1
00:00:03,938 --> 00:00:08,068
Narrator: Stars --
they're big, they're hot,
2
00:00:08,075 --> 00:00:10,339
and they are everywhere.
3
00:00:10,344 --> 00:00:12,836
Stars rule the universe.
4
00:00:12,847 --> 00:00:16,715
Our destiny is linked
to the destiny of stars.
5
00:00:16,717 --> 00:00:21,814
Narrator: Born in violence,
dying in epic explosions.
6
00:00:23,457 --> 00:00:26,984
They fill the universe
with stardust,
7
00:00:26,994 --> 00:00:29,554
the building blocks of life.
8
00:00:29,563 --> 00:00:31,861
Every atom in your body
9
00:00:31,866 --> 00:00:35,063
was produced
inside the fiery core of a star.
10
00:00:35,069 --> 00:00:39,028
Narrator: Stars are what
make our universe work.
11
00:00:39,039 --> 00:00:41,872
All life begins here.
12
00:00:57,358 --> 00:01:02,228
The night sky is packed
with stars.
13
00:01:07,935 --> 00:01:10,199
On a clear night in the country,
if you're lucky,
14
00:01:10,204 --> 00:01:12,070
you can see maybe 3,000 stars.
15
00:01:12,072 --> 00:01:14,734
But that's just the tip
of a vast cosmic iceberg.
16
00:01:15,943 --> 00:01:20,210
In our galaxy alone, there are
over 100 billion stars.
17
00:01:20,214 --> 00:01:22,808
And, in fact, there are
over 100 billion galaxies
18
00:01:22,816 --> 00:01:24,318
in the observable universe.
19
00:01:24,318 --> 00:01:27,413
There are more stars than there
are specks of sand on Earth.
20
00:01:30,624 --> 00:01:33,025
Narrator:
Every star is powerful,
21
00:01:33,027 --> 00:01:34,859
creating the basic matter
22
00:01:34,862 --> 00:01:37,126
for everything
in the universe...
23
00:01:39,633 --> 00:01:41,567
...including us.
24
00:01:50,344 --> 00:01:54,577
Most are so far away,
we know little about them.
25
00:01:57,217 --> 00:02:00,881
But there is one star
that's really close,
26
00:02:00,888 --> 00:02:04,085
and virtually everything
we know about stars,
27
00:02:04,091 --> 00:02:06,389
we've learned
from that neighbor.
28
00:02:06,393 --> 00:02:09,090
The sunlight from our sun
that bathes us
29
00:02:09,096 --> 00:02:12,532
and warms us every day
is nothing but starlight
30
00:02:12,533 --> 00:02:16,470
because our sun is nothing
but a star like all the rest.
31
00:02:18,072 --> 00:02:19,938
Narrator:
Seen from Earth,
32
00:02:19,940 --> 00:02:23,467
our sun is a blinding ball
of light.
33
00:02:23,477 --> 00:02:25,411
But take away the glare,
34
00:02:25,412 --> 00:02:28,973
and one of the most
powerful objects in the universe
35
00:02:28,983 --> 00:02:31,850
appears in our own backyard.
36
00:02:31,852 --> 00:02:36,016
It's a ball of superheated gas
that's been lighting
37
00:02:36,023 --> 00:02:39,960
our solar system
for 4.6 billion years
38
00:02:39,960 --> 00:02:43,828
and dominates all life on Earth.
39
00:02:43,831 --> 00:02:46,892
The Sun
is 93 million miles away.
40
00:02:46,900 --> 00:02:49,369
And that means,
in actuality, it's immense.
41
00:02:50,337 --> 00:02:53,500
You could fit a million Earths
inside the Sun.
42
00:02:59,313 --> 00:03:01,714
Narrator: It's nearly
a million miles in diameter,
43
00:03:01,715 --> 00:03:03,774
yet our sun is tiny
44
00:03:03,784 --> 00:03:06,776
compared to the really
big stars out there.
45
00:03:10,758 --> 00:03:15,719
Eta Carinae -- over five million
times larger than our sun.
46
00:03:20,434 --> 00:03:25,804
Betelgeuse -- 300 times larger
than Eta Carinae.
47
00:03:25,806 --> 00:03:30,175
If it was our sun, it would
reach as far out as Jupiter.
48
00:03:33,180 --> 00:03:37,981
And then there's this monster --
V.Y. Canis Majoris,
49
00:03:37,985 --> 00:03:40,852
the largest star
ever discovered.
50
00:03:40,854 --> 00:03:44,381
A billion times bigger
than our sun.
51
00:03:49,697 --> 00:03:55,067
Stars burn in different colors,
from red to yellow to blue.
52
00:03:55,069 --> 00:03:57,367
Some live alone.
53
00:03:59,073 --> 00:04:03,135
Others in pairs,
orbiting each other...
54
00:04:06,246 --> 00:04:10,183
...and coming together
in huge galaxies --
55
00:04:10,184 --> 00:04:14,610
entire cities
made up of billions of stars.
56
00:04:23,764 --> 00:04:26,859
Each star is a one of a kind.
57
00:04:28,802 --> 00:04:32,136
But they all start life
in the same way...
58
00:04:32,139 --> 00:04:36,372
As clouds of dust and gas
called nebulas.
59
00:04:41,715 --> 00:04:44,343
Many billions of miles across,
60
00:04:44,351 --> 00:04:48,322
they drift through space,
forming spectacular shapes.
61
00:04:51,258 --> 00:04:53,625
The Flame nebula.
62
00:04:57,498 --> 00:04:59,933
The Horsehead nebula.
63
00:05:02,903 --> 00:05:04,462
The Orion nebula.
64
00:05:04,471 --> 00:05:07,065
Each nebula is a star nursery
65
00:05:07,074 --> 00:05:11,341
where millions of new stars
are being born.
66
00:05:15,783 --> 00:05:19,048
But this birth
is hidden from view.
67
00:05:21,255 --> 00:05:23,587
Dr. Thaller: Some of the more
dramatic parts of a nebula
68
00:05:23,590 --> 00:05:25,581
are not
the beautiful glowing gas
69
00:05:25,592 --> 00:05:28,118
that you see but the dark parts.
70
00:05:28,128 --> 00:05:31,120
The dark parts have areas
of dense gas and dust,
71
00:05:31,131 --> 00:05:33,429
and that's where
the real action is happening
72
00:05:33,433 --> 00:05:34,798
in terms of star formation.
73
00:05:36,670 --> 00:05:39,105
The dust clouds are so thick,
74
00:05:39,106 --> 00:05:42,235
regular telescopes
can't see inside.
75
00:05:43,644 --> 00:05:46,773
Dr. Thaller: There's nothing
more important to us than stars,
76
00:05:46,780 --> 00:05:47,975
but for a long time,
77
00:05:47,981 --> 00:05:49,972
the way they formed
was a complete mystery.
78
00:05:49,983 --> 00:05:51,974
We couldn't observe them.
Imagine that.
79
00:05:51,985 --> 00:05:55,114
We could not see the first
moments of a star at all.
80
00:05:55,122 --> 00:06:00,253
Narrator: Until 2004 when NASA
launched the Spitzer space telescope.
81
00:06:00,260 --> 00:06:02,922
Man:
And liftoff.
82
00:06:02,930 --> 00:06:04,227
Seeking hidden secrets
83
00:06:04,231 --> 00:06:06,893
and the evolution
of our universe.
84
00:06:24,718 --> 00:06:27,585
Spitzer is
an infrared telescope.
85
00:06:27,588 --> 00:06:29,852
It only sees heat.
86
00:06:32,226 --> 00:06:35,355
Heat passes through
the thick dust of the nebulas,
87
00:06:35,362 --> 00:06:41,131
allowing Spitzer to see
new stars coming to life inside.
88
00:06:42,135 --> 00:06:44,627
These remarkable pictures
89
00:06:44,638 --> 00:06:47,801
capture the earliest moments
in a star's life
90
00:06:47,808 --> 00:06:51,870
as pockets of hydrogen gas
begin to heat up.
91
00:06:52,779 --> 00:06:56,682
Dr. Thaller: Any little bit
of gas and dust is glowing.
92
00:06:56,683 --> 00:07:00,847
Areas that were entirely dark
now became bright.
93
00:07:02,656 --> 00:07:04,750
We can actually see
the very earliest parts
94
00:07:04,758 --> 00:07:05,725
of star formation.
95
00:07:11,531 --> 00:07:16,628
All you need to make a star
is hydrogen, gravity, and time.
96
00:07:16,637 --> 00:07:23,475
Narrator: Gravity pulls the dust and
gas into a giant swirling vortex.
97
00:07:23,477 --> 00:07:25,969
Dr. Thaller:
Gravity brings matter together.
98
00:07:25,979 --> 00:07:27,845
And when you bring
matter together
99
00:07:27,848 --> 00:07:30,613
and you squeeze things
into smaller spaces,
100
00:07:30,617 --> 00:07:31,880
they necessarily heat up.
101
00:07:31,885 --> 00:07:33,512
It's a simple law of chemistry.
102
00:07:33,520 --> 00:07:36,649
You compress something,
you drive the temperature up.
103
00:07:37,958 --> 00:07:40,723
Narrator: Over hundreds
of thousands of years,
104
00:07:40,727 --> 00:07:45,597
the cloud gets thicker
and forms a giant spinning disk
105
00:07:45,599 --> 00:07:47,795
bigger than
our entire solar system.
106
00:07:47,801 --> 00:07:51,169
At its center,
gravity crushes the gas
107
00:07:51,171 --> 00:07:55,768
into a superdense,
super-hot ball.
108
00:07:55,776 --> 00:07:59,144
Pressure builds
until huge jets of gas
109
00:07:59,146 --> 00:08:00,773
burst out from the center.
110
00:08:04,651 --> 00:08:06,176
Dr. Thaller:
That really shows you
111
00:08:06,186 --> 00:08:09,156
how violent a process
star formation is.
112
00:08:11,325 --> 00:08:14,260
These jets
are many light-years across.
113
00:08:14,261 --> 00:08:17,561
Something is literally
accelerating material very fast
114
00:08:17,564 --> 00:08:19,498
across unimaginable distances.
115
00:08:23,971 --> 00:08:26,440
Narrator:
Gravity keeps the pressure on,
116
00:08:26,440 --> 00:08:28,909
sucking in gas
and dust particles
117
00:08:28,909 --> 00:08:33,210
that smash into each other,
generating more and more heat.
118
00:08:37,417 --> 00:08:40,079
Over the next
half a million years,
119
00:08:40,087 --> 00:08:44,547
the young star gets smaller,
brighter, and hotter.
120
00:08:44,558 --> 00:08:48,552
Temperatures at its core
reach 15 million degrees.
121
00:08:53,333 --> 00:08:55,995
Only at that
mind-boggling temperature
122
00:08:56,003 --> 00:08:59,166
can atoms of gas
begin to fuse together,
123
00:08:59,172 --> 00:09:02,164
releasing massive amounts
of energy.
124
00:09:19,192 --> 00:09:22,651
And just like that,
a star is born.
125
00:09:30,203 --> 00:09:33,104
It will shine for millions,
126
00:09:33,106 --> 00:09:34,540
even billions,
127
00:09:34,541 --> 00:09:39,445
or perhaps even trillions
of years.
128
00:09:58,999 --> 00:10:02,367
Narrator: Stars produce massive
amounts of heat and light
129
00:10:02,369 --> 00:10:04,133
over billions of years.
130
00:10:10,710 --> 00:10:13,680
But that takes fuel
and lots of it.
131
00:10:16,616 --> 00:10:18,948
Until the early 20th century,
132
00:10:18,952 --> 00:10:23,719
no one had any idea
what this fuel was.
133
00:10:23,723 --> 00:10:26,658
The greatest problem
facing physics
134
00:10:26,660 --> 00:10:28,492
at the turn
of the last century was,
135
00:10:28,495 --> 00:10:31,226
what drives the energy of stars?
136
00:10:31,231 --> 00:10:32,824
All you had to do
was look outside
137
00:10:32,833 --> 00:10:34,790
and realize
there was a huge gaping hole
138
00:10:34,801 --> 00:10:35,859
in our understanding.
139
00:10:37,604 --> 00:10:40,096
To solve the secret
of the stars,
140
00:10:40,107 --> 00:10:42,201
we needed a new engine.
141
00:10:42,209 --> 00:10:44,940
We needed
a fabulous source of energy
142
00:10:44,945 --> 00:10:48,404
that could drive a star
for billions of years at a time.
143
00:10:50,550 --> 00:10:53,713
Narrator: And it took a genius
to discover it --
144
00:10:53,720 --> 00:10:55,188
Albert Einstein.
145
00:10:57,724 --> 00:10:59,624
His theories proved
146
00:10:59,626 --> 00:11:04,257
that stars could tap
into the energy inside atoms.
147
00:11:07,868 --> 00:11:14,069
Kaku: The secret of the stars
is Einstein's equation e=mc2.
148
00:11:14,074 --> 00:11:17,408
In some sense, matter,
which makes up our body,
149
00:11:17,410 --> 00:11:21,574
is concentrated energy,
condensed energy --
150
00:11:21,581 --> 00:11:24,312
energy that has condensed
into the atoms
151
00:11:24,317 --> 00:11:25,910
that make up our universe.
152
00:11:30,023 --> 00:11:32,583
Narrator: Einstein showed
that it's possible
153
00:11:32,592 --> 00:11:37,029
to release this energy
by smashing atoms together.
154
00:11:38,098 --> 00:11:43,195
It's called fusion, the same
force that powers stars.
155
00:11:44,604 --> 00:11:47,505
It's astonishing to realize
that the physics
156
00:11:47,507 --> 00:11:51,205
of the very small
subatomic particle physics
157
00:11:51,211 --> 00:11:54,647
determines the structure
and nature of stars.
158
00:11:55,949 --> 00:11:57,815
Narrator:
From Einstein's theories,
159
00:11:57,817 --> 00:12:02,653
we learned how to release
the energy inside an atom.
160
00:12:02,656 --> 00:12:04,420
[explosion]
161
00:12:06,693 --> 00:12:09,628
Now science
is trying to simulate
162
00:12:09,629 --> 00:12:11,495
a star's energy source
163
00:12:11,498 --> 00:12:15,526
to control the power
of fusion in a lab.
164
00:12:25,045 --> 00:12:27,742
Inside this laboratory
near Oxford, England,
165
00:12:27,747 --> 00:12:30,341
there's an 80,000-pound machine.
166
00:12:30,350 --> 00:12:33,320
Every day,
Andy Kirk and his team
167
00:12:33,320 --> 00:12:36,051
transform it into a star...
168
00:12:36,056 --> 00:12:37,785
On Earth.
169
00:12:37,791 --> 00:12:40,749
Dr. Kirk: This machine
is called a tokamak.
170
00:12:40,760 --> 00:12:44,424
It's effectively
a large magnetic bottle --
171
00:12:44,431 --> 00:12:48,095
a cage to hold
a very hot plasma.
172
00:12:48,101 --> 00:12:51,366
We're able to re-create
the conditions within a star.
173
00:12:54,307 --> 00:12:55,775
Narrator:
Inside the tokamak,
174
00:12:55,775 --> 00:12:58,767
hydrogen atoms
naturally repel each other.
175
00:13:07,621 --> 00:13:10,090
To smash
hydrogen atoms together,
176
00:13:10,090 --> 00:13:14,721
the tokamak heats them to more
than 300 million degrees.
177
00:13:15,595 --> 00:13:18,155
At these temperatures,
the energized hydrogen atoms
178
00:13:18,164 --> 00:13:19,689
are moving so fast,
179
00:13:19,699 --> 00:13:22,293
they can't avoid smashing
into each other.
180
00:13:26,406 --> 00:13:29,671
If you heat it up,
heat is motion.
181
00:13:29,676 --> 00:13:31,906
And the motion of hot particles
182
00:13:31,911 --> 00:13:34,676
will be enough to overcome
the repulsive force.
183
00:13:43,690 --> 00:13:45,419
[alarm blaring]
184
00:13:45,425 --> 00:13:48,087
Woman: All personnel,
be prepared to leave.
185
00:13:48,094 --> 00:13:50,688
Come off the machine area.
186
00:13:52,232 --> 00:13:53,996
Narrator:
When everything goes right,
187
00:13:54,000 --> 00:13:58,335
the result is the single best
power plant in the universe --
188
00:13:58,338 --> 00:14:00,272
nuclear fusion.
189
00:14:01,474 --> 00:14:04,876
[electronic crackling]
190
00:14:10,784 --> 00:14:13,742
Traveling at 1,000 miles
a second,
191
00:14:13,753 --> 00:14:18,452
the hydrogen atoms smash
into each other and fuse...
192
00:14:20,527 --> 00:14:24,691
...creating a new element --
helium...
193
00:14:26,266 --> 00:14:30,499
...and a small amount
of pure energy.
194
00:14:34,774 --> 00:14:37,800
Kaku: The hydrogen gas weighs
slightly more than the helium.
195
00:14:37,811 --> 00:14:41,042
You lost mass
in the process of burning.
196
00:14:41,047 --> 00:14:43,880
That mass that you lost,
the missing mass,
197
00:14:43,883 --> 00:14:45,351
turns into energy.
198
00:14:47,487 --> 00:14:50,422
Narrator: The tokamak
can only maintain fusion
199
00:14:50,423 --> 00:14:52,551
for a fraction of a second.
200
00:14:56,563 --> 00:14:58,224
But inside a real star,
201
00:14:58,231 --> 00:15:01,963
fusion continues
for billions of years.
202
00:15:03,903 --> 00:15:07,396
The reason is simple -- size.
203
00:15:08,608 --> 00:15:12,135
Kaku: The engine
which drives a star is gravity.
204
00:15:12,145 --> 00:15:13,704
That's why stars are big.
205
00:15:13,713 --> 00:15:15,374
Stars are huge.
206
00:15:15,382 --> 00:15:19,478
You need that amount of gravity
in order to compress the star
207
00:15:19,486 --> 00:15:21,955
to create fantastic amounts
of heat
208
00:15:21,955 --> 00:15:25,448
sufficient to ignite
nuclear fusion.
209
00:15:30,830 --> 00:15:33,060
That is the secret of the stars.
210
00:15:33,066 --> 00:15:35,467
That's why stars shine.
211
00:15:39,038 --> 00:15:43,532
Narrator: Fusion at the core of a
star generates the explosive force
212
00:15:43,543 --> 00:15:48,447
of a billion nuclear bombs
every second.
213
00:15:48,448 --> 00:15:51,543
Kaku: A star is
a gigantic hydrogen bomb,
214
00:15:51,551 --> 00:15:53,918
so why doesn't it
simply blow apart?
215
00:15:53,920 --> 00:15:56,753
It's because gravity
is compressing the outer layers
216
00:15:56,756 --> 00:15:57,780
of the star.
217
00:16:04,564 --> 00:16:09,126
Narrator: Gravity and fusion
lock horns in an epic battle.
218
00:16:09,135 --> 00:16:11,763
Kaku: We have this constant
tension between gravity,
219
00:16:11,771 --> 00:16:15,298
which wants to crush a star
to smithereens,
220
00:16:15,308 --> 00:16:18,539
and, also, the energy released
by the fusion process,
221
00:16:18,545 --> 00:16:20,604
which wants
to blow the star apart.
222
00:16:21,648 --> 00:16:24,276
And that tension,
that balancing act,
223
00:16:24,284 --> 00:16:26,309
creates a star.
224
00:16:27,220 --> 00:16:29,655
Narrator:
This power struggle plays out
225
00:16:29,656 --> 00:16:32,091
over the entire life
of a star --
226
00:16:32,091 --> 00:16:36,722
two awesome forces of nature
in a dynamic standoff.
227
00:16:36,729 --> 00:16:41,394
As that battle rages, the star
blasts out light and heat
228
00:16:41,401 --> 00:16:45,963
but also something
far more destructive.
229
00:16:53,880 --> 00:16:57,942
Narrator: Each beam of starlight
makes an epic journey.
230
00:17:00,820 --> 00:17:04,916
Light travels
at 670 million miles an hour.
231
00:17:04,924 --> 00:17:07,416
A beam of light
could travel around the Earth
232
00:17:07,427 --> 00:17:10,089
seven times in one second.
233
00:17:10,096 --> 00:17:14,090
Nothing in the universe
moves faster.
234
00:17:14,100 --> 00:17:17,263
Yet most stars are so far away,
235
00:17:17,270 --> 00:17:20,501
their light takes hundreds,
thousands, millions,
236
00:17:20,507 --> 00:17:24,603
even billions of years
to reach us.
237
00:17:24,611 --> 00:17:26,375
So, when
the Hubble space telescope
238
00:17:26,379 --> 00:17:29,246
looks into the far corners
of our universe,
239
00:17:29,249 --> 00:17:34,813
it sees light that's been
traveling for billions of years.
240
00:17:36,089 --> 00:17:39,423
The light we see today
from Eta Carinae
241
00:17:39,425 --> 00:17:42,326
left that star
when our ancestors
242
00:17:42,328 --> 00:17:46,629
first farmed the land
8,000 years ago.
243
00:17:46,633 --> 00:17:48,692
Light from Betelgeuse
has been traveling
244
00:17:48,701 --> 00:17:53,662
since Columbus discovered
America 500 years ago.
245
00:17:55,441 --> 00:18:00,971
Even light from our own sun
takes eight minutes to reach us.
246
00:18:04,551 --> 00:18:08,818
But even before light starts
its journey through space,
247
00:18:08,821 --> 00:18:12,382
it's already been traveling
for thousands of years.
248
00:18:12,392 --> 00:18:16,295
When the Sun fuses hydrogen
into helium in its core,
249
00:18:16,296 --> 00:18:18,822
it creates a photon of light,
a particle of light.
250
00:18:20,800 --> 00:18:23,770
Narrator: That new ray of light
has a long way to go
251
00:18:23,770 --> 00:18:26,967
just to reach
the star's surface.
252
00:18:26,973 --> 00:18:29,670
Dr. Plait:
There's a whole star in its way.
253
00:18:29,676 --> 00:18:31,735
And so when the photon
is created,
254
00:18:31,744 --> 00:18:33,109
it doesn't get very far
255
00:18:33,112 --> 00:18:35,877
before it immediately slams
into another atom --
256
00:18:35,882 --> 00:18:38,374
another proton,
another neutron, something.
257
00:18:38,384 --> 00:18:41,718
It gets absorbed and then
shot off in another direction.
258
00:18:41,721 --> 00:18:45,316
And so it's sort of randomly
moving around inside of the Sun,
259
00:18:45,325 --> 00:18:47,020
and it has to work its way out.
260
00:18:49,529 --> 00:18:52,726
Narrator: For the photons,
it's a wild ride,
261
00:18:52,732 --> 00:18:56,293
smashing into atoms of gas
billions of times
262
00:18:56,302 --> 00:18:59,863
as they struggle to escape
from inside the star.
263
00:19:01,074 --> 00:19:03,202
Dr. Plait: What's funny
about this whole process
264
00:19:03,209 --> 00:19:07,510
is that it takes the photon
thousands and thousands of years
265
00:19:07,513 --> 00:19:10,278
to get from the core of the Sun
to the surface.
266
00:19:10,283 --> 00:19:12,183
And yet
once it hits the surface,
267
00:19:12,185 --> 00:19:15,086
it's only an eight-minute trip
from there to here.
268
00:19:17,523 --> 00:19:20,424
Narrator: Photons are the
source of light and heat,
269
00:19:20,426 --> 00:19:23,828
but they also cause something
far more destructive --
270
00:19:23,830 --> 00:19:26,322
the solar wind.
271
00:19:29,736 --> 00:19:31,329
As they reach the surface,
272
00:19:31,337 --> 00:19:35,137
photons heat up
the outer layers of the Sun...
273
00:19:38,478 --> 00:19:40,708
...sending it hurtling
around the star,
274
00:19:40,713 --> 00:19:44,650
creating extreme turbulence
and intense shock waves.
275
00:19:46,786 --> 00:19:51,087
It's so violent,
we can actually hear it.
276
00:19:51,090 --> 00:19:54,151
Picked up
by the orbiting SOHO satellite,
277
00:19:54,160 --> 00:19:57,596
this is the sound of the Sun.
278
00:19:57,597 --> 00:20:00,362
[crackling]
279
00:20:03,436 --> 00:20:08,431
The speeding gases also generate
powerful magnetic fields.
280
00:20:08,441 --> 00:20:10,307
As the star rotates,
281
00:20:10,309 --> 00:20:13,301
the fields clash
and burst through the surface.
282
00:20:17,016 --> 00:20:22,250
Giant magnetic loops
erupt into space.
283
00:20:22,255 --> 00:20:23,745
Some are so large,
284
00:20:23,756 --> 00:20:26,123
the Earth could pass
right through them
285
00:20:26,125 --> 00:20:28,924
with thousands of miles
to spare.
286
00:20:29,996 --> 00:20:33,455
They are spectacular,
and they are deadly,
287
00:20:33,466 --> 00:20:37,994
blasting a stream of electrical
particles deep into space.
288
00:20:40,807 --> 00:20:43,902
This is the solar wind.
289
00:20:45,411 --> 00:20:48,005
It can damage
spaceships and satellites,
290
00:20:48,014 --> 00:20:51,951
even put astronauts' lives
in jeopardy.
291
00:20:53,286 --> 00:20:57,280
To discover how the magnetic
loops trigger the solar wind,
292
00:20:57,290 --> 00:21:01,989
a team of scientists at CalTech
re-create the surface of a star
293
00:21:01,994 --> 00:21:03,826
right here on Earth.
294
00:21:03,830 --> 00:21:05,696
[speaking indistinctly]
295
00:21:05,698 --> 00:21:10,329
It's very exciting to be able
to create in a laboratory
296
00:21:10,336 --> 00:21:12,828
the same sort of physics
that are on the solar surface.
297
00:21:14,440 --> 00:21:16,636
We can't go there.
We can't even send probes there.
298
00:21:16,642 --> 00:21:19,475
But we can try to study
what's happening there.
299
00:21:24,350 --> 00:21:28,617
Narrator: An airless chamber
simulates the vacuum of space.
300
00:21:30,089 --> 00:21:32,251
An enormous electric current
301
00:21:32,258 --> 00:21:36,252
produces a pair
of man-made magnetic loops.
302
00:21:43,402 --> 00:21:44,494
Stenson:
The main difference
303
00:21:44,504 --> 00:21:45,903
between the plasma loops
we make in the lab
304
00:21:45,905 --> 00:21:47,236
and the ones
on the surface of the Sun
305
00:21:47,240 --> 00:21:48,674
is just their size.
306
00:21:48,674 --> 00:21:51,473
The ones we make in lab
are, you know, about this big,
307
00:21:51,477 --> 00:21:53,172
and the ones
on the surface of the Sun
308
00:21:53,179 --> 00:21:54,806
can be many times
the size of the Earth.
309
00:21:58,117 --> 00:21:59,881
Narrator:
Their experiment reveals
310
00:21:59,886 --> 00:22:02,753
that when magnetic
loops clash in the lab,
311
00:22:02,755 --> 00:22:05,122
they trigger a massive
burst of energy.
312
00:22:16,602 --> 00:22:20,835
When giant loops collide
on the surface of a star,
313
00:22:20,840 --> 00:22:24,333
the energy released
sends temperatures soaring
314
00:22:24,343 --> 00:22:27,836
from 10,000
to 10 million degrees.
315
00:22:29,949 --> 00:22:33,180
That extreme heat
triggers the solar wind,
316
00:22:33,186 --> 00:22:35,883
sending millions of tons
of particles
317
00:22:35,888 --> 00:22:38,983
streaming out into space.
318
00:22:47,233 --> 00:22:50,863
The bigger the star,
the more deadly the wind.
319
00:22:53,172 --> 00:22:55,971
If we were orbiting a star
like Eta Carinae
320
00:22:55,975 --> 00:22:57,101
at the same distance,
321
00:22:57,109 --> 00:23:00,670
it would be hell on earth,
quite literally.
322
00:23:00,680 --> 00:23:03,547
The amount of energy
blasting down on the Earth
323
00:23:03,549 --> 00:23:04,880
would strip away our atmosphere,
324
00:23:04,884 --> 00:23:07,080
boil our oceans,
melt the surface.
325
00:23:11,057 --> 00:23:15,824
Narrator: Understanding how stars
work could help us protect ourselves
326
00:23:15,828 --> 00:23:20,163
by predicting
their most destructive forces.
327
00:23:20,166 --> 00:23:22,567
But there's nothing we can do
328
00:23:22,568 --> 00:23:25,936
to protect ourselves
when a star dies.
329
00:23:28,074 --> 00:23:30,168
In its final moments,
330
00:23:30,176 --> 00:23:33,578
it annihilates
everything around it.
331
00:23:47,994 --> 00:23:49,689
Narrator:
From the moment of its birth,
332
00:23:49,695 --> 00:23:52,960
every star is destined to die.
333
00:23:53,833 --> 00:23:56,928
Its fuel will run out.
334
00:23:59,605 --> 00:24:03,337
Then gravity
will win the battle with fusion,
335
00:24:03,342 --> 00:24:07,575
triggering a chain of events
that will destroy the star.
336
00:24:17,657 --> 00:24:20,820
Our sun is no exception.
337
00:24:20,826 --> 00:24:24,990
Every second, it burns
through 600 million tons
338
00:24:24,997 --> 00:24:27,694
of the hydrogen
fueled in its core.
339
00:24:29,769 --> 00:24:33,637
At that rate,
the hydrogen will run out...
340
00:24:33,639 --> 00:24:36,074
In about seven billion years.
341
00:24:41,580 --> 00:24:43,878
As the hydrogen gets used up,
342
00:24:43,883 --> 00:24:47,046
it slows down the fusion
at the star's core.
343
00:24:47,053 --> 00:24:49,784
This gives gravity the edge.
344
00:24:49,789 --> 00:24:52,383
With less fusion
pushing outward,
345
00:24:52,391 --> 00:24:56,089
gravity crushes the star
in on itself.
346
00:24:56,095 --> 00:25:00,293
But fusion fights back,
heating the star's outer layers.
347
00:25:02,368 --> 00:25:05,030
Dr. Plait: When you heat up
a gas, it expands.
348
00:25:05,037 --> 00:25:07,802
And so the Sun
will actually expand up.
349
00:25:07,807 --> 00:25:10,538
Instead of being a million miles
across like it is now,
350
00:25:10,543 --> 00:25:15,276
it'll swell up until it's about
100 million miles across.
351
00:25:17,183 --> 00:25:21,279
Narrator:
Our sun will become a red giant.
352
00:25:22,755 --> 00:25:25,622
Dr. Plait:
Imagine a sunrise 7 billion A.D.
353
00:25:28,494 --> 00:25:30,656
It's not just
a little, yellow disk
354
00:25:30,663 --> 00:25:32,688
coming up all cheerful and nice.
355
00:25:32,698 --> 00:25:36,566
What you would see is a huge,
swollen, bloated, red disk
356
00:25:36,569 --> 00:25:38,435
slowly reaching up
over the horizon.
357
00:25:38,437 --> 00:25:41,134
And when the Sun
is fully up in the sky,
358
00:25:41,140 --> 00:25:43,302
it's blasting down heat
on the Earth.
359
00:25:43,309 --> 00:25:46,836
It would be like sticking your
head in an oven set to "broil."
360
00:25:52,451 --> 00:25:57,082
Narrator: Temperatures here on Earth
will reach thousands of degrees.
361
00:25:58,424 --> 00:26:01,257
Kaku: The oceans will boil,
the mountains will melt,
362
00:26:01,260 --> 00:26:05,163
and we'll have the last nice
day on the planet Earth.
363
00:26:09,602 --> 00:26:13,835
Narrator: Then the bloated star
will engulf the Earth.
364
00:26:25,284 --> 00:26:29,187
But the giant red star
is self-destructing.
365
00:26:30,556 --> 00:26:34,618
Its core becomes
dangerously unstable.
366
00:26:37,129 --> 00:26:39,791
With no hydrogen left
to fuel it,
367
00:26:39,799 --> 00:26:44,361
the star begins burning helium
and fusing it into carbon.
368
00:26:44,370 --> 00:26:48,603
The star is now destroying
itself from the inside out,
369
00:26:48,607 --> 00:26:51,133
blasting violent surges
of energy
370
00:26:51,143 --> 00:26:54,044
from its core to its surface.
371
00:26:56,082 --> 00:27:00,644
These energy waves blow away
the star's outer layers.
372
00:27:10,296 --> 00:27:13,197
Slowly, it disintegrates.
373
00:27:18,737 --> 00:27:21,707
The star is dead.
374
00:27:22,908 --> 00:27:27,436
All that remains
is an intensely hot, dense core.
375
00:27:28,414 --> 00:27:31,907
The red giant
has become a white dwarf.
376
00:27:33,552 --> 00:27:37,420
Kaku: By the time a star
reaches the white-dwarf stage,
377
00:27:37,423 --> 00:27:39,755
the fusion process has stopped.
378
00:27:39,758 --> 00:27:42,887
The engine
has finally come to rest.
379
00:27:44,730 --> 00:27:47,893
Narrator: Our sun will end
its life as a white dwarf
380
00:27:47,900 --> 00:27:52,861
no larger than the Earth
but a million times denser.
381
00:27:52,872 --> 00:27:55,830
Dr. Plait: A white dwarf
is a pretty amazing object.
382
00:27:55,841 --> 00:27:57,104
It's incredibly dense.
383
00:27:57,109 --> 00:27:58,201
If you could take
384
00:27:58,210 --> 00:28:00,542
a sugar-cube-sized chunk
of white dwarf
385
00:28:00,546 --> 00:28:02,139
and put it on the surface
of the Earth,
386
00:28:02,148 --> 00:28:03,240
it would be so dense,
387
00:28:03,249 --> 00:28:04,910
it would fall
right through the ground.
388
00:28:08,854 --> 00:28:10,879
Narrator:
At the heart of a white dwarf,
389
00:28:10,890 --> 00:28:13,951
astronomers believe
there's a giant crystal
390
00:28:13,959 --> 00:28:15,893
of pure carbon.
391
00:28:17,396 --> 00:28:21,856
A cosmic diamond
thousands of miles across.
392
00:28:25,337 --> 00:28:27,305
Dr. Thaller: The idea
that the Sun will become
393
00:28:27,306 --> 00:28:30,401
this sort of cool, dark lump
of cinder material
394
00:28:30,409 --> 00:28:31,570
is kind of sad.
395
00:28:31,577 --> 00:28:33,636
But that really will be
396
00:28:33,646 --> 00:28:36,581
sort of a trillion-trillion-
trillion-karat diamond.
397
00:28:36,582 --> 00:28:38,448
Think of that --
a diamond in the sky.
398
00:28:45,858 --> 00:28:48,225
Narrator:
But stars can create something
399
00:28:48,227 --> 00:28:51,492
much more precious
than a massive diamond.
400
00:28:54,700 --> 00:28:57,863
When stars
much bigger than our sun die,
401
00:28:57,870 --> 00:29:01,170
their death
is much more violent.
402
00:29:01,173 --> 00:29:07,169
But in dying, they create
the building blocks of life.
403
00:29:15,287 --> 00:29:20,384
Giant stars live fast,
burn bright, and die hard.
404
00:29:21,794 --> 00:29:25,424
But from their destruction
comes life.
405
00:29:27,366 --> 00:29:29,425
The death of massive stars
406
00:29:29,435 --> 00:29:32,564
creates the building blocks
of the universe...
407
00:29:32,571 --> 00:29:35,973
The seeds of life itself.
408
00:29:40,212 --> 00:29:43,011
Less than 600 light-years
from Earth,
409
00:29:43,015 --> 00:29:46,542
the monster star Betelgeuse
is near death --
410
00:29:46,552 --> 00:29:48,816
well, in space years.
411
00:29:48,821 --> 00:29:50,448
It's younger than our sun --
412
00:29:50,456 --> 00:29:53,323
millions,
not billions of years old.
413
00:29:53,325 --> 00:29:57,489
But the fusion at its core
is far more intense.
414
00:29:57,496 --> 00:30:01,194
Dr. Plait: Betelgeuse is a different
beast from the Sun entirely.
415
00:30:01,200 --> 00:30:03,396
It's a red supergiant.
416
00:30:03,402 --> 00:30:06,997
And the reason is because
Betelgeuse is more massive.
417
00:30:07,006 --> 00:30:09,668
It has 20 times
the mass of the Sun,
418
00:30:09,675 --> 00:30:12,337
and that means
what's going on in its core
419
00:30:12,344 --> 00:30:15,143
is very different than
what's going on in the Sun's.
420
00:30:18,617 --> 00:30:21,848
Narrator: Massive stars generate
pressures and temperatures
421
00:30:21,854 --> 00:30:25,381
greater than anywhere else
in the universe.
422
00:30:32,398 --> 00:30:35,561
The gravity of Betelgeuse
is so powerful,
423
00:30:35,567 --> 00:30:39,060
it can smash together
bigger and bigger atoms.
424
00:30:43,208 --> 00:30:47,042
The core of a massive star
is a kind of factory,
425
00:30:47,046 --> 00:30:50,471
manufacturing heavier
and heavier elements...
426
00:30:52,251 --> 00:30:56,745
...which is what also leads
to the star's destruction.
427
00:30:58,223 --> 00:31:02,785
Once it makes the element iron,
the star is doomed.
428
00:31:05,764 --> 00:31:08,199
In the world of science fiction,
there are many ideas
429
00:31:08,200 --> 00:31:10,726
about what a star-killer
machine might be like.
430
00:31:10,736 --> 00:31:13,933
Strangely enough, it's as run of
the mill as something as iron.
431
00:31:13,939 --> 00:31:15,168
To a star,
432
00:31:15,174 --> 00:31:17,575
iron is the most dangerous
element in the universe.
433
00:31:17,576 --> 00:31:18,543
It's poison.
434
00:31:22,815 --> 00:31:25,944
Narrator:
Iron absorbs energy.
435
00:31:26,952 --> 00:31:30,252
From the moment
a massive star creates iron,
436
00:31:30,255 --> 00:31:33,020
it has only seconds to live.
437
00:31:34,927 --> 00:31:38,386
The star is trying to dump
energy into that iron ball
438
00:31:38,397 --> 00:31:40,923
and trying to make it fuse,
but it can't.
439
00:31:40,933 --> 00:31:43,868
And so that ball
is robbing the star of energy,
440
00:31:43,869 --> 00:31:47,533
and it's that energy that
is supporting the star itself.
441
00:31:47,539 --> 00:31:50,873
So, as soon as that iron starts
to be created in the core,
442
00:31:50,876 --> 00:31:53,470
the star has written
its own death sentence.
443
00:31:53,479 --> 00:31:56,710
Narrator: The battle between
gravity trying to crush the star
444
00:31:56,715 --> 00:32:00,276
and fusion trying
to blow it apart is over.
445
00:32:00,285 --> 00:32:03,255
With iron,
fusion hits a dead end.
446
00:32:03,255 --> 00:32:06,088
Gravity always wins.
447
00:32:10,329 --> 00:32:12,821
Dr. Plait:
The iron core collapses.
448
00:32:12,831 --> 00:32:14,959
The outer layers of the star
slam down into it,
449
00:32:14,967 --> 00:32:16,901
and a huge explosion
is generated.
450
00:32:23,876 --> 00:32:27,335
It's the single most
violent event in the universe --
451
00:32:27,346 --> 00:32:28,609
a supernova.
452
00:32:28,614 --> 00:32:30,912
[explosion]
453
00:32:30,916 --> 00:32:32,816
Narrator:
In just a few seconds,
454
00:32:32,818 --> 00:32:36,812
supernovas create more energy
than our sun ever will.
455
00:32:39,091 --> 00:32:42,527
Dr. Thaller: Within a couple seconds
after beginning to make iron,
456
00:32:42,528 --> 00:32:44,462
the star explodes
in a supernova.
457
00:32:44,463 --> 00:32:45,760
So, think about that
458
00:32:45,764 --> 00:32:47,858
when you're holding
one of your iron frying pans.
459
00:32:47,866 --> 00:32:51,097
The iron killed a star
in just a few seconds --
460
00:32:51,103 --> 00:32:53,094
dangerous stuff.
461
00:32:58,610 --> 00:33:03,776
Narrator: Telescopes around the world
scan the skies for supernovas.
462
00:33:03,782 --> 00:33:07,753
In 1987,
a brilliant light appeared
463
00:33:07,753 --> 00:33:13,556
in a nearby galaxy
170,000 light-years away.
464
00:33:14,760 --> 00:33:16,592
These pictures record the events
465
00:33:16,595 --> 00:33:20,031
following the death
of a massive star
466
00:33:20,032 --> 00:33:23,195
as a fireball
trillions of miles wide
467
00:33:23,202 --> 00:33:25,796
hurtles out into space.
468
00:33:32,911 --> 00:33:36,347
But there's no record
of the actual moment of death
469
00:33:36,348 --> 00:33:40,080
when the star
first ripped itself apart.
470
00:33:48,694 --> 00:33:50,890
The only way to know
what happens
471
00:33:50,896 --> 00:33:53,661
inside a massive star
when it explodes
472
00:33:53,665 --> 00:33:56,362
is to make our own supernova.
473
00:33:57,402 --> 00:33:59,461
What's amazing
when these stars explode
474
00:33:59,471 --> 00:34:01,405
is that they almost
turn inside out.
475
00:34:01,406 --> 00:34:03,500
[alarm blaring]
476
00:34:03,509 --> 00:34:06,535
Narrator: Here in this lab
in Rochester, New York,
477
00:34:06,545 --> 00:34:11,381
scientists are making
a supernova with a giant laser.
478
00:34:13,151 --> 00:34:16,451
Drake: Telescopes can't see
inside the dying star.
479
00:34:16,455 --> 00:34:18,981
With this laser,
we can detect the processes
480
00:34:18,991 --> 00:34:21,756
that occur as the star explodes.
481
00:34:21,760 --> 00:34:23,489
Working with these tools
482
00:34:23,495 --> 00:34:26,658
is the most exciting thing
I can imagine doing.
483
00:34:28,133 --> 00:34:31,228
Narrator: This massive machine
amplifies the power
484
00:34:31,236 --> 00:34:35,639
of a single laser beam
1,000 million million times.
485
00:34:35,641 --> 00:34:40,340
That's enough power to supply
30 cities the size of Detroit.
486
00:34:40,345 --> 00:34:43,007
And all that energy
will be directed
487
00:34:43,015 --> 00:34:46,110
toward an area
the size of a pinhead.
488
00:34:46,118 --> 00:34:51,079
Look at this tiny target
as a star's core.
489
00:34:51,089 --> 00:34:53,023
The laser simulates
490
00:34:53,025 --> 00:34:55,289
the most violent explosion
in the universe.
491
00:34:55,294 --> 00:34:58,662
This would not be a safe place
to be when the laser was fired.
492
00:34:59,798 --> 00:35:02,290
If a human were struck
by all these laser beams,
493
00:35:02,301 --> 00:35:03,735
they would drill a hole
right through them.
494
00:35:05,671 --> 00:35:08,106
Now going to closed access
in the laser bay.
495
00:35:08,106 --> 00:35:10,598
Main doors locked.
[speaks indistinctly]
496
00:35:11,843 --> 00:35:13,208
Final preparations are complete.
497
00:35:14,446 --> 00:35:21,148
5...4...3...2...1
498
00:35:26,725 --> 00:35:29,592
Narrator: The target
is vaporized by the laser.
499
00:35:33,298 --> 00:35:37,633
The explosion lasts
just 1l100,000 of a second.
500
00:35:37,636 --> 00:35:39,229
But a high-speed camera
501
00:35:39,237 --> 00:35:42,366
captures the shock wave
expanding outwards.
502
00:35:42,374 --> 00:35:45,173
Some of the inner material
comes out
503
00:35:45,177 --> 00:35:47,271
and trades places
with the outer material,
504
00:35:47,279 --> 00:35:48,474
and that turning inside out
505
00:35:48,480 --> 00:35:51,279
is just what happens
in a stellar explosion.
506
00:35:55,921 --> 00:35:59,585
Narrator: Material
from deep inside a star's core
507
00:35:59,591 --> 00:36:03,391
surfs the shock wave
out into space.
508
00:36:03,395 --> 00:36:07,127
In the extreme heat and turmoil
of the explosion,
509
00:36:07,132 --> 00:36:09,931
heavier elements are forged.
510
00:36:13,372 --> 00:36:17,331
Among them,
gold, silver, and platinum.
511
00:36:17,342 --> 00:36:20,835
And because there's so little
time for the elements to form,
512
00:36:20,846 --> 00:36:25,079
they are the rarest and most
valuable in the universe.
513
00:36:25,083 --> 00:36:27,814
Drake: Silver, gold,
everything else are created
514
00:36:27,819 --> 00:36:31,153
by the explosion of the star,
by the immense energy released,
515
00:36:31,156 --> 00:36:32,590
and that's how they come to us.
516
00:36:36,828 --> 00:36:40,696
Narrator: But even after the
universe's most violent explosion,
517
00:36:40,699 --> 00:36:43,498
there's something left behind.
518
00:36:43,502 --> 00:36:45,698
Kaku:
We scientists used to believe
519
00:36:45,704 --> 00:36:48,401
that after
a supernova explosion,
520
00:36:48,407 --> 00:36:50,899
a star would literally
blow itself to bits,
521
00:36:50,909 --> 00:36:52,741
and there'd be nothing left.
522
00:36:52,744 --> 00:36:54,303
Well, we were wrong.
523
00:36:54,312 --> 00:36:58,283
There's a corpse -- a corpse
of a supernova explosion.
524
00:36:58,283 --> 00:37:01,548
Some of the most exotic matter
known to science
525
00:37:01,553 --> 00:37:05,786
called a neutron star --
solid nucleonic matter,
526
00:37:05,791 --> 00:37:10,695
the most fantastic state
of matter in the universe.
527
00:37:13,365 --> 00:37:18,201
Narrator: The superdense core
is now a neutron star.
528
00:37:19,838 --> 00:37:24,799
It's around 20 miles across
and unbelievably heavy.
529
00:37:26,511 --> 00:37:28,843
Dr. Plait:
It's incredibly dense.
530
00:37:28,847 --> 00:37:30,144
Just a cubic centimeter,
531
00:37:30,148 --> 00:37:33,209
just the size of a sugar cube
of neutron-star material
532
00:37:33,218 --> 00:37:35,653
would weigh as much
as all the cars
533
00:37:35,654 --> 00:37:37,918
in the United States
of America combined.
534
00:37:41,827 --> 00:37:43,090
Narrator:
The dying star
535
00:37:43,095 --> 00:37:45,757
doesn't just leave the corpse
of a neutron star.
536
00:37:45,764 --> 00:37:50,258
It blasts the new elements
far out into space.
537
00:37:51,369 --> 00:37:54,430
These clouds
contain the building blocks
538
00:37:54,439 --> 00:37:55,838
of the universe.
539
00:37:55,841 --> 00:38:01,211
Everything we know and love
is built from this stardust.
540
00:38:05,250 --> 00:38:10,313
Kaku: Only a supernova has enough
energy to fuse these elements,
541
00:38:10,322 --> 00:38:13,019
which are so essential for life.
542
00:38:13,024 --> 00:38:15,550
Without supernovae,
there's no life.
543
00:38:15,560 --> 00:38:17,722
There's no you,
and there's no me.
544
00:38:19,064 --> 00:38:21,294
Narrator:
When massive stars die...
545
00:38:21,299 --> 00:38:23,427
[explosion]
546
00:38:23,435 --> 00:38:27,531
...they seed the universe
with stardust...
547
00:38:37,482 --> 00:38:40,281
...full of elements
like hydrogen...
548
00:38:40,285 --> 00:38:41,844
carbon...
549
00:38:41,853 --> 00:38:43,321
oxygen...
550
00:38:43,321 --> 00:38:44,846
silicon...
551
00:38:44,856 --> 00:38:46,585
and iron.
552
00:38:49,761 --> 00:38:53,220
The raw materials
to build new stars,
553
00:38:53,231 --> 00:38:58,465
solar systems, planets,
and, of course, us.
554
00:39:00,539 --> 00:39:03,065
Everything we see around us
555
00:39:03,074 --> 00:39:07,705
once blasted out
from the core of a star.
556
00:39:07,712 --> 00:39:10,113
Krauss:
You may wonder what stardust is.
557
00:39:10,115 --> 00:39:13,642
Well, you're stardust
because every atom in your body
558
00:39:13,652 --> 00:39:16,781
was produced
inside the fiery core of a star.
559
00:39:17,789 --> 00:39:21,623
The atoms in your left hand
may come from a different star
560
00:39:21,626 --> 00:39:23,253
from the atoms
in your right hand,
561
00:39:23,261 --> 00:39:26,822
but you are literally
a star child.
562
00:39:32,437 --> 00:39:35,896
Narrator: Long-dead stars
provided the stardust
563
00:39:35,907 --> 00:39:39,002
to create our solar system,
the planets,
564
00:39:39,010 --> 00:39:40,774
and everything on them.
565
00:39:46,117 --> 00:39:48,586
Dr. Thaller: So, you're made of
carbon, you're made of oxygen.
566
00:39:48,587 --> 00:39:49,952
There's iron in your blood.
567
00:39:49,955 --> 00:39:52,117
All of those things
had to be generated
568
00:39:52,123 --> 00:39:53,648
inside the core of a star.
569
00:39:53,658 --> 00:39:55,717
There's no other way
to get them.
570
00:39:55,727 --> 00:39:58,788
So, when you think about
star stuff, look around you.
571
00:39:58,797 --> 00:40:00,128
Everything that you're made of,
572
00:40:00,131 --> 00:40:01,997
everything in the world
around you is made of
573
00:40:02,000 --> 00:40:03,627
had to come
from the belly of a star
574
00:40:03,635 --> 00:40:05,194
that blew up a long time ago.
575
00:40:07,973 --> 00:40:11,432
Narrator: Even the atoms
in our own sun are recycled.
576
00:40:12,911 --> 00:40:15,073
They're third
or fourth generation --
577
00:40:15,080 --> 00:40:20,951
leftover debris shot into space
by dying stars a long time ago.
578
00:40:22,387 --> 00:40:24,856
Kaku:
Our sun is our stepmother.
579
00:40:24,856 --> 00:40:29,089
Our true mother died
in a supernova explosion
580
00:40:29,094 --> 00:40:32,792
to give birth to the elements
which made up our body.
581
00:40:32,797 --> 00:40:35,596
But how come the poets
and the songwriters,
582
00:40:35,600 --> 00:40:38,399
how come they don't write
poems to our true mother?
583
00:40:38,403 --> 00:40:40,963
It's perhaps they don't
understand physics
584
00:40:40,972 --> 00:40:42,906
and the laws
of stellar evolution.
585
00:40:44,943 --> 00:40:48,038
Narrator:
We live in an age of stars.
586
00:40:48,046 --> 00:40:51,846
But it will come to an end.
587
00:40:51,850 --> 00:40:56,048
There's only so much hydrogen
in the universe.
588
00:40:56,054 --> 00:41:00,116
Trillions of years from now,
it'll all be used up.
589
00:41:01,359 --> 00:41:03,828
And when there's
no hydrogen left,
590
00:41:03,828 --> 00:41:06,729
there'll be no new stars.
591
00:41:06,731 --> 00:41:11,498
Kaku: We live in a very brief period
in the history of the universe.
592
00:41:11,503 --> 00:41:15,201
Well, we still have stars
illuminating the sky,
593
00:41:15,206 --> 00:41:17,607
stars creating life
as we know it,
594
00:41:17,609 --> 00:41:19,441
but it's not gonna last forever.
595
00:41:20,979 --> 00:41:24,438
Sooner or later, the stars
will begin to blink out.
596
00:41:24,449 --> 00:41:27,680
Narrator: First,
the massive stars will burn out,
597
00:41:27,686 --> 00:41:31,020
then midsized stars
like our sun,
598
00:41:31,022 --> 00:41:33,753
leaving only the smallest.
599
00:41:33,758 --> 00:41:38,719
Trillions of years later,
they, too, will fade away.
600
00:41:39,664 --> 00:41:42,759
Slowly, inexorably,
601
00:41:42,767 --> 00:41:45,259
the universe
will get colder and darker
602
00:41:45,270 --> 00:41:48,797
until the last star burns out
603
00:41:48,807 --> 00:41:54,109
and the universe
becomes dark once again.
604
00:41:54,112 --> 00:41:57,673
Narrator:
The age of stars will be over.
605
00:41:57,682 --> 00:42:00,344
Honestly, the future of
the universe looks kind of grim,
606
00:42:00,352 --> 00:42:02,514
but you can take
something positive out of that.
607
00:42:02,520 --> 00:42:04,386
This is the best time
to be alive.
608
00:42:04,389 --> 00:42:07,791
This is the time where life
can flourish, stars can form.
609
00:42:07,792 --> 00:42:10,420
We are in the golden age
of the universe right now.
610
00:42:11,830 --> 00:42:15,960
Dr. Plait: We live in a season for
life in the universe, if you will,
611
00:42:15,967 --> 00:42:18,493
that lasts
for a few billion years.
612
00:42:18,503 --> 00:42:20,096
And that makes me, at least,
613
00:42:20,105 --> 00:42:22,403
appreciate the way
things are right now
614
00:42:22,407 --> 00:42:24,603
because they weren't
always that way,
615
00:42:24,609 --> 00:42:26,373
and they won't always be.
616
00:42:26,378 --> 00:42:28,574
Kaku:
We live in the stage
617
00:42:28,580 --> 00:42:32,039
where stars glow
and illuminate the night sky,
618
00:42:32,050 --> 00:42:34,883
when stars create life
as we know it.
619
00:42:34,886 --> 00:42:38,413
We live in the best
of all stages of the universe.
620
00:42:43,428 --> 00:42:48,161
Narrator: For now, stars will
continue to shape our universe,
621
00:42:48,166 --> 00:42:51,761
generating the building blocks
of new worlds,
622
00:42:51,770 --> 00:42:58,039
creating new stars and filling
the darkness with light.