Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated:
1
00:00:04,120 --> 00:00:08,960
Our galaxy, far in the future.
2
00:00:11,500 --> 00:00:16,360
A planet shrouded
in turbulent, dense clouds.
3
00:00:21,870 --> 00:00:23,170
Buried deep below,
4
00:00:23,170 --> 00:00:25,810
an alien landscape...
5
00:00:28,180 --> 00:00:31,310
Extreme pressures,
and a scorched surface
6
00:00:31,310 --> 00:00:34,550
with sky-high temperatures.
7
00:00:36,950 --> 00:00:41,360
But this isn't a
distant extraterrestrial world.
8
00:00:45,400 --> 00:00:51,600
It's earth's future,
maybe a billion years from now.
9
00:00:51,600 --> 00:00:56,810
We know this
because earth has a twin...
10
00:00:56,810 --> 00:00:58,540
Venus.
11
00:00:58,540 --> 00:01:02,410
And Venus has already
descended into hell.
12
00:01:07,780 --> 00:01:11,850
Have you ever dreamed about
travelling out of this world?
13
00:01:11,860 --> 00:01:13,390
My name is Mike Massimino,
14
00:01:13,390 --> 00:01:15,720
and I turned that fantasy
into a reality
15
00:01:15,730 --> 00:01:18,830
when I space-walked to repair
the Hubble space telescope.
16
00:01:18,830 --> 00:01:21,800
Great job, Mike.
17
00:01:21,800 --> 00:01:24,600
Now, as we expand our knowledge
of our solar system
18
00:01:24,600 --> 00:01:27,500
from Mercury
to the cosmic unknowns,
19
00:01:27,500 --> 00:01:30,000
I want to take you
on a personal journey to...
20
00:01:34,440 --> 00:01:38,150
"The planets."
21
00:01:38,150 --> 00:01:39,710
Welcome to "the planets."
22
00:01:39,720 --> 00:01:41,350
I'm Mike Massimino.
23
00:01:41,350 --> 00:01:43,380
I got to live out
my childhood dream
24
00:01:43,390 --> 00:01:44,690
when I first travelled to space
25
00:01:44,690 --> 00:01:47,020
in 2002.
26
00:01:47,020 --> 00:01:48,860
Looking down at the earth
from the Hubble space telescope,
27
00:01:48,860 --> 00:01:52,130
I was blown away by
this perfect blue sphere
28
00:01:52,130 --> 00:01:53,600
in the middle of space.
29
00:01:53,600 --> 00:01:56,630
As peaceful and inviting
as our planet is,
30
00:01:56,630 --> 00:02:00,000
our neighbor, Venus,
is the complete opposite...
31
00:02:00,000 --> 00:02:02,700
No water,
scorching temperatures,
32
00:02:02,710 --> 00:02:04,410
and crushing pressure.
33
00:02:04,410 --> 00:02:06,540
And just when you think
there's nothing in common
34
00:02:06,540 --> 00:02:08,380
between these two planets,
35
00:02:08,380 --> 00:02:11,710
it turns out
they're actually siblings.
36
00:02:13,420 --> 00:02:17,250
Take a look
around the solar system...
37
00:02:17,250 --> 00:02:22,990
Eight planets orbiting
a central star, the sun.
38
00:02:22,990 --> 00:02:25,230
Among them is earth
39
00:02:25,230 --> 00:02:27,730
and its neighbor, Venus.
40
00:02:29,830 --> 00:02:34,840
Earth, our home,
is an oasis for life.
41
00:02:34,840 --> 00:02:37,840
Venus is the stuff
of nightmares.
42
00:02:40,110 --> 00:02:43,650
Venus and earth
couldn't be more different.
43
00:02:43,650 --> 00:02:45,310
The earth is
this beautiful planet,
44
00:02:45,320 --> 00:02:46,610
and there's water everywhere.
45
00:02:46,620 --> 00:02:49,150
It's ice at the poles.
It's water in the ocean.
46
00:02:49,150 --> 00:02:51,850
It's in the atmosphere
as water vapor.
47
00:02:53,660 --> 00:02:55,290
But then you look at Venus.
48
00:02:55,290 --> 00:02:57,760
It is the worst place
imaginable.
49
00:02:57,760 --> 00:03:00,800
It is so hot on the surface,
crushing pressures.
50
00:03:00,800 --> 00:03:04,370
It couldn't be
any less supportive of life.
51
00:03:06,440 --> 00:03:07,770
To me, the planet Venus
52
00:03:07,770 --> 00:03:10,440
is sort of a classic definition
of the word "hell."
53
00:03:12,880 --> 00:03:14,810
If you were to transport
to Venus
54
00:03:14,810 --> 00:03:18,010
and experience
the environment there,
55
00:03:18,010 --> 00:03:21,220
you'd quickly want
to return back to earth.
56
00:03:21,220 --> 00:03:22,720
The conditions on Venus
57
00:03:22,720 --> 00:03:27,760
are among the most inhospitable
in the solar system.
58
00:03:27,760 --> 00:03:29,960
It's going to be a competition
between whether or not
59
00:03:29,960 --> 00:03:32,830
you're gonna be cooked to death
or crushed to death.
60
00:03:38,770 --> 00:03:45,870
Earth and Venus may
seem like very different worlds,
61
00:03:45,880 --> 00:03:48,880
but they shouldn't be.
62
00:03:48,880 --> 00:03:53,680
They're roughly
the same size, same mass,
63
00:03:53,680 --> 00:03:57,990
and made from the same stuff.
64
00:03:57,990 --> 00:04:01,090
And they started out as twins.
65
00:04:01,090 --> 00:04:03,860
Early Venus and early earth
were very similar.
66
00:04:03,860 --> 00:04:05,290
They were twins,
67
00:04:05,300 --> 00:04:09,400
probably nearly identical twins,
at their earliest stages.
68
00:04:09,400 --> 00:04:13,640
Given that Venus is
so earth-like in so many ways,
69
00:04:13,640 --> 00:04:16,270
it's really odd that it is
so different than the earth.
70
00:04:16,270 --> 00:04:18,410
And this makes it
one of the biggest mysteries
71
00:04:18,410 --> 00:04:20,580
in the solar system.
72
00:04:20,580 --> 00:04:23,610
Somewhere in their
two histories,
73
00:04:23,610 --> 00:04:28,150
the earth and Venus
took two very different paths.
74
00:04:28,150 --> 00:04:29,180
The result?
75
00:04:29,190 --> 00:04:32,650
Two totally different worlds.
76
00:04:32,660 --> 00:04:35,160
Their paths were so different,
you could hardly believe
77
00:04:35,160 --> 00:04:36,890
that one would have been related
to the other.
78
00:04:36,890 --> 00:04:39,060
But now, the opposite thing's
going to happen.
79
00:04:39,060 --> 00:04:41,260
We're gonna catch up
with our twin.
80
00:04:41,260 --> 00:04:45,900
We're gonna evolve to be a lot
more like Venus in the future.
81
00:04:45,900 --> 00:04:46,970
In the future,
82
00:04:46,970 --> 00:04:50,300
the two planets' paths
will converge,
83
00:04:50,310 --> 00:04:54,410
and they will become twin-like
once again.
84
00:04:56,350 --> 00:05:01,620
There is going to be
hell on earth.
85
00:05:01,620 --> 00:05:05,650
The oceans will vaporize.
The land will melt.
86
00:05:05,660 --> 00:05:08,960
Our hospitable blue planet
will vanish,
87
00:05:08,960 --> 00:05:13,960
replaced by
a fiery, molten world.
88
00:05:13,960 --> 00:05:15,800
We are actually
on the earth at a time
89
00:05:15,800 --> 00:05:17,500
when there's water and rain,
90
00:05:17,500 --> 00:05:19,600
and it was so easy
for life to take hold.
91
00:05:19,600 --> 00:05:21,040
But that's gonna change.
92
00:05:21,040 --> 00:05:24,410
And take a look in at Venus
and have a look at our future.
93
00:05:31,880 --> 00:05:33,920
How will this happen?
94
00:05:39,090 --> 00:05:41,290
The roots of
our home world's destruction
95
00:05:41,290 --> 00:05:44,860
are buried deep
in our twin planet's past.
96
00:05:47,400 --> 00:05:50,930
It's very much true that,
in studying the past of Venus,
97
00:05:50,930 --> 00:05:55,670
we are also studying
the distant future of earth.
98
00:05:55,670 --> 00:05:59,610
Both planets share
a violent birth,
99
00:05:59,610 --> 00:06:03,140
scarred by brutal
planet formation,
100
00:06:03,150 --> 00:06:07,180
giant cosmic impacts,
and rampant volcanism.
101
00:06:07,180 --> 00:06:09,220
We're trying
to reconstruct things
102
00:06:09,220 --> 00:06:10,990
that happened
in the ancient, ancient past.
103
00:06:10,990 --> 00:06:13,690
It's almost like
forensic planetary geology.
104
00:06:17,560 --> 00:06:22,060
4.6 billion years ago,
hundreds of infant planets
105
00:06:22,070 --> 00:06:24,830
begin to form
around the new sun.
106
00:06:27,900 --> 00:06:32,510
Among them,
the baby Venus and earth.
107
00:06:32,510 --> 00:06:35,610
And as they hurtle
around the sun,
108
00:06:35,610 --> 00:06:38,580
collisions are inevitable.
109
00:06:40,350 --> 00:06:43,520
Planet formation
is like a demolition derby.
110
00:06:43,520 --> 00:06:45,550
In a derby, the cars are racing
around a track,
111
00:06:45,560 --> 00:06:48,760
going around in circles
at different speeds.
112
00:06:48,760 --> 00:06:50,420
Well, it's the same thing
with planets.
113
00:06:50,430 --> 00:06:51,890
The material
is orbiting the sun.
114
00:06:51,900 --> 00:06:54,260
It's going around, and they're
all going at different speeds,
115
00:06:54,260 --> 00:06:56,030
at different angels,
different trajectories.
116
00:06:56,030 --> 00:06:57,900
And sometimes, boom.
117
00:07:06,540 --> 00:07:10,550
In this derby,
planet hits planet.
118
00:07:10,550 --> 00:07:12,910
Two become one...
119
00:07:12,920 --> 00:07:14,250
Violently.
120
00:07:19,560 --> 00:07:21,720
You have these large bodies
that are hitting each other
121
00:07:21,720 --> 00:07:23,190
at really high velocity.
122
00:07:26,360 --> 00:07:29,800
It's really a very hot,
violent mess.
123
00:07:33,200 --> 00:07:34,240
The amount of energy released
124
00:07:34,240 --> 00:07:36,370
in these impacts is huge.
125
00:07:36,370 --> 00:07:38,040
It completely dwarfs
126
00:07:38,040 --> 00:07:40,880
all of the nuclear weapons
on earth combined.
127
00:07:40,880 --> 00:07:43,380
And yet, somehow,
on these scales,
128
00:07:43,380 --> 00:07:47,220
you wind up forming gigantic
objects that we call planets.
129
00:07:49,820 --> 00:07:56,620
Earth and Venus
become voracious planet eaters.
130
00:07:56,630 --> 00:08:00,130
But two spectacular collisions
set the twins
131
00:08:00,130 --> 00:08:03,760
on very different paths.
132
00:08:03,770 --> 00:08:06,500
That was the moment
Venus and earth went through
133
00:08:06,500 --> 00:08:08,940
this divergence
to what has now become
134
00:08:08,940 --> 00:08:11,170
these really
dramatically different worlds.
135
00:08:13,240 --> 00:08:14,680
The divergence begins
136
00:08:14,680 --> 00:08:17,480
when a Mars-sized object
hits earth.
137
00:08:24,220 --> 00:08:29,420
The impact makes our planet
spin faster.
138
00:08:29,430 --> 00:08:32,060
The core spins with it,
generating
139
00:08:32,060 --> 00:08:35,930
a powerful magnetic field
around the planet.
140
00:08:39,340 --> 00:08:43,910
The field fends off the worst
of the sun's radiation.
141
00:08:48,880 --> 00:08:50,710
Around the same time,
142
00:08:50,710 --> 00:08:54,350
Venus takes a head-on hit
from another infant planet.
143
00:08:56,690 --> 00:09:02,390
This impact explains something
very weird about Venus.
144
00:09:02,390 --> 00:09:03,960
Venus is actually rotating
145
00:09:03,960 --> 00:09:05,890
in the wrong direction.
146
00:09:05,900 --> 00:09:07,160
How could that be?
147
00:09:07,160 --> 00:09:10,600
Well, what if it got hit
really hard by some object?
148
00:09:10,600 --> 00:09:11,630
That could do it.
149
00:09:13,770 --> 00:09:16,000
An object so huge,
150
00:09:16,010 --> 00:09:21,740
Venus stops in its tracks
and begins to spin backwards.
151
00:09:21,740 --> 00:09:24,610
If you think about
how much energy
152
00:09:24,610 --> 00:09:28,780
and what size you need
to change a planet's spin,
153
00:09:28,790 --> 00:09:31,390
that is an incredibly large hit.
154
00:09:34,360 --> 00:09:36,860
But the backspin is slow...
155
00:09:36,860 --> 00:09:40,630
243 times slower than earth.
156
00:09:43,800 --> 00:09:45,670
Without a fast spin,
157
00:09:45,670 --> 00:09:50,810
Venus' core can't generate
a strong magnetic field.
158
00:09:50,810 --> 00:09:53,370
It has no protection
from the deadly stream
159
00:09:53,380 --> 00:09:57,910
of particles blasted
from the sun.
160
00:09:57,910 --> 00:10:00,920
Venus does not have
a strong magnetic field,
161
00:10:00,920 --> 00:10:03,380
and so it has suffered
the full brunt
162
00:10:03,390 --> 00:10:05,790
of this wind
blasted out from the sun.
163
00:10:08,860 --> 00:10:11,190
The tale of two planets
164
00:10:11,190 --> 00:10:13,090
now splits radically.
165
00:10:15,100 --> 00:10:16,830
Venus will roast
166
00:10:16,830 --> 00:10:20,330
under a violent,
suffocating atmosphere.
167
00:10:20,340 --> 00:10:23,300
Earth will give birth to oceans,
168
00:10:23,310 --> 00:10:27,070
life, and intelligence.
169
00:10:27,080 --> 00:10:30,040
But ultimately,
these twins' fates
170
00:10:30,050 --> 00:10:32,550
are the same.
171
00:10:32,550 --> 00:10:36,580
Earth's future is Venus...
172
00:10:36,590 --> 00:10:38,390
Pure hell.
173
00:10:43,860 --> 00:10:46,690
4.6 billion years ago,
174
00:10:46,700 --> 00:10:49,260
two nearly-identical planets
formed...
175
00:10:49,270 --> 00:10:51,130
Earth and Venus.
176
00:10:51,130 --> 00:10:53,630
Earth blossomed into
a colorful haven
177
00:10:53,640 --> 00:10:55,300
for life to thrive,
178
00:10:55,300 --> 00:10:58,470
while Venus is
the definition of hell.
179
00:10:58,470 --> 00:11:00,770
How did they turn out
so different?
180
00:11:00,780 --> 00:11:04,480
Images from space probes sent
to Venus provide the answer.
181
00:11:08,050 --> 00:11:10,990
Venus is a vision of hell.
182
00:11:10,990 --> 00:11:16,160
And one day,
we'll meet our twin's fate.
183
00:11:16,160 --> 00:11:17,790
So, how will our blue planet
184
00:11:17,790 --> 00:11:20,900
become a superheated wasteland?
185
00:11:20,900 --> 00:11:23,630
Only Venus can really tell us.
186
00:11:25,940 --> 00:11:28,500
Something happened to Venus
long in its past
187
00:11:28,500 --> 00:11:31,040
to make it
a completely different planet
188
00:11:31,040 --> 00:11:33,140
with a completely
different personality
189
00:11:33,140 --> 00:11:35,540
than the earth
as we know it today.
190
00:11:35,550 --> 00:11:39,480
Two, three, four.
191
00:11:39,480 --> 00:11:41,920
We earthlings
sent our first probe
192
00:11:41,920 --> 00:11:44,990
to our sister planet in 1967,
193
00:11:44,990 --> 00:11:47,520
and we've been sending them
ever since.
194
00:11:50,490 --> 00:11:58,300
What they found
blew scientists' minds...
195
00:11:58,300 --> 00:12:01,870
Rocks that look like granite.
196
00:12:01,870 --> 00:12:04,410
What makes that interesting
is that, to make granite,
197
00:12:04,410 --> 00:12:06,040
you need water.
198
00:12:08,040 --> 00:12:11,010
That means that there
must have been abundant water
199
00:12:11,010 --> 00:12:13,450
for it to have formed
in the first place.
200
00:12:18,250 --> 00:12:21,690
Abundant water
on scorched Venus?
201
00:12:21,690 --> 00:12:23,420
Hard to imagine.
202
00:12:26,330 --> 00:12:29,330
But Dr. Lewis Dartnell
thinks you can get a glimpse
203
00:12:29,330 --> 00:12:32,500
of a wet Venus here in Iceland.
204
00:12:35,910 --> 00:12:38,040
There's the possibility
205
00:12:38,040 --> 00:12:40,270
that, maybe,
in the early solar system,
206
00:12:40,280 --> 00:12:43,040
there were not one,
but two planets with oceans...
207
00:12:43,050 --> 00:12:47,150
Two water worlds...
Earth and Venus.
208
00:12:47,150 --> 00:12:50,250
And if Venus did
once have oceans,
209
00:12:50,250 --> 00:12:53,450
maybe they would've looked
a lot like this here,
210
00:12:53,460 --> 00:12:57,220
with a raw, volcanic landscape
211
00:12:57,230 --> 00:12:58,630
descending down into the ocean
212
00:12:58,630 --> 00:13:01,300
with the waves
lapping against the coastline,
213
00:13:01,300 --> 00:13:06,170
and maybe a overcast
and a misty, hazy atmosphere,
214
00:13:06,170 --> 00:13:08,270
not unlike
what we are seeing here today.
215
00:13:10,610 --> 00:13:13,570
But Venus
couldn't hold on to its water.
216
00:13:17,780 --> 00:13:19,810
All of that water is gone.
217
00:13:19,820 --> 00:13:22,150
It's just gone.
Where did it go?
218
00:13:22,150 --> 00:13:25,720
Something happened, either
catastrophically or over time,
219
00:13:25,720 --> 00:13:29,520
to basically dry out
this twin of the earth.
220
00:13:31,760 --> 00:13:34,500
The culprit was the young sun.
221
00:13:34,500 --> 00:13:38,630
Since its birth,
it's grown stronger.
222
00:13:38,630 --> 00:13:40,500
Our sun, when we look
out at it during the day,
223
00:13:40,500 --> 00:13:42,700
seems the same today
as it was yesterday.
224
00:13:42,710 --> 00:13:44,340
But that's on
a human time scale.
225
00:13:44,340 --> 00:13:45,440
On cosmic time scale,
226
00:13:45,440 --> 00:13:47,410
the sun has been getting
hotter and hotter.
227
00:13:49,480 --> 00:13:53,880
Every billion years,
the sun gets 10% hotter,
228
00:13:53,880 --> 00:13:57,250
slowly turning up
the temperature on Venus.
229
00:14:00,460 --> 00:14:02,060
Not only that,
230
00:14:02,060 --> 00:14:07,900
Venus formed 26 million miles
closer to our star.
231
00:14:07,900 --> 00:14:11,930
As it turns out, that distance
to the sun was critical.
232
00:14:11,930 --> 00:14:14,470
It's just
an unfortunate circumstance
233
00:14:14,470 --> 00:14:18,910
of being in the wrong place
at the wrong time.
234
00:14:18,910 --> 00:14:21,380
Earth is far enough
away from the sun
235
00:14:21,380 --> 00:14:23,140
to hold on to its water.
236
00:14:25,250 --> 00:14:29,020
But Venus can't take the heat.
237
00:14:29,020 --> 00:14:31,820
The intensity
of its sunlight got sort of
238
00:14:31,820 --> 00:14:33,350
just a little bit too much.
239
00:14:33,360 --> 00:14:35,560
It passed this threshold
where Venus
240
00:14:35,560 --> 00:14:39,730
couldn't hold its water
on the surface anymore.
241
00:14:39,730 --> 00:14:41,560
As temperatures rise,
242
00:14:41,560 --> 00:14:45,900
the oceans start to evaporate.
243
00:14:45,900 --> 00:14:47,800
All of that water in the oceans,
244
00:14:47,800 --> 00:14:50,140
all of those millions
of cubic miles of water,
245
00:14:50,140 --> 00:14:51,870
would become water vapor...
246
00:14:51,870 --> 00:14:54,710
Basically steam clouds
covering the entire planet,
247
00:14:54,710 --> 00:14:58,450
hiding the surface
from the outside.
248
00:14:58,450 --> 00:15:01,180
Water vapor is a greenhouse gas.
249
00:15:01,180 --> 00:15:04,850
The clouds covering Venus
trap the sun's heat.
250
00:15:08,120 --> 00:15:12,930
Temperatures on
the surface rise.
251
00:15:12,930 --> 00:15:17,930
But the process
can't go on forever,
252
00:15:17,930 --> 00:15:20,570
because the clouds
of water vapor in the atmosphere
253
00:15:20,570 --> 00:15:24,100
start to disappear,
254
00:15:24,110 --> 00:15:27,040
ripped away by the solar wind.
255
00:15:29,280 --> 00:15:31,880
Over time, if a water molecule
was in the upper part
256
00:15:31,880 --> 00:15:33,180
of Venus' atmosphere,
257
00:15:33,180 --> 00:15:35,280
light from the sun
could break it apart
258
00:15:35,280 --> 00:15:37,420
into oxygen and hydrogen.
259
00:15:37,420 --> 00:15:40,950
And then, the solar wind
could blow that stuff away.
260
00:15:44,960 --> 00:15:47,390
But that is just the beginning.
261
00:15:47,400 --> 00:15:49,730
Without its water vapor
to trap heat,
262
00:15:49,730 --> 00:15:53,930
the temperature
stops rising temporarily.
263
00:15:55,700 --> 00:15:57,370
Soon, a new force
264
00:15:57,370 --> 00:16:01,310
will send surface temperatures
rocketing again.
265
00:16:01,310 --> 00:16:03,840
It will become so hot,
266
00:16:03,850 --> 00:16:06,650
metal snow will fall.
267
00:16:11,950 --> 00:16:13,550
When I think of Venus,
268
00:16:13,560 --> 00:16:16,760
the words "hot," "hazy,"
and "dead zone"
269
00:16:16,760 --> 00:16:18,030
come to mind...
270
00:16:18,030 --> 00:16:20,890
The exact opposite
of our planet.
271
00:16:20,900 --> 00:16:23,500
But scientists believe
that one day,
272
00:16:23,500 --> 00:16:26,200
these might be the words
to describe earth.
273
00:16:26,200 --> 00:16:29,770
By studying volcanoes,
you can start to understand why.
274
00:16:32,910 --> 00:16:34,710
Four billion years ago,
275
00:16:34,710 --> 00:16:38,010
Venus and earth were twins
with oceans.
276
00:16:38,010 --> 00:16:43,280
But soon,
the two planets' paths diverged.
277
00:16:43,290 --> 00:16:47,020
The growing sun
burned off Venus' oceans...
278
00:16:47,020 --> 00:16:51,730
A terrible omen for earth.
279
00:16:51,730 --> 00:16:53,230
On the planet Venus,
280
00:16:53,230 --> 00:16:56,330
we think there could have been
oceans, lakes, water, and rain.
281
00:16:56,330 --> 00:17:00,470
But all of that came to an end.
282
00:17:00,470 --> 00:17:03,670
That tells you that the earth's
environment has to change, too.
283
00:17:03,670 --> 00:17:04,770
Nothing is forever.
284
00:17:07,780 --> 00:17:09,540
A few billion years ago,
285
00:17:09,550 --> 00:17:10,980
when you looked
in our solar system,
286
00:17:10,980 --> 00:17:12,750
you might have seen two earths.
287
00:17:12,750 --> 00:17:15,850
Well, a few billion years
from now, in the future,
288
00:17:15,850 --> 00:17:17,550
you might look at
our solar system
289
00:17:17,550 --> 00:17:19,620
and see two Venuses.
290
00:17:22,260 --> 00:17:27,660
So we can look to
Venus' past and see our fate.
291
00:17:27,660 --> 00:17:30,460
We know
that temperatures skyrocketed,
292
00:17:30,470 --> 00:17:33,570
and the scarred surface
hints at why.
293
00:17:35,570 --> 00:17:38,940
In Hawaii, planetary geologist
Jani Radebaugh
294
00:17:38,940 --> 00:17:42,910
studies the islands' volcanoes.
295
00:17:42,910 --> 00:17:46,750
These volcanoes are
a perfect model for early Venus.
296
00:17:50,020 --> 00:17:53,590
What we're seeing out here
are lava flows
297
00:17:53,590 --> 00:17:56,990
encroaching on
the town of Pahoa,
298
00:17:56,990 --> 00:17:59,890
come all the way down
from the Pu'u 'o'o vent
299
00:17:59,900 --> 00:18:04,000
which is about 15 miles away.
300
00:18:04,000 --> 00:18:05,870
Oh, there's hot.
You can see that hot stuff.
301
00:18:05,870 --> 00:18:07,600
You can see hot.
Quick, quick, quick, quick.
302
00:18:07,600 --> 00:18:09,940
Right there.
303
00:18:09,940 --> 00:18:11,210
It's really beautiful.
304
00:18:14,180 --> 00:18:16,380
Hawaii's volcanic lava fields
305
00:18:16,380 --> 00:18:21,450
look like Venus in miniature.
306
00:18:21,450 --> 00:18:24,990
Both produce
the same kind of runny lava,
307
00:18:24,990 --> 00:18:27,590
building flat,
shield-like volcanoes.
308
00:18:29,730 --> 00:18:30,960
The big difference is
309
00:18:30,960 --> 00:18:34,460
there are only
five active volcanoes on Hawaii.
310
00:18:38,030 --> 00:18:42,300
Venus is covered in them.
311
00:18:42,300 --> 00:18:44,540
One thing that really
jumps out all around the planet
312
00:18:44,540 --> 00:18:48,480
is the number and variety
of volcanoes.
313
00:18:48,480 --> 00:18:53,310
I mean, Venus could almost be
nicknamed "volcano world."
314
00:18:53,320 --> 00:18:55,220
But it's not the erupting lava
315
00:18:55,220 --> 00:18:57,080
that turns up the heat.
316
00:18:57,090 --> 00:18:58,850
It's what comes out with it.
317
00:18:58,850 --> 00:19:01,160
When you think back
to the histories of Venus,
318
00:19:01,160 --> 00:19:02,523
I think we must have seen
a landscape
319
00:19:02,530 --> 00:19:04,320
very similar to this one,
320
00:19:04,330 --> 00:19:06,360
where you have
massive amounts of lava
321
00:19:06,360 --> 00:19:08,230
flowing out of the surface,
322
00:19:08,230 --> 00:19:10,530
dumping huge amounts of gases
into the atmosphere,
323
00:19:10,530 --> 00:19:13,230
carbon dioxide, tons of the gas
into the atmosphere
324
00:19:13,240 --> 00:19:15,270
every single day.
325
00:19:15,270 --> 00:19:17,140
It would have been amazing
to see.
326
00:19:23,280 --> 00:19:25,080
Up close on the surface,
327
00:19:25,080 --> 00:19:27,980
Jani can see
the origin of the gases.
328
00:19:30,550 --> 00:19:33,450
If we look behind us,
we can see volcanic gases
329
00:19:33,460 --> 00:19:35,090
gushing out of steam vents.
330
00:19:35,090 --> 00:19:37,590
We've got carbon dioxide being
delivered to the atmosphere.
331
00:19:37,590 --> 00:19:40,030
It's exactly like
what has happened on Venus.
332
00:19:42,830 --> 00:19:45,000
Carbon dioxide has been
delivered out of volcanoes
333
00:19:45,000 --> 00:19:49,500
over and over and over again
throughout its history,
334
00:19:49,510 --> 00:19:50,640
so that now we have
335
00:19:50,640 --> 00:19:53,810
just a tremendously thick,
dense atmosphere.
336
00:19:55,710 --> 00:19:58,210
The net result
of all of these volcanic gases
337
00:19:58,210 --> 00:20:01,950
pouring out of volcanoes,
major greenhouse gases,
338
00:20:01,950 --> 00:20:03,220
is that they have been
absorbing heat
339
00:20:03,220 --> 00:20:06,050
for billions of years
of the history of Venus.
340
00:20:06,060 --> 00:20:08,490
The temperature
has been gradually creeping up
341
00:20:08,490 --> 00:20:12,890
until, today, the surface
of Venus is 900 degrees.
342
00:20:14,900 --> 00:20:16,500
It's like if you go
into your kitchen
343
00:20:16,500 --> 00:20:18,530
and set your oven to broil,
344
00:20:18,530 --> 00:20:21,030
wait a couple of minutes
and stick your head in it,
345
00:20:21,040 --> 00:20:23,940
and even that's
not quite hot enough.
346
00:20:23,940 --> 00:20:27,370
It's a crazy, horrible,
hellish spot.
347
00:20:32,580 --> 00:20:38,490
It's hard to imagine
such extreme temperatures.
348
00:20:38,490 --> 00:20:40,520
But probes orbiting the planet
349
00:20:40,520 --> 00:20:46,130
revealed just
how insanely hot it is.
350
00:20:46,130 --> 00:20:48,060
Scientists studying the images
351
00:20:48,060 --> 00:20:53,600
noticed something strange
on the planet's mountains.
352
00:20:53,600 --> 00:20:55,470
It looks like, on the mountains,
353
00:20:55,470 --> 00:20:57,910
that there's apparently
snow-like structures.
354
00:21:00,510 --> 00:21:05,380
But this is unlike
any snow found on earth.
355
00:21:05,380 --> 00:21:08,650
So, if you look at the
white-peaked mountains of Venus,
356
00:21:08,650 --> 00:21:10,120
you would think
that it was snow,
357
00:21:10,120 --> 00:21:12,250
but it's actually metals
that have rained down
358
00:21:12,250 --> 00:21:14,790
and deposited
on the top of those mountains.
359
00:21:17,860 --> 00:21:20,590
Metals like
bismuth and lead melt.
360
00:21:22,830 --> 00:21:25,670
Then, they evaporate
into the atmosphere.
361
00:21:28,870 --> 00:21:31,840
As they rise, they cool
362
00:21:31,840 --> 00:21:36,640
until they finally fall
like snow on the mountaintops.
363
00:21:38,680 --> 00:21:40,910
It's pretty insane...
Raining metals.
364
00:21:40,920 --> 00:21:44,320
Where would you ever think
about that existing?
365
00:21:44,320 --> 00:21:45,590
On Venus.
366
00:21:48,920 --> 00:21:50,260
In the future,
367
00:21:50,260 --> 00:21:54,490
metallic snow
is forecast for earth, too.
368
00:21:54,500 --> 00:21:58,830
And our scorching mountain caps
will glitter like Venus.
369
00:22:02,470 --> 00:22:07,610
But Venus tells us
that things will get even worse.
370
00:22:11,550 --> 00:22:16,680
The atmosphere will grow
heavy enough to crush cars.
371
00:22:22,790 --> 00:22:24,590
Earth and Venus...
372
00:22:24,590 --> 00:22:27,790
In the beginning, they were not
so different.
373
00:22:27,800 --> 00:22:30,660
But these two planets have
such similar births,
374
00:22:30,670 --> 00:22:33,700
how has earth been able
to defend itself
375
00:22:33,700 --> 00:22:37,300
against the gruesome forces
that so changed Venus?
376
00:22:37,310 --> 00:22:40,970
The answers are found
in our atmosphere.
377
00:22:44,210 --> 00:22:47,480
Earth and Venus were born twins,
378
00:22:47,480 --> 00:22:49,880
but they took different paths.
379
00:22:49,890 --> 00:22:53,920
Earth slowly evolved
into a habitable world.
380
00:22:57,360 --> 00:23:01,030
Venus was covered
in thick volcanic gases,
381
00:23:01,030 --> 00:23:03,160
trapping the sun's heat.
382
00:23:03,170 --> 00:23:07,700
Temperatures Rose
to 900 degrees.
383
00:23:11,210 --> 00:23:12,710
Extreme temperatures
384
00:23:12,710 --> 00:23:15,640
weren't the only problem
on Venus' surface.
385
00:23:18,950 --> 00:23:24,150
The thick clouds of gas
kept on building up.
386
00:23:24,150 --> 00:23:28,960
A 155-mile-deep
layer of carbon dioxide
387
00:23:28,960 --> 00:23:31,330
piles up around the planet.
388
00:23:31,330 --> 00:23:33,860
We don't think about gases
as weighing anything,
389
00:23:33,860 --> 00:23:35,430
but they actually do.
390
00:23:35,430 --> 00:23:37,930
Trillions and trillions of tons
391
00:23:37,930 --> 00:23:41,470
of gas press downwards.
392
00:23:41,470 --> 00:23:44,270
There is simply
so much air on Venus
393
00:23:44,270 --> 00:23:46,370
that, on the surface,
it's pushing down
394
00:23:46,380 --> 00:23:47,810
with a huge amount of force.
395
00:23:47,810 --> 00:23:50,840
Well, atmospheric pressure
on Venus is a monster.
396
00:23:50,850 --> 00:23:53,810
Think about it this way.
397
00:23:53,820 --> 00:23:55,750
All right, car.
398
00:23:55,750 --> 00:23:57,620
It's time
for you to be crushed, baby.
399
00:24:04,090 --> 00:24:06,030
If you're on Venus,
you're gonna have
400
00:24:06,030 --> 00:24:09,400
155 miles of atmosphere
above your head.
401
00:24:09,400 --> 00:24:10,630
As a result,
402
00:24:10,630 --> 00:24:13,830
atmospheric pressure
is 90 times that on earth.
403
00:24:13,840 --> 00:24:19,870
So, on earth, it's about
14.6 pounds per square inch.
404
00:24:19,880 --> 00:24:23,840
On Venus, we're talking about
1,300 pounds per square inch.
405
00:24:23,850 --> 00:24:26,680
So, if you're driving
your car in Venus,
406
00:24:26,680 --> 00:24:28,620
this is what might happen.
407
00:24:32,550 --> 00:24:35,960
This crusher delivers
the same force
408
00:24:35,960 --> 00:24:38,690
as the weight
of Venus' atmosphere.
409
00:24:38,690 --> 00:24:41,130
This is pretty serious stuff.
410
00:24:47,770 --> 00:24:49,770
And this is why
it's so hard on Venus.
411
00:24:49,770 --> 00:24:51,270
You get down to the surface,
412
00:24:51,270 --> 00:24:54,310
you have the crushing atmosphere
to deal with.
413
00:24:57,950 --> 00:24:59,950
The extreme pressure and heat
414
00:24:59,950 --> 00:25:04,280
makes Venus
nearly impossible to explore.
415
00:25:09,260 --> 00:25:14,190
Only one nation has ever gotten
a probe to the planet's surface.
416
00:25:17,200 --> 00:25:19,770
Truly, one of the engineering
triumphs of the human race
417
00:25:19,770 --> 00:25:22,040
was the Soviet union's
Venera program.
418
00:25:22,040 --> 00:25:26,040
The Russians sent over a dozen
probes to the planet Venus.
419
00:25:26,040 --> 00:25:28,710
And only a few of them
were able to survive long enough
420
00:25:28,710 --> 00:25:31,240
to even be able to take pictures
from the surface.
421
00:25:34,280 --> 00:25:36,620
The probe
that sent back these images
422
00:25:36,620 --> 00:25:39,720
was crushed and burnt out
in 90 minutes.
423
00:25:42,460 --> 00:25:43,720
Some day in the future,
424
00:25:43,730 --> 00:25:46,190
there are going to be
interplanetary tour guides
425
00:25:46,200 --> 00:25:48,500
taking people to every planet
in the solar system.
426
00:25:48,500 --> 00:25:51,570
And you can imagine going
to Saturn and seeing the rings
427
00:25:51,570 --> 00:25:53,970
and Jupiter
and it's panoply of moons.
428
00:25:53,970 --> 00:25:55,800
There are all
these great tourist attractions
429
00:25:55,800 --> 00:25:56,970
in the solar system.
430
00:25:56,970 --> 00:26:01,010
At the very bottom
of that list is Venus.
431
00:26:01,010 --> 00:26:03,510
That is the last place
in the solar system
432
00:26:03,510 --> 00:26:05,310
I would ever want to visit.
433
00:26:07,820 --> 00:26:10,450
The sun's heat
and volcanic gases
434
00:26:10,450 --> 00:26:14,320
have transformed Venus
into a nightmarish world.
435
00:26:18,660 --> 00:26:23,130
So, why hasn't earth
followed the same path?
436
00:26:23,130 --> 00:26:26,700
That's because earth formed
farther away from the sun,
437
00:26:26,700 --> 00:26:31,610
staying cool enough
to hold on to its oceans.
438
00:26:31,610 --> 00:26:34,270
Oceans do
a lot of things for us on earth
439
00:26:34,280 --> 00:26:36,610
because not only, obviously,
are we water creatures,
440
00:26:36,610 --> 00:26:40,280
and we depend on the water cycle
for our existence
441
00:26:40,280 --> 00:26:41,410
in so many ways,
442
00:26:41,420 --> 00:26:43,720
but people don't realize
the oceans also help
443
00:26:43,720 --> 00:26:46,290
to regulate
the climate of earth.
444
00:26:46,290 --> 00:26:49,360
Our oceans
are full of tiny creatures
445
00:26:49,360 --> 00:26:51,730
that eat carbon dioxide.
446
00:26:54,630 --> 00:26:57,600
Richard Zeebe
from the university of Hawaii
447
00:26:57,600 --> 00:27:02,270
is diving on
the island's coral reefs.
448
00:27:02,270 --> 00:27:05,040
He's studying
how tiny marine organisms
449
00:27:05,040 --> 00:27:10,010
turn carbon dioxide into rock.
450
00:27:10,010 --> 00:27:12,110
What you see here
as this white stuff,
451
00:27:12,110 --> 00:27:14,280
this is what we call
calcium carbonate.
452
00:27:14,280 --> 00:27:16,780
And on top of this, where
you see these brown layers,
453
00:27:16,790 --> 00:27:19,220
this is essentially
the living organism.
454
00:27:19,220 --> 00:27:21,390
This is the coral itself.
455
00:27:21,390 --> 00:27:23,260
It takes calcium
out of the seawater
456
00:27:23,260 --> 00:27:25,030
and takes carbonate
out of the seawater,
457
00:27:25,030 --> 00:27:29,400
combines them, and makes
this piece of calcium carbonate.
458
00:27:29,400 --> 00:27:32,500
There's over
70 million billion tons
459
00:27:32,500 --> 00:27:36,500
of carbon locked up
in carbonate rocks.
460
00:27:36,510 --> 00:27:38,840
This helps regulate
carbon dioxide levels
461
00:27:38,840 --> 00:27:43,480
in the atmosphere, keeping
temperatures from rising.
462
00:27:43,480 --> 00:27:47,080
If all the carbon that is being
locked up in carbonate rocks
463
00:27:47,080 --> 00:27:50,980
in these corals would be
put into the atmosphere as co2,
464
00:27:50,990 --> 00:27:53,320
that would be
certainly bad news for us.
465
00:27:53,320 --> 00:27:55,460
Currently, our carbon cycle
466
00:27:55,460 --> 00:27:58,660
helps stabilize our climate.
467
00:27:58,660 --> 00:28:02,400
But in the future,
this won't be able to save us.
468
00:28:07,270 --> 00:28:10,600
Forces far greater
than the ones at work on earth
469
00:28:10,610 --> 00:28:12,840
will overpower our systems.
470
00:28:15,510 --> 00:28:19,750
Like Venus,
our oceans will burn off.
471
00:28:19,750 --> 00:28:21,650
Temperatures will rocket
472
00:28:21,650 --> 00:28:26,020
as our live-giving sun
becomes a monster.
473
00:28:32,890 --> 00:28:34,790
By looking at Venus' past,
474
00:28:34,800 --> 00:28:37,230
we can get a glimpse into
earth's future.
475
00:28:37,230 --> 00:28:39,170
And it doesn't look bright.
476
00:28:39,170 --> 00:28:41,070
One of our
best planetary features
477
00:28:41,070 --> 00:28:43,400
might become our worst enemy.
478
00:28:45,470 --> 00:28:47,640
Venus' hellish landscape
479
00:28:47,640 --> 00:28:51,340
is a glimpse
into earth's future.
480
00:28:51,350 --> 00:28:52,780
There will be no more rain.
481
00:28:52,780 --> 00:28:54,280
There will be no more oceans.
482
00:28:54,280 --> 00:28:57,180
This wonderful, life-friendly
environment we enjoy now
483
00:28:57,190 --> 00:29:00,590
just won't be here in some
hundreds of millions of years.
484
00:29:05,560 --> 00:29:09,300
Right now, we live just the
right distance from the sun,
485
00:29:09,300 --> 00:29:10,730
where it's just
the right temperature
486
00:29:10,730 --> 00:29:13,300
for water to exist as a liquid.
487
00:29:16,040 --> 00:29:22,510
But that's going to change,
just as it did for Venus.
488
00:29:22,510 --> 00:29:24,840
Venus started off,
probably, in the habitable zone.
489
00:29:24,850 --> 00:29:28,550
And then the inner limit
of the habitable zone crossed
490
00:29:28,550 --> 00:29:30,550
the distance of Venus' orbit.
491
00:29:30,550 --> 00:29:33,150
Well, it's gonna cross the
distance of earth's orbit, too.
492
00:29:33,150 --> 00:29:35,420
There is an expiration date
to the earth.
493
00:29:35,420 --> 00:29:37,720
And that's due
to the sun's evolution.
494
00:29:40,260 --> 00:29:45,730
Ever since its birth,
the sun has been getting hotter.
495
00:29:45,730 --> 00:29:50,440
That increased heat
devastated Venus.
496
00:29:50,440 --> 00:29:55,610
And, in the future,
it will destroy earth.
497
00:29:55,610 --> 00:29:57,680
In 1.1 billion years,
498
00:29:57,680 --> 00:30:02,080
the sun is 10% hotter
than today.
499
00:30:02,080 --> 00:30:06,520
The oceans start to evaporate
into thick clouds,
500
00:30:06,520 --> 00:30:10,460
which trap
more of the sun's heat.
501
00:30:10,460 --> 00:30:14,490
Catastrophically, very rapidly
on a geological time scale,
502
00:30:14,500 --> 00:30:17,530
the oceans will put so much
water vapor into the atmosphere
503
00:30:17,530 --> 00:30:19,970
that we will get
a runaway greenhouse effect.
504
00:30:21,400 --> 00:30:24,170
The clouds
forming in the atmosphere
505
00:30:24,170 --> 00:30:26,340
trap more and more heat,
506
00:30:26,340 --> 00:30:29,110
driving temperatures
even higher.
507
00:30:31,650 --> 00:30:35,180
Spiraling temperatures
cause more evaporation,
508
00:30:35,180 --> 00:30:37,550
so the clouds get thicker.
509
00:30:39,790 --> 00:30:42,790
Which led to more heating,
which led to more evaporation.
510
00:30:42,790 --> 00:30:44,190
And you can see
where this is going.
511
00:30:44,190 --> 00:30:47,190
It's a vicious cycle.
It's a positive feedback.
512
00:30:49,960 --> 00:30:53,070
We have all of this water that
will go into the atmosphere,
513
00:30:53,070 --> 00:30:56,540
covering the earth and shrouding
it in, basically, steam.
514
00:31:00,680 --> 00:31:04,680
Earth has had oceans
for billions of years,
515
00:31:04,680 --> 00:31:08,180
but it could lose them
in just 10,000.
516
00:31:10,920 --> 00:31:12,890
All of the water
in the earth's oceans
517
00:31:12,890 --> 00:31:14,150
will be in the atmosphere.
518
00:31:14,160 --> 00:31:17,060
We'll have an incredibly dense
cloud cover system
519
00:31:17,060 --> 00:31:18,590
where the temperatures on earth
520
00:31:18,590 --> 00:31:22,660
will be approaching
1,000 degrees.
521
00:31:22,660 --> 00:31:24,500
Like Venus in the past,
522
00:31:24,500 --> 00:31:26,970
earth will get
hotter and hotter.
523
00:31:26,970 --> 00:31:32,040
But unlike Venus,
which topped out at 900 degrees,
524
00:31:32,040 --> 00:31:35,310
temperatures on earth
will keep on climbing.
525
00:31:39,050 --> 00:31:45,380
Venus lost its water to space,
blasted away by the solar wind.
526
00:31:45,390 --> 00:31:49,690
But earth holds on to its water.
527
00:31:49,690 --> 00:31:53,360
It's protected
by our magnetic shield.
528
00:31:53,360 --> 00:31:57,960
But that's no longer
a good thing.
529
00:31:57,970 --> 00:32:00,000
That water will stay with us.
530
00:32:00,000 --> 00:32:04,840
The earth could have a thicker,
hotter greenhouse atmosphere
531
00:32:04,840 --> 00:32:08,640
than Venus does today,
much worse.
532
00:32:09,880 --> 00:32:12,440
This huge volume of water vapor
533
00:32:12,450 --> 00:32:17,150
all pushes down on the surface,
534
00:32:17,150 --> 00:32:20,220
around 4,000 pounds.
535
00:32:20,220 --> 00:32:22,920
That's the weight
of the average American car
536
00:32:22,920 --> 00:32:26,390
pressing down
on every square inch of earth.
537
00:32:29,830 --> 00:32:32,300
Surface pressure
goes through the roof,
538
00:32:32,300 --> 00:32:37,600
reaching 270 times higher
than today.
539
00:32:37,610 --> 00:32:40,340
It is ironic to think
that the water on earth
540
00:32:40,340 --> 00:32:43,240
will one day help contribute
to its demise.
541
00:32:43,240 --> 00:32:46,650
After all, the water has been
the source of life on earth.
542
00:32:46,650 --> 00:32:49,350
But, in the far future,
it'll become our enemy.
543
00:32:52,220 --> 00:32:55,550
And with no oceans
and their microscopic creatures
544
00:32:55,560 --> 00:32:58,220
to absorb the carbon dioxide,
545
00:32:58,230 --> 00:33:03,530
there is nothing to hold back
the rising temperatures.
546
00:33:03,530 --> 00:33:08,000
There's no way back
for the earth.
547
00:33:15,080 --> 00:33:17,280
In 1.2 billion years,
548
00:33:17,280 --> 00:33:23,550
a probe visiting earth
would see an alien world...
549
00:33:23,550 --> 00:33:26,320
A scorched, barren landscape.
550
00:33:29,520 --> 00:33:32,890
The pressure is crushing.
551
00:33:32,890 --> 00:33:37,900
Temperatures reach
1,200 degrees.
552
00:33:37,900 --> 00:33:43,540
Molten metals
snow down on the mountaintops.
553
00:33:43,540 --> 00:33:47,240
It's so hot
that granite rock melts.
554
00:33:49,940 --> 00:33:54,210
The surface liquefies.
555
00:33:54,220 --> 00:33:56,880
At that point, the earth
will become a molten ball
556
00:33:56,880 --> 00:34:00,450
very similar to what it was
at the very beginning.
557
00:34:00,450 --> 00:34:04,820
Earth and Venus
started as twins.
558
00:34:04,830 --> 00:34:09,390
Venus was destroyed
by rampant global warming.
559
00:34:09,400 --> 00:34:15,070
Earth will follow the same path,
then overtake it.
560
00:34:15,070 --> 00:34:18,240
It is inevitable
that the earth will someday
561
00:34:18,240 --> 00:34:21,240
not only be like Venus,
but actually put it to shame.
562
00:34:23,940 --> 00:34:31,450
In 1.3 billion years,
earth could hit 3,600 degrees,
563
00:34:31,450 --> 00:34:34,220
four times hotter than Venus.
564
00:34:36,820 --> 00:34:39,730
It will be
the hottest and deadliest planet
565
00:34:39,730 --> 00:34:41,690
in our solar system.
566
00:34:46,030 --> 00:34:50,870
For earth and its inhabitants,
it's the end of the road.
567
00:34:50,870 --> 00:34:53,870
We couldn't survive
the extreme temperatures
568
00:34:53,870 --> 00:34:56,110
or crushing pressure.
569
00:34:56,110 --> 00:35:00,010
Maybe we'll escape to space.
570
00:35:00,010 --> 00:35:05,980
But there's one absolutely
crazy way we could stay here...
571
00:35:05,990 --> 00:35:10,420
Move our planet
further away from the sun.
572
00:35:16,360 --> 00:35:19,930
I've seen my fair share of
crazy ideas at NASA
573
00:35:19,930 --> 00:35:21,470
that end up being the solution
574
00:35:21,470 --> 00:35:23,170
to a big problem.
575
00:35:23,170 --> 00:35:25,670
During my final mission
aboard Atlantis,
576
00:35:25,670 --> 00:35:28,270
while a making a repair to
the Hubble space telescope,
577
00:35:28,280 --> 00:35:31,840
I stripped a screw
and was completely stuck.
578
00:35:31,850 --> 00:35:34,980
Mission control suggested
using brute force
579
00:35:34,980 --> 00:35:36,850
and a simple piece of tape.
580
00:35:36,850 --> 00:35:40,350
Likewise, scientists have come
up with an unusual solution
581
00:35:40,350 --> 00:35:42,990
to save earth from ending up
like Venus.
582
00:35:48,000 --> 00:35:49,830
Earth of the future will become
583
00:35:49,830 --> 00:35:53,830
the most inhospitable planet
in the solar system.
584
00:35:53,830 --> 00:35:59,670
Its ocean will boil off,
and its surface will melt.
585
00:35:59,670 --> 00:36:01,310
A billion years from now,
586
00:36:01,310 --> 00:36:06,880
earth could be
an unimaginably terrible place.
587
00:36:06,880 --> 00:36:09,980
Right now, today,
Venus is the evil twin of earth.
588
00:36:09,980 --> 00:36:11,620
But in the distance future,
589
00:36:11,620 --> 00:36:14,720
earth could be
the evil twin of Venus.
590
00:36:14,720 --> 00:36:16,260
Earth's surface temperature
591
00:36:16,260 --> 00:36:18,890
will reach 3,600 degrees
592
00:36:18,890 --> 00:36:24,400
with pressure 270 times
than today.
593
00:36:24,400 --> 00:36:26,030
At these kind of temperatures,
594
00:36:26,030 --> 00:36:29,570
where rock on the surface
of the earth is molten,
595
00:36:29,570 --> 00:36:32,270
it's hard to imagine
any place there could be life.
596
00:36:35,940 --> 00:36:38,210
But there is hope.
597
00:36:41,820 --> 00:36:44,120
Astrobiologist
Lewis Dartnell thinks
598
00:36:44,120 --> 00:36:46,690
that some forms of life
could survive
599
00:36:46,690 --> 00:36:50,690
such terrible conditions.
600
00:36:50,690 --> 00:36:54,530
We're here on top of
a volcanic outcrop in Iceland
601
00:36:54,530 --> 00:36:57,660
with this howling Gale
whistling past our ears,
602
00:36:57,670 --> 00:37:01,670
the stench of hydrogen sulfide,
of sulfurous fumes,
603
00:37:01,670 --> 00:37:03,170
filling our nostrils.
604
00:37:03,170 --> 00:37:05,640
And this is about as close
as you get can on earth
605
00:37:05,640 --> 00:37:08,670
to high up
in the Venusian atmosphere.
606
00:37:08,680 --> 00:37:13,150
About 30, 35 miles above
the surface of the planet Venus,
607
00:37:13,150 --> 00:37:15,250
the air pressure
is about the same
608
00:37:15,250 --> 00:37:16,620
as on the earth's surface.
609
00:37:16,620 --> 00:37:20,450
The temperature
is pretty similar, as well.
610
00:37:20,450 --> 00:37:24,620
But the cloud droplets are full
of concentrated sulfuric acid,
611
00:37:24,630 --> 00:37:27,930
many, many times more
concentrated than battery acid.
612
00:37:27,930 --> 00:37:32,100
It's a hostile,
horrible environment.
613
00:37:32,100 --> 00:37:33,900
But bizarrely enough,
614
00:37:33,900 --> 00:37:36,170
there's good reasons
to think that there may be life,
615
00:37:36,170 --> 00:37:38,870
Venusian life,
high up in the clouds
616
00:37:38,870 --> 00:37:42,880
that are kind of
high-altitude aerial biosphere.
617
00:37:45,550 --> 00:37:48,510
High above Venus,
there are nutrients,
618
00:37:48,520 --> 00:37:53,390
solar energy,
and traces of water.
619
00:37:53,390 --> 00:37:57,720
If life can live up there,
then perhaps it might survive
620
00:37:57,730 --> 00:38:02,360
high up in the clouds
of future earth.
621
00:38:02,360 --> 00:38:06,100
You can easily imagine these
micro-organisms evaporating
622
00:38:06,100 --> 00:38:08,270
in water particles
and being transported
623
00:38:08,270 --> 00:38:10,600
to the upper atmosphere.
624
00:38:10,600 --> 00:38:15,110
Even though it turned into
this toxic greenhouse planet,
625
00:38:15,110 --> 00:38:16,980
life could potentially
still survive
626
00:38:16,980 --> 00:38:18,710
in that upper atmosphere.
627
00:38:21,720 --> 00:38:24,050
But what about us?
628
00:38:24,050 --> 00:38:26,250
We couldn't survive
the high temperatures
629
00:38:26,250 --> 00:38:28,620
or pressures at the surface.
630
00:38:28,620 --> 00:38:32,420
And a life in the clouds
doesn't seem likely.
631
00:38:32,430 --> 00:38:35,760
What's our future?
632
00:38:35,760 --> 00:38:38,060
If there was this life on Venus,
633
00:38:38,070 --> 00:38:40,300
clearly, they weren't advanced
enough
634
00:38:40,300 --> 00:38:42,630
to stop the changes
in their atmosphere
635
00:38:42,640 --> 00:38:44,700
that led to Venus'
current state.
636
00:38:44,710 --> 00:38:46,670
The question is, are we?
637
00:38:48,840 --> 00:38:51,240
Perhaps we will leave our planet
638
00:38:51,250 --> 00:38:53,450
and find a new home.
639
00:38:56,620 --> 00:38:59,650
But there is
a more outlandish solution...
640
00:38:59,650 --> 00:39:03,690
Stay on earth and move it
farther from the sun.
641
00:39:03,690 --> 00:39:06,890
Moving the earth is at least
imaginable because, in fact,
642
00:39:06,890 --> 00:39:09,060
as objects exchange
gravitational energy,
643
00:39:09,060 --> 00:39:10,930
they move in or out
in the solar system.
644
00:39:10,930 --> 00:39:12,360
It's happened to our planet.
645
00:39:12,370 --> 00:39:14,900
So I could imagine
engineering things
646
00:39:14,900 --> 00:39:17,570
where we directed
large asteroids and comets
647
00:39:17,570 --> 00:39:19,770
close to the earth,
but not to hit it.
648
00:39:23,110 --> 00:39:25,440
The gravity
from these large objects
649
00:39:25,450 --> 00:39:29,250
would slowly alter our orbit.
650
00:39:29,250 --> 00:39:30,920
Gravitational energy
would be exchanged,
651
00:39:30,920 --> 00:39:33,620
and the earth
could slowly move out.
652
00:39:37,160 --> 00:39:38,720
Each gravitational jolt
653
00:39:38,730 --> 00:39:43,330
would only move earth
a short distance.
654
00:39:43,330 --> 00:39:46,970
But do it thousands
or millions of times,
655
00:39:46,970 --> 00:39:50,300
and we could push the earth
away from the sun...
656
00:39:50,300 --> 00:39:53,440
In theory, at least.
657
00:39:53,440 --> 00:39:56,140
Over a billion-year period,
it's possible to imagine.
658
00:39:56,140 --> 00:39:58,140
It would require
incredible technology
659
00:39:58,150 --> 00:40:00,310
and incredible coordination.
660
00:40:00,310 --> 00:40:01,880
The technology is possible.
661
00:40:01,880 --> 00:40:04,750
Whether humanity as a species
could ever coordinate it
662
00:40:04,750 --> 00:40:08,720
is something I'm a little
more skeptical about.
663
00:40:08,720 --> 00:40:12,420
It's a crazy option,
but if we don't do something,
664
00:40:12,430 --> 00:40:15,230
earth and all of us will die,
665
00:40:15,230 --> 00:40:19,000
and we'll become
just like Venus.
666
00:40:23,100 --> 00:40:25,000
Earth and Venus
were probably born together
667
00:40:25,010 --> 00:40:27,770
as identical twins,
but then their paths diverged.
668
00:40:27,780 --> 00:40:30,980
But now, lifetime is gonna send
that cycle all the way back,
669
00:40:30,980 --> 00:40:35,550
and they'll die
as identical twins again.
670
00:40:35,550 --> 00:40:37,420
In the grand scheme of things,
671
00:40:37,420 --> 00:40:39,450
they'll just be
two charred twins
672
00:40:39,450 --> 00:40:43,020
spinning to oblivion in
a backwater of the universe.
673
00:40:47,490 --> 00:40:51,460
On the cosmic scale,
life is short.
674
00:40:53,470 --> 00:40:57,570
When you look at how earth
evolved and how Venus evolved,
675
00:40:57,570 --> 00:40:59,400
you can see the difference,
676
00:40:59,410 --> 00:41:02,640
even though
it's two almost twin planets,
677
00:41:02,640 --> 00:41:06,580
how life and habitability
could change over time.
678
00:41:06,580 --> 00:41:11,520
So, habitability
isn't always a permanent thing.
679
00:41:11,520 --> 00:41:12,720
On human scales,
680
00:41:12,720 --> 00:41:16,190
the universe seems
the same every single day.
681
00:41:16,190 --> 00:41:19,090
But, of course,
that's because human life
682
00:41:19,090 --> 00:41:20,190
and human civilization
683
00:41:20,190 --> 00:41:24,460
is but a brief instant
in cosmic time.
684
00:41:24,470 --> 00:41:28,470
On cosmic scales, the universe
evolves and changes,
685
00:41:28,470 --> 00:41:31,670
and that makes the history
of the universe remarkable.
686
00:41:34,740 --> 00:41:38,840
Our tale of two
planets converges in the end,
687
00:41:38,850 --> 00:41:43,780
a cautionary tale
about forces beyond our control.
688
00:41:46,820 --> 00:41:50,490
Perhaps a billion years
of learning from Venus
689
00:41:50,490 --> 00:41:54,890
will save us from
the same terrible fate.
690
00:41:54,900 --> 00:41:57,900
Captions by vitac...
www.Vitac.Com
691
00:41:57,900 --> 00:42:00,670
captions paid for by
discovery communications
54217
Can't find what you're looking for?
Get subtitles in any language from opensubtitles.com, and translate them here.