1
00:00:07,220 --> 00:00:10,290
Neutron stars.

2
00:00:10,290 --> 00:00:12,360
Super heavy, super dense.

3
00:00:12,360 --> 00:00:13,760
Extreme.

4
00:00:13,760 --> 00:00:18,000
Gravitational, magnetic, hot.

5
00:00:18,000 --> 00:00:19,670
Scary.

6
00:00:19,670 --> 00:00:22,640
They destroy planets.

7
00:00:22,640 --> 00:00:25,410
They can even destroy stars.

8
00:00:25,410 --> 00:00:27,810
A cosmic conundrum.

9
00:00:27,810 --> 00:00:30,710
They're very, very massive,

10
00:00:30,710 --> 00:00:32,650
but they're also
really, really small.

11
00:00:32,650 --> 00:00:34,980
Tiny cosmic super powers

12
00:00:34,990 --> 00:00:40,260
long overshadowed by black holes...
Until now.

13
00:00:40,260 --> 00:00:42,360
Neutron stars have
been thrust very much

14
00:00:42,360 --> 00:00:44,830
to the forefront of
modern astrophysics.

15
00:00:44,830 --> 00:00:48,200
The world's astronomers know
that something is happening.

16
00:00:48,200 --> 00:00:51,200
Something's up, it's new,
and it's different.

17
00:00:51,200 --> 00:00:55,270
Neutron stars are
the most interesting

18
00:00:55,270 --> 00:00:58,640
astrophysical object
in the universe.

19
00:00:58,640 --> 00:01:01,310
Now firmly in the limelight,

20
00:01:01,310 --> 00:01:06,450
neutron stars, creators of
our most precious elements

21
00:01:06,450 --> 00:01:08,250
and life itself.

22
00:01:08,250 --> 00:01:11,250
Captions by vitac...
www.vitac.com

23
00:01:11,250 --> 00:01:14,290
captions paid for by
discovery communications

24
00:01:26,600 --> 00:01:30,340
130 million
light years form earth,

25
00:01:30,340 --> 00:01:35,280
a galaxy called
"NGC-4993."

26
00:01:35,280 --> 00:01:40,050
Two dead stars trapped in
a rapidly diminishing spiral.

27
00:01:46,620 --> 00:01:50,020
It's like listening to the
ringing of the cosmos itself.

28
00:01:50,030 --> 00:01:52,130
The sound of that collision,
if you will,

29
00:01:52,130 --> 00:01:56,660
imprinted on the fabric
of space and time itself.

30
00:01:56,670 --> 00:02:02,300
Livingston, Louisiana,
the advanced LiGO observatory.

31
00:02:02,310 --> 00:02:05,310
Its mission...
To detect gravitational waves

32
00:02:05,310 --> 00:02:06,940
generated in space.

33
00:02:09,210 --> 00:02:12,710
A gravitational wave is
a distortion of space time

34
00:02:12,720 --> 00:02:14,120
that's caused by, usually,

35
00:02:14,120 --> 00:02:18,120
some kind of very traumatic
gravitational event.

36
00:02:18,120 --> 00:02:20,820
Events such as a supernova,

37
00:02:20,820 --> 00:02:24,360
or the collision of black holes,
or massive stars.

38
00:02:26,200 --> 00:02:31,570
2015... LiGO makes history
by detecting gravitational waves

39
00:02:31,570 --> 00:02:33,130
for the first time,

40
00:02:33,140 --> 00:02:37,470
100 years after
Einstein's prediction.

41
00:02:37,470 --> 00:02:42,580
It's the signature of
the crash of black holes.

42
00:02:42,580 --> 00:02:44,650
It's almost like
listening to the sound

43
00:02:44,650 --> 00:02:47,820
of a distant car crash
that you didn't witness.

44
00:02:47,820 --> 00:02:49,680
But you're so clever,

45
00:02:49,690 --> 00:02:52,950
and the sound of this car crash
is such a unique signature,

46
00:02:52,960 --> 00:02:55,690
that you are able to use
your computers to model

47
00:02:55,690 --> 00:03:00,660
exactly the type of cars that
must have collided together.

48
00:03:00,660 --> 00:03:06,800
In 2017, LiGO picks up a
different kind of signal.

49
00:03:06,800 --> 00:03:09,440
The unfolding of
the August 2017 event

50
00:03:09,440 --> 00:03:12,110
was nothing short
of extraordinary.

51
00:03:12,110 --> 00:03:15,610
So, the signal comes in,
and the signal is strange.

52
00:03:15,610 --> 00:03:18,510
It has a long-lasting signal.

53
00:03:18,520 --> 00:03:20,050
It's over 100 seconds.

54
00:03:20,050 --> 00:03:22,950
Less than two seconds later,
a gamma-ray telescope

55
00:03:22,950 --> 00:03:25,520
detected a flash of gamma rays

56
00:03:25,520 --> 00:03:27,960
from that same part of the sky.

57
00:03:27,960 --> 00:03:31,090
And very quickly,
the world's astronomers

58
00:03:31,090 --> 00:03:33,030
know that something
is happening.

59
00:03:33,030 --> 00:03:36,060
Something's up, it's new,
and it's different.

60
00:03:39,140 --> 00:03:42,500
This combination of
a long gravitational wave signal

61
00:03:42,510 --> 00:03:46,710
and a blaze of gamma rays...

62
00:03:46,710 --> 00:03:49,210
Acts as a beacon
for astronomers.

63
00:03:51,880 --> 00:03:53,680
When they saw this event,

64
00:03:53,680 --> 00:03:55,820
they sent out a worldwide alert

65
00:03:55,820 --> 00:03:58,050
to astronomers
across the globe, saying,

66
00:03:58,050 --> 00:04:01,060
"hey, we saw
something interesting,

67
00:04:01,060 --> 00:04:03,830
and it came from
a particular patch of sky.

68
00:04:03,830 --> 00:04:05,890
Then, all the chatter started

69
00:04:05,900 --> 00:04:07,960
amongst the
astronomical community,

70
00:04:07,960 --> 00:04:10,270
and everyone starting
pointing their telescopes

71
00:04:10,270 --> 00:04:13,330
at this one part of the sky.

72
00:04:13,340 --> 00:04:15,900
Within hours,
thousands of astronomers

73
00:04:15,910 --> 00:04:19,040
and physicists across the globe
are frantically

74
00:04:19,040 --> 00:04:23,210
collecting data
on this mysterious event.

75
00:04:23,210 --> 00:04:25,380
There is not just
the gravitational waves,

76
00:04:25,380 --> 00:04:27,080
there is not just
the gamma rays.

77
00:04:27,080 --> 00:04:29,380
There's a visible light,
there's infrared light,

78
00:04:29,390 --> 00:04:31,090
there's ultraviolet light.

79
00:04:31,090 --> 00:04:34,390
And all these signals together
tell us a story.

80
00:04:34,390 --> 00:04:36,560
And this was the very first time

81
00:04:36,560 --> 00:04:39,230
we've seen these two
multiple messengers at once...

82
00:04:39,230 --> 00:04:41,800
Gravitational waves
and regular light.

83
00:04:41,800 --> 00:04:44,800
So, that was a groundbreaking
moment for astronomy.

84
00:04:48,470 --> 00:04:50,170
Scientists realize

85
00:04:50,170 --> 00:04:53,270
this isn't another
black-hole collision.

86
00:04:53,280 --> 00:04:56,210
This is something different.

87
00:04:56,210 --> 00:04:58,780
When you see an explosion
in the universe,

88
00:04:58,780 --> 00:05:01,180
there aren't exactly
a lot of candidates.

89
00:05:01,180 --> 00:05:04,450
There's not a lot of things
in the universe that blow up.

90
00:05:06,660 --> 00:05:10,430
But the length of
the signal is the smoking gun.

91
00:05:10,430 --> 00:05:13,630
The collision
of two black holes was quick.

92
00:05:13,630 --> 00:05:19,600
This one was the longer,
slower, death end-spiral

93
00:05:19,600 --> 00:05:21,770
of two neutron stars.

94
00:05:21,770 --> 00:05:25,610
Spiraling in,
closer and closer, speeding up.

95
00:05:25,610 --> 00:05:27,280
And then, when they
finally collide,

96
00:05:27,280 --> 00:05:29,780
when they finally touch,
releasing a tremendous

97
00:05:29,780 --> 00:05:32,710
amount of energy
into the surrounding system.

98
00:05:34,980 --> 00:05:37,890
The collision
throws up huge clouds of matter,

99
00:05:37,890 --> 00:05:41,160
which may have slowed down
the light very slightly.

100
00:05:41,160 --> 00:05:43,420
The light
and gravitational waves

101
00:05:43,430 --> 00:05:46,760
travel for 130 million years,

102
00:05:46,760 --> 00:05:51,200
arriving at earth
almost simultaneously.

103
00:05:51,200 --> 00:05:55,740
It's the first time astronomers
see neutron stars collide.

104
00:05:55,740 --> 00:05:58,340
They call it a "kilonova."

105
00:05:58,340 --> 00:06:00,910
And this spectacular
cosmic event

106
00:06:00,910 --> 00:06:03,640
doesn't just release energy.

107
00:06:03,650 --> 00:06:05,910
The aftermath of this
neutron-star collision,

108
00:06:05,920 --> 00:06:08,980
this kilonova, created
a tremendous amount of debris,

109
00:06:08,990 --> 00:06:10,990
which blasted out into space.

110
00:06:10,990 --> 00:06:12,990
And this may finally
have provided us

111
00:06:12,990 --> 00:06:15,590
the evidence of where
some very special

112
00:06:15,590 --> 00:06:17,860
heavy elements are created.

113
00:06:17,860 --> 00:06:22,800
Through the destruction of
a neutron star comes the seeds

114
00:06:22,800 --> 00:06:25,900
for the essential ingredients
of life itself.

115
00:06:25,900 --> 00:06:29,500
We breathe oxygen
molecules... O2.

116
00:06:29,510 --> 00:06:31,640
Water is hydrogen and oxygen.

117
00:06:31,640 --> 00:06:35,110
Most of our body is made up
of carbon compounds

118
00:06:35,110 --> 00:06:37,010
that include nitrogen,
phosphorus.

119
00:06:37,010 --> 00:06:39,680
One of the big questions
in science

120
00:06:39,680 --> 00:06:42,180
over the history of humanity
has been,

121
00:06:42,190 --> 00:06:45,020
"what are the origins
of these elements?"

122
00:06:45,020 --> 00:06:49,220
And it turns out that neutron
stars play a critical role

123
00:06:49,230 --> 00:06:51,830
in creating many of
the heavy elements.

124
00:06:55,060 --> 00:07:00,640
Most of the elements
on earth are made in stars.

125
00:07:00,640 --> 00:07:03,270
But how the heaviest
elements are made

126
00:07:03,270 --> 00:07:07,010
has been one of science's
longest-running mysteries.

127
00:07:08,980 --> 00:07:10,780
For a long time,
we knew there was a problem

128
00:07:10,780 --> 00:07:12,450
with making these
heavier atoms...

129
00:07:12,450 --> 00:07:15,820
Things like gold and platinum,
all the way out towards uranium.

130
00:07:15,820 --> 00:07:17,520
And really, the most
energetic thing we had

131
00:07:17,520 --> 00:07:19,990
in the universe
was supernova explosions.

132
00:07:19,990 --> 00:07:23,060
So, they had to be created
somehow in supernovas.

133
00:07:23,060 --> 00:07:26,090
But when scientists
ran computer simulations,

134
00:07:26,100 --> 00:07:30,830
virtual supernovas failed to
forge these oversized atoms.

135
00:07:34,040 --> 00:07:37,970
In 2016, astronomer
Edo Berger explained

136
00:07:37,970 --> 00:07:40,610
a potential solution
to the mystery.

137
00:07:44,310 --> 00:07:46,110
If you open
any one of these books,

138
00:07:46,120 --> 00:07:49,150
and flip to the page that
tells you where gold came from,

139
00:07:49,150 --> 00:07:51,920
it will tell you that gold
came from supernova explosions.

140
00:07:57,960 --> 00:08:02,000
But it was becoming clear that
the textbooks were out of date.

141
00:08:07,140 --> 00:08:09,700
To form heavy elements
requires a lot of neutrons,

142
00:08:09,710 --> 00:08:12,110
and so, another possible
theory was that

143
00:08:12,110 --> 00:08:14,880
the heaviest elements
were produced in the mergers

144
00:08:14,880 --> 00:08:18,150
of two neutron stars
in a binary system.

145
00:08:18,150 --> 00:08:20,720
But at the time,
no one had actually seen

146
00:08:20,720 --> 00:08:22,750
a neutron-star collision.

147
00:08:22,750 --> 00:08:25,020
It was difficult
to convince the community

148
00:08:25,020 --> 00:08:27,090
that this was
a potential channel

149
00:08:27,090 --> 00:08:29,390
for the production
of heavy elements.

150
00:08:29,390 --> 00:08:31,930
The proof is to actually
see this process

151
00:08:31,930 --> 00:08:33,190
happening in the universe.

152
00:08:35,160 --> 00:08:37,130
The 2017 kilonova

153
00:08:37,130 --> 00:08:39,700
provides the
perfect opportunity.

154
00:08:39,700 --> 00:08:43,570
It generates thousands
of hours of data.

155
00:08:43,570 --> 00:08:46,110
Scientists notice a pattern...

156
00:08:46,110 --> 00:08:51,380
Subtle changes in the color
of the kilonova remnants.

157
00:08:51,380 --> 00:08:54,180
In space, when you have
an event that is very bright,

158
00:08:54,180 --> 00:08:55,720
it emits a certain
amount of light,

159
00:08:55,720 --> 00:08:57,520
and it emits it at
certain wavelengths...

160
00:08:57,520 --> 00:08:59,950
What we think of as colors.

161
00:08:59,960 --> 00:09:02,960
Different colors
in a pyrotechnics display

162
00:09:02,960 --> 00:09:06,530
indicate the use of different
chemicals in fireworks.

163
00:09:06,530 --> 00:09:10,000
In the same way, scientists
can uncover the elements

164
00:09:10,000 --> 00:09:14,940
in the kilonova
by the colors in the explosion.

165
00:09:14,940 --> 00:09:18,810
As the kilonova turns red,
they realize it's the result

166
00:09:18,810 --> 00:09:20,940
of newly-created heavy elements

167
00:09:20,940 --> 00:09:24,050
starting to absorb blue light.

168
00:09:24,050 --> 00:09:26,410
As we watched
this remnant change...

169
00:09:26,420 --> 00:09:29,520
The explosion change in
color, expand and cool...

170
00:09:29,520 --> 00:09:32,490
We could estimate what sort of
elements were being produced.

171
00:09:34,790 --> 00:09:36,890
The light from the debris shifts

172
00:09:36,890 --> 00:09:40,700
from blue and Violet
to red and infrared.

173
00:09:40,700 --> 00:09:43,460
The color change provides clues

174
00:09:43,470 --> 00:09:46,930
about the presence
of certain heavy metals.

175
00:09:54,910 --> 00:09:57,850
Well, this neutron-star
collision, this kilonova,

176
00:09:57,850 --> 00:10:00,920
produced brightness
and a color spectrum

177
00:10:00,920 --> 00:10:04,350
that are consistent
with models of predictions

178
00:10:04,350 --> 00:10:06,520
that produce gold and platinum.

179
00:10:08,960 --> 00:10:11,860
This model
is called "The R-process,"

180
00:10:11,860 --> 00:10:14,830
short for
"rapid neutron capture."

181
00:10:14,830 --> 00:10:17,200
That is a bit of
a complicated term

182
00:10:17,200 --> 00:10:20,670
that describes how we make atoms
heavier than iron.

183
00:10:20,670 --> 00:10:23,000
You need a really
neutron-rich environment.

184
00:10:23,010 --> 00:10:25,810
And as you might imagine,
a neutron-star collision

185
00:10:25,810 --> 00:10:28,380
is a very neutron-rich
environment.

186
00:10:28,380 --> 00:10:30,140
If these models are correct...

187
00:10:30,150 --> 00:10:32,350
And this blows me away...

188
00:10:32,350 --> 00:10:34,250
This collision, this kilonova,

189
00:10:34,250 --> 00:10:38,450
produced several dozen times
the mass of the Earth

190
00:10:38,450 --> 00:10:40,490
in just gold.

191
00:10:47,130 --> 00:10:50,530
The 2017 kilonova
not only reveals

192
00:10:50,530 --> 00:10:52,800
the origin of key elements,

193
00:10:52,800 --> 00:10:56,500
it sheds light on
the neutron star's interior...

194
00:10:56,510 --> 00:10:59,610
The strongest material
in the universe

195
00:10:59,610 --> 00:11:01,440
creating a magnetic field

196
00:11:01,440 --> 00:11:05,210
a trillion times greater
than that of earth.

197
00:11:18,460 --> 00:11:23,730
Two neutron stars
caught in a death spiral.

198
00:11:23,730 --> 00:11:27,800
This massive kilonova explosion
not only sheds light

199
00:11:27,800 --> 00:11:29,840
on the creation
of heavy elements,

200
00:11:29,840 --> 00:11:32,170
such as gold and platinum,

201
00:11:32,180 --> 00:11:35,410
it also provides scientists
with a unique insight

202
00:11:35,410 --> 00:11:39,710
into one of the most mysterious
objects in the universe.

203
00:11:39,720 --> 00:11:42,780
Trying to imagine what
a neutron star is really like

204
00:11:42,790 --> 00:11:44,590
really challenges
our imagination.

205
00:11:44,590 --> 00:11:46,850
It also challenges
our theoretical physics.

206
00:11:46,860 --> 00:11:49,360
We have to go to our computer
models, our mathematics,

207
00:11:49,360 --> 00:11:53,330
to have some estimate
of what this might be like.

208
00:11:53,330 --> 00:11:55,860
Now,
scientists don't have to rely

209
00:11:55,870 --> 00:11:57,430
on their imaginations.

210
00:11:58,770 --> 00:12:02,470
They can use hard data
from the kilonova

211
00:12:02,470 --> 00:12:05,640
to work out what makes
neutron stars tick.

212
00:12:10,080 --> 00:12:12,150
There's so much information
we got from observing

213
00:12:12,150 --> 00:12:15,620
that one single event, that one
colliding neutron star pair.

214
00:12:15,620 --> 00:12:18,120
Now, for the first time,
we have an accurate estimate

215
00:12:18,120 --> 00:12:20,550
of the mass of a neutron star,
and the diameter.

216
00:12:20,560 --> 00:12:22,260
We can finally begin
to piece together

217
00:12:22,260 --> 00:12:25,830
how neutron stars really work.

218
00:12:25,830 --> 00:12:30,030
They calculate
the diameter is just 12.4 miles,

219
00:12:30,030 --> 00:12:34,770
1 mile less than
the length of Manhattan.

220
00:12:34,770 --> 00:12:37,240
Nailing down
any physical characteristic

221
00:12:37,240 --> 00:12:38,570
is really important.

222
00:12:38,570 --> 00:12:39,870
And if there's gonna be one,

223
00:12:39,880 --> 00:12:42,510
the radius is a big one,
because from there,

224
00:12:42,510 --> 00:12:44,280
if you know the mass,
you can get the density.

225
00:12:44,280 --> 00:12:45,910
And if you know
the overall density,

226
00:12:45,920 --> 00:12:47,650
you can start to figure out
what the layering

227
00:12:47,650 --> 00:12:49,580
inside of a neutron star
is like.

228
00:12:53,560 --> 00:12:57,120
For physicists,
the interior of a neutron star

229
00:12:57,130 --> 00:13:01,560
is one of the most intriguing
places in the universe.

230
00:13:01,560 --> 00:13:03,130
You have to realize
that the conditions

231
00:13:03,130 --> 00:13:05,230
inside a neutron star are very,
very different

232
00:13:05,230 --> 00:13:07,330
than the conditions
that exist here on earth.

233
00:13:07,340 --> 00:13:09,400
We're talking about material
that's so dense

234
00:13:09,410 --> 00:13:12,710
that even the nuclei of atoms
can't hold together.

235
00:13:12,710 --> 00:13:14,880
With a neutron star,
you're taking something

236
00:13:14,880 --> 00:13:17,280
that weighs more than the sun,

237
00:13:17,280 --> 00:13:20,980
and compressing it down
to be smaller than a city.

238
00:13:20,980 --> 00:13:23,780
It's so dense that, if you
tried to put it on the ground,

239
00:13:23,790 --> 00:13:25,750
it would fall
right through the Earth.

240
00:13:27,720 --> 00:13:30,720
High density
means high gravity...

241
00:13:30,730 --> 00:13:35,530
Gravity 200 billion times
greater than on earth.

242
00:13:35,530 --> 00:13:37,130
Imagine climbing up on
a table on the surface

243
00:13:37,130 --> 00:13:39,000
of a neutron star
and jumping off.

244
00:13:39,000 --> 00:13:41,200
You're gonna just
get flattened instantly,

245
00:13:41,200 --> 00:13:43,770
and just spread out
on that surface.

246
00:13:43,770 --> 00:13:48,180
So, don't even think about
trying to do push-ups.

247
00:13:48,180 --> 00:13:49,980
Added to the intense gravity

248
00:13:49,980 --> 00:13:52,680
are hugely powerful
magnetic fields,

249
00:13:52,680 --> 00:13:54,780
awesome X-ray radiation,

250
00:13:54,780 --> 00:13:58,550
electric fields 30 million times
more powerful

251
00:13:58,550 --> 00:14:00,550
than lightning bolts,

252
00:14:00,560 --> 00:14:04,630
and blizzards of
high-energy particles.

253
00:14:04,630 --> 00:14:08,660
This isn't a good neighborhood
for a space traveler.

254
00:14:11,630 --> 00:14:14,540
If you were to
find yourself in the vicinity

255
00:14:14,540 --> 00:14:18,170
of a neutron star,
it's gonna be bad news.

256
00:14:18,170 --> 00:14:20,170
First, you would be torn apart

257
00:14:20,180 --> 00:14:22,840
by the incredibly strong
magnetic fields.

258
00:14:22,850 --> 00:14:27,720
Then, the X-ray radiation
would blast you to a crisp.

259
00:14:27,720 --> 00:14:29,550
And as it pulled you closer,

260
00:14:29,550 --> 00:14:31,950
its intense gravity
would stretch out

261
00:14:31,950 --> 00:14:35,520
your atoms and molecules
into a long, thin stream.

262
00:14:35,520 --> 00:14:38,390
You would build your speed
faster and faster,

263
00:14:38,390 --> 00:14:41,500
and then, you would finally
impact the surface,

264
00:14:41,500 --> 00:14:43,230
splatter across it.

265
00:14:43,230 --> 00:14:46,230
And that process would
release as much energy

266
00:14:46,240 --> 00:14:47,370
as a nuclear bomb.

267
00:14:50,440 --> 00:14:53,640
If I had the choice between
falling into a neutron star

268
00:14:53,640 --> 00:14:56,880
versus a black hole,
I think I'd pick the black hole.

269
00:14:56,880 --> 00:14:58,980
'Cause I don't really feel like
being torn apart

270
00:14:58,980 --> 00:15:01,620
by a magnetic field
and blasted with x-rays.

271
00:15:06,020 --> 00:15:10,560
On a cosmic scale,
neutron stars may be pint-sized,

272
00:15:10,560 --> 00:15:13,290
but they sure pack
a serious punch.

273
00:15:13,300 --> 00:15:15,800
The secret to
all this pent-up power

274
00:15:15,800 --> 00:15:20,330
is what's going on
below the surface.

275
00:15:20,340 --> 00:15:22,870
Armed with
the new kilonova data,

276
00:15:22,870 --> 00:15:24,610
we can now take
a virtual journey

277
00:15:24,610 --> 00:15:27,340
into the heart
of a neutron star.

278
00:15:27,340 --> 00:15:31,610
First, we must pass
through its atmosphere.

279
00:15:31,610 --> 00:15:32,950
Now, it's not like
the Earth's atmosphere,

280
00:15:32,950 --> 00:15:34,780
which goes up,
like, a 100 miles.

281
00:15:34,780 --> 00:15:38,220
On a neutron star, the
atmosphere is about this deep,

282
00:15:38,220 --> 00:15:43,390
and it's extremely dense
compared to the air around us.

283
00:15:43,390 --> 00:15:48,030
Below the compressed atmosphere
is a crust of ionized iron,

284
00:15:48,030 --> 00:15:50,430
a mixture of
crystal iron nuclei,

285
00:15:50,430 --> 00:15:53,770
and free-flowing iron electrons.

286
00:15:53,770 --> 00:15:55,740
Now, the gravity's so strong

287
00:15:55,740 --> 00:15:58,170
that it's almost
perfectly smooth.

288
00:15:58,170 --> 00:15:59,640
The biggest mountains
on the surface

289
00:15:59,640 --> 00:16:02,040
are gonna be less than
a quarter of an inch high.

290
00:16:02,040 --> 00:16:07,480
A quarter-inch
mountain range may sound odd...

291
00:16:07,480 --> 00:16:11,790
But things get even stranger
as we go below the surface.

292
00:16:13,890 --> 00:16:17,860
This is home to the strongest
material in the universe.

293
00:16:20,930 --> 00:16:27,100
It's so weird, scientists
liken it to nuclear pasta.

294
00:16:27,100 --> 00:16:30,070
As we dive beneath
the crust of a neutron star,

295
00:16:30,070 --> 00:16:33,340
the neutrons themselves start
to glue themselves together

296
00:16:33,340 --> 00:16:35,280
into exotic shapes.

297
00:16:35,280 --> 00:16:40,550
First, they form clumps that
look something like gnocchi,

298
00:16:40,550 --> 00:16:43,620
then, deeper, the gnocchi
glue themselves together

299
00:16:43,620 --> 00:16:47,590
to form long strands
that look like spaghetti.

300
00:16:47,590 --> 00:16:50,190
Even deeper,
the spaghetti fuse together

301
00:16:50,190 --> 00:16:53,660
to form sheets of lasagna.

302
00:16:53,660 --> 00:16:56,630
And then, finally,
the lasagna fuse together

303
00:16:56,630 --> 00:17:01,240
to become a uniform mass,
but with holes in it.

304
00:17:01,240 --> 00:17:03,670
So, it looks like penne.

305
00:17:03,670 --> 00:17:07,140
This is pasta, nuclear style,

306
00:17:07,140 --> 00:17:08,410
simmering at a temperature

307
00:17:08,410 --> 00:17:11,180
of over one million
degrees Fahrenheit.

308
00:17:11,180 --> 00:17:14,950
Extreme gravity bends,
squeezes, stretches,

309
00:17:14,950 --> 00:17:17,890
and buckles neutrons,
creating a material

310
00:17:17,890 --> 00:17:22,190
100,000 billion times
denser than iron.

311
00:17:22,190 --> 00:17:25,990
But the journey
gets even more extreme.

312
00:17:26,000 --> 00:17:29,830
Even deeper is more mysterious
and harder to understand.

313
00:17:29,830 --> 00:17:31,870
The core of a neutron star...

314
00:17:31,870 --> 00:17:34,600
Which is very far away
from these layers,

315
00:17:34,600 --> 00:17:36,700
which we call
the "nuclear pasta"...

316
00:17:36,710 --> 00:17:39,970
Is perhaps the most
exotic form of matter.

317
00:17:39,980 --> 00:17:44,140
So exotic it might be
the last bastion of matter

318
00:17:44,150 --> 00:17:48,480
before complete gravitational
collapse into a black hole.

319
00:17:50,490 --> 00:17:52,790
Data from NASA's
Chandra observatory

320
00:17:52,790 --> 00:17:56,160
suggests the core
is made up of a super fluid...

321
00:17:56,160 --> 00:17:59,960
A bizarre friction-free
state of matter.

322
00:17:59,960 --> 00:18:02,660
Similar super fluids
produced in the lab

323
00:18:02,670 --> 00:18:04,700
exhibit strange properties,

324
00:18:04,700 --> 00:18:07,330
such as the ability
to flow upwards

325
00:18:07,340 --> 00:18:11,270
and escape airtight containers.

326
00:18:11,270 --> 00:18:13,570
Although our knowledge
of the star's interior

327
00:18:13,580 --> 00:18:15,810
is still hazy,
there's not mystery

328
00:18:15,810 --> 00:18:17,950
about its dazzling birth.

329
00:18:17,950 --> 00:18:22,050
Forged into life during
the most spectacular event

330
00:18:22,050 --> 00:18:23,980
the universe has to offer...

331
00:18:23,990 --> 00:18:27,490
The explosive death
of a massive star.

332
00:18:38,270 --> 00:18:40,270
Neutron stars...

333
00:18:40,270 --> 00:18:46,840
Manhattan-sized, but with a mass
twice that of our sun.

334
00:18:46,840 --> 00:18:52,910
So dense a teaspoon of their
matter weighs a billion tons.

335
00:18:52,920 --> 00:18:57,250
Mind-blowing objects
that arrive with a bang.

336
00:18:57,250 --> 00:18:59,220
Neutron stars spark into life

337
00:18:59,220 --> 00:19:01,190
amid the death
of their parent star.

338
00:19:01,190 --> 00:19:03,890
They're the ultimate story
of resurrection,

339
00:19:03,890 --> 00:19:06,560
or of life from death.

340
00:19:06,560 --> 00:19:10,630
It's all part of a cosmic cycle.

341
00:19:10,630 --> 00:19:14,970
Stars are born from giant
clouds of very cold gas.

342
00:19:14,970 --> 00:19:18,010
Those clouds collapse
under their own gravity,

343
00:19:18,010 --> 00:19:21,140
and the density of the core
at the center of the collapse

344
00:19:21,140 --> 00:19:22,310
starts to increase.

345
00:19:27,420 --> 00:19:31,350
A star is a huge
nuclear fusion reactor.

346
00:19:31,350 --> 00:19:33,920
The force of its gravity
is so powerful

347
00:19:33,920 --> 00:19:35,690
that it fuses atoms together

348
00:19:35,690 --> 00:19:40,590
to make progressively
heavier and heavier elements.

349
00:19:40,600 --> 00:19:43,730
The star fuses hydrogen
into helium.

350
00:19:43,730 --> 00:19:46,930
Once it exhausts its hydrogen,
then, if it's massive enough,

351
00:19:46,940 --> 00:19:49,370
it can start fusing helium
at its core.

352
00:19:51,810 --> 00:19:54,470
Fusion continues,
forming carbon,

353
00:19:54,480 --> 00:20:00,450
oxygen, nitrogen,
all the way up to iron.

354
00:20:00,450 --> 00:20:02,780
Once a star
has iron in the core,

355
00:20:02,790 --> 00:20:04,750
it's almost like
you've poisoned it,

356
00:20:04,750 --> 00:20:08,420
because this extinguishes
the nuclear reactions

357
00:20:08,420 --> 00:20:09,760
in the core of the star.

358
00:20:09,760 --> 00:20:13,990
You fuse something into iron,
and you get no energy.

359
00:20:14,000 --> 00:20:15,830
All of a sudden,
there's nothing to support

360
00:20:15,830 --> 00:20:17,100
the crush of gravity.

361
00:20:17,100 --> 00:20:18,800
No radiation pressure
pushing out

362
00:20:18,800 --> 00:20:22,770
means no pressure keeping the
outer regions from falling in,

363
00:20:22,770 --> 00:20:24,640
and that's what they do.

364
00:20:24,640 --> 00:20:27,740
As the star collapses
in its death throes,

365
00:20:27,740 --> 00:20:31,180
its core becomes
the wildest, craziest,

366
00:20:31,180 --> 00:20:35,420
and freakiest pressure cooker
in the whole universe.

367
00:20:37,550 --> 00:20:40,020
The ingredients
are all in place.

368
00:20:40,020 --> 00:20:44,890
It's time to start cooking up
a neutron star.

369
00:20:44,890 --> 00:20:47,630
If we were to scale up
an atomic nucleus

370
00:20:47,630 --> 00:20:49,500
to be the size of a baseball,

371
00:20:49,500 --> 00:20:53,670
in a normal atom,
the nearest electron would be

372
00:20:53,670 --> 00:20:55,700
way over in those trees,

373
00:20:55,700 --> 00:20:57,800
but in the extreme
conditions that lead to

374
00:20:57,810 --> 00:20:59,970
the formation of a neutron star,

375
00:20:59,980 --> 00:21:04,010
those electrons can be pushed
closer to the nucleus.

376
00:21:04,010 --> 00:21:07,180
They can come zipping in
from any direction.

377
00:21:07,180 --> 00:21:10,080
And if the temperatures
and pressures are high enough,

378
00:21:10,090 --> 00:21:12,050
they can even strike the nucleus

379
00:21:12,050 --> 00:21:14,960
and enter it,
and they can hit a proton.

380
00:21:14,960 --> 00:21:19,490
And when they do, they become
converted into more neutrons.

381
00:21:19,500 --> 00:21:22,130
So, in the formation
of one of these objects,

382
00:21:22,130 --> 00:21:24,460
the protons and
electrons disappear,

383
00:21:24,470 --> 00:21:27,470
and you're left with
almost entirely pure neutrons,

384
00:21:27,470 --> 00:21:30,540
with nothing to stop them
from cramming together

385
00:21:30,540 --> 00:21:33,410
and filling up
this entire baseball

386
00:21:33,410 --> 00:21:38,950
with neutrons leading to
incredibly high densities.

387
00:21:38,950 --> 00:21:40,310
With the sea of electrons

388
00:21:40,320 --> 00:21:42,880
now absorbed
in the atomic nuclei,

389
00:21:42,890 --> 00:21:47,820
the matter in the stars can now
press together a lot tighter.

390
00:21:47,820 --> 00:21:51,020
It's like squeezing
300 million tons of mass

391
00:21:51,030 --> 00:21:54,360
into a single sugar cube.

392
00:21:54,360 --> 00:21:56,130
As the star collapses,

393
00:21:56,130 --> 00:21:59,300
enormous amounts of gas
fall towards the core.

394
00:22:01,970 --> 00:22:06,470
The core is small in size,
but huge in mass.

395
00:22:06,480 --> 00:22:09,280
Billions of tons of gas
bounce off of it,

396
00:22:09,280 --> 00:22:12,750
then erupt into
the biggest fireworks display

397
00:22:12,750 --> 00:22:18,220
in the cosmos... A supernova.

398
00:22:18,220 --> 00:22:19,520
It's massive.

399
00:22:19,520 --> 00:22:20,620
It's bright.

400
00:22:20,620 --> 00:22:21,920
It's imposing.

401
00:22:21,920 --> 00:22:25,030
Supernova are among
the most dramatic events

402
00:22:25,030 --> 00:22:26,490
to happen in the universe.

403
00:22:26,500 --> 00:22:28,130
A single star dying...

404
00:22:28,130 --> 00:22:33,200
One star dying...
Can outshine an entire galaxy.

405
00:22:37,040 --> 00:22:39,510
And arising
out of this cataclysm,

406
00:22:39,510 --> 00:22:42,940
a new and very strange
cosmic entity.

407
00:22:45,910 --> 00:22:48,780
When the smoke finally clears
from the supernova explosion,

408
00:22:48,780 --> 00:22:51,520
you're left with one of
the most real, fascinating,

409
00:22:51,520 --> 00:22:54,690
unbelievable monsters
of the entire universe.

410
00:22:54,690 --> 00:22:56,360
Humans have been
witnessing supernovas

411
00:22:56,360 --> 00:22:57,990
for thousands of years,

412
00:22:57,990 --> 00:23:00,730
but we're only now
just starting to understand

413
00:23:00,730 --> 00:23:03,530
what we've truly
been witnessing...

414
00:23:03,530 --> 00:23:07,470
The births of neutron stars.

415
00:23:07,470 --> 00:23:10,570
But while supernovas
are big and bright,

416
00:23:10,570 --> 00:23:13,110
neutron stars are small,

417
00:23:13,110 --> 00:23:16,280
and many don't even
give off light.

418
00:23:16,280 --> 00:23:20,250
So, how many neutron stars
are out there?

419
00:23:20,250 --> 00:23:23,820
We know of about 2,000
neutron stars in our galaxy,

420
00:23:23,820 --> 00:23:25,420
but there probably are many,
many, more.

421
00:23:25,420 --> 00:23:28,260
I'm talking about tens of
millions in the milky way alone,

422
00:23:28,260 --> 00:23:32,530
and certainly billions
throughout the universe.

423
00:23:32,530 --> 00:23:38,330
Neutron stars may be small,
but some give themselves away,

424
00:23:38,330 --> 00:23:41,800
shooting beams
across the universe...

425
00:23:41,800 --> 00:23:47,070
Unmistakable, pulsing strobes
of a cosmic lighthouse.

426
00:24:00,760 --> 00:24:05,260
Our knowledge of
neutron stars is expanding fast.

427
00:24:07,800 --> 00:24:09,900
But we didn't even know
they existed

428
00:24:09,900 --> 00:24:13,470
until a lucky discovery
just over 50 years ago.

429
00:24:15,500 --> 00:24:18,640
Cambridge,
the Mullard radio observatory,

430
00:24:18,640 --> 00:24:20,540
Jocelyn bell, grad student,

431
00:24:20,540 --> 00:24:24,110
operating the new
radio telescope.

432
00:24:24,110 --> 00:24:27,210
Scanning the sky, doing all
sorts of cool astronomy stuff,

433
00:24:27,220 --> 00:24:32,650
and sees what she calls
"a bit of scruff" in the data.

434
00:24:32,650 --> 00:24:34,090
This scruff is a short

435
00:24:34,090 --> 00:24:37,420
but constantly repeating
burst of radiation

436
00:24:37,430 --> 00:24:41,700
originating 1,000 light years
from earth.

437
00:24:41,700 --> 00:24:44,830
It's so stable and regular
that bell is convinced

438
00:24:44,830 --> 00:24:47,600
there's a fault
with her telescope.

439
00:24:47,600 --> 00:24:49,540
She returns to that spot,

440
00:24:49,540 --> 00:24:53,840
and finds a repeating,
regular signal...

441
00:24:53,840 --> 00:24:59,380
A single point in the sky that
is flashing at us continually,

442
00:24:59,380 --> 00:25:02,180
saying "Hi. Hi. Hi."

443
00:25:02,180 --> 00:25:03,880
Blip, blip, blip.

444
00:25:03,890 --> 00:25:06,250
Boom, boom, boom.

445
00:25:06,260 --> 00:25:08,150
Pulse, pulse, pulse.

446
00:25:08,160 --> 00:25:10,160
Nothing that we know of
in the universe,

447
00:25:10,160 --> 00:25:14,730
has such a steady,
perfectly-spaced in time, pulse.

448
00:25:14,730 --> 00:25:18,970
It seemed so perfect that
it must have been artificial.

449
00:25:18,970 --> 00:25:22,340
It looks like
someone is making that,

450
00:25:22,340 --> 00:25:26,310
but it turns out, it's not
a person, but a thing.

451
00:25:26,310 --> 00:25:29,180
What she discovered
was called a "pulsar."

452
00:25:32,010 --> 00:25:34,610
A pulsar is
a type of rapidly spinning

453
00:25:34,620 --> 00:25:35,980
neutron star.

454
00:25:38,790 --> 00:25:42,660
Neutron stars had been theorized
in the 1930s,

455
00:25:42,660 --> 00:25:46,560
but were thought to be
too faint to be detected.

456
00:25:46,560 --> 00:25:51,160
Neutron stars were
hypothesized to exist,

457
00:25:51,170 --> 00:25:54,070
but not really taken seriously.

458
00:25:54,070 --> 00:25:56,540
It was just a, "oh, that's cute.

459
00:25:56,540 --> 00:25:59,140
Maybe they're out there,
but probably not."

460
00:26:00,280 --> 00:26:02,110
The signal bell detected

461
00:26:02,110 --> 00:26:06,110
seemed like something
from science fiction.

462
00:26:06,110 --> 00:26:08,880
No one had ever seen this
in astronomy before,

463
00:26:08,880 --> 00:26:13,020
and some people even speculated
that it was an alien signal.

464
00:26:13,020 --> 00:26:15,360
She even called them
"LGM objects"...

465
00:26:15,360 --> 00:26:18,330
"little green men."

466
00:26:18,330 --> 00:26:20,830
But then,
bell found a second signal.

467
00:26:23,670 --> 00:26:26,830
Little green men
went back to being fiction,

468
00:26:26,840 --> 00:26:30,500
and pulsars became science fact.

469
00:26:30,510 --> 00:26:32,770
The discovery of pulsars
came out of the blue.

470
00:26:32,770 --> 00:26:34,370
Nobody was expecting this.

471
00:26:34,380 --> 00:26:36,580
So, it was
an amazing breakthrough...

472
00:26:36,580 --> 00:26:37,780
Really important.

473
00:26:40,950 --> 00:26:45,350
Pulsars pulse
because they are born to spin.

474
00:26:45,350 --> 00:26:49,590
They burst into life
as their parent star collapses

475
00:26:49,590 --> 00:26:51,120
during a supernova.

476
00:26:53,300 --> 00:26:55,660
Any object at all
that is undergoing

477
00:26:55,660 --> 00:26:57,800
any sort of compression event,

478
00:26:57,800 --> 00:27:01,030
if it has any initial
angular momentum at all,

479
00:27:01,040 --> 00:27:05,140
it will eventually
end up spinning.

480
00:27:05,140 --> 00:27:09,240
As the star shrinks,
it spins faster and faster.

481
00:27:11,210 --> 00:27:15,350
They spin so quickly
because the Earth-sized core

482
00:27:15,350 --> 00:27:16,720
of a massive star

483
00:27:16,720 --> 00:27:19,990
collapsed to something
as small as a city.

484
00:27:19,990 --> 00:27:24,090
So, because the size of the
object became so much smaller,

485
00:27:24,090 --> 00:27:28,830
the rate of spin had to increase
by a tremendous amount.

486
00:27:28,830 --> 00:27:32,100
Neutron stars can spin
really, really, fast.

487
00:27:32,100 --> 00:27:34,570
Their surface is moving so fast.

488
00:27:34,570 --> 00:27:38,370
It's moving at about 20% the
speed of light, in some cases.

489
00:27:38,370 --> 00:27:41,640
So, if you were to
get on the neutron star ride...

490
00:27:41,640 --> 00:27:45,610
No pregnant women, no bad backs,
no heart issues,

491
00:27:45,610 --> 00:27:48,380
keep your arms and legs
inside the ride at all times,

492
00:27:48,380 --> 00:27:50,720
because they are about
to be obliterated.

493
00:27:52,620 --> 00:27:57,890
And as they spin, they generate
flashing beams of energy.

494
00:27:57,890 --> 00:28:00,290
This beam is like
a lighthouse beam.

495
00:28:00,300 --> 00:28:03,700
You see these periodic flashes
many times per second.

496
00:28:03,700 --> 00:28:08,570
So, every time you see it...
Beam, beam, beam.

497
00:28:08,570 --> 00:28:11,570
These beams
are the pulsar's calling card.

498
00:28:11,570 --> 00:28:14,270
They're generated
by the elemental chaos

499
00:28:14,280 --> 00:28:16,910
raging inside a neutron star.

500
00:28:16,910 --> 00:28:18,780
Although the star
is predominantly

501
00:28:18,780 --> 00:28:20,650
a ball of neutrons,

502
00:28:20,650 --> 00:28:24,380
the crust is sprinkled
with protons and electrons,

503
00:28:24,390 --> 00:28:26,620
spinning hundreds
of times a second,

504
00:28:26,620 --> 00:28:29,360
generating an incredible
magnetic field.

505
00:28:31,060 --> 00:28:32,890
And with this strong
magnetic field,

506
00:28:32,890 --> 00:28:34,990
you can create strong
electric fields.

507
00:28:35,000 --> 00:28:36,660
And the electric
and magnetic fields

508
00:28:36,670 --> 00:28:40,270
can work off of each other
and become radiation.

509
00:28:40,270 --> 00:28:46,040
These neutron stars send jets...
Beams of radiation...

510
00:28:46,040 --> 00:28:48,140
Out of their spinning poles.

511
00:28:48,140 --> 00:28:50,610
And if their spinning pole
is misaligned,

512
00:28:50,610 --> 00:28:52,210
if they're a little bit tilted,

513
00:28:52,210 --> 00:28:56,480
this beam will make circles,
across the universe.

514
00:28:56,490 --> 00:28:59,250
And if we're in the path
of one of these circles,

515
00:28:59,250 --> 00:29:02,990
we'll see a flash... A flash.

516
00:29:02,990 --> 00:29:04,660
Just like if you're on a ship,

517
00:29:04,660 --> 00:29:07,330
and you observe a distant
lighthouse in a foggy night,

518
00:29:07,330 --> 00:29:11,300
you can see pulsars across
the vast expanse of space

519
00:29:11,300 --> 00:29:14,900
because they are immensely
powerful beams of light.

520
00:29:14,900 --> 00:29:18,200
But sometimes,
pulsars get an extra push

521
00:29:18,210 --> 00:29:21,980
that accelerates
the spin even more.

522
00:29:21,980 --> 00:29:24,110
The way you make it spin
even faster

523
00:29:24,110 --> 00:29:27,280
is by subsequently
dumping more material onto it.

524
00:29:27,280 --> 00:29:29,780
That's called "accretion,"
and you end up spinning it up

525
00:29:29,790 --> 00:29:31,890
even faster than it
was already spinning.

526
00:29:31,890 --> 00:29:33,990
Like stellar vampires,

527
00:29:33,990 --> 00:29:36,220
pulsars are ready
to suck the life

528
00:29:36,220 --> 00:29:39,630
out of any objects
that stray too close.

529
00:29:39,630 --> 00:29:42,060
Gravity is bringing
that material in,

530
00:29:42,060 --> 00:29:44,730
which means that any spin
it has is accelerated.

531
00:29:44,730 --> 00:29:46,530
It spins faster and faster.

532
00:29:46,540 --> 00:29:48,840
These millisecond pulsars

533
00:29:48,840 --> 00:29:53,040
spin at around
700 revolutions per second.

534
00:29:53,040 --> 00:29:55,140
They are the ultimate
kitchen blender...

535
00:29:55,140 --> 00:29:59,480
They will chop, they will slice,
they will even julienne fry.

536
00:30:02,180 --> 00:30:04,220
So, what stops neutron stars

537
00:30:04,220 --> 00:30:07,390
from simply tearing
themselves apart?

538
00:30:07,390 --> 00:30:10,690
Neutron stars are
incredibly exotic objects

539
00:30:10,690 --> 00:30:14,730
with immense, immense forces
that bind them together,

540
00:30:14,730 --> 00:30:16,930
and so, they can be
held rigid even against

541
00:30:16,930 --> 00:30:19,230
these incredibly fast
rotation speeds.

542
00:30:22,900 --> 00:30:24,770
They have
incredibly strong gravity,

543
00:30:24,770 --> 00:30:26,670
and this is what allows them
to hold together

544
00:30:26,680 --> 00:30:28,840
even though they're
spinning around so fast.

545
00:30:31,910 --> 00:30:37,280
The speed of the spin
is hard to imagine.

546
00:30:37,290 --> 00:30:39,450
On earth, a day
is 24 hours long.

547
00:30:39,450 --> 00:30:44,490
On a neutron star,
it's a 700th of a second long.

548
00:30:44,490 --> 00:30:48,530
Super-speeding pulsars are
not the only weird stars

549
00:30:48,530 --> 00:30:51,060
that scientists
are coming to grips with.

550
00:30:51,070 --> 00:30:53,430
There is one other type
of neutron star,

551
00:30:53,440 --> 00:30:57,340
that has the most powerful
magnetic field in the universe.

552
00:30:57,340 --> 00:31:01,740
This magnetic monster
is called a "magnetar."

553
00:31:11,850 --> 00:31:14,990
Astronomers monitoring
pulsing neutron stars

554
00:31:14,990 --> 00:31:17,960
have noticed something very odd.

555
00:31:17,960 --> 00:31:23,560
On very rare occasions,
they can suddenly speed up.

556
00:31:23,570 --> 00:31:24,760
That's amazing.

557
00:31:24,770 --> 00:31:26,770
I mean, you've got this
incredibly dense object,

558
00:31:26,770 --> 00:31:28,200
and suddenly,
it's spinning faster.

559
00:31:28,200 --> 00:31:30,270
It happens... Instantly.

560
00:31:30,270 --> 00:31:32,110
They'll suddenly
change frequency.

561
00:31:32,110 --> 00:31:35,380
It would take an amazing
amount of power to do that.

562
00:31:35,380 --> 00:31:36,980
What's doing it?

563
00:31:36,980 --> 00:31:41,680
These sudden changes
in speed are called "glitches."

564
00:31:41,680 --> 00:31:44,050
One leading idea for
what causes these glitches

565
00:31:44,050 --> 00:31:46,690
is that the core material
latches onto the crust,

566
00:31:46,690 --> 00:31:49,890
and this affects
the way it can spin around.

567
00:31:49,890 --> 00:31:53,760
Excess material beneath
the crust cracks it open,

568
00:31:53,760 --> 00:31:55,760
causing the glitch.

569
00:31:55,760 --> 00:31:59,670
This process releases a
tremendous amount of radiation,

570
00:31:59,670 --> 00:32:04,200
a blast of x-rays, causes
the face of the neutron star

571
00:32:04,210 --> 00:32:08,570
to rearrange itself, and for
the rotation speed to change.

572
00:32:08,580 --> 00:32:11,180
But there's another
possible explanation.

573
00:32:11,180 --> 00:32:15,520
Glitches could also be caused
by starquakes.

574
00:32:15,520 --> 00:32:17,980
Sometimes,
the crust gets ruptured.

575
00:32:17,990 --> 00:32:22,120
Anything that basically changes
the geometry of the pulsar

576
00:32:22,120 --> 00:32:25,090
can change the rate
at which it spins.

577
00:32:25,090 --> 00:32:26,590
So,
what could be powerful enough

578
00:32:26,590 --> 00:32:29,930
to cause these starquakes?

579
00:32:29,930 --> 00:32:30,960
It's hard to believe

580
00:32:30,970 --> 00:32:33,300
that there's any
force in the universe

581
00:32:33,300 --> 00:32:36,370
that could deform the matter
inside of a neutron star,

582
00:32:36,370 --> 00:32:39,140
which is undergoing
tremendous gravity.

583
00:32:39,140 --> 00:32:40,870
But when it comes to
a neutron star,

584
00:32:40,880 --> 00:32:44,080
if there's one thing that
can do it, it's magnetism.

585
00:32:44,080 --> 00:32:45,810
Extreme magnetic fields

586
00:32:45,810 --> 00:32:48,610
within the star
can get so twisted

587
00:32:48,620 --> 00:32:51,320
they can rip the crust
wide open.

588
00:32:51,320 --> 00:32:53,920
And so, the surface
can restructure itself,

589
00:32:53,920 --> 00:32:55,490
and constantly reshape.

590
00:32:55,490 --> 00:32:58,160
And just a tiny reconfiguration

591
00:32:58,160 --> 00:32:59,930
of the surface
of a neutron star,

592
00:32:59,930 --> 00:33:01,560
on the order of
a few millimeters,

593
00:33:01,560 --> 00:33:06,030
would be associated with
an enormous release of energy.

594
00:33:06,030 --> 00:33:08,200
The neutron star's
immense gravity

595
00:33:08,200 --> 00:33:13,340
smooths over the star's surface
almost instantaneously.

596
00:33:13,340 --> 00:33:15,880
It's like the glitch
never happened.

597
00:33:19,350 --> 00:33:21,450
When it comes to neutron stars,

598
00:33:21,450 --> 00:33:26,050
there is no end
to magnetic mayhem.

599
00:33:26,050 --> 00:33:28,020
Meet the reigning champion

600
00:33:28,020 --> 00:33:32,560
in the universal "strongest
magnetic field" competition...

601
00:33:32,560 --> 00:33:35,060
The magnetar.

602
00:33:35,060 --> 00:33:38,630
1 in 10 neutron stars
formed during a supernova

603
00:33:38,630 --> 00:33:41,130
becomes a magnetar.

604
00:33:41,140 --> 00:33:45,710
The thing about magnetars,
as is implied in their name...

605
00:33:45,710 --> 00:33:48,010
The magnetic field
on them is so strong,

606
00:33:48,010 --> 00:33:50,540
that even somebody who is
used to using big numbers...

607
00:33:50,550 --> 00:33:52,310
Like, say, an astronomer...

608
00:33:52,310 --> 00:33:55,380
Is still kind of in awe
of these things.

609
00:33:55,380 --> 00:33:57,750
Magnetars have a magnetic field

610
00:33:57,750 --> 00:34:01,920
one thousand trillion times
stronger than that of earth's.

611
00:34:01,920 --> 00:34:03,820
This amount of magnetism

612
00:34:03,830 --> 00:34:08,630
will seriously mess up
anything that comes close.

613
00:34:08,630 --> 00:34:11,130
Any normal object
that we are familiar with,

614
00:34:11,130 --> 00:34:14,770
if it got close to a magnetar,
it would just be shredded.

615
00:34:14,770 --> 00:34:17,070
Any charged particle
with any movement at all,

616
00:34:17,070 --> 00:34:18,910
would just be torn
from its atom.

617
00:34:18,910 --> 00:34:22,310
It would be just
an insane situation.

618
00:34:22,310 --> 00:34:26,710
Magnetars burn brightly,
but their lives are brief.

619
00:34:26,710 --> 00:34:27,980
We think magnetars...

620
00:34:27,980 --> 00:34:30,620
These intensely
magnetized neutron stars...

621
00:34:30,620 --> 00:34:32,550
Can only be really short-lived.

622
00:34:32,550 --> 00:34:34,820
Their magnetic field
is so powerful

623
00:34:34,820 --> 00:34:37,360
that it should decay
over very rapid time scales,

624
00:34:37,360 --> 00:34:39,890
only on the order of
a few ten thousand years.

625
00:34:39,890 --> 00:34:44,360
It seems their very strength
leads to their downfall.

626
00:34:44,370 --> 00:34:46,300
That magnetic field is so strong

627
00:34:46,300 --> 00:34:49,340
that it's picking up material
around it, and accelerating it.

628
00:34:49,340 --> 00:34:51,370
Well, that acts like a drag,
slowing it down.

629
00:34:51,370 --> 00:34:54,540
So, over time, the spin
of the neutron star slows,

630
00:34:54,540 --> 00:34:56,380
and the magnetic field
dies away.

631
00:34:58,680 --> 00:34:59,980
During their lives,

632
00:34:59,980 --> 00:35:03,580
magnetars operate very
differently than pulsars.

633
00:35:03,590 --> 00:35:05,220
They don't have beams.

634
00:35:05,220 --> 00:35:08,190
Their magnetic fields
shoot out gigantic bursts

635
00:35:08,190 --> 00:35:11,620
of high-intensity radiation.

636
00:35:11,630 --> 00:35:15,290
But recently, astronomers
have spotted one neutron star

637
00:35:15,300 --> 00:35:17,760
that's hard to classify.

638
00:35:17,770 --> 00:35:22,030
It behaves like a stellar
Jekyll and Hyde.

639
00:35:24,040 --> 00:35:27,940
So, this particular neutron star
is a really weird example.

640
00:35:27,940 --> 00:35:30,310
It behaves both like
a radio pulsar,

641
00:35:30,310 --> 00:35:33,250
and also a highly-magnetized
magnetar.

642
00:35:33,250 --> 00:35:35,580
It has the extreme
magnetic fields,

643
00:35:35,580 --> 00:35:38,320
it can have these
magnetic outbursts,

644
00:35:38,320 --> 00:35:41,050
but it also has
this strong jet of radiation

645
00:35:41,060 --> 00:35:42,320
coming out of its poles.

646
00:35:42,320 --> 00:35:46,360
It's almost like it has
a split personality.

647
00:35:46,360 --> 00:35:48,630
When first sighted in 2000,

648
00:35:48,630 --> 00:35:51,130
this star was emitting
radio waves...

649
00:35:51,130 --> 00:35:54,070
Typical pulsar behavior.

650
00:35:54,070 --> 00:35:58,070
Then, 16 years later,
it stopped pulsing,

651
00:35:58,070 --> 00:36:02,510
and suddenly started sending out
massive X-ray bursts...

652
00:36:02,510 --> 00:36:05,440
The actions of a magnetar.

653
00:36:05,450 --> 00:36:08,480
Scientists were baffled.

654
00:36:08,480 --> 00:36:11,680
We don't know if this thing is a
pulsar turning into a magnetar,

655
00:36:11,690 --> 00:36:14,250
or a magnetar turning
into a pulsar.

656
00:36:14,260 --> 00:36:17,190
One theory is that
these X-ray bursts happened

657
00:36:17,190 --> 00:36:21,260
because the star's magnetic
field suddenly twisted.

658
00:36:21,260 --> 00:36:25,700
The stress became so great,
the star cracked wide open,

659
00:36:25,700 --> 00:36:29,700
releasing the X-rays
from the fractured crust.

660
00:36:29,700 --> 00:36:31,970
A neutron star
is the densest material

661
00:36:31,970 --> 00:36:33,910
that we know of in the universe.

662
00:36:33,910 --> 00:36:35,140
And yet, we've seen things

663
00:36:35,140 --> 00:36:37,580
that actually make it shift
and pull apart.

664
00:36:37,580 --> 00:36:40,210
This neutron star is actually
ripping itself apart

665
00:36:40,220 --> 00:36:42,280
under the forces
of the magnetic field.

666
00:36:42,280 --> 00:36:43,780
If this is the case,

667
00:36:43,790 --> 00:36:48,350
placid neutron stars
turn into raging magnetars,

668
00:36:48,360 --> 00:36:51,790
growing old disgracefully.

669
00:36:51,790 --> 00:36:53,790
When you think about the
life cycle of a human being,

670
00:36:53,800 --> 00:36:55,630
we seem to kind of
slow down over age,

671
00:36:55,630 --> 00:36:57,100
become a little more calmer.

672
00:36:57,100 --> 00:36:58,760
Neutron stars do the opposite.

673
00:36:58,770 --> 00:37:00,570
They can be spinning
faster than they were

674
00:37:00,570 --> 00:37:01,870
when they were formed,

675
00:37:01,870 --> 00:37:04,200
and the magnetic field can
get stronger over time.

676
00:37:04,210 --> 00:37:07,370
It's sort of
a reverse aging process.

677
00:37:07,380 --> 00:37:10,640
But these strange
changes are extremely rare.

678
00:37:10,650 --> 00:37:15,720
Most pulsars
are as regular as clockwork.

679
00:37:15,720 --> 00:37:17,680
Pulsars are normally
incredibly regular.

680
00:37:17,690 --> 00:37:20,850
You can literally set your watch
to the timing of their pulse.

681
00:37:20,860 --> 00:37:23,420
And it's this
stability that we may use

682
00:37:23,420 --> 00:37:27,060
in our future exploration
of the universe.

683
00:37:27,060 --> 00:37:28,930
You know,
if you're a starship captain,

684
00:37:28,930 --> 00:37:32,100
what you need is
a galactic GPS system.

685
00:37:32,100 --> 00:37:35,230
Well it turns out,
neutron stars may be the answer.

686
00:37:45,310 --> 00:37:47,150
Astronomers often compare

687
00:37:47,150 --> 00:37:51,420
the steady flash of spinning
neutron stars, called "pulsars,"

688
00:37:51,420 --> 00:37:53,490
to cosmic lighthouses.

689
00:37:53,490 --> 00:37:57,260
These flashes are not only
remarkably reliable,

690
00:37:57,260 --> 00:38:02,800
each pulsar has its very own
distinct flickering beam.

691
00:38:02,800 --> 00:38:05,230
Each one has a slightly
different frequency.

692
00:38:05,230 --> 00:38:08,070
Each one has a slightly
different rate.

693
00:38:08,070 --> 00:38:11,440
Anyone in the galaxy,
no matter where you are,

694
00:38:11,440 --> 00:38:17,680
can all agree on the positions
of these pulsars.

695
00:38:17,680 --> 00:38:20,010
The unique signature of pulsars

696
00:38:20,010 --> 00:38:22,650
opens up intriguing
possibilities

697
00:38:22,650 --> 00:38:24,250
for the future of space travel.

698
00:38:29,690 --> 00:38:32,090
We would
basically be using pulsars

699
00:38:32,090 --> 00:38:34,990
to be able to sort of
triangulate where we're at.

700
00:38:35,000 --> 00:38:37,360
And because those pulses
are so precise,

701
00:38:37,370 --> 00:38:40,570
we can use that in a similar way
that we use GPS satellites

702
00:38:40,570 --> 00:38:42,100
that are stationed
above the Earth.

703
00:38:45,040 --> 00:38:47,910
Using pulsars
as navigational aids

704
00:38:47,910 --> 00:38:49,740
is not a new idea.

705
00:38:49,740 --> 00:38:53,110
It was recognized
by the NASA voyager mission

706
00:38:53,110 --> 00:38:56,120
in the 1970's.

707
00:38:56,120 --> 00:38:58,480
Affixed to the surface
of those spacecraft

708
00:38:58,490 --> 00:38:59,750
is a golden record.

709
00:38:59,750 --> 00:39:01,750
And on the plate
that covers that record

710
00:39:01,760 --> 00:39:05,190
is a pulsar map,
which in principle could tell

711
00:39:05,190 --> 00:39:08,590
an advanced alien civilization
how to find earth,

712
00:39:08,600 --> 00:39:11,100
because it uses
the position of earth

713
00:39:11,100 --> 00:39:13,270
relative to 14 known pulsars,

714
00:39:13,270 --> 00:39:15,430
as, effectively,
a way to triangulate

715
00:39:15,440 --> 00:39:16,970
the position of our planet

716
00:39:16,970 --> 00:39:19,910
relative to all
of these pulsars.

717
00:39:19,910 --> 00:39:25,910
Aliens haven't made contact,
but NASA still uses pulsar maps.

718
00:39:25,910 --> 00:39:27,810
NASA recently
launched a satellite

719
00:39:27,820 --> 00:39:29,450
called "nicer sextant"

720
00:39:29,450 --> 00:39:32,050
that exists on the
international space station,

721
00:39:32,050 --> 00:39:34,750
that is being used to test
these types of theories.

722
00:39:43,460 --> 00:39:45,930
They've used pulsars
to figure out the location

723
00:39:45,930 --> 00:39:47,930
of an object orbiting
around the Earth

724
00:39:47,940 --> 00:39:50,240
at 17,000 miles an hour,

725
00:39:50,240 --> 00:39:52,070
and they were able to
pinpoint its location

726
00:39:52,070 --> 00:39:53,570
to within three miles.

727
00:39:53,570 --> 00:39:55,640
That's pretty incredible.

728
00:39:55,640 --> 00:40:00,010
By recognizing their position
relative to known pulsars,

729
00:40:00,010 --> 00:40:03,720
future space missions
could navigate the universe.

730
00:40:10,260 --> 00:40:13,230
Neutron stars are gonna take us
on this incredible journey...

731
00:40:13,230 --> 00:40:14,660
Something as necessary

732
00:40:14,660 --> 00:40:16,530
as knowing where you are
in the galaxy.

733
00:40:16,530 --> 00:40:18,430
We could be many hundreds
of light years away,

734
00:40:18,430 --> 00:40:20,230
but neutron stars
can actually show us

735
00:40:20,230 --> 00:40:21,800
where in the milky way we are.

736
00:40:29,610 --> 00:40:30,910
I read a lot of science fiction,

737
00:40:30,910 --> 00:40:33,610
and I love the idea
of being able to go

738
00:40:33,610 --> 00:40:36,180
from star to star,
planet to planet.

739
00:40:36,180 --> 00:40:39,950
It's kind of weird to think
that, in the future,

740
00:40:39,950 --> 00:40:42,460
as a galactic coordinate grid,

741
00:40:42,460 --> 00:40:46,690
we might wind up using
these gigantic atomic nuclei,

742
00:40:46,690 --> 00:40:49,800
these rapidly spinning,
bizarrely-constructed,

743
00:40:49,800 --> 00:40:54,270
magnetic, fiercely gravitational
objects like neutron stars.

744
00:40:57,370 --> 00:41:00,210
Neutron stars
have come a long way

745
00:41:00,210 --> 00:41:04,910
since being mistaken
for little green men.

746
00:41:04,910 --> 00:41:09,450
Once overlooked
as astronomical oddities,

747
00:41:09,450 --> 00:41:16,890
they've now taken center stage
as genuine stellar superstars.

748
00:41:16,890 --> 00:41:19,330
What's really exciting
about neutron stars is that,

749
00:41:19,330 --> 00:41:21,630
we're at the beginning
of studying them.

750
00:41:21,630 --> 00:41:23,960
We're not at the conclusion.
We've learned a lot,

751
00:41:23,970 --> 00:41:25,800
but there's a lot more
to be learned.

752
00:41:25,800 --> 00:41:30,470
From the humble neutron
comes the most powerful,

753
00:41:30,470 --> 00:41:33,910
the most rapid,
the strongest magnetic field,

754
00:41:33,910 --> 00:41:37,740
the most exotic objects
in the cosmos.

755
00:41:37,750 --> 00:41:39,450
I love the idea of a Phoenix,

756
00:41:39,450 --> 00:41:41,980
something actually rising
from its own ashes.

757
00:41:41,980 --> 00:41:44,550
You think something dies,
and that's the end of the story,

758
00:41:44,550 --> 00:41:46,120
but something even
more beautiful,

759
00:41:46,120 --> 00:41:48,550
even more fascinating,
comes afterwards.

760
00:41:48,560 --> 00:41:50,790
I told you at the beginning,
and you didn't believe me,

761
00:41:50,790 --> 00:41:52,160
but now, I hope you do...

762
00:41:52,160 --> 00:41:54,760
Neutron stars
are the most fascinating

763
00:41:54,760 --> 00:41:57,400
astrophysical objects
in the universe.