREDS OF MILLIONS
OF MILES FROM THE YOUNG EARTH.

479
00:33:15,067 --> 00:33:19,167
THEN SOMETHING CHANGES --

480
00:33:19,167 --> 00:33:23,400
AN EVENT THAT TOSSES
THE ASTEROIDS AND COMETS

481
00:33:23,400 --> 00:33:26,067
RIGHT ACROSS THE SOLAR SYSTEM.

482
00:33:27,600 --> 00:33:33,667
JUPITER, SATURN, NEPTUNE, URANUS

483
00:33:33,667 --> 00:33:39,567
TAKE
A COSMIC ROLLER-COASTER RIDE.

484
00:33:39,567 --> 00:33:42,300
Dr. Levison: SO, THIS IS
AN EVENT THAT HAPPENED

485
00:33:42,300 --> 00:33:44,100
WHEN THE SOLAR SYSTEM WAS YOUNG.

486
00:33:44,100 --> 00:33:46,933
THINK OF IT AS MORE
OF ITS TEENAGE BREAKOUT YEARS

487
00:33:46,933 --> 00:33:49,333
WHERE IT JUST STARTED
TO PARTY FOR A WHILE.

488
00:33:49,333 --> 00:33:56,933
Narrator: THE YOUNG PLANETS HAVE NOT
YET SETTLED INTO STABLE ORBITS.

489
00:33:56,933 --> 00:33:58,733
AS THEIR ORBITS SHIFT,

490
00:33:58,733 --> 00:34:04,900
JUPITER AND SATURN FALL
INTO AN INTRICATE DANCE.

491
00:34:04,900 --> 00:34:08,833
EVERY TIME
SATURN ORBITS THE SUN ONCE,

492
00:34:08,833 --> 00:34:12,233
JUPITER ORBITS TWICE,

493
00:34:12,233 --> 00:34:15,933
SO THEY ALWAYS LINE UP
AT THE SAME SPOT.

494
00:34:15,933 --> 00:34:20,733
EACH TIME, GRAVITY TUGS THEM
IN THE SAME DIRECTION.

495
00:34:20,733 --> 00:34:24,333
FIRST, THEY DESTABILIZE
EACH OTHER

496
00:34:24,333 --> 00:34:28,467
AND THEN
THE ENTIRE SOLAR SYSTEM.

497
00:34:28,467 --> 00:34:30,467
THE WHOLE THING JUST GOES
KAPLOOEY.

498
00:34:30,467 --> 00:34:33,567
THE ANALOGY I LIKE TO USE IS
WHEN A BOWLING BALL HITS PINS,

499
00:34:33,567 --> 00:34:35,600
IT JUST GOES "BAM!"
ALL OVER THE PLACE.

500
00:34:35,600 --> 00:34:36,967
THAT'S WHAT THIS WOULD HAVE
LOOKED LIKE.

501
00:34:36,967 --> 00:34:41,067
Narrator: PLANETARY PANDEMONIUM.

502
00:34:41,067 --> 00:34:44,167
NEPTUNE AND URANUS
SWITCH PLACES.

503
00:34:44,167 --> 00:34:48,300
SATURN RACES OUTWARDS.

504
00:34:48,300 --> 00:34:53,067
THE GIANT PLANETS SCATTER
BILLIONS OF ASTEROIDS AND COMETS

505
00:34:53,067 --> 00:34:54,400
ONTO NEW PATHS.

506
00:34:56,467 --> 00:35:00,167
MANY HEAD FOR EARTH.

507
00:35:00,167 --> 00:35:02,333
Dr. Levison: THESE ASTEROIDS AND
COMETS WOULD HAVE BEEN SCATTERED

508
00:35:02,333 --> 00:35:04,167
ALL OVER THE PLACE, RIGHT,

509
00:35:04,167 --> 00:35:05,733
SOME OF THEM HITTING
THE EARTH AND MOON.

510
00:35:05,733 --> 00:35:12,667
Narrator: COSMIC MISSILES
BOMBARD THE EARTH.

511
00:35:12,667 --> 00:35:13,867
Dr. Levison: WE BELIEVE

512
00:35:13,867 --> 00:35:16,100
THAT EVERY SQUARE INCH
OF THE EARTH GOT HIT

513
00:35:16,100 --> 00:35:19,133
BY A COMET OR AN ASTEROID
DURING THIS PERIOD.

514
00:35:19,133 --> 00:35:21,267
IT WOULD NOT HAVE BEEN
A FUN TIME TO BE HERE.

515
00:35:23,200 --> 00:35:29,900
Narrator: THE BOMBARDMENT LASTS
HUNDREDS OF MILLIONS OF YEARS

516
00:35:29,900 --> 00:35:34,200
UNTIL, FINALLY,
THE GAS PLANETS SETTLE

517
00:35:34,200 --> 00:35:38,633
INTO THE STABLE ORBITS
WE SEE TODAY,

518
00:35:38,633 --> 00:35:40,733
RESTORING ORDER.

519
00:35:43,533 --> 00:35:48,600
BUT EARTH ITSELF HAS
FUNDAMENTALLY CHANGED.

520
00:35:48,600 --> 00:35:54,467
THOSE COMETS AND ASTEROIDS WERE
NOT JUST MADE OF ROCK

521
00:35:54,467 --> 00:35:59,833
BUT OF ICE, FROZEN WATER.

522
00:35:59,833 --> 00:36:02,067
COMETS, WE KNOW,
ARE MADE OUT OF ICE.

523
00:36:02,067 --> 00:36:04,167
THEY'RE DIRTY SNOWBALLS
IN OUTER SPACE,

524
00:36:04,167 --> 00:36:08,167
AND EVEN ASTEROIDS CAN BRING
WATER AND ICE TO THE EARTH.

525
00:36:08,167 --> 00:36:16,067
Narrator: OUR OCEANS ARE FULL
THANKS TO THE COSMIC HAILSTORM.

526
00:36:16,067 --> 00:36:19,700
Kaku: SO NEXT TIME YOU'RE DRINKING
A GLASS OF WATER, REALIZE

527
00:36:19,700 --> 00:36:22,967
THAT YOU'RE PROBABLY DRINKING
COMET AND ASTEROID JUICE.

528
00:36:22,967 --> 00:36:28,067
Narrator: THE ARRIVAL OF WATER
IS THE FINAL STEP

529
00:36:28,067 --> 00:36:31,133
TO CREATE A HABITABLE PLANET.

530
00:36:34,133 --> 00:36:38,333
A SEQUENCE OF CATASTROPHES HAS
CREATED A WORLD

531
00:36:38,333 --> 00:36:42,600
THAT'S PERFECT FOR LIFE.

532
00:36:42,600 --> 00:36:47,167
BUT HAS IT HAPPENED
ELSEWHERE AMONG THE STARS?

533
00:36:47,167 --> 00:36:50,067
OR ARE WE ALONE?

534
00:37:03,400 --> 00:37:06,300
Narrator: HOW DID WE GET HERE?

535
00:37:06,300 --> 00:37:09,400
PLANET EARTH ONLY EXISTS

536
00:37:09,400 --> 00:37:13,533
BECAUSE OF A CHAIN
OF EXTRAORDINARY EVENTS,

537
00:37:15,067 --> 00:37:18,233
A LUCKY THROW OF COSMIC DICE.

538
00:37:20,500 --> 00:37:22,067
Krauss:
FIVE BILLION YEARS AGO,

539
00:37:22,067 --> 00:37:23,933
THE ODDS WOULD HAVE SEEMED
EXTREMELY SLIM

540
00:37:23,933 --> 00:37:25,067
THAT A PLANET LIKE EARTH

541
00:37:25,067 --> 00:37:27,500
WOULD FORM
IN A RATHER UNREMARKABLE ARM

542
00:37:27,500 --> 00:37:28,967
IN THE MILKY WAY GALAXY.

543
00:37:28,967 --> 00:37:31,667
IT'S LIKE
TRYING TO THROW TWO SIXES

544
00:37:31,667 --> 00:37:34,733
BUT WITH DICE
THAT HAVE THOUSANDS OF SIDES.

545
00:37:38,767 --> 00:37:42,367
Narrator: WE KNOW IT HAPPENED
ONCE, ELSE WE WOULDN'T BE HERE.

546
00:37:42,367 --> 00:37:46,567
BUT WHAT ARE THE ODDS
IT HAPPENED ELSEWHERE?

547
00:37:48,533 --> 00:37:52,567
THAT OTHER PLANETS HAVE LIFE?

548
00:37:52,567 --> 00:37:55,533
LIFE LIKE OURS NEEDS A PLANET

549
00:37:55,533 --> 00:37:59,433
WITH THE RIGHT TEMPERATURE
AND SIZE,

550
00:37:59,433 --> 00:38:04,767
A STABILIZING MOON,
A PROTECTIVE MAGNETIC FIELD,

551
00:38:04,767 --> 00:38:08,833
AND JUST THE RIGHT AMOUNT
OF WATER.

552
00:38:08,833 --> 00:38:12,467
THE CONDITIONS MUST BE PERFECT.

553
00:38:18,167 --> 00:38:21,133
YET, AMAZINGLY, THERE MAY BE

554
00:38:21,133 --> 00:38:27,300
COUNTLESS EARTH-LIKE PLANETS
OUT THERE, WAITING TO BE FOUND.

555
00:38:27,300 --> 00:38:32,633
THANKS TO THE SHEER SCALE
OF THE UNIVERSE,

556
00:38:32,633 --> 00:38:40,467
WE MAY FIND ONE ANY DAY NOW
WITH THE KEPLER SPACE TELESCOPE.

557
00:38:40,467 --> 00:38:44,300
GEOFF MARCY IS
MISSION CO-INVESTIGATOR.

558
00:38:44,300 --> 00:38:46,200
Marcy: IT HAS ONLY ONE GOAL,

559
00:38:46,200 --> 00:38:49,100
AND THAT'S TO DISCOVER
EARTH-SIZE PLANETS

560
00:38:49,100 --> 00:38:52,533
AROUND OTHER STARS
THAT YOU SEE IN THE NIGHT SKY.

561
00:38:52,533 --> 00:38:57,833
Narrator: EARTH-SIZE PLANETS ARE
HARD TO SPOT.

562
00:38:57,833 --> 00:39:01,767
BEFORE KEPLER,
ASTRONOMERS TOOK 20 YEARS

563
00:39:01,767 --> 00:39:06,067
TO DISCOVER AROUND 500 PLANETS.

564
00:39:06,067 --> 00:39:07,800
MOST WERE GAS GIANTS

565
00:39:07,800 --> 00:39:10,967
HUNDREDS OF TIMES BIGGER
THAN EARTH.

566
00:39:10,967 --> 00:39:16,700
SINCE KEPLER,
THAT NUMBER HAS EXPLODED.

567
00:39:16,700 --> 00:39:19,367
Marcy:
KEPLER HAS ALREADY DISCOVERED

568
00:39:19,367 --> 00:39:22,867
A COUPLE THOUSAND
PLANET CANDIDATES.

569
00:39:22,867 --> 00:39:26,167
MANY OF THEM ARE MEMBERS
OF MULTI-PLANET SYSTEMS --

570
00:39:26,167 --> 00:39:29,067
TWO, THREE, FOUR, FIVE,
AND EVEN SIX PLANETS

571
00:39:29,067 --> 00:39:31,367
ALL ORBITING THE SAME STAR.

572
00:39:31,367 --> 00:39:34,867
SO, WE'RE FINDING
AN ABSOLUTE AVALANCHE OF PLANETS

573
00:39:34,867 --> 00:39:36,867
OUT THERE AMONG THE STARS.

574
00:39:36,867 --> 00:39:44,300
Narrator: KEPLER HAS FOUND ONE
PLANET ONLY TWICE THE SIZE OF EARTH

575
00:39:44,300 --> 00:39:48,100
AND THE RIGHT TEMPERATURE
FOR LIFE.

576
00:39:48,100 --> 00:39:53,733
WE DON'T KNOW YET IF THIS PLANET
HAS OTHER EARTH-LIKE ATTRIBUTES,

577
00:39:53,733 --> 00:39:57,200
LIKE LIQUID WATER.

578
00:39:57,200 --> 00:39:59,333
BUT EVEN IF IT DOESN'T,

579
00:39:59,333 --> 00:40:02,900
THERE ARE
MANY MORE PLANETS OUT THERE.

580
00:40:02,900 --> 00:40:09,167
KEPLER HAS FOUND
ONLY A TINY FRACTION OF THEM

581
00:40:09,167 --> 00:40:14,467
BECAUSE IT ONLY LOOKS
AT A SMALL PART OF THE SKY.

582
00:40:14,467 --> 00:40:16,100
Plait: IT'S NOT EVEN LOOKING
AT THE WHOLE SKY.

583
00:40:16,100 --> 00:40:18,867
IT'S LOOKING
AT A VERY TINY SLICE OF STARS

584
00:40:18,867 --> 00:40:19,967
IN THE GALAXY.

585
00:40:19,967 --> 00:40:21,700
AND, IN FACT,
IF YOU WERE TO LOOK UP,

586
00:40:21,700 --> 00:40:23,533
YOU COULD COVER IT
WITH JUST YOUR THUMB.

587
00:40:23,533 --> 00:40:31,433
Narrator: IN THE WHOLE OF OUR GALAXY,
THERE ARE 200 BILLION STARS.

588
00:40:31,433 --> 00:40:34,167
MANY WILL HAVE PLANETS.

589
00:40:34,167 --> 00:40:37,500
Marcy: BASED ON OUR KNOWLEDGE
FROM KEPLER AND OTHER SEARCHES,

590
00:40:37,500 --> 00:40:39,733
SOMETHING LIKE
HALF OF THOSE STARS,

591
00:40:39,733 --> 00:40:42,600
PERHAPS EVEN MORE,
HARBOR PLANETS.

592
00:40:42,600 --> 00:40:47,433
Narrator: THAT MEANS
AT LEAST 100 BILLION PLANETS

593
00:40:47,433 --> 00:40:51,767
HAVE FORMED IN THE MILKY WAY.

594
00:40:51,767 --> 00:40:54,767
EARTH-LIKE WORLDS MAY BE RARE,

595
00:40:54,767 --> 00:41:00,067
BUT IT SEEMS A SAFE BET
THEY'RE OUT THERE SOMEWHERE.

596
00:41:00,067 --> 00:41:02,633
SO, THE ODDS OF GETTING
AN EARTH-LIKE PLANET

597
00:41:02,633 --> 00:41:04,267
ARE EXTREMELY SMALL --

598
00:41:04,267 --> 00:41:07,967
MUCH SMALLER THAN GETTING
A DOUBLE SIX AT CRAPS.

599
00:41:07,967 --> 00:41:12,467
BUT IF YOU HAVE A LOT OF DICE,
YOU'RE GUARANTEED TO GET SIXES.

600
00:41:12,467 --> 00:41:17,100
Narrator: AND IF YOU HAVE
A LOT OF PLANETS,

601
00:41:17,100 --> 00:41:19,733
YOU'RE GUARANTEED TO GET EARTHS.

602
00:41:22,500 --> 00:41:26,167
THERE ARE
SO MANY PLANETS IN OUR GALAXY,

603
00:41:26,167 --> 00:41:29,867
EVEN IF THE CHANCES ARE
ONE IN A MILLION,

604
00:41:29,867 --> 00:41:34,267
THERE SHOULD BE
THOUSANDS OF EARTH-LIKE WORLDS.

605
00:41:36,333 --> 00:41:38,233
Marcy: OUR UNIVERSE, AT LARGE,

606
00:41:38,233 --> 00:41:40,767
HAS HUNDREDS OF BILLIONS
OF GALAXIES,

607
00:41:40,767 --> 00:41:44,333
EACH OF WHICH IS
MORE OR LESS LIKE OUR MILKY WAY.

608
00:41:44,333 --> 00:41:46,367
SO, THE NUMBER
OF PLANETS IN OUR UNIVERSE

609
00:41:46,367 --> 00:41:48,233
IS VIRTUALLY UNCOUNTABLE.

610
00:41:48,233 --> 00:41:53,467
Narrator:
ALIEN EARTHS MUST BE EVERYWHERE.

611
00:41:53,467 --> 00:41:56,433
Plait: NOW, WE HAVEN'T
DISCOVERED EVEN ONE OF THEM YET.

612
00:41:56,433 --> 00:42:00,067
BUT STATISTICALLY SPEAKING,
IT IS A ROCK-SOLID CERTAINTY.

613
00:42:00,067 --> 00:42:03,700
THERE ARE MILLIONS OF BILLIONS
OF PLANETS LIKE THE EARTH

614
00:42:03,700 --> 00:42:06,067
OUT THERE.

615
00:42:06,067 --> 00:42:09,333
Narrator: AND WITH
THAT MANY EARTH-LIKE PLANETS,

616
00:42:09,333 --> 00:42:13,933
SURELY, SOME OF THEM WILL HAVE
INTELLIGENT LIFE.

617
00:42:13,933 --> 00:42:15,633
Plait: I WOULD BET EVERYTHING.

618
00:42:15,633 --> 00:42:16,967
I WOULD BET MY HOUSE

619
00:42:16,967 --> 00:42:20,067
THAT THERE IS ANOTHER EARTH
OUT THERE SOMEWHERE.

620
00:42:20,067 --> 00:42:25,067
Marcy:
THERE REALLY CAN BE NO DOUBT
THAT, ELSEWHERE IN OUR UNIVERSE,

621
00:42:25,067 --> 00:42:28,600
THERE ARE OTHER SMART CRITTERS
WHO ARE ASKING THEMSELVES,

622
00:42:28,600 --> 00:42:32,067
"GEE, I WONDER IF THERE ARE
ANY OTHER INTELLIGENT SPECIES

623
00:42:32,067 --> 00:42:33,700
OUT THERE IN THE UNIVERSE?"

624
00:42:36,333 --> 00:42:40,800
Narrator: THE STORY OF THE BIRTH
OF OUR PLANET REVEALS

625
00:42:40,800 --> 00:42:46,200
THAT WE CANNOT POSSIBLY BE ALONE
IN THE UNIVERSE.

626
00:42:46,200 --> 00:42:49,933
THE QUESTION IS NOT,
"ARE WE ALONE?"

627
00:42:49,933 --> 00:42:54,100
IT'S, "HOW FAR AWAY ARE
OUR NEIGHBORS,

628
00:42:54,100 --> 00:42:57,333
AND WHEN WILL WE MEET?"