Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated:
1
00:00:06,800 --> 00:00:09,870
Neutron stars.
2
00:00:09,870 --> 00:00:11,940
Super heavy, super dense.
3
00:00:11,940 --> 00:00:13,340
Extreme.
4
00:00:13,340 --> 00:00:17,580
Gravitational, magnetic, hot.
5
00:00:17,580 --> 00:00:19,250
Scary.
6
00:00:19,250 --> 00:00:22,220
They destroy planets.
7
00:00:22,220 --> 00:00:24,990
They can even destroy stars.
8
00:00:24,990 --> 00:00:27,390
A cosmic conundrum.
9
00:00:27,390 --> 00:00:30,290
They're very, very massive,
10
00:00:30,290 --> 00:00:32,230
but they're also
really, really small.
11
00:00:32,230 --> 00:00:34,560
Tiny cosmic super powers
12
00:00:34,570 --> 00:00:39,840
long overshadowed by black holes...
Until now.
13
00:00:39,840 --> 00:00:41,940
Neutron stars have
been thrust very much
14
00:00:41,940 --> 00:00:44,410
to the forefront of
modern astrophysics.
15
00:00:44,410 --> 00:00:47,780
The world's astronomers know
that something is happening.
16
00:00:47,780 --> 00:00:50,780
Something's up, it's new,
and it's different.
17
00:00:50,780 --> 00:00:54,850
Neutron stars are
the most interesting
18
00:00:54,850 --> 00:00:58,220
astrophysical object
in the universe.
19
00:00:58,220 --> 00:01:00,890
Now firmly in the limelight,
20
00:01:00,890 --> 00:01:06,030
neutron stars, creators of
our most precious elements
21
00:01:06,030 --> 00:01:07,830
and life itself.
22
00:01:07,830 --> 00:01:10,830
Captions by vitac...
www.vitac.com
23
00:01:10,830 --> 00:01:13,870
captions paid for by
discovery communications
24
00:01:26,180 --> 00:01:29,920
130 million
light years form earth,
25
00:01:29,920 --> 00:01:34,860
a galaxy called
"NGC-4993."
26
00:01:34,860 --> 00:01:39,630
Two dead stars trapped in
a rapidly diminishing spiral.
27
00:01:46,200 --> 00:01:49,600
It's like listening to the
ringing of the cosmos itself.
28
00:01:49,610 --> 00:01:51,710
The sound of that collision,
if you will,
29
00:01:51,710 --> 00:01:56,240
imprinted on the fabric
of space and time itself.
30
00:01:56,250 --> 00:02:01,880
Livingston, Louisiana,
the advanced LiGO observatory.
31
00:02:01,890 --> 00:02:04,890
Its mission...
To detect gravitational waves
32
00:02:04,890 --> 00:02:06,520
generated in space.
33
00:02:08,790 --> 00:02:12,290
A gravitational wave is
a distortion of space time
34
00:02:12,300 --> 00:02:13,700
that's caused by, usually,
35
00:02:13,700 --> 00:02:17,700
some kind of very traumatic
gravitational event.
36
00:02:17,700 --> 00:02:20,400
Events such as a supernova,
37
00:02:20,400 --> 00:02:23,940
or the collision of black holes,
or massive stars.
38
00:02:25,780 --> 00:02:31,150
2015... LiGO makes history
by detecting gravitational waves
39
00:02:31,150 --> 00:02:32,710
for the first time,
40
00:02:32,720 --> 00:02:37,050
100 years after
Einstein's prediction.
41
00:02:37,050 --> 00:02:42,160
It's the signature of
the crash of black holes.
42
00:02:42,160 --> 00:02:44,230
It's almost like
listening to the sound
43
00:02:44,230 --> 00:02:47,400
of a distant car crash
that you didn't witness.
44
00:02:47,400 --> 00:02:49,260
But you're so clever,
45
00:02:49,270 --> 00:02:52,530
and the sound of this car crash
is such a unique signature,
46
00:02:52,540 --> 00:02:55,270
that you are able to use
your computers to model
47
00:02:55,270 --> 00:03:00,240
exactly the type of cars that
must have collided together.
48
00:03:00,240 --> 00:03:06,380
In 2017, LiGO picks up a
different kind of signal.
49
00:03:06,380 --> 00:03:09,020
The unfolding of
the August 2017 event
50
00:03:09,020 --> 00:03:11,690
was nothing short
of extraordinary.
51
00:03:11,690 --> 00:03:15,190
So, the signal comes in,
and the signal is strange.
52
00:03:15,190 --> 00:03:18,090
It has a long-lasting signal.
53
00:03:18,100 --> 00:03:19,630
It's over 100 seconds.
54
00:03:19,630 --> 00:03:22,530
Less than two seconds later,
a gamma-ray telescope
55
00:03:22,530 --> 00:03:25,100
detected a flash of gamma rays
56
00:03:25,100 --> 00:03:27,540
from that same part of the sky.
57
00:03:27,540 --> 00:03:30,670
And very quickly,
the world's astronomers
58
00:03:30,670 --> 00:03:32,610
know that something
is happening.
59
00:03:32,610 --> 00:03:35,640
Something's up, it's new,
and it's different.
60
00:03:38,720 --> 00:03:42,080
This combination of
a long gravitational wave signal
61
00:03:42,090 --> 00:03:46,290
and a blaze of gamma rays...
62
00:03:46,290 --> 00:03:48,790
Acts as a beacon
for astronomers.
63
00:03:51,460 --> 00:03:53,260
When they saw this event,
64
00:03:53,260 --> 00:03:55,400
they sent out a worldwide alert
65
00:03:55,400 --> 00:03:57,630
to astronomers
across the globe, saying,
66
00:03:57,630 --> 00:04:00,640
"hey, we saw
something interesting,
67
00:04:00,640 --> 00:04:03,410
and it came from
a particular patch of sky.
68
00:04:03,410 --> 00:04:05,470
Then, all the chatter started
69
00:04:05,480 --> 00:04:07,540
amongst the
astronomical community,
70
00:04:07,540 --> 00:04:09,850
and everyone starting
pointing their telescopes
71
00:04:09,850 --> 00:04:12,910
at this one part of the sky.
72
00:04:12,920 --> 00:04:15,480
Within hours,
thousands of astronomers
73
00:04:15,490 --> 00:04:18,620
and physicists across the globe
are frantically
74
00:04:18,620 --> 00:04:22,790
collecting data
on this mysterious event.
75
00:04:22,790 --> 00:04:24,960
There is not just
the gravitational waves,
76
00:04:24,960 --> 00:04:26,660
there is not just
the gamma rays.
77
00:04:26,660 --> 00:04:28,960
There's a visible light,
there's infrared light,
78
00:04:28,970 --> 00:04:30,670
there's ultraviolet light.
79
00:04:30,670 --> 00:04:33,970
And all these signals together
tell us a story.
80
00:04:33,970 --> 00:04:36,140
And this was the very first time
81
00:04:36,140 --> 00:04:38,810
we've seen these two
multiple messengers at once...
82
00:04:38,810 --> 00:04:41,380
Gravitational waves
and regular light.
83
00:04:41,380 --> 00:04:44,380
So, that was a groundbreaking
moment for astronomy.
84
00:04:48,050 --> 00:04:49,750
Scientists realize
85
00:04:49,750 --> 00:04:52,850
this isn't another
black-hole collision.
86
00:04:52,860 --> 00:04:55,790
This is something different.
87
00:04:55,790 --> 00:04:58,360
When you see an explosion
in the universe,
88
00:04:58,360 --> 00:05:00,760
there aren't exactly
a lot of candidates.
89
00:05:00,760 --> 00:05:04,030
There's not a lot of things
in the universe that blow up.
90
00:05:06,240 --> 00:05:10,010
But the length of
the signal is the smoking gun.
91
00:05:10,010 --> 00:05:13,210
The collision
of two black holes was quick.
92
00:05:13,210 --> 00:05:19,180
This one was the longer,
slower, death end-spiral
93
00:05:19,180 --> 00:05:21,350
of two neutron stars.
94
00:05:21,350 --> 00:05:25,190
Spiraling in,
closer and closer, speeding up.
95
00:05:25,190 --> 00:05:26,860
And then, when they
finally collide,
96
00:05:26,860 --> 00:05:29,360
when they finally touch,
releasing a tremendous
97
00:05:29,360 --> 00:05:32,290
amount of energy
into the surrounding system.
98
00:05:34,560 --> 00:05:37,470
The collision
throws up huge clouds of matter,
99
00:05:37,470 --> 00:05:40,740
which may have slowed down
the light very slightly.
100
00:05:40,740 --> 00:05:43,000
The light
and gravitational waves
101
00:05:43,010 --> 00:05:46,340
travel for 130 million years,
102
00:05:46,340 --> 00:05:50,780
arriving at earth
almost simultaneously.
103
00:05:50,780 --> 00:05:55,320
It's the first time astronomers
see neutron stars collide.
104
00:05:55,320 --> 00:05:57,920
They call it a "kilonova."
105
00:05:57,920 --> 00:06:00,490
And this spectacular
cosmic event
106
00:06:00,490 --> 00:06:03,220
doesn't just release energy.
107
00:06:03,230 --> 00:06:05,490
The aftermath of this
neutron-star collision,
108
00:06:05,500 --> 00:06:08,560
this kilonova, created
a tremendous amount of debris,
109
00:06:08,570 --> 00:06:10,570
which blasted out into space.
110
00:06:10,570 --> 00:06:12,570
And this may finally
have provided us
111
00:06:12,570 --> 00:06:15,170
the evidence of where
some very special
112
00:06:15,170 --> 00:06:17,440
heavy elements are created.
113
00:06:17,440 --> 00:06:22,380
Through the destruction of
a neutron star comes the seeds
114
00:06:22,380 --> 00:06:25,480
for the essential ingredients
of life itself.
115
00:06:25,480 --> 00:06:29,080
We breathe oxygen
molecules... O2.
116
00:06:29,090 --> 00:06:31,220
Water is hydrogen and oxygen.
117
00:06:31,220 --> 00:06:34,690
Most of our body is made up
of carbon compounds
118
00:06:34,690 --> 00:06:36,590
that include nitrogen,
phosphorus.
119
00:06:36,590 --> 00:06:39,260
One of the big questions
in science
120
00:06:39,260 --> 00:06:41,760
over the history of humanity
has been,
121
00:06:41,770 --> 00:06:44,600
"what are the origins
of these elements?"
122
00:06:44,600 --> 00:06:48,800
And it turns out that neutron
stars play a critical role
123
00:06:48,810 --> 00:06:51,410
in creating many of
the heavy elements.
124
00:06:54,640 --> 00:07:00,220
Most of the elements
on earth are made in stars.
125
00:07:00,220 --> 00:07:02,850
But how the heaviest
elements are made
126
00:07:02,850 --> 00:07:06,590
has been one of science's
longest-running mysteries.
127
00:07:08,560 --> 00:07:10,360
For a long time,
we knew there was a problem
128
00:07:10,360 --> 00:07:12,030
with making these
heavier atoms...
129
00:07:12,030 --> 00:07:15,400
Things like gold and platinum,
all the way out towards uranium.
130
00:07:15,400 --> 00:07:17,100
And really, the most
energetic thing we had
131
00:07:17,100 --> 00:07:19,570
in the universe
was supernova explosions.
132
00:07:19,570 --> 00:07:22,640
So, they had to be created
somehow in supernovas.
133
00:07:22,640 --> 00:07:25,670
But when scientists
ran computer simulations,
134
00:07:25,680 --> 00:07:30,410
virtual supernovas failed to
forge these oversized atoms.
135
00:07:33,620 --> 00:07:37,550
In 2016, astronomer
Edo Berger explained
136
00:07:37,550 --> 00:07:40,190
a potential solution
to the mystery.
137
00:07:43,890 --> 00:07:45,690
If you open
any one of these books,
138
00:07:45,700 --> 00:07:48,730
and flip to the page that
tells you where gold came from,
139
00:07:48,730 --> 00:07:51,500
it will tell you that gold
came from supernova explosions.
140
00:07:57,540 --> 00:08:01,580
But it was becoming clear that
the textbooks were out of date.
141
00:08:06,720 --> 00:08:09,280
To form heavy elements
requires a lot of neutrons,
142
00:08:09,290 --> 00:08:11,690
and so, another possible
theory was that
143
00:08:11,690 --> 00:08:14,460
the heaviest elements
were produced in the mergers
144
00:08:14,460 --> 00:08:17,730
of two neutron stars
in a binary system.
145
00:08:17,730 --> 00:08:20,300
But at the time,
no one had actually seen
146
00:08:20,300 --> 00:08:22,330
a neutron-star collision.
147
00:08:22,330 --> 00:08:24,600
It was difficult
to convince the community
148
00:08:24,600 --> 00:08:26,670
that this was
a potential channel
149
00:08:26,670 --> 00:08:28,970
for the production
of heavy elements.
150
00:08:28,970 --> 00:08:31,510
The proof is to actually
see this process
151
00:08:31,510 --> 00:08:32,770
happening in the universe.
152
00:08:34,740 --> 00:08:36,710
The 2017 kilonova
153
00:08:36,710 --> 00:08:39,280
provides the
perfect opportunity.
154
00:08:39,280 --> 00:08:43,150
It generates thousands
of hours of data.
155
00:08:43,150 --> 00:08:45,690
Scientists notice a pattern...
156
00:08:45,690 --> 00:08:50,960
Subtle changes in the color
of the kilonova remnants.
157
00:08:50,960 --> 00:08:53,760
In space, when you have
an event that is very bright,
158
00:08:53,760 --> 00:08:55,300
it emits a certain
amount of light,
159
00:08:55,300 --> 00:08:57,100
and it emits it at
certain wavelengths...
160
00:08:57,100 --> 00:08:59,530
What we think of as colors.
161
00:08:59,540 --> 00:09:02,540
Different colors
in a pyrotechnics display
162
00:09:02,540 --> 00:09:06,110
indicate the use of different
chemicals in fireworks.
163
00:09:06,110 --> 00:09:09,580
In the same way, scientists
can uncover the elements
164
00:09:09,580 --> 00:09:14,520
in the kilonova
by the colors in the explosion.
165
00:09:14,520 --> 00:09:18,390
As the kilonova turns red,
they realize it's the result
166
00:09:18,390 --> 00:09:20,520
of newly-created heavy elements
167
00:09:20,520 --> 00:09:23,630
starting to absorb blue light.
168
00:09:23,630 --> 00:09:25,990
As we watched
this remnant change...
169
00:09:26,000 --> 00:09:29,100
The explosion change in
color, expand and cool...
170
00:09:29,100 --> 00:09:32,070
We could estimate what sort of
elements were being produced.
171
00:09:34,370 --> 00:09:36,470
The light from the debris shifts
172
00:09:36,470 --> 00:09:40,280
from blue and Violet
to red and infrared.
173
00:09:40,280 --> 00:09:43,040
The color change provides clues
174
00:09:43,050 --> 00:09:46,510
about the presence
of certain heavy metals.
175
00:09:54,490 --> 00:09:57,430
Well, this neutron-star
collision, this kilonova,
176
00:09:57,430 --> 00:10:00,500
produced brightness
and a color spectrum
177
00:10:00,500 --> 00:10:03,930
that are consistent
with models of predictions
178
00:10:03,930 --> 00:10:06,100
that produce gold and platinum.
179
00:10:08,540 --> 00:10:11,440
This model
is called "The R-process,"
180
00:10:11,440 --> 00:10:14,410
short for
"rapid neutron capture."
181
00:10:14,410 --> 00:10:16,780
That is a bit of
a complicated term
182
00:10:16,780 --> 00:10:20,250
that describes how we make atoms
heavier than iron.
183
00:10:20,250 --> 00:10:22,580
You need a really
neutron-rich environment.
184
00:10:22,590 --> 00:10:25,390
And as you might imagine,
a neutron-star collision
185
00:10:25,390 --> 00:10:27,960
is a very neutron-rich
environment.
186
00:10:27,960 --> 00:10:29,720
If these models are correct...
187
00:10:29,730 --> 00:10:31,930
And this blows me away...
188
00:10:31,930 --> 00:10:33,830
This collision, this kilonova,
189
00:10:33,830 --> 00:10:38,030
produced several dozen times
the mass of the Earth
190
00:10:38,030 --> 00:10:40,070
in just gold.
191
00:10:46,710 --> 00:10:50,110
The 2017 kilonova
not only reveals
192
00:10:50,110 --> 00:10:52,380
the origin of key elements,
193
00:10:52,380 --> 00:10:56,080
it sheds light on
the neutron star's interior...
194
00:10:56,090 --> 00:10:59,190
The strongest material
in the universe
195
00:10:59,190 --> 00:11:01,020
creating a magnetic field
196
00:11:01,020 --> 00:11:04,790
a trillion times greater
than that of earth.
197
00:11:23,200 --> 00:11:28,470
Two neutron stars
caught in a death spiral.
198
00:11:28,470 --> 00:11:32,540
This massive kilonova explosion
not only sheds light
199
00:11:32,540 --> 00:11:34,580
on the creation
of heavy elements,
200
00:11:34,580 --> 00:11:36,910
such as gold and platinum,
201
00:11:36,920 --> 00:11:40,150
it also provides scientists
with a unique insight
202
00:11:40,150 --> 00:11:44,450
into one of the most mysterious
objects in the universe.
203
00:11:44,460 --> 00:11:47,520
Trying to imagine what
a neutron star is really like
204
00:11:47,530 --> 00:11:49,330
really challenges
our imagination.
205
00:11:49,330 --> 00:11:51,590
It also challenges
our theoretical physics.
206
00:11:51,600 --> 00:11:54,100
We have to go to our computer
models, our mathematics,
207
00:11:54,100 --> 00:11:58,070
to have some estimate
of what this might be like.
208
00:11:58,070 --> 00:12:00,600
Now,
scientists don't have to rely
209
00:12:00,610 --> 00:12:02,170
on their imaginations.
210
00:12:03,510 --> 00:12:07,210
They can use hard data
from the kilonova
211
00:12:07,210 --> 00:12:10,380
to work out what makes
neutron stars tick.
212
00:12:14,820 --> 00:12:16,890
There's so much information
we got from observing
213
00:12:16,890 --> 00:12:20,360
that one single event, that one
colliding neutron star pair.
214
00:12:20,360 --> 00:12:22,860
Now, for the first time,
we have an accurate estimate
215
00:12:22,860 --> 00:12:25,290
of the mass of a neutron star,
and the diameter.
216
00:12:25,300 --> 00:12:27,000
We can finally begin
to piece together
217
00:12:27,000 --> 00:12:30,570
how neutron stars really work.
218
00:12:30,570 --> 00:12:34,770
They calculate
the diameter is just 12.4 miles,
219
00:12:34,770 --> 00:12:39,510
1 mile less than
the length of Manhattan.
220
00:12:39,510 --> 00:12:41,980
Nailing down
any physical characteristic
221
00:12:41,980 --> 00:12:43,310
is really important.
222
00:12:43,310 --> 00:12:44,610
And if there's gonna be one,
223
00:12:44,620 --> 00:12:47,250
the radius is a big one,
because from there,
224
00:12:47,250 --> 00:12:49,020
if you know the mass,
you can get the density.
225
00:12:49,020 --> 00:12:50,650
And if you know
the overall density,
226
00:12:50,660 --> 00:12:52,390
you can start to figure out
what the layering
227
00:12:52,390 --> 00:12:54,320
inside of a neutron star
is like.
228
00:12:58,300 --> 00:13:01,860
For physicists,
the interior of a neutron star
229
00:13:01,870 --> 00:13:06,300
is one of the most intriguing
places in the universe.
230
00:13:06,300 --> 00:13:07,870
You have to realize
that the conditions
231
00:13:07,870 --> 00:13:09,970
inside a neutron star are very,
very different
232
00:13:09,970 --> 00:13:12,070
than the conditions
that exist here on earth.
233
00:13:12,080 --> 00:13:14,140
We're talking about material
that's so dense
234
00:13:14,150 --> 00:13:17,450
that even the nuclei of atoms
can't hold together.
235
00:13:17,450 --> 00:13:19,620
With a neutron star,
you're taking something
236
00:13:19,620 --> 00:13:22,020
that weighs more than the sun,
237
00:13:22,020 --> 00:13:25,720
and compressing it down
to be smaller than a city.
238
00:13:25,720 --> 00:13:28,520
It's so dense that, if you
tried to put it on the ground,
239
00:13:28,530 --> 00:13:30,490
it would fall
right through the Earth.
240
00:13:32,460 --> 00:13:35,460
High density
means high gravity...
241
00:13:35,470 --> 00:13:40,270
Gravity 200 billion times
greater than on earth.
242
00:13:40,270 --> 00:13:41,870
Imagine climbing up on
a table on the surface
243
00:13:41,870 --> 00:13:43,740
of a neutron star
and jumping off.
244
00:13:43,740 --> 00:13:45,940
You're gonna just
get flattened instantly,
245
00:13:45,940 --> 00:13:48,510
and just spread out
on that surface.
246
00:13:48,510 --> 00:13:52,920
So, don't even think about
trying to do push-ups.
247
00:13:52,920 --> 00:13:54,720
Added to the intense gravity
248
00:13:54,720 --> 00:13:57,420
are hugely powerful
magnetic fields,
249
00:13:57,420 --> 00:13:59,520
awesome X-ray radiation,
250
00:13:59,520 --> 00:14:03,290
electric fields 30 million times
more powerful
251
00:14:03,290 --> 00:14:05,290
than lightning bolts,
252
00:14:05,300 --> 00:14:09,370
and blizzards of
high-energy particles.
253
00:14:09,370 --> 00:14:13,400
This isn't a good neighborhood
for a space traveler.
254
00:14:16,370 --> 00:14:19,280
If you were to
find yourself in the vicinity
255
00:14:19,280 --> 00:14:22,910
of a neutron star,
it's gonna be bad news.
256
00:14:22,910 --> 00:14:24,910
First, you would be torn apart
257
00:14:24,920 --> 00:14:27,580
by the incredibly strong
magnetic fields.
258
00:14:27,590 --> 00:14:32,460
Then, the X-ray radiation
would blast you to a crisp.
259
00:14:32,460 --> 00:14:34,290
And as it pulled you closer,
260
00:14:34,290 --> 00:14:36,690
its intense gravity
would stretch out
261
00:14:36,690 --> 00:14:40,260
your atoms and molecules
into a long, thin stream.
262
00:14:40,260 --> 00:14:43,130
You would build your speed
faster and faster,
263
00:14:43,130 --> 00:14:46,240
and then, you would finally
impact the surface,
264
00:14:46,240 --> 00:14:47,970
splatter across it.
265
00:14:47,970 --> 00:14:50,970
And that process would
release as much energy
266
00:14:50,980 --> 00:14:52,110
as a nuclear bomb.
267
00:14:55,180 --> 00:14:58,380
If I had the choice between
falling into a neutron star
268
00:14:58,380 --> 00:15:01,620
versus a black hole,
I think I'd pick the black hole.
269
00:15:01,620 --> 00:15:03,720
'Cause I don't really feel like
being torn apart
270
00:15:03,720 --> 00:15:06,360
by a magnetic field
and blasted with x-rays.
271
00:15:10,760 --> 00:15:15,300
On a cosmic scale,
neutron stars may be pint-sized,
272
00:15:15,300 --> 00:15:18,030
but they sure pack
a serious punch.
273
00:15:18,040 --> 00:15:20,540
The secret to
all this pent-up power
274
00:15:20,540 --> 00:15:25,070
is what's going on
below the surface.
275
00:15:25,080 --> 00:15:27,610
Armed with
the new kilonova data,
276
00:15:27,610 --> 00:15:29,350
we can now take
a virtual journey
277
00:15:29,350 --> 00:15:32,080
into the heart
of a neutron star.
278
00:15:32,080 --> 00:15:36,350
First, we must pass
through its atmosphere.
279
00:15:36,350 --> 00:15:37,690
Now, it's not like
the Earth's atmosphere,
280
00:15:37,690 --> 00:15:39,520
which goes up,
like, a 100 miles.
281
00:15:39,520 --> 00:15:42,960
On a neutron star, the
atmosphere is about this deep,
282
00:15:42,960 --> 00:15:48,130
and it's extremely dense
compared to the air around us.
283
00:15:48,130 --> 00:15:52,770
Below the compressed atmosphere
is a crust of ionized iron,
284
00:15:52,770 --> 00:15:55,170
a mixture of
crystal iron nuclei,
285
00:15:55,170 --> 00:15:58,510
and free-flowing iron electrons.
286
00:15:58,510 --> 00:16:00,480
Now, the gravity's so strong
287
00:16:00,480 --> 00:16:02,910
that it's almost
perfectly smooth.
288
00:16:02,910 --> 00:16:04,380
The biggest mountains
on the surface
289
00:16:04,380 --> 00:16:06,780
are gonna be less than
a quarter of an inch high.
290
00:16:06,780 --> 00:16:12,220
A quarter-inch
mountain range may sound odd...
291
00:16:12,220 --> 00:16:16,530
But things get even stranger
as we go below the surface.
292
00:16:18,630 --> 00:16:22,600
This is home to the strongest
material in the universe.
293
00:16:25,670 --> 00:16:31,840
It's so weird, scientists
liken it to nuclear pasta.
294
00:16:31,840 --> 00:16:34,810
As we dive beneath
the crust of a neutron star,
295
00:16:34,810 --> 00:16:38,080
the neutrons themselves start
to glue themselves together
296
00:16:38,080 --> 00:16:40,020
into exotic shapes.
297
00:16:40,020 --> 00:16:45,290
First, they form clumps that
look something like gnocchi,
298
00:16:45,290 --> 00:16:48,360
then, deeper, the gnocchi
glue themselves together
299
00:16:48,360 --> 00:16:52,330
to form long strands
that look like spaghetti.
300
00:16:52,330 --> 00:16:54,930
Even deeper,
the spaghetti fuse together
301
00:16:54,930 --> 00:16:58,400
to form sheets of lasagna.
302
00:16:58,400 --> 00:17:01,370
And then, finally,
the lasagna fuse together
303
00:17:01,370 --> 00:17:05,980
to become a uniform mass,
but with holes in it.
304
00:17:05,980 --> 00:17:08,410
So, it looks like penne.
305
00:17:08,410 --> 00:17:11,880
This is pasta, nuclear style,
306
00:17:11,880 --> 00:17:13,150
simmering at a temperature
307
00:17:13,150 --> 00:17:15,920
of over one million
degrees Fahrenheit.
308
00:17:15,920 --> 00:17:19,690
Extreme gravity bends,
squeezes, stretches,
309
00:17:19,690 --> 00:17:22,630
and buckles neutrons,
creating a material
310
00:17:22,630 --> 00:17:26,930
100,000 billion times
denser than iron.
311
00:17:26,930 --> 00:17:30,730
But the journey
gets even more extreme.
312
00:17:30,740 --> 00:17:34,570
Even deeper is more mysterious
and harder to understand.
313
00:17:34,570 --> 00:17:36,610
The core of a neutron star...
314
00:17:36,610 --> 00:17:39,340
Which is very far away
from these layers,
315
00:17:39,340 --> 00:17:41,440
which we call
the "nuclear pasta"...
316
00:17:41,450 --> 00:17:44,710
Is perhaps the most
exotic form of matter.
317
00:17:44,720 --> 00:17:48,880
So exotic it might be
the last bastion of matter
318
00:17:48,890 --> 00:17:53,220
before complete gravitational
collapse into a black hole.
319
00:17:55,230 --> 00:17:57,530
Data from NASA's
Chandra observatory
320
00:17:57,530 --> 00:18:00,900
suggests the core
is made up of a super fluid...
321
00:18:00,900 --> 00:18:04,700
A bizarre friction-free
state of matter.
322
00:18:04,700 --> 00:18:07,400
Similar super fluids
produced in the lab
323
00:18:07,410 --> 00:18:09,440
exhibit strange properties,
324
00:18:09,440 --> 00:18:12,070
such as the ability
to flow upwards
325
00:18:12,080 --> 00:18:16,010
and escape airtight containers.
326
00:18:16,010 --> 00:18:18,310
Although our knowledge
of the star's interior
327
00:18:18,320 --> 00:18:20,550
is still hazy,
there's not mystery
328
00:18:20,550 --> 00:18:22,690
about its dazzling birth.
329
00:18:22,690 --> 00:18:26,790
Forged into life during
the most spectacular event
330
00:18:26,790 --> 00:18:28,720
the universe has to offer...
331
00:18:28,730 --> 00:18:32,230
The explosive death
of a massive star.
332
00:18:48,600 --> 00:18:50,600
Neutron stars...
333
00:18:50,600 --> 00:18:57,170
Manhattan-sized, but with a mass
twice that of our sun.
334
00:18:57,170 --> 00:19:03,240
So dense a teaspoon of their
matter weighs a billion tons.
335
00:19:03,250 --> 00:19:07,580
Mind-blowing objects
that arrive with a bang.
336
00:19:07,580 --> 00:19:09,550
Neutron stars spark into life
337
00:19:09,550 --> 00:19:11,520
amid the death
of their parent star.
338
00:19:11,520 --> 00:19:14,220
They're the ultimate story
of resurrection,
339
00:19:14,220 --> 00:19:16,890
or of life from death.
340
00:19:16,890 --> 00:19:20,960
It's all part of a cosmic cycle.
341
00:19:20,960 --> 00:19:25,300
Stars are born from giant
clouds of very cold gas.
342
00:19:25,300 --> 00:19:28,340
Those clouds collapse
under their own gravity,
343
00:19:28,340 --> 00:19:31,470
and the density of the core
at the center of the collapse
344
00:19:31,470 --> 00:19:32,640
starts to increase.
345
00:19:37,750 --> 00:19:41,680
A star is a huge
nuclear fusion reactor.
346
00:19:41,680 --> 00:19:44,250
The force of its gravity
is so powerful
347
00:19:44,250 --> 00:19:46,020
that it fuses atoms together
348
00:19:46,020 --> 00:19:50,920
to make progressively
heavier and heavier elements.
349
00:19:50,930 --> 00:19:54,060
The star fuses hydrogen
into helium.
350
00:19:54,060 --> 00:19:57,260
Once it exhausts its hydrogen,
then, if it's massive enough,
351
00:19:57,270 --> 00:19:59,700
it can start fusing helium
at its core.
352
00:20:02,140 --> 00:20:04,800
Fusion continues,
forming carbon,
353
00:20:04,810 --> 00:20:10,780
oxygen, nitrogen,
all the way up to iron.
354
00:20:10,780 --> 00:20:13,110
Once a star
has iron in the core,
355
00:20:13,120 --> 00:20:15,080
it's almost like
you've poisoned it,
356
00:20:15,080 --> 00:20:18,750
because this extinguishes
the nuclear reactions
357
00:20:18,750 --> 00:20:20,090
in the core of the star.
358
00:20:20,090 --> 00:20:24,320
You fuse something into iron,
and you get no energy.
359
00:20:24,330 --> 00:20:26,160
All of a sudden,
there's nothing to support
360
00:20:26,160 --> 00:20:27,430
the crush of gravity.
361
00:20:27,430 --> 00:20:29,130
No radiation pressure
pushing out
362
00:20:29,130 --> 00:20:33,100
means no pressure keeping the
outer regions from falling in,
363
00:20:33,100 --> 00:20:34,970
and that's what they do.
364
00:20:34,970 --> 00:20:38,070
As the star collapses
in its death throes,
365
00:20:38,070 --> 00:20:41,510
its core becomes
the wildest, craziest,
366
00:20:41,510 --> 00:20:45,750
and freakiest pressure cooker
in the whole universe.
367
00:20:47,880 --> 00:20:50,350
The ingredients
are all in place.
368
00:20:50,350 --> 00:20:55,220
It's time to start cooking up
a neutron star.
369
00:20:55,220 --> 00:20:57,960
If we were to scale up
an atomic nucleus
370
00:20:57,960 --> 00:20:59,830
to be the size of a baseball,
371
00:20:59,830 --> 00:21:04,000
in a normal atom,
the nearest electron would be
372
00:21:04,000 --> 00:21:06,030
way over in those trees,
373
00:21:06,030 --> 00:21:08,130
but in the extreme
conditions that lead to
374
00:21:08,140 --> 00:21:10,300
the formation of a neutron star,
375
00:21:10,310 --> 00:21:14,340
those electrons can be pushed
closer to the nucleus.
376
00:21:14,340 --> 00:21:17,510
They can come zipping in
from any direction.
377
00:21:17,510 --> 00:21:20,410
And if the temperatures
and pressures are high enough,
378
00:21:20,420 --> 00:21:22,380
they can even strike the nucleus
379
00:21:22,380 --> 00:21:25,290
and enter it,
and they can hit a proton.
380
00:21:25,290 --> 00:21:29,820
And when they do, they become
converted into more neutrons.
381
00:21:29,830 --> 00:21:32,460
So, in the formation
of one of these objects,
382
00:21:32,460 --> 00:21:34,790
the protons and
electrons disappear,
383
00:21:34,800 --> 00:21:37,800
and you're left with
almost entirely pure neutrons,
384
00:21:37,800 --> 00:21:40,870
with nothing to stop them
from cramming together
385
00:21:40,870 --> 00:21:43,740
and filling up
this entire baseball
386
00:21:43,740 --> 00:21:49,280
with neutrons leading to
incredibly high densities.
387
00:21:49,280 --> 00:21:50,640
With the sea of electrons
388
00:21:50,650 --> 00:21:53,210
now absorbed
in the atomic nuclei,
389
00:21:53,220 --> 00:21:58,150
the matter in the stars can now
press together a lot tighter.
390
00:21:58,150 --> 00:22:01,350
It's like squeezing
300 million tons of mass
391
00:22:01,360 --> 00:22:04,690
into a single sugar cube.
392
00:22:04,690 --> 00:22:06,460
As the star collapses,
393
00:22:06,460 --> 00:22:09,630
enormous amounts of gas
fall towards the core.
394
00:22:12,300 --> 00:22:16,800
The core is small in size,
but huge in mass.
395
00:22:16,810 --> 00:22:19,610
Billions of tons of gas
bounce off of it,
396
00:22:19,610 --> 00:22:23,080
then erupt into
the biggest fireworks display
397
00:22:23,080 --> 00:22:28,550
in the cosmos... A supernova.
398
00:22:28,550 --> 00:22:29,850
It's massive.
399
00:22:29,850 --> 00:22:30,950
It's bright.
400
00:22:30,950 --> 00:22:32,250
It's imposing.
401
00:22:32,250 --> 00:22:35,360
Supernova are among
the most dramatic events
402
00:22:35,360 --> 00:22:36,820
to happen in the universe.
403
00:22:36,830 --> 00:22:38,460
A single star dying...
404
00:22:38,460 --> 00:22:43,530
One star dying...
Can outshine an entire galaxy.
405
00:22:47,370 --> 00:22:49,840
And arising
out of this cataclysm,
406
00:22:49,840 --> 00:22:53,270
a new and very strange
cosmic entity.
407
00:22:56,240 --> 00:22:59,110
When the smoke finally clears
from the supernova explosion,
408
00:22:59,110 --> 00:23:01,850
you're left with one of
the most real, fascinating,
409
00:23:01,850 --> 00:23:05,020
unbelievable monsters
of the entire universe.
410
00:23:05,020 --> 00:23:06,690
Humans have been
witnessing supernovas
411
00:23:06,690 --> 00:23:08,320
for thousands of years,
412
00:23:08,320 --> 00:23:11,060
but we're only now
just starting to understand
413
00:23:11,060 --> 00:23:13,860
what we've truly
been witnessing...
414
00:23:13,860 --> 00:23:17,800
The births of neutron stars.
415
00:23:17,800 --> 00:23:20,900
But while supernovas
are big and bright,
416
00:23:20,900 --> 00:23:23,440
neutron stars are small,
417
00:23:23,440 --> 00:23:26,610
and many don't even
give off light.
418
00:23:26,610 --> 00:23:30,580
So, how many neutron stars
are out there?
419
00:23:30,580 --> 00:23:34,150
We know of about 2,000
neutron stars in our galaxy,
420
00:23:34,150 --> 00:23:35,750
but there probably are many,
many, more.
421
00:23:35,750 --> 00:23:38,590
I'm talking about tens of
millions in the milky way alone,
422
00:23:38,590 --> 00:23:42,860
and certainly billions
throughout the universe.
423
00:23:42,860 --> 00:23:48,660
Neutron stars may be small,
but some give themselves away,
424
00:23:48,660 --> 00:23:52,130
shooting beams
across the universe...
425
00:23:52,130 --> 00:23:57,400
Unmistakable, pulsing strobes
of a cosmic lighthouse.
426
00:24:16,400 --> 00:24:20,900
Our knowledge of
neutron stars is expanding fast.
427
00:24:23,440 --> 00:24:25,540
But we didn't even know
they existed
428
00:24:25,540 --> 00:24:29,110
until a lucky discovery
just over 50 years ago.
429
00:24:31,140 --> 00:24:34,280
Cambridge,
the Mullard radio observatory,
430
00:24:34,280 --> 00:24:36,180
Jocelyn bell, grad student,
431
00:24:36,180 --> 00:24:39,750
operating the new
radio telescope.
432
00:24:39,750 --> 00:24:42,850
Scanning the sky, doing all
sorts of cool astronomy stuff,
433
00:24:42,860 --> 00:24:48,290
and sees what she calls
"a bit of scruff" in the data.
434
00:24:48,290 --> 00:24:49,730
This scruff is a short
435
00:24:49,730 --> 00:24:53,060
but constantly repeating
burst of radiation
436
00:24:53,070 --> 00:24:57,340
originating 1,000 light years
from earth.
437
00:24:57,340 --> 00:25:00,470
It's so stable and regular
that bell is convinced
438
00:25:00,470 --> 00:25:03,240
there's a fault
with her telescope.
439
00:25:03,240 --> 00:25:05,180
She returns to that spot,
440
00:25:05,180 --> 00:25:09,480
and finds a repeating,
regular signal...
441
00:25:09,480 --> 00:25:15,020
A single point in the sky that
is flashing at us continually,
442
00:25:15,020 --> 00:25:17,820
saying "Hi. Hi. Hi."
443
00:25:17,820 --> 00:25:19,520
Blip, blip, blip.
444
00:25:19,530 --> 00:25:21,890
Boom, boom, boom.
445
00:25:21,900 --> 00:25:23,790
Pulse, pulse, pulse.
446
00:25:23,800 --> 00:25:25,800
Nothing that we know of
in the universe,
447
00:25:25,800 --> 00:25:30,370
has such a steady,
perfectly-spaced in time, pulse.
448
00:25:30,370 --> 00:25:34,610
It seemed so perfect that
it must have been artificial.
449
00:25:34,610 --> 00:25:37,980
It looks like
someone is making that,
450
00:25:37,980 --> 00:25:41,950
but it turns out, it's not
a person, but a thing.
451
00:25:41,950 --> 00:25:44,820
What she discovered
was called a "pulsar."
452
00:25:47,650 --> 00:25:50,250
A pulsar is
a type of rapidly spinning
453
00:25:50,260 --> 00:25:51,620
neutron star.
454
00:25:54,430 --> 00:25:58,300
Neutron stars had been theorized
in the 1930s,
455
00:25:58,300 --> 00:26:02,200
but were thought to be
too faint to be detected.
456
00:26:02,200 --> 00:26:06,800
Neutron stars were
hypothesized to exist,
457
00:26:06,810 --> 00:26:09,710
but not really taken seriously.
458
00:26:09,710 --> 00:26:12,180
It was just a, "oh, that's cute.
459
00:26:12,180 --> 00:26:14,780
Maybe they're out there,
but probably not."
460
00:26:15,920 --> 00:26:17,750
The signal bell detected
461
00:26:17,750 --> 00:26:21,750
seemed like something
from science fiction.
462
00:26:21,750 --> 00:26:24,520
No one had ever seen this
in astronomy before,
463
00:26:24,520 --> 00:26:28,660
and some people even speculated
that it was an alien signal.
464
00:26:28,660 --> 00:26:31,000
She even called them
"LGM objects"...
465
00:26:31,000 --> 00:26:33,970
"little green men."
466
00:26:33,970 --> 00:26:36,470
But then,
bell found a second signal.
467
00:26:39,310 --> 00:26:42,470
Little green men
went back to being fiction,
468
00:26:42,480 --> 00:26:46,140
and pulsars became science fact.
469
00:26:46,150 --> 00:26:48,410
The discovery of pulsars
came out of the blue.
470
00:26:48,410 --> 00:26:50,010
Nobody was expecting this.
471
00:26:50,020 --> 00:26:52,220
So, it was
an amazing breakthrough...
472
00:26:52,220 --> 00:26:53,420
Really important.
473
00:26:56,590 --> 00:27:00,990
Pulsars pulse
because they are born to spin.
474
00:27:00,990 --> 00:27:05,230
They burst into life
as their parent star collapses
475
00:27:05,230 --> 00:27:06,760
during a supernova.
476
00:27:08,940 --> 00:27:11,300
Any object at all
that is undergoing
477
00:27:11,300 --> 00:27:13,440
any sort of compression event,
478
00:27:13,440 --> 00:27:16,670
if it has any initial
angular momentum at all,
479
00:27:16,680 --> 00:27:20,780
it will eventually
end up spinning.
480
00:27:20,780 --> 00:27:24,880
As the star shrinks,
it spins faster and faster.
481
00:27:26,850 --> 00:27:30,990
They spin so quickly
because the Earth-sized core
482
00:27:30,990 --> 00:27:32,360
of a massive star
483
00:27:32,360 --> 00:27:35,630
collapsed to something
as small as a city.
484
00:27:35,630 --> 00:27:39,730
So, because the size of the
object became so much smaller,
485
00:27:39,730 --> 00:27:44,470
the rate of spin had to increase
by a tremendous amount.
486
00:27:44,470 --> 00:27:47,740
Neutron stars can spin
really, really, fast.
487
00:27:47,740 --> 00:27:50,210
Their surface is moving so fast.
488
00:27:50,210 --> 00:27:54,010
It's moving at about 20% the
speed of light, in some cases.
489
00:27:54,010 --> 00:27:57,280
So, if you were to
get on the neutron star ride...
490
00:27:57,280 --> 00:28:01,250
No pregnant women, no bad backs,
no heart issues,
491
00:28:01,250 --> 00:28:04,020
keep your arms and legs
inside the ride at all times,
492
00:28:04,020 --> 00:28:06,360
because they are about
to be obliterated.
493
00:28:08,260 --> 00:28:13,530
And as they spin, they generate
flashing beams of energy.
494
00:28:13,530 --> 00:28:15,930
This beam is like
a lighthouse beam.
495
00:28:15,940 --> 00:28:19,340
You see these periodic flashes
many times per second.
496
00:28:19,340 --> 00:28:24,210
So, every time you see it...
Beam, beam, beam.
497
00:28:24,210 --> 00:28:27,210
These beams
are the pulsar's calling card.
498
00:28:27,210 --> 00:28:29,910
They're generated
by the elemental chaos
499
00:28:29,920 --> 00:28:32,550
raging inside a neutron star.
500
00:28:32,550 --> 00:28:34,420
Although the star
is predominantly
501
00:28:34,420 --> 00:28:36,290
a ball of neutrons,
502
00:28:36,290 --> 00:28:40,020
the crust is sprinkled
with protons and electrons,
503
00:28:40,030 --> 00:28:42,260
spinning hundreds
of times a second,
504
00:28:42,260 --> 00:28:45,000
generating an incredible
magnetic field.
505
00:28:46,700 --> 00:28:48,530
And with this strong
magnetic field,
506
00:28:48,530 --> 00:28:50,630
you can create strong
electric fields.
507
00:28:50,640 --> 00:28:52,300
And the electric
and magnetic fields
508
00:28:52,310 --> 00:28:55,910
can work off of each other
and become radiation.
509
00:28:55,910 --> 00:29:01,680
These neutron stars send jets...
Beams of radiation...
510
00:29:01,680 --> 00:29:03,780
Out of their spinning poles.
511
00:29:03,780 --> 00:29:06,250
And if their spinning pole
is misaligned,
512
00:29:06,250 --> 00:29:07,850
if they're a little bit tilted,
513
00:29:07,850 --> 00:29:12,120
this beam will make circles,
across the universe.
514
00:29:12,130 --> 00:29:14,890
And if we're in the path
of one of these circles,
515
00:29:14,890 --> 00:29:18,630
we'll see a flash... A flash.
516
00:29:18,630 --> 00:29:20,300
Just like if you're on a ship,
517
00:29:20,300 --> 00:29:22,970
and you observe a distant
lighthouse in a foggy night,
518
00:29:22,970 --> 00:29:26,940
you can see pulsars across
the vast expanse of space
519
00:29:26,940 --> 00:29:30,540
because they are immensely
powerful beams of light.
520
00:29:30,540 --> 00:29:33,840
But sometimes,
pulsars get an extra push
521
00:29:33,850 --> 00:29:37,620
that accelerates
the spin even more.
522
00:29:37,620 --> 00:29:39,750
The way you make it spin
even faster
523
00:29:39,750 --> 00:29:42,920
is by subsequently
dumping more material onto it.
524
00:29:42,920 --> 00:29:45,420
That's called "accretion,"
and you end up spinning it up
525
00:29:45,430 --> 00:29:47,530
even faster than it
was already spinning.
526
00:29:47,530 --> 00:29:49,630
Like stellar vampires,
527
00:29:49,630 --> 00:29:51,860
pulsars are ready
to suck the life
528
00:29:51,860 --> 00:29:55,270
out of any objects
that stray too close.
529
00:29:55,270 --> 00:29:57,700
Gravity is bringing
that material in,
530
00:29:57,700 --> 00:30:00,370
which means that any spin
it has is accelerated.
531
00:30:00,370 --> 00:30:02,170
It spins faster and faster.
532
00:30:02,180 --> 00:30:04,480
These millisecond pulsars
533
00:30:04,480 --> 00:30:08,680
spin at around
700 revolutions per second.
534
00:30:08,680 --> 00:30:10,780
They are the ultimate
kitchen blender...
535
00:30:10,780 --> 00:30:15,120
They will chop, they will slice,
they will even julienne fry.
536
00:30:17,820 --> 00:30:19,860
So, what stops neutron stars
537
00:30:19,860 --> 00:30:23,030
from simply tearing
themselves apart?
538
00:30:23,030 --> 00:30:26,330
Neutron stars are
incredibly exotic objects
539
00:30:26,330 --> 00:30:30,370
with immense, immense forces
that bind them together,
540
00:30:30,370 --> 00:30:32,570
and so, they can be
held rigid even against
541
00:30:32,570 --> 00:30:34,870
these incredibly fast
rotation speeds.
542
00:30:38,540 --> 00:30:40,410
They have
incredibly strong gravity,
543
00:30:40,410 --> 00:30:42,310
and this is what allows them
to hold together
544
00:30:42,320 --> 00:30:44,480
even though they're
spinning around so fast.
545
00:30:47,550 --> 00:30:52,920
The speed of the spin
is hard to imagine.
546
00:30:52,930 --> 00:30:55,090
On earth, a day
is 24 hours long.
547
00:30:55,090 --> 00:31:00,130
On a neutron star,
it's a 700th of a second long.
548
00:31:00,130 --> 00:31:04,170
Super-speeding pulsars are
not the only weird stars
549
00:31:04,170 --> 00:31:06,700
that scientists
are coming to grips with.
550
00:31:06,710 --> 00:31:09,070
There is one other type
of neutron star,
551
00:31:09,080 --> 00:31:12,980
that has the most powerful
magnetic field in the universe.
552
00:31:12,980 --> 00:31:17,380
This magnetic monster
is called a "magnetar."
553
00:31:33,200 --> 00:31:36,340
Astronomers monitoring
pulsing neutron stars
554
00:31:36,340 --> 00:31:39,310
have noticed something very odd.
555
00:31:39,310 --> 00:31:44,910
On very rare occasions,
they can suddenly speed up.
556
00:31:44,920 --> 00:31:46,110
That's amazing.
557
00:31:46,120 --> 00:31:48,120
I mean, you've got this
incredibly dense object,
558
00:31:48,120 --> 00:31:49,550
and suddenly,
it's spinning faster.
559
00:31:49,550 --> 00:31:51,620
It happens... Instantly.
560
00:31:51,620 --> 00:31:53,460
They'll suddenly
change frequency.
561
00:31:53,460 --> 00:31:56,730
It would take an amazing
amount of power to do that.
562
00:31:56,730 --> 00:31:58,330
What's doing it?
563
00:31:58,330 --> 00:32:03,030
These sudden changes
in speed are called "glitches."
564
00:32:03,030 --> 00:32:05,400
One leading idea for
what causes these glitches
565
00:32:05,400 --> 00:32:08,040
is that the core material
latches onto the crust,
566
00:32:08,040 --> 00:32:11,240
and this affects
the way it can spin around.
567
00:32:11,240 --> 00:32:15,110
Excess material beneath
the crust cracks it open,
568
00:32:15,110 --> 00:32:17,110
causing the glitch.
569
00:32:17,110 --> 00:32:21,020
This process releases a
tremendous amount of radiation,
570
00:32:21,020 --> 00:32:25,550
a blast of x-rays, causes
the face of the neutron star
571
00:32:25,560 --> 00:32:29,920
to rearrange itself, and for
the rotation speed to change.
572
00:32:29,930 --> 00:32:32,530
But there's another
possible explanation.
573
00:32:32,530 --> 00:32:36,870
Glitches could also be caused
by starquakes.
574
00:32:36,870 --> 00:32:39,330
Sometimes,
the crust gets ruptured.
575
00:32:39,340 --> 00:32:43,470
Anything that basically changes
the geometry of the pulsar
576
00:32:43,470 --> 00:32:46,440
can change the rate
at which it spins.
577
00:32:46,440 --> 00:32:47,940
So,
what could be powerful enough
578
00:32:47,940 --> 00:32:51,280
to cause these starquakes?
579
00:32:51,280 --> 00:32:52,310
It's hard to believe
580
00:32:52,320 --> 00:32:54,650
that there's any
force in the universe
581
00:32:54,650 --> 00:32:57,720
that could deform the matter
inside of a neutron star,
582
00:32:57,720 --> 00:33:00,490
which is undergoing
tremendous gravity.
583
00:33:00,490 --> 00:33:02,220
But when it comes to
a neutron star,
584
00:33:02,230 --> 00:33:05,430
if there's one thing that
can do it, it's magnetism.
585
00:33:05,430 --> 00:33:07,160
Extreme magnetic fields
586
00:33:07,160 --> 00:33:09,960
within the star
can get so twisted
587
00:33:09,970 --> 00:33:12,670
they can rip the crust
wide open.
588
00:33:12,670 --> 00:33:15,270
And so, the surface
can restructure itself,
589
00:33:15,270 --> 00:33:16,840
and constantly reshape.
590
00:33:16,840 --> 00:33:19,510
And just a tiny reconfiguration
591
00:33:19,510 --> 00:33:21,280
of the surface
of a neutron star,
592
00:33:21,280 --> 00:33:22,910
on the order of
a few millimeters,
593
00:33:22,910 --> 00:33:27,380
would be associated with
an enormous release of energy.
594
00:33:27,380 --> 00:33:29,550
The neutron star's
immense gravity
595
00:33:29,550 --> 00:33:34,690
smooths over the star's surface
almost instantaneously.
596
00:33:34,690 --> 00:33:37,230
It's like the glitch
never happened.
597
00:33:40,700 --> 00:33:42,800
When it comes to neutron stars,
598
00:33:42,800 --> 00:33:47,400
there is no end
to magnetic mayhem.
599
00:33:47,400 --> 00:33:49,370
Meet the reigning champion
600
00:33:49,370 --> 00:33:53,910
in the universal "strongest
magnetic field" competition...
601
00:33:53,910 --> 00:33:56,410
The magnetar.
602
00:33:56,410 --> 00:33:59,980
1 in 10 neutron stars
formed during a supernova
603
00:33:59,980 --> 00:34:02,480
becomes a magnetar.
604
00:34:02,490 --> 00:34:07,060
The thing about magnetars,
as is implied in their name...
605
00:34:07,060 --> 00:34:09,360
The magnetic field
on them is so strong,
606
00:34:09,360 --> 00:34:11,890
that even somebody who is
used to using big numbers...
607
00:34:11,900 --> 00:34:13,660
Like, say, an astronomer...
608
00:34:13,660 --> 00:34:16,730
Is still kind of in awe
of these things.
609
00:34:16,730 --> 00:34:19,100
Magnetars have a magnetic field
610
00:34:19,100 --> 00:34:23,270
one thousand trillion times
stronger than that of earth's.
611
00:34:23,270 --> 00:34:25,170
This amount of magnetism
612
00:34:25,180 --> 00:34:29,980
will seriously mess up
anything that comes close.
613
00:34:29,980 --> 00:34:32,480
Any normal object
that we are familiar with,
614
00:34:32,480 --> 00:34:36,120
if it got close to a magnetar,
it would just be shredded.
615
00:34:36,120 --> 00:34:38,420
Any charged particle
with any movement at all,
616
00:34:38,420 --> 00:34:40,260
would just be torn
from its atom.
617
00:34:40,260 --> 00:34:43,660
It would be just
an insane situation.
618
00:34:43,660 --> 00:34:48,060
Magnetars burn brightly,
but their lives are brief.
619
00:34:48,060 --> 00:34:49,330
We think magnetars...
620
00:34:49,330 --> 00:34:51,970
These intensely
magnetized neutron stars...
621
00:34:51,970 --> 00:34:53,900
Can only be really short-lived.
622
00:34:53,900 --> 00:34:56,170
Their magnetic field
is so powerful
623
00:34:56,170 --> 00:34:58,710
that it should decay
over very rapid time scales,
624
00:34:58,710 --> 00:35:01,240
only on the order of
a few ten thousand years.
625
00:35:01,240 --> 00:35:05,710
It seems their very strength
leads to their downfall.
626
00:35:05,720 --> 00:35:07,650
That magnetic field is so strong
627
00:35:07,650 --> 00:35:10,690
that it's picking up material
around it, and accelerating it.
628
00:35:10,690 --> 00:35:12,720
Well, that acts like a drag,
slowing it down.
629
00:35:12,720 --> 00:35:15,890
So, over time, the spin
of the neutron star slows,
630
00:35:15,890 --> 00:35:17,730
and the magnetic field
dies away.
631
00:35:20,030 --> 00:35:21,330
During their lives,
632
00:35:21,330 --> 00:35:24,930
magnetars operate very
differently than pulsars.
633
00:35:24,940 --> 00:35:26,570
They don't have beams.
634
00:35:26,570 --> 00:35:29,540
Their magnetic fields
shoot out gigantic bursts
635
00:35:29,540 --> 00:35:32,970
of high-intensity radiation.
636
00:35:32,980 --> 00:35:36,640
But recently, astronomers
have spotted one neutron star
637
00:35:36,650 --> 00:35:39,110
that's hard to classify.
638
00:35:39,120 --> 00:35:43,380
It behaves like a stellar
Jekyll and Hyde.
639
00:35:45,000 --> 00:35:48,900
So, this particular neutron star
is a really weird example.
640
00:35:48,900 --> 00:35:51,270
It behaves both like
a radio pulsar,
641
00:35:51,270 --> 00:35:54,210
and also a highly-magnetized
magnetar.
642
00:35:54,210 --> 00:35:56,540
It has the extreme
magnetic fields,
643
00:35:56,540 --> 00:35:59,280
it can have these
magnetic outbursts,
644
00:35:59,280 --> 00:36:02,010
but it also has
this strong jet of radiation
645
00:36:02,020 --> 00:36:03,280
coming out of its poles.
646
00:36:03,280 --> 00:36:07,320
It's almost like it has
a split personality.
647
00:36:07,320 --> 00:36:09,590
When first sighted in 2000,
648
00:36:09,590 --> 00:36:12,090
this star was emitting
radio waves...
649
00:36:12,090 --> 00:36:15,030
Typical pulsar behavior.
650
00:36:15,030 --> 00:36:19,030
Then, 16 years later,
it stopped pulsing,
651
00:36:19,030 --> 00:36:23,470
and suddenly started sending out
massive X-ray bursts...
652
00:36:23,470 --> 00:36:26,400
The actions of a magnetar.
653
00:36:26,410 --> 00:36:29,440
Scientists were baffled.
654
00:36:29,440 --> 00:36:32,640
We don't know if this thing is a
pulsar turning into a magnetar,
655
00:36:32,650 --> 00:36:35,210
or a magnetar turning
into a pulsar.
656
00:36:35,220 --> 00:36:38,150
One theory is that
these X-ray bursts happened
657
00:36:38,150 --> 00:36:42,220
because the star's magnetic
field suddenly twisted.
658
00:36:42,220 --> 00:36:46,660
The stress became so great,
the star cracked wide open,
659
00:36:46,660 --> 00:36:50,660
releasing the X-rays
from the fractured crust.
660
00:36:50,660 --> 00:36:52,930
A neutron star
is the densest material
661
00:36:52,930 --> 00:36:54,870
that we know of in the universe.
662
00:36:54,870 --> 00:36:56,100
And yet, we've seen things
663
00:36:56,100 --> 00:36:58,540
that actually make it shift
and pull apart.
664
00:36:58,540 --> 00:37:01,170
This neutron star is actually
ripping itself apart
665
00:37:01,180 --> 00:37:03,240
under the forces
of the magnetic field.
666
00:37:03,240 --> 00:37:04,740
If this is the case,
667
00:37:04,750 --> 00:37:09,310
placid neutron stars
turn into raging magnetars,
668
00:37:09,320 --> 00:37:12,750
growing old disgracefully.
669
00:37:12,750 --> 00:37:14,750
When you think about the
life cycle of a human being,
670
00:37:14,760 --> 00:37:16,590
we seem to kind of
slow down over age,
671
00:37:16,590 --> 00:37:18,060
become a little more calmer.
672
00:37:18,060 --> 00:37:19,720
Neutron stars do the opposite.
673
00:37:19,730 --> 00:37:21,530
They can be spinning
faster than they were
674
00:37:21,530 --> 00:37:22,830
when they were formed,
675
00:37:22,830 --> 00:37:25,160
and the magnetic field can
get stronger over time.
676
00:37:25,170 --> 00:37:28,330
It's sort of
a reverse aging process.
677
00:37:28,340 --> 00:37:31,600
But these strange
changes are extremely rare.
678
00:37:31,610 --> 00:37:36,680
Most pulsars
are as regular as clockwork.
679
00:37:36,680 --> 00:37:38,640
Pulsars are normally
incredibly regular.
680
00:37:38,650 --> 00:37:41,810
You can literally set your watch
to the timing of their pulse.
681
00:37:41,820 --> 00:37:44,380
And it's this
stability that we may use
682
00:37:44,380 --> 00:37:48,020
in our future exploration
of the universe.
683
00:37:48,020 --> 00:37:49,890
You know,
if you're a starship captain,
684
00:37:49,890 --> 00:37:53,060
what you need is
a galactic GPS system.
685
00:37:53,060 --> 00:37:56,190
Well it turns out,
neutron stars may be the answer.
686
00:38:11,600 --> 00:38:13,440
Astronomers often compare
687
00:38:13,440 --> 00:38:17,710
the steady flash of spinning
neutron stars, called "pulsars,"
688
00:38:17,710 --> 00:38:19,780
to cosmic lighthouses.
689
00:38:19,780 --> 00:38:23,550
These flashes are not only
remarkably reliable,
690
00:38:23,550 --> 00:38:29,090
each pulsar has its very own
distinct flickering beam.
691
00:38:29,090 --> 00:38:31,520
Each one has a slightly
different frequency.
692
00:38:31,520 --> 00:38:34,360
Each one has a slightly
different rate.
693
00:38:34,360 --> 00:38:37,730
Anyone in the galaxy,
no matter where you are,
694
00:38:37,730 --> 00:38:43,970
can all agree on the positions
of these pulsars.
695
00:38:43,970 --> 00:38:46,300
The unique signature of pulsars
696
00:38:46,300 --> 00:38:48,940
opens up intriguing
possibilities
697
00:38:48,940 --> 00:38:50,540
for the future of space travel.
698
00:38:55,980 --> 00:38:58,380
We would
basically be using pulsars
699
00:38:58,380 --> 00:39:01,280
to be able to sort of
triangulate where we're at.
700
00:39:01,290 --> 00:39:03,650
And because those pulses
are so precise,
701
00:39:03,660 --> 00:39:06,860
we can use that in a similar way
that we use GPS satellites
702
00:39:06,860 --> 00:39:08,390
that are stationed
above the Earth.
703
00:39:11,330 --> 00:39:14,200
Using pulsars
as navigational aids
704
00:39:14,200 --> 00:39:16,030
is not a new idea.
705
00:39:16,030 --> 00:39:19,400
It was recognized
by the NASA voyager mission
706
00:39:19,400 --> 00:39:22,410
in the 1970's.
707
00:39:22,410 --> 00:39:24,770
Affixed to the surface
of those spacecraft
708
00:39:24,780 --> 00:39:26,040
is a golden record.
709
00:39:26,040 --> 00:39:28,040
And on the plate
that covers that record
710
00:39:28,050 --> 00:39:31,480
is a pulsar map,
which in principle could tell
711
00:39:31,480 --> 00:39:34,880
an advanced alien civilization
how to find earth,
712
00:39:34,890 --> 00:39:37,390
because it uses
the position of earth
713
00:39:37,390 --> 00:39:39,560
relative to 14 known pulsars,
714
00:39:39,560 --> 00:39:41,720
as, effectively,
a way to triangulate
715
00:39:41,730 --> 00:39:43,260
the position of our planet
716
00:39:43,260 --> 00:39:46,200
relative to all
of these pulsars.
717
00:39:46,200 --> 00:39:52,200
Aliens haven't made contact,
but NASA still uses pulsar maps.
718
00:39:52,200 --> 00:39:54,100
NASA recently
launched a satellite
719
00:39:54,110 --> 00:39:55,740
called "nicer sextant"
720
00:39:55,740 --> 00:39:58,340
that exists on the
international space station,
721
00:39:58,340 --> 00:40:01,040
that is being used to test
these types of theories.
722
00:40:09,750 --> 00:40:12,220
They've used pulsars
to figure out the location
723
00:40:12,220 --> 00:40:14,220
of an object orbiting
around the Earth
724
00:40:14,230 --> 00:40:16,530
at 17,000 miles an hour,
725
00:40:16,530 --> 00:40:18,360
and they were able to
pinpoint its location
726
00:40:18,360 --> 00:40:19,860
to within three miles.
727
00:40:19,860 --> 00:40:21,930
That's pretty incredible.
728
00:40:21,930 --> 00:40:26,300
By recognizing their position
relative to known pulsars,
729
00:40:26,300 --> 00:40:30,010
future space missions
could navigate the universe.
730
00:40:36,550 --> 00:40:39,520
Neutron stars are gonna take us
on this incredible journey...
731
00:40:39,520 --> 00:40:40,950
Something as necessary
732
00:40:40,950 --> 00:40:42,820
as knowing where you are
in the galaxy.
733
00:40:42,820 --> 00:40:44,720
We could be many hundreds
of light years away,
734
00:40:44,720 --> 00:40:46,520
but neutron stars
can actually show us
735
00:40:46,520 --> 00:40:48,090
where in the milky way we are.
736
00:40:55,900 --> 00:40:57,200
I read a lot of science fiction,
737
00:40:57,200 --> 00:40:59,900
and I love the idea
of being able to go
738
00:40:59,900 --> 00:41:02,470
from star to star,
planet to planet.
739
00:41:02,470 --> 00:41:06,240
It's kind of weird to think
that, in the future,
740
00:41:06,240 --> 00:41:08,750
as a galactic coordinate grid,
741
00:41:08,750 --> 00:41:12,980
we might wind up using
these gigantic atomic nuclei,
742
00:41:12,980 --> 00:41:16,090
these rapidly spinning,
bizarrely-constructed,
743
00:41:16,090 --> 00:41:20,560
magnetic, fiercely gravitational
objects like neutron stars.
744
00:41:23,660 --> 00:41:26,500
Neutron stars
have come a long way
745
00:41:26,500 --> 00:41:31,200
since being mistaken
for little green men.
746
00:41:31,200 --> 00:41:35,740
Once overlooked
as astronomical oddities,
747
00:41:35,740 --> 00:41:43,180
they've now taken center stage
as genuine stellar superstars.
748
00:41:43,180 --> 00:41:45,620
What's really exciting
about neutron stars is that,
749
00:41:45,620 --> 00:41:47,920
we're at the beginning
of studying them.
750
00:41:47,920 --> 00:41:50,250
We're not at the conclusion.
We've learned a lot,
751
00:41:50,260 --> 00:41:52,090
but there's a lot more
to be learned.
752
00:41:52,090 --> 00:41:56,760
From the humble neutron
comes the most powerful,
753
00:41:56,760 --> 00:42:00,200
the most rapid,
the strongest magnetic field,
754
00:42:00,200 --> 00:42:04,030
the most exotic objects
in the cosmos.
755
00:42:04,040 --> 00:42:05,740
I love the idea of a Phoenix,
756
00:42:05,740 --> 00:42:08,270
something actually rising
from its own ashes.
757
00:42:08,270 --> 00:42:10,840
You think something dies,
and that's the end of the story,
758
00:42:10,840 --> 00:42:12,410
but something even
more beautiful,
759
00:42:12,410 --> 00:42:14,840
even more fascinating,
comes afterwards.
760
00:42:14,850 --> 00:42:17,080
I told you at the beginning,
and you didn't believe me,
761
00:42:17,080 --> 00:42:18,450
but now, I hope you do...
762
00:42:18,450 --> 00:42:21,050
Neutron stars
are the most fascinating
763
00:42:21,050 --> 00:42:23,690
astrophysical objects
in the universe.
764
00:42:23,740 --> 00:42:28,290
Repair and Synchronization by
Easy Subtitles Synchronizer 1.0.0.0
61511
Can't find what you're looking for?
Get subtitles in any language from opensubtitles.com, and translate them here.