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Nothing can escape.
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They can suck in whole galaxies.
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00:01:23,840 --> 00:01:27,110
Black holes
used to be science fiction.
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Now we know they're real.
5
00:01:29,550 --> 00:01:31,110
When I was a PhD student,
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People used to giggle when
you'd hear about black holes.
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00:01:34,550 --> 00:01:37,220
They're like unicorns,
mythical creatures.
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00:01:37,220 --> 00:01:38,990
We called this
the "giggle factor."
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People would say,
"beam me up, Scotty."
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Well,
no one is laughing anymore.
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00:01:45,030 --> 00:01:47,430
Krauss:
So, they're not science fiction.
12
00:01:47,430 --> 00:01:49,560
Even though
we've never landed in one,
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00:01:49,570 --> 00:01:51,930
We have enough evidence to know
that they're really out there.
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00:01:57,770 --> 00:02:01,040
Narrator: This image might not
look like much to you and me,
15
00:02:01,040 --> 00:02:05,780
But to a scientist, it's proof
that black holes exist.
16
00:02:05,780 --> 00:02:10,350
It's an actual movie
of a black hole devouring a star
17
00:02:10,350 --> 00:02:12,990
In the constellation of Aquila.
18
00:02:12,990 --> 00:02:15,160
Black holes are messy eaters.
19
00:02:15,160 --> 00:02:17,290
The red spots you see are gas
20
00:02:17,290 --> 00:02:21,800
That's being spit
out of the hole, into space.
21
00:02:21,800 --> 00:02:24,900
Eventually,
over the next million years,
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00:02:24,900 --> 00:02:29,770
This star will be eaten alive
and disappear.
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00:02:37,850 --> 00:02:40,250
A black hole is pretty much
the end point of everything.
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00:02:40,250 --> 00:02:42,750
It's the end point of a star.
It's the end point of matter.
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00:02:42,750 --> 00:02:45,320
It's the end point of energy.
It's the end point of gravity.
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00:02:45,320 --> 00:02:49,990
I mean, that's really it.
That's the top of the scale.
27
00:02:54,460 --> 00:02:56,900
Narrator: Although
they have the power to destroy
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Like nothing else
in the universe,
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00:02:58,700 --> 00:03:02,740
Black holes also help build
galaxies --
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00:03:02,740 --> 00:03:06,740
A vital part
of the great cosmic machine.
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00:03:06,740 --> 00:03:08,640
Some astronomers think
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00:03:08,640 --> 00:03:12,580
They could even be gateways
to parallel universes.
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00:03:17,720 --> 00:03:20,790
Dr. Kaku: We are now entering
the golden age of research
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00:03:20,790 --> 00:03:22,060
In black-hole physics.
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00:03:22,060 --> 00:03:24,730
They could be the key
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00:03:24,730 --> 00:03:27,530
To understanding
the birth of the universe,
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00:03:27,530 --> 00:03:29,860
Its formation,
and then its death.
38
00:03:34,740 --> 00:03:36,770
Dr. Krauss:
Black holes really represent,
39
00:03:36,770 --> 00:03:39,040
In one sense, the frontier
of modern astronomy.
40
00:03:39,040 --> 00:03:41,780
And they're changing our ideas
about how galaxies form
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00:03:41,780 --> 00:03:43,710
And, indeed,
how the universe works.
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00:03:43,710 --> 00:03:46,580
Narrator:
Their power comes
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00:03:46,580 --> 00:03:50,380
From one of the primary forces
in nature -- gravity.
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00:03:53,120 --> 00:03:55,290
Dr. Kaku:
I teach astronomy.
45
00:03:55,290 --> 00:03:56,860
And we teach our students
46
00:03:56,860 --> 00:04:00,590
That the fundamental principle
of gravity is, "gravity sucks."
47
00:04:00,600 --> 00:04:04,170
Narrator: Gravity keeps our feet
on the ground
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00:04:04,170 --> 00:04:07,270
And our planet
orbiting around the sun.
49
00:04:09,600 --> 00:04:15,180
But in a black hole, the force
of gravity is off the charts --
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00:04:15,180 --> 00:04:18,910
So strong,
it sucks in anything nearby.
51
00:04:18,910 --> 00:04:24,450
It can even bend
the light from distant stars.
52
00:04:24,450 --> 00:04:27,460
And if that light
gets too close,
53
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The black hole swallows it.
54
00:04:29,730 --> 00:04:31,460
Think of it like this.
55
00:04:31,460 --> 00:04:34,330
Imagine a black hole
as a waterfall.
56
00:04:34,330 --> 00:04:37,630
Gravity is the river
flowing toward the falls,
57
00:04:37,630 --> 00:04:40,030
And a beam of light --
the kayak.
58
00:04:40,040 --> 00:04:43,270
Upriver from the waterfall,
the current is weak.
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00:04:43,270 --> 00:04:46,840
The kayaker can paddle
against it and get away.
60
00:04:46,840 --> 00:04:50,340
But closer to the waterfall,
the current is stronger,
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00:04:50,350 --> 00:04:55,320
And the kayaker struggles
to escape.
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00:04:55,320 --> 00:05:01,260
The edge of the waterfall is
like the edge of a black hole.
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00:05:01,260 --> 00:05:06,160
No matter how strong
the kayaker is, he's going down.
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00:05:06,160 --> 00:05:07,900
It's the same in space.
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00:05:07,900 --> 00:05:11,070
The way black holes
are really devastating
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00:05:11,070 --> 00:05:13,400
Is because
when you get close to them,
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00:05:13,400 --> 00:05:15,140
The gravity gets super-strong.
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00:05:20,240 --> 00:05:23,240
Narrator:
So strong that they eat light.
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00:05:23,250 --> 00:05:26,680
That's why black holes
are black.
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00:05:31,390 --> 00:05:33,950
A black hole
is like a roach motel.
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00:05:33,960 --> 00:05:36,890
Everything checks in.
Nothing checks out.
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00:05:41,100 --> 00:05:44,200
Narrator: Anything
that gets too close is doomed --
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00:05:44,200 --> 00:05:49,900
Planets, stars,
even whole solar systems.
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00:05:56,680 --> 00:06:00,180
And don't think
this is some faraway phenomenon.
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00:06:00,180 --> 00:06:02,520
Black holes are on the loose
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00:06:02,520 --> 00:06:06,150
Right here
in our own cosmic neighborhood.
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00:06:06,150 --> 00:06:08,620
We now know
there are wandering nomads
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00:06:08,620 --> 00:06:10,860
Throughout
the milky way galaxy --
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00:06:10,860 --> 00:06:13,960
Vagabonds throughout the galaxy,
80
00:06:13,960 --> 00:06:17,160
Where black holes can come up
right behind you
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00:06:17,170 --> 00:06:19,930
And perhaps gobble you up,
and they won't even burp.
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00:06:19,940 --> 00:06:23,570
If one ever comes close,
watch out.
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00:06:23,570 --> 00:06:28,080
Narrator: If a black hole found
its way into our solar system,
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00:06:28,080 --> 00:06:29,810
It would rip us apart.
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00:06:29,810 --> 00:06:31,780
Dr. Plait:
Any kind of black hole
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00:06:31,780 --> 00:06:34,050
That could pass
through the solar system
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Would be pulling
on all the planets
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Harder than the sun does.
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00:06:37,190 --> 00:06:38,850
And so it's just
gonna totally disrupt
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00:06:38,850 --> 00:06:41,020
The gravitational balance
of the solar system.
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00:06:41,020 --> 00:06:46,490
Narrator: The black hole would literally
tear planets from their orbits
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And smash them into each other.
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It's just an epic disaster.
It's a bull in a china shop.
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00:07:03,010 --> 00:07:06,410
If it got close enough
to, say, Jupiter,
95
00:07:06,410 --> 00:07:08,950
It could actually pull
the moons of Jupiter
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00:07:08,950 --> 00:07:11,150
Away from the planet itself.
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00:07:13,260 --> 00:07:15,590
It would just be flinging
planets left and right
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00:07:15,590 --> 00:07:17,930
Everywhere as it whipped
through the solar system,
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00:07:17,930 --> 00:07:20,330
Leaving disaster in its wake.
100
00:07:25,070 --> 00:07:28,100
Narrator: If a black hole
approached earth,
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00:07:28,100 --> 00:07:31,810
All that gravity would rip
asteroids from their orbits
102
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And hurl them toward our planet.
103
00:07:42,620 --> 00:07:45,590
The earth's surface
would become an inferno.
104
00:07:45,590 --> 00:07:49,360
It would be
the beginning of the end.
105
00:07:53,960 --> 00:07:56,630
First, it would swallow up
the atmosphere,
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00:07:56,630 --> 00:07:59,200
Then the planet itself.
107
00:08:04,510 --> 00:08:06,940
Destroying
an entire solar system
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00:08:06,940 --> 00:08:09,380
Is nothing to a black hole.
109
00:08:09,380 --> 00:08:14,350
But it's more than just a big,
empty, sucking piece of space.
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00:08:14,350 --> 00:08:17,150
It's incredibly heavy.
111
00:08:17,150 --> 00:08:21,620
To get an idea just how heavy
and Dee a black hole is,
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00:08:21,620 --> 00:08:23,320
Imagine the earth.
113
00:08:23,330 --> 00:08:26,660
Now start to crush it...
114
00:08:29,260 --> 00:08:32,700
...And keep crushing
until it's packed so tight
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00:08:32,700 --> 00:08:35,870
Even the atoms themselves
collapse.
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00:08:38,710 --> 00:08:43,010
When the earth crushes down
to just 2 inches across,
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00:08:43,010 --> 00:08:45,980
That's the density
of a black hole.
118
00:08:45,980 --> 00:08:48,750
It would be
the size of a golf ball,
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00:08:48,750 --> 00:08:54,620
Yet weigh the same as e earth,
with the same amount of gravity.
120
00:08:54,620 --> 00:08:58,230
What can make
something that small,
121
00:08:58,230 --> 00:09:02,100
That dense, and that powerful?
122
00:09:02,100 --> 00:09:06,300
We don't have external forces,
large pistons in the universe,
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00:09:06,300 --> 00:09:07,900
To create black holes.
124
00:09:07,900 --> 00:09:10,670
So the only way the real
black holes of the universe form
125
00:09:10,670 --> 00:09:12,540
Is if gravity
can do the job itself.
126
00:09:12,540 --> 00:09:16,410
Narrator: There is only
one place in the universe
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00:09:16,410 --> 00:09:19,210
That generates
that much gravity.
128
00:09:19,210 --> 00:09:22,080
And it's
inside the largest stars.
129
00:09:22,080 --> 00:09:27,420
When massive stars 10 times
heavier than our sun die,
130
00:09:27,420 --> 00:09:29,290
Gravity crushes them,
131
00:09:29,290 --> 00:09:32,890
Creating a huge explosion,
a supernova.
132
00:09:43,100 --> 00:09:48,510
But some stars
are even bigger than that.
133
00:09:48,510 --> 00:09:53,550
These supermassive stars weigh
100 times more than our sun
134
00:09:53,550 --> 00:09:56,420
And have 100 times more gravity.
135
00:09:56,420 --> 00:09:58,820
When one of these stars dies,
136
00:09:58,820 --> 00:10:04,560
It sets off the biggest
explosion in the universe...
137
00:10:04,560 --> 00:10:06,560
A hypernova.
138
00:10:16,570 --> 00:10:20,940
This is the birth
of a black hole.
139
00:10:31,940 --> 00:10:36,480
Narrator:
Our universe is full of stars.
140
00:10:36,480 --> 00:10:40,850
At the end of their lives,
some die quietly.
141
00:10:40,850 --> 00:10:45,150
Others go out
in spectacular explosions.
142
00:10:45,160 --> 00:10:50,630
And some give birth
to black holes.
143
00:10:50,630 --> 00:10:52,560
Dr. Plait:
If you have a star,
144
00:10:52,560 --> 00:10:55,860
A supermassive star that's
100 times the mass of the sun,
145
00:10:55,870 --> 00:10:58,830
At the end of its life,
the core runs out of fuel.
146
00:10:58,840 --> 00:11:00,740
There's nothing left
to hold it up,
147
00:11:00,740 --> 00:11:03,110
And the core collapses
down into a black hole.
148
00:11:03,110 --> 00:11:06,840
Narrator: When that happens,
the enormous gravity
149
00:11:06,840 --> 00:11:11,910
Generated at the heart
of supermassive stars runs wild.
150
00:11:14,720 --> 00:11:19,590
This is the dying star
v.Y. Canis majoris.
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00:11:19,590 --> 00:11:24,190
It's more than
a billion miles across.
152
00:11:27,360 --> 00:11:31,800
Like all stars, it's a giant
nuclear-fusion reactor,
153
00:11:31,800 --> 00:11:34,200
Pumping energy outward.
154
00:11:34,200 --> 00:11:39,710
At the same time, the star's
extreme gravity crushes inward.
155
00:11:39,710 --> 00:11:41,740
For a few million years,
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00:11:41,750 --> 00:11:45,850
Fusion and gravity
are locked in standoff.
157
00:11:45,850 --> 00:11:48,920
But when the star
runs out of fuel,
158
00:11:48,920 --> 00:11:52,820
Fusion stops
and the stalemate ends.
159
00:11:52,820 --> 00:11:54,620
Gravity wins.
160
00:11:57,030 --> 00:11:59,090
In a millisecond,
161
00:11:59,100 --> 00:12:02,430
The core shrinks to a fraction
of its original size
162
00:12:02,430 --> 00:12:06,570
And a baby black hole is born.
163
00:12:06,570 --> 00:12:08,170
Immediately,
164
00:12:08,170 --> 00:12:12,010
It starts to cannibalize
what's left of the star.
165
00:12:12,010 --> 00:12:15,440
As matter swirls into the black
hole, it gets incredibly hot.
166
00:12:15,450 --> 00:12:17,980
And there are magnetic forces
and frictional forces,
167
00:12:17,980 --> 00:12:20,080
And it's just a witch's brew,
a nightmare,
168
00:12:20,080 --> 00:12:22,850
What's going on right above
the surface of the black hole.
169
00:12:22,850 --> 00:12:25,520
Narrator:
The new black hole in the middle
170
00:12:25,520 --> 00:12:28,490
Keeps feeding on the body
of the star around it.
171
00:12:28,490 --> 00:12:33,260
It eats the gas so fast,
it chokes and coughs,
172
00:12:33,260 --> 00:12:36,500
Blasting out
huge beams of energy.
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00:12:40,600 --> 00:12:43,610
Dr. Plait: They basically
eat their way out from the star.
174
00:12:43,610 --> 00:12:45,440
This happens in milliseconds.
175
00:12:45,440 --> 00:12:48,280
It happens before
the rest of the star even knows
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00:12:48,280 --> 00:12:49,780
The core is gone.
177
00:12:49,780 --> 00:12:54,280
And so basically, the star is
dead before it hits the ground.
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00:12:57,890 --> 00:13:01,760
Narrator:
Finally, the star explodes.
179
00:13:04,430 --> 00:13:09,700
In one second, it blasts out
100 times more energy
180
00:13:09,700 --> 00:13:13,970
Than our sun will produce
over its entire life.
181
00:13:16,370 --> 00:13:21,180
What's left is a new black hole
and two jets of energy
182
00:13:21,180 --> 00:13:25,850
Hurtling through the universe
at the speed of light.
183
00:13:25,850 --> 00:13:29,550
These jets are called
"gamma-ray bursts."
184
00:13:34,920 --> 00:13:38,060
Dr. Plait: They're
incredibly energetic events.
185
00:13:38,060 --> 00:13:40,400
In terms
of raw energy and power,
186
00:13:40,400 --> 00:13:43,570
Gamma ray bursts are second
only to the big bang itself.
187
00:13:45,270 --> 00:13:48,270
Narrator: Most of them last
only a few seconds.
188
00:13:48,270 --> 00:13:51,770
And they fry
anything in their way.
189
00:13:55,610 --> 00:13:58,980
They're so intense that
if there was a gamma-ray burster
190
00:13:58,980 --> 00:14:02,020
In the region of our galaxy
near our solar system,
191
00:14:02,020 --> 00:14:05,420
It could literally vaporize
the entire planet.
192
00:14:05,420 --> 00:14:10,530
Narrator: Fortunately, most gamma-ray
bursts occur outside our galaxy.
193
00:14:17,470 --> 00:14:20,440
But they tell us
something important
194
00:14:20,440 --> 00:14:25,470
About black holes
and how our universe works.
195
00:14:25,480 --> 00:14:28,840
What we were seeing every time
a gamma-ray burst went off
196
00:14:28,850 --> 00:14:31,550
Was basically
the birth cry of a black hole.
197
00:14:31,550 --> 00:14:36,750
Narrator: By counting gamma-ray
bursts, astronomers can figure out
198
00:14:36,750 --> 00:14:39,450
How many black holes
are being created.
199
00:14:39,460 --> 00:14:43,730
In 2004, NASA launched
the swift probe
200
00:14:43,730 --> 00:14:46,860
To scan the universe
for gamma-ray bursts.
201
00:14:46,860 --> 00:14:47,860
Man: Five...
202
00:14:47,860 --> 00:14:48,900
Four...
203
00:14:48,900 --> 00:14:49,930
Three...
204
00:14:49,930 --> 00:14:51,070
Two...
205
00:14:51,070 --> 00:14:53,200
One...
We have ignition.
206
00:14:53,200 --> 00:14:56,610
And we have lift-off
of NASA's swift spacecraft,
207
00:14:56,610 --> 00:14:59,910
On a mission to study
and understand gamma-ray bursts
208
00:14:59,910 --> 00:15:01,440
Throughout the universe.
209
00:15:07,780 --> 00:15:10,890
Narrator: This is the most
powerful gamma-ray burst
210
00:15:10,890 --> 00:15:13,060
Swift has detected so far.
211
00:15:13,060 --> 00:15:17,030
The flash of light announces
the birth of a new black hole
212
00:15:17,030 --> 00:15:19,560
On the other side
of the universe.
213
00:15:23,770 --> 00:15:28,600
Swift can only look at
a fraction of what's out there.
214
00:15:32,710 --> 00:15:37,580
Still, it detects at least
one gamma-ray burst every day.
215
00:15:39,480 --> 00:15:44,150
That discovery rocked astronomy
to its foundations.
216
00:15:46,520 --> 00:15:49,360
Dr. Kaku: We once thought
that black holes, like unicorns,
217
00:15:49,360 --> 00:15:51,990
Could never be found.
218
00:15:52,000 --> 00:15:55,400
We now believe that there are
perhaps billions of black holes
219
00:15:55,400 --> 00:15:56,700
In the night sky.
220
00:15:56,700 --> 00:15:59,400
When we look around our galaxy
and other galaxies,
221
00:15:59,400 --> 00:16:04,270
It's clear that the universe
is full of powerful black holes.
222
00:16:04,270 --> 00:16:06,840
Narrator: Finding black holes
is one thing.
223
00:16:06,840 --> 00:16:08,510
Figuring out how they work --
224
00:16:08,510 --> 00:16:10,680
That's a whole different
ball game.
225
00:16:10,680 --> 00:16:13,450
The only way to find out
is to visit one.
226
00:16:13,450 --> 00:16:17,850
You'd have to take a spacecraft
across the vastness of space
227
00:16:17,850 --> 00:16:19,690
Just to get close to it.
228
00:16:19,690 --> 00:16:23,930
Then you'd have to go
inside the black hole.
229
00:16:23,930 --> 00:16:25,830
There, you'd find a place
230
00:16:25,830 --> 00:16:30,070
Where reality breaks down
and time stands still.
231
00:16:37,760 --> 00:16:41,530
Narrator: There are billions
of black holes in the universe.
232
00:16:41,530 --> 00:16:44,900
We can detect them
with telescopes and satellites.
233
00:16:44,900 --> 00:16:49,570
But we don't actually know
what they're like up-close.
234
00:16:49,570 --> 00:16:50,970
It's a long way off,
235
00:16:50,970 --> 00:16:53,610
But scientists
are already speculating
236
00:16:53,610 --> 00:16:56,980
About a mission
to a black hole...
237
00:16:56,980 --> 00:17:01,780
A one-way trip to the most
dangerous place in the universe.
238
00:17:05,450 --> 00:17:07,150
Dr. Kaku:
Originally,
239
00:17:07,150 --> 00:17:11,490
Physicists were horrified
at the idea of black holes.
240
00:17:11,490 --> 00:17:13,130
They wanted to banish them,
241
00:17:13,130 --> 00:17:15,900
Because the laws of physics,
as we know them,
242
00:17:15,900 --> 00:17:18,900
Seem to break down
at the instant of a black hole.
243
00:17:18,900 --> 00:17:20,400
Time stops.
244
00:17:21,800 --> 00:17:24,370
Gravity becomes infinite.
245
00:17:24,370 --> 00:17:27,970
This is a nightmare.
246
00:17:27,970 --> 00:17:31,810
Narrator: Obviously, we can't send
humans anywhere near a black hole.
247
00:17:31,810 --> 00:17:34,550
But a robot?
Well, sure.
248
00:17:34,550 --> 00:17:37,680
A robotic probe
could transmit data back
249
00:17:37,680 --> 00:17:40,420
Just before
it goes over the edge.
250
00:17:40,420 --> 00:17:44,920
That edge of a black hole
is called the "event horizon."
251
00:17:44,930 --> 00:17:47,630
It's the edge
of time and space --
252
00:17:47,630 --> 00:17:50,760
At least,
in the universe we know.
253
00:17:50,760 --> 00:17:52,870
We call the event horizon
"event horizon"
254
00:17:52,870 --> 00:17:54,230
Quite simply because
255
00:17:54,230 --> 00:17:55,800
It separates space
into two regions.
256
00:17:58,040 --> 00:17:59,870
It's not a physical surface.
257
00:17:59,870 --> 00:18:03,810
You might not even notice it
if you were falling through it,
258
00:18:03,810 --> 00:18:06,410
But ultimately, once you're
inside of it, you're doomed.
259
00:18:06,410 --> 00:18:09,280
Narrator: As you approach
the event horizon,
260
00:18:09,280 --> 00:18:11,050
Gravity gets stronger
261
00:18:11,050 --> 00:18:15,150
And very strange things
start to happen.
262
00:18:15,160 --> 00:18:17,820
Dr. Plait: As you fall
into a black hole feet-first,
263
00:18:17,820 --> 00:18:19,930
Your feet are closer
to the black hole.
264
00:18:19,930 --> 00:18:24,000
And so the gravity they feel
is stronger.
265
00:18:24,000 --> 00:18:25,530
Your head is not quite as close,
266
00:18:25,530 --> 00:18:27,370
And so the gravity it feels
is less.
267
00:18:27,370 --> 00:18:30,900
And basically, what happens is,
you get stretched out.
268
00:18:30,900 --> 00:18:33,140
Your feet are being pulled
much harder than your head,
269
00:18:33,140 --> 00:18:34,470
And you're like a piece of taffy
270
00:18:34,470 --> 00:18:36,180
Being pulled
between two strong people.
271
00:18:39,310 --> 00:18:41,450
As you get thinner
and thinner and thinner,
272
00:18:41,450 --> 00:18:43,480
As you get closer
and closer and closer,
273
00:18:43,480 --> 00:18:47,050
You're undergoing a process
we call "spaghettification"
274
00:18:47,050 --> 00:18:51,090
Because you're basically turned
into a long, thin tube of pasta.
275
00:18:54,960 --> 00:18:58,500
Narrator: Gravity would stretch
our robotic probe to the limit,
276
00:18:58,500 --> 00:19:00,270
Then rip it apart.
277
00:19:07,770 --> 00:19:10,640
But imagine
if the probe was strong enough
278
00:19:10,640 --> 00:19:13,480
To survive and keep going.
279
00:19:15,850 --> 00:19:21,820
As it gets close to the event
horizon, everything goes crazy.
280
00:19:21,820 --> 00:19:26,830
Gravity is so extreme,
it stops time.
281
00:19:26,830 --> 00:19:29,190
Dr. Kaku: We think of time
as being endless.
282
00:19:29,200 --> 00:19:32,400
However, in a black hole,
in some sense, time stops.
283
00:19:36,270 --> 00:19:40,540
Dr. Plait: This sounds like it's
nuts, but that's the way it works.
284
00:19:40,540 --> 00:19:41,970
It's in the math.
285
00:19:41,980 --> 00:19:45,440
It's actually woven into the
fabric of the universe itself.
286
00:19:45,450 --> 00:19:48,210
Narrator: If you were to watch
from a distance,
287
00:19:48,210 --> 00:19:50,580
The robot probe
would seem to slow down
288
00:19:50,580 --> 00:19:53,620
As it gets closer
to the black hole.
289
00:19:53,620 --> 00:19:56,920
Then it would appear to stop
completely.
290
00:19:56,920 --> 00:20:00,060
The whole process
might just take a brief moment.
291
00:20:00,060 --> 00:20:01,460
But from the outside,
292
00:20:01,460 --> 00:20:05,660
You appear to freeze
and fall ever more slowly.
293
00:20:05,670 --> 00:20:08,370
You actually can never observe
an object fall
294
00:20:08,370 --> 00:20:10,740
All the way
through the event horizon.
295
00:20:10,740 --> 00:20:13,070
It literally freezes
at the surface
296
00:20:13,070 --> 00:20:16,340
Because its clock
is going infinitely slowly
297
00:20:16,340 --> 00:20:17,740
Compared to yours.
298
00:20:17,740 --> 00:20:22,750
Narrator: In reality,
the probe hasn't stopped at all.
299
00:20:22,750 --> 00:20:27,020
It keeps going
and crosses the event horizon.
300
00:20:28,860 --> 00:20:31,820
If the probe
points its cameras backwards,
301
00:20:31,830 --> 00:20:34,290
Towards the entrance
of the black hole,
302
00:20:34,290 --> 00:20:39,970
It will see light
being sucked in.
303
00:20:39,970 --> 00:20:45,040
If it points the camera forward,
at first it sees only black,
304
00:20:45,040 --> 00:20:48,440
But as it moves toward the heart
of the black hole,
305
00:20:48,440 --> 00:20:53,280
It encounters the most bizarre
place in the universe.
306
00:20:54,850 --> 00:20:58,850
The black hole's immense gravity
pulls everything down
307
00:20:58,850 --> 00:21:02,250
To an unimaginably small point
at its center.
308
00:21:02,260 --> 00:21:06,860
Scientists call it
the "singularity."
309
00:21:06,860 --> 00:21:09,430
We really just don't know
310
00:21:09,430 --> 00:21:11,460
What happens
at the center of a black hole.
311
00:21:11,460 --> 00:21:12,930
The densities are so great
312
00:21:12,930 --> 00:21:15,200
That the laws of physics
break down, as we know them.
313
00:21:15,200 --> 00:21:20,040
A singularity is a point
of infinite gravity,
314
00:21:20,040 --> 00:21:23,210
Where space and time
become meaningless.
315
00:21:23,210 --> 00:21:25,080
Now, that is ridiculous.
316
00:21:25,080 --> 00:21:29,720
A singularity is basically a
word for saying "I don't know."
317
00:21:29,720 --> 00:21:32,180
It's a word for saying
"I'm clueless."
318
00:21:35,920 --> 00:21:37,120
Narrator: Even now,
319
00:21:37,120 --> 00:21:39,690
Scientists can't really answer
the question,
320
00:21:39,690 --> 00:21:41,060
"what is a black hole?"
321
00:21:41,060 --> 00:21:42,800
Dr. Plait:
It's upsetting, a little bit,
322
00:21:42,800 --> 00:21:44,560
To think that there are objects
out there
323
00:21:44,560 --> 00:21:47,170
That are breaking
the laws of physics.
324
00:21:47,170 --> 00:21:49,070
There must be bigger laws
325
00:21:49,070 --> 00:21:51,100
That are being used
by these black holes,
326
00:21:51,100 --> 00:21:53,240
That are being obeyed
by these black holes,
327
00:21:53,240 --> 00:21:54,970
That we just
don't understand yet.
328
00:21:57,980 --> 00:22:01,150
Narrator: Okay, so,
the one thing we do understand
329
00:22:01,150 --> 00:22:04,650
Is that black holes are born
from dying stars.
330
00:22:07,350 --> 00:22:10,890
And most are small --
around 20 miles across.
331
00:22:14,160 --> 00:22:17,200
But now
scientists have discovered
332
00:22:17,200 --> 00:22:20,500
That some black holes
are much bigger.
333
00:22:20,500 --> 00:22:23,700
They're called
"supermassive black holes."
334
00:22:23,700 --> 00:22:27,510
They're the same size
as our entire solar system.
335
00:22:27,510 --> 00:22:33,680
And one of these monsters lies
at the heart of our own galaxy.
336
00:22:41,820 --> 00:22:46,290
Narrator: Our solar system lies
in the milky way galaxy.
337
00:22:46,290 --> 00:22:50,960
It's made up of billions
of stars, including our sun...
338
00:22:52,970 --> 00:22:56,670
...All revolving
around a mysterious region
339
00:22:56,670 --> 00:22:59,340
Right at the center.
340
00:22:59,340 --> 00:23:02,210
Dr. Kaku:
Children ask the question --
341
00:23:02,210 --> 00:23:03,910
If the moon goes
around the earth,
342
00:23:03,910 --> 00:23:05,280
The earth goes around the sun,
343
00:23:05,280 --> 00:23:06,950
Then what does the sun
go around?
344
00:23:06,950 --> 00:23:09,080
Narrator:
It's a good question.
345
00:23:09,080 --> 00:23:11,450
And astronomers ask
the same thing.
346
00:23:11,450 --> 00:23:13,550
Maybe there was something
going on
347
00:23:13,550 --> 00:23:15,360
At the heart of the milky way --
348
00:23:15,360 --> 00:23:20,790
Perhaps a black hole
at the very center.
349
00:23:20,800 --> 00:23:24,260
But because we can't
actually see a black hole,
350
00:23:24,270 --> 00:23:29,440
The best they could do
was look for telltale signs.
351
00:23:29,440 --> 00:23:31,170
Using infrared telescopes,
352
00:23:31,170 --> 00:23:33,870
They looked
at the middle of the galaxy
353
00:23:33,870 --> 00:23:37,240
And discovered
a densely packed swarm
354
00:23:37,240 --> 00:23:39,150
Of millions of stars.
355
00:23:39,150 --> 00:23:43,080
But they couldn't see
what was at the center.
356
00:23:48,060 --> 00:23:52,630
One team has spent 15 years
looking for clues.
357
00:23:57,230 --> 00:24:00,530
High above the clouds
on Mauna Kea, in Hawaii,
358
00:24:00,530 --> 00:24:03,900
The giant Keck telescope
has the power
359
00:24:03,900 --> 00:24:08,310
To see right through
to the center of the milky way.
360
00:24:15,120 --> 00:24:17,820
The region
which we have to study
361
00:24:17,820 --> 00:24:21,190
To prove that there's a
black hole is incredibly small.
362
00:24:21,190 --> 00:24:22,820
It is absolutely the case
363
00:24:22,820 --> 00:24:25,360
Of looking
for a needle in a haystack,
364
00:24:25,360 --> 00:24:28,160
Except we know
exactly where the needle is.
365
00:24:30,160 --> 00:24:33,100
Narrator: Andrea Ghez
has spent countless nights
366
00:24:33,100 --> 00:24:35,240
Scanning
the center of the galaxy
367
00:24:35,240 --> 00:24:38,370
For signs of a black hole.
368
00:24:38,370 --> 00:24:40,240
To be able
to do this experiment,
369
00:24:40,240 --> 00:24:41,880
One has to be able to see
370
00:24:41,880 --> 00:24:44,510
The stars that are very close
to the center of the galaxy
371
00:24:44,510 --> 00:24:47,350
And to position them
incredibly accurately.
372
00:24:47,350 --> 00:24:49,150
And this would be equivalent
373
00:24:49,150 --> 00:24:52,220
To me in Los Angeles
looking at you in new York
374
00:24:52,220 --> 00:24:56,220
And seeing you be able to move
your finger like this.
375
00:24:59,930 --> 00:25:02,260
[ motors whirring ]
376
00:25:09,940 --> 00:25:11,940
Narrator:
As the Keck kicks into action,
377
00:25:11,940 --> 00:25:16,040
A laser beam detects tiny
disturbances in the atmosphere
378
00:25:16,040 --> 00:25:18,480
That would distort the image.
379
00:25:21,150 --> 00:25:27,090
Motors then adjust the huge
30-foot mirror to compensate.
380
00:25:27,090 --> 00:25:29,320
The image is clear enough
381
00:25:29,320 --> 00:25:33,430
To track the stars
at the heart of our galaxy.
382
00:25:35,700 --> 00:25:40,130
Ghez has taken thousands of
images over the last 15 years.
383
00:25:40,130 --> 00:25:45,670
And what they reveal is amazing.
384
00:25:45,670 --> 00:25:48,370
The stars
at the center of the galaxy
385
00:25:48,380 --> 00:25:51,310
Are moving
at millions of miles an hour.
386
00:25:57,720 --> 00:26:02,160
The center of the galaxy
is a very extreme environment.
387
00:26:02,160 --> 00:26:04,120
The speeds with which stars move
388
00:26:04,120 --> 00:26:07,160
Is much higher than
anywhere else in our galaxy.
389
00:26:07,160 --> 00:26:09,930
And that is absolutely
the signpost of the black hole.
390
00:26:15,270 --> 00:26:21,070
Narrator: They look like tiny planets
racing around an invisible sun.
391
00:26:21,080 --> 00:26:24,610
But they're not planets.
They're stars.
392
00:26:24,610 --> 00:26:26,680
It takes a lot of gravity
393
00:26:26,680 --> 00:26:31,020
To swing huge stars around
in such fast, tight orbits.
394
00:26:31,020 --> 00:26:36,060
There's only one thing in the
universe with that much pull...
395
00:26:36,060 --> 00:26:41,090
A supermassive black hole.
396
00:26:41,100 --> 00:26:43,360
Watching these things
shows the presence
397
00:26:43,360 --> 00:26:46,230
Of a 4-million-times-
the-mass-of-our-sun black hole,
398
00:26:46,230 --> 00:26:48,570
Located right at the heart
of our galaxy.
399
00:26:50,170 --> 00:26:52,370
Narrator:
It is a huge discovery.
400
00:26:52,370 --> 00:26:56,210
Everything in our galaxy,
including our own solar system,
401
00:26:56,210 --> 00:27:00,950
Orbits around
a supermassive black hole.
402
00:27:00,950 --> 00:27:04,050
But the milky way
isn't the only galaxy
403
00:27:04,050 --> 00:27:06,420
With a black hole in the middle.
404
00:27:06,420 --> 00:27:08,660
There are
supermassive black holes
405
00:27:08,660 --> 00:27:12,130
At the heart of most galaxies
in the universe.
406
00:27:12,130 --> 00:27:15,700
The Andromeda galaxy
is our closest neighbor.
407
00:27:15,700 --> 00:27:19,200
It circles around
a supermassive black hole
408
00:27:19,200 --> 00:27:23,800
Weighing 140 million times
more than our sun.
409
00:27:23,800 --> 00:27:27,170
Other galaxies,
like this one, m87,
410
00:27:27,170 --> 00:27:33,110
Have black holes weighing
as much as 20 billion suns.
411
00:27:33,110 --> 00:27:35,750
How do black holes get so big,
412
00:27:35,750 --> 00:27:40,190
And what are they doing
at the center of galaxies?
413
00:27:40,190 --> 00:27:45,660
For answers, we have to go back
nearly 14 billion years
414
00:27:45,660 --> 00:27:49,660
To the beginning
of the universe.
415
00:27:49,660 --> 00:27:51,400
Back then,
416
00:27:51,400 --> 00:27:56,040
The universe was filled with
clouds of gas from the big bang.
417
00:27:56,040 --> 00:27:57,640
In some places,
418
00:27:57,640 --> 00:28:01,540
The gas was thick enough
for millions of stars to form.
419
00:28:06,380 --> 00:28:09,520
Most of these new stars
were supermassive.
420
00:28:09,520 --> 00:28:11,580
They burned hot and fast
421
00:28:11,590 --> 00:28:15,690
And then exploded,
creating lots of black holes.
422
00:28:26,200 --> 00:28:29,040
The early universe
was a wild-and-crazy place
423
00:28:29,040 --> 00:28:32,670
Where huge regions of mass were
collapsing catastrophically,
424
00:28:32,670 --> 00:28:34,010
Producing black holes.
425
00:28:34,010 --> 00:28:36,780
And, in fact, the early universe
might have been
426
00:28:36,780 --> 00:28:39,210
Full of emerging black holes
everywhere.
427
00:28:41,850 --> 00:28:44,620
Narrator: Gravity pulled
many of them together.
428
00:28:44,620 --> 00:28:46,950
All over the early universe,
429
00:28:46,950 --> 00:28:51,220
They merged, creating
larger and larger black holes.
430
00:28:54,160 --> 00:28:57,960
Over hundreds of millions
of years, each black hole grew,
431
00:28:57,970 --> 00:29:02,400
Producing stronger gravity and
pulling in more and more gas.
432
00:29:02,400 --> 00:29:07,070
New stars were born from the
gas, forming primitive galaxies.
433
00:29:09,080 --> 00:29:12,950
But the black hole
kept on sucking in gas,
434
00:29:12,950 --> 00:29:14,810
Until it could take no more,
435
00:29:14,820 --> 00:29:18,990
Igniting the most powerful
flamethrower in the universe.
436
00:29:37,500 --> 00:29:41,340
Narrator: A young galaxy
is a vast cluster of stars,
437
00:29:41,340 --> 00:29:44,440
Stars that formed
from clouds of gas.
438
00:29:49,310 --> 00:29:51,850
At the center of the new galaxy
439
00:29:51,850 --> 00:29:56,320
Is a young, supermassive
black hole feeding on the gas,
440
00:29:56,320 --> 00:29:58,320
Getting bigger and bigger.
441
00:29:58,320 --> 00:30:00,120
Dr. Plait:
If you can imagine,
442
00:30:00,130 --> 00:30:02,660
When a galaxy is very young
and still forming,
443
00:30:02,660 --> 00:30:05,500
There's a supermassive
black hole forming at the core,
444
00:30:05,500 --> 00:30:07,500
And the gas
is still falling into it
445
00:30:07,500 --> 00:30:09,030
And still forming the galaxy.
446
00:30:09,030 --> 00:30:11,340
Well,
near that central black hole,
447
00:30:11,340 --> 00:30:13,040
Things are getting very hot.
448
00:30:13,040 --> 00:30:14,740
That material is heating up.
449
00:30:14,740 --> 00:30:18,380
Narrator: Gas is speeding
into the black hole.
450
00:30:18,380 --> 00:30:20,880
But it overloads,
451
00:30:20,880 --> 00:30:25,620
And there is no room
for all that excess hot gas.
452
00:30:25,620 --> 00:30:29,990
It has nowhere to go but out.
453
00:30:29,990 --> 00:30:35,130
It's blasted into space
in huge jets of energy.
454
00:30:39,660 --> 00:30:43,200
Each jet is 20 times wider
than our solar system
455
00:30:43,200 --> 00:30:47,440
And shoots
clear through the galaxy.
456
00:30:47,440 --> 00:30:53,340
The supermassive black hole
has ignited a quasar.
457
00:30:53,350 --> 00:30:55,110
Quasars are literally
458
00:30:55,110 --> 00:30:57,280
The brightest objects
in the universe.
459
00:30:57,280 --> 00:31:00,220
They're so intense, they can
outshine an entire galaxy.
460
00:31:00,220 --> 00:31:03,050
Narrator:
This is a real photograph
461
00:31:03,050 --> 00:31:06,920
Of a real quasar
in the galaxy m87,
462
00:31:06,930 --> 00:31:10,590
50 million light-years away.
463
00:31:14,000 --> 00:31:17,670
Quasars blast away
huge quantities of gas
464
00:31:17,670 --> 00:31:19,670
From the surrounding galaxy...
465
00:31:22,310 --> 00:31:26,910
...The equivalent
of 10 earths every minute.
466
00:31:30,280 --> 00:31:34,520
Dr. Plait: When you heat up a gas, it
tends to expand and it blows outward.
467
00:31:34,520 --> 00:31:37,350
And it's sort of like a wind,
but on a huge scale.
468
00:31:37,360 --> 00:31:39,390
And you get a black-hole wind,
469
00:31:39,390 --> 00:31:41,990
Gas blowing out
from the black hole.
470
00:31:41,990 --> 00:31:46,630
Narrator: Black holes suck gas in.
Quasars blow it out.
471
00:31:46,630 --> 00:31:51,270
But eventually there's no gas
left to make stars,
472
00:31:51,270 --> 00:31:53,040
And the galaxy stops growing.
473
00:31:53,040 --> 00:31:55,810
Dr. Plait: So we think
that the eventual size
474
00:31:55,810 --> 00:31:57,370
That a galaxy can achieve
475
00:31:57,380 --> 00:31:59,940
Depends on the black hole
in its center.
476
00:31:59,940 --> 00:32:01,550
The two are tied together.
477
00:32:03,450 --> 00:32:08,320
Narrator: With no gas left to feed
on, the quasar jets shrink and die.
478
00:32:09,720 --> 00:32:12,790
What's left
is a supermassive black hole
479
00:32:12,790 --> 00:32:17,260
At the center of the galaxy,
with a whole lot of young stars,
480
00:32:17,260 --> 00:32:21,270
Just like our milky way
back when it was young.
481
00:32:21,270 --> 00:32:24,000
Dr. Plait: Early on
in the history of the milky way,
482
00:32:24,000 --> 00:32:27,400
When it was a young galaxy,
we were probably a quasar.
483
00:32:27,410 --> 00:32:30,910
Probably every big galaxy
was a quasar when it was young.
484
00:32:30,910 --> 00:32:32,480
But right now we're old enough
485
00:32:32,480 --> 00:32:34,380
That the galaxy
has quieted down.
486
00:32:36,210 --> 00:32:40,150
Narrator: Now astronomers
are looking for quasars,
487
00:32:40,150 --> 00:32:43,550
The secret
to finding more black holes
488
00:32:43,560 --> 00:32:46,190
And figuring out how they work.
489
00:32:46,190 --> 00:32:49,260
The Chandra observatory
is a space telescope
490
00:32:49,260 --> 00:32:55,230
That can detect the powerful
x-rays quasars send out.
491
00:32:55,230 --> 00:32:58,140
It's found thousands.
492
00:32:58,140 --> 00:33:00,670
These remarkable images show
493
00:33:00,670 --> 00:33:05,640
Quasars of all shapes and sizes
firing out into space.
494
00:33:09,650 --> 00:33:11,850
Each one is a signpost
495
00:33:11,850 --> 00:33:15,950
For a young galaxy with
a new black hole at its center.
496
00:33:19,720 --> 00:33:22,790
These quasars
will eventually calm down
497
00:33:22,790 --> 00:33:28,130
As their galaxy matures
and takes its final shape.
498
00:33:28,130 --> 00:33:30,070
I guess the universe
is a lot like people --
499
00:33:30,070 --> 00:33:31,800
Active when they're young,
500
00:33:31,800 --> 00:33:33,670
A little bit quieter and more
relaxed when they get older.
501
00:33:36,040 --> 00:33:39,080
Narrator: We now know
that supermassive black holes
502
00:33:39,080 --> 00:33:43,150
And the quasars they create
control galaxies.
503
00:33:43,150 --> 00:33:47,180
Dr. Ghez: Black holes are central
to understanding how galaxies form.
504
00:33:47,190 --> 00:33:50,220
They're a key to understanding
how they evolve with time.
505
00:33:50,220 --> 00:33:52,390
So, in fact,
rather than being obscura,
506
00:33:52,390 --> 00:33:54,460
They're fundamental
to our understanding
507
00:33:54,460 --> 00:33:56,260
Of our galaxies
and our universe.
508
00:33:56,260 --> 00:34:00,530
Narrator: The only way to
find out more about black holes
509
00:34:00,530 --> 00:34:02,570
Is to get a good look at one.
510
00:34:02,570 --> 00:34:06,370
And since an up-close visit
is, well, not a good idea,
511
00:34:06,370 --> 00:34:09,340
Astronomers are trying to devise
a way to take a picture
512
00:34:09,340 --> 00:34:13,210
Of the supermassive black hole
at the heart of our own galaxy.
513
00:34:13,210 --> 00:34:14,910
To get it,
514
00:34:14,910 --> 00:34:18,880
They'll need a telescope
as large as earth itself.
515
00:34:36,310 --> 00:34:39,550
Narrator: There's
a supermassive black hole
516
00:34:39,550 --> 00:34:43,220
At the center of the milky way.
517
00:34:45,390 --> 00:34:48,360
It's hidden
by a dense cluster of stars
518
00:34:48,360 --> 00:34:50,930
Circling
the heart of the galaxy.
519
00:34:53,700 --> 00:34:58,200
But soon,
we hope we'll be able to see it.
520
00:34:58,200 --> 00:35:01,040
Dr. Kaku:
Seeing is believing.
521
00:35:01,040 --> 00:35:04,870
It would be spectacular
if we can go right up there,
522
00:35:04,870 --> 00:35:07,780
Nose-to-nose
with the event horizon
523
00:35:07,780 --> 00:35:11,250
Of the black hole at the center
of the milky way galaxy.
524
00:35:11,250 --> 00:35:14,550
And that's the holy grail.
525
00:35:14,550 --> 00:35:17,850
Narrator: A supermassive
black hole lies hidden
526
00:35:17,850 --> 00:35:19,950
At the center of most galaxies.
527
00:35:19,960 --> 00:35:21,760
We only know they're there
528
00:35:21,760 --> 00:35:24,730
Because the stars around them
are drawn in
529
00:35:24,730 --> 00:35:26,960
At millions of miles per hour.
530
00:35:26,960 --> 00:35:28,660
But there might still be a way
531
00:35:28,660 --> 00:35:32,230
To take a picture of the
very edge of the black hole --
532
00:35:32,230 --> 00:35:34,400
The event horizon.
533
00:35:34,400 --> 00:35:38,210
Shep Doeleman and his team
are trying to capture an image
534
00:35:38,210 --> 00:35:40,340
That shows its outline.
535
00:35:40,340 --> 00:35:42,610
We're essentially looking
for the shadow,
536
00:35:42,610 --> 00:35:44,650
Or the silhouette,
of the black hole,
537
00:35:44,650 --> 00:35:48,150
Within this cloud of gas
that's swirling around it.
538
00:35:48,150 --> 00:35:51,890
This technique
that we're exploiting
539
00:35:51,890 --> 00:35:54,960
Is the best hope I think we have
540
00:35:54,960 --> 00:35:57,760
To actually image
a region of the universe
541
00:35:57,760 --> 00:36:01,060
Which has hitherto been
completely invisible to us.
542
00:36:01,060 --> 00:36:03,360
Narrator:
Optical telescopes
543
00:36:03,370 --> 00:36:06,900
Can't see the black hole
directly.
544
00:36:06,900 --> 00:36:10,770
But the glowing, super-heated
gas surrounding the black hole
545
00:36:10,770 --> 00:36:14,440
Sends out radio waves that can
be used to make an image.
546
00:36:16,410 --> 00:36:21,680
Huge radio telescopes pick up
these signals from space.
547
00:36:21,680 --> 00:36:24,290
The antenna will move
in azimuth and elevation.
548
00:36:24,290 --> 00:36:26,620
[ beeping ]
549
00:36:26,620 --> 00:36:29,160
[ whirring ]
550
00:36:30,860 --> 00:36:34,630
Narrator: This one, at the
m.I.T. Observatory near Boston,
551
00:36:34,630 --> 00:36:37,360
Is more than 100 feet wide.
552
00:36:37,370 --> 00:36:41,470
It's big enough to detect
very faint radio emissions
553
00:36:41,470 --> 00:36:46,440
From the black hole in our own
galaxy, 25,000 light-years away.
554
00:36:46,440 --> 00:36:50,710
But it's not nearly big enough
to capture an image.
555
00:36:50,710 --> 00:36:54,250
We need to take multiple copies
of these telescopes,
556
00:36:54,250 --> 00:36:56,120
Place them around the world
557
00:36:56,120 --> 00:37:00,720
To create a virtual telescope
as large as the earth itself.
558
00:37:00,720 --> 00:37:03,690
Narrator: Doeleman's team
will link up radio telescopes
559
00:37:03,690 --> 00:37:07,930
Around the globe,
from Hawaii to Chile to Africa.
560
00:37:14,100 --> 00:37:16,770
When the whole network
is connected,
561
00:37:16,770 --> 00:37:20,940
They'll have a virtual dish
over 10,000 miles across,
562
00:37:20,940 --> 00:37:25,510
With 500 times the power
of a single telescope.
563
00:37:28,880 --> 00:37:31,450
They think
it will be powerful enough
564
00:37:31,450 --> 00:37:34,090
To take a picture
of the event horizon
565
00:37:34,090 --> 00:37:39,590
Of the supermassive black hole
at the center of the milky way.
566
00:37:39,590 --> 00:37:42,060
They're already picking up
signals
567
00:37:42,060 --> 00:37:44,570
From the dark heart
of our galaxy.
568
00:37:44,570 --> 00:37:47,200
Dr. Doeleman:
When we saw the first detection,
569
00:37:47,200 --> 00:37:49,940
It was a moment where I just
looked at the computer screen
570
00:37:49,940 --> 00:37:52,710
And said to myself,
"my god, we've done it.
571
00:37:52,710 --> 00:37:55,640
"we've actually seen something
that's so small
572
00:37:55,640 --> 00:37:59,710
That it has to be coming from
right around the event horizon."
573
00:37:59,710 --> 00:38:03,250
Narrator: The signals are still too
weak to give a complete picture,
574
00:38:03,250 --> 00:38:06,890
But doeleman expects the images
to improve
575
00:38:06,890 --> 00:38:11,860
As more telescopes come online
over the next few years.
576
00:38:11,860 --> 00:38:17,160
Eventually, the outline of the
black hole itself should emerge.
577
00:38:19,730 --> 00:38:24,970
But even a picture can't compare
to witnessing it for yourself.
578
00:38:27,210 --> 00:38:30,610
In the distant future,
we may have the technology
579
00:38:30,610 --> 00:38:35,080
To actually enter
and pass through a black hole
580
00:38:35,080 --> 00:38:38,220
And maybe even
survive the journey.
581
00:38:43,760 --> 00:38:47,130
Then we might finally answer
the question --
582
00:38:47,130 --> 00:38:51,170
What lies
at the heart of a black hole?
583
00:38:53,270 --> 00:38:54,700
Some scientists believe
584
00:38:54,700 --> 00:38:57,470
We could use black holes
as a kind of portal,
585
00:38:57,470 --> 00:39:00,770
With the potential
for travel across the universe.
586
00:39:00,780 --> 00:39:03,580
Dr. Kaku:
This is still very speculative,
587
00:39:03,580 --> 00:39:06,080
But the mathematics
seem to indicate
588
00:39:06,080 --> 00:39:08,420
That as you fall
through a black hole
589
00:39:08,420 --> 00:39:10,080
That you don't simply die --
590
00:39:10,090 --> 00:39:12,790
You fall
right through a wormhole,
591
00:39:12,790 --> 00:39:17,490
Which is a gateway, a shortcut
through space and time.
592
00:39:17,490 --> 00:39:21,230
Perhaps we could simply
rocket across the universe
593
00:39:21,230 --> 00:39:26,500
Through a subway system
that we call a black hole.
594
00:39:26,500 --> 00:39:30,800
Narrator: If black holes are
shortcuts through space and time,
595
00:39:30,810 --> 00:39:34,910
It could turn one of the coolest
ideas from science fiction
596
00:39:34,910 --> 00:39:38,650
Into reality.
597
00:39:38,650 --> 00:39:42,220
Time travel is possible,
but not very practical.
598
00:39:42,220 --> 00:39:45,790
You see, the energy source,
the material that you need
599
00:39:45,790 --> 00:39:48,320
To keep the throat
of a wormhole open
600
00:39:48,320 --> 00:39:49,790
Is something so exotic
601
00:39:49,790 --> 00:39:52,690
That we cannot produce it
in the laboratory.
602
00:39:52,690 --> 00:39:55,660
But if you could,
it might be possible
603
00:39:55,660 --> 00:39:59,730
To exploit the power of
black holes to visit yesterday.
604
00:40:01,440 --> 00:40:04,200
Perhaps our descendants
in the future
605
00:40:04,210 --> 00:40:07,010
Have already mastered
this technology.
606
00:40:07,010 --> 00:40:09,210
So one day,
if somebody knocks on your door
607
00:40:09,210 --> 00:40:10,810
And claims to be
608
00:40:10,810 --> 00:40:13,050
Your great-great-great-great-
great-great granddaughter,
609
00:40:13,050 --> 00:40:14,110
Don't slam the door.
610
00:40:18,090 --> 00:40:22,460
Narrator: Black holes might even
be gateways to other universes.
611
00:40:22,460 --> 00:40:25,030
On the other side
of a black hole,
612
00:40:25,030 --> 00:40:28,100
There could even be...
A big bang.
613
00:40:31,330 --> 00:40:35,000
As a black hole collapses
and matter falls into it,
614
00:40:35,000 --> 00:40:38,470
Perhaps the matter is blown out
the other side in a white hole.
615
00:40:38,470 --> 00:40:40,710
Doesn't that sound
like the big bang?
616
00:40:46,250 --> 00:40:49,920
Narrator: If a big bang is just
the flip side of a black hole,
617
00:40:49,920 --> 00:40:53,990
This could be
how our own universe was born.
618
00:40:55,720 --> 00:40:58,260
If you look at the equations
for a black hole
619
00:40:58,260 --> 00:41:00,160
And put in the parameters
of the universe --
620
00:41:00,160 --> 00:41:02,400
The mass of the universe,
the size of the universe --
621
00:41:02,400 --> 00:41:03,460
Bingo!
622
00:41:03,470 --> 00:41:04,900
You find that our universe
623
00:41:04,900 --> 00:41:07,530
Actually solves the equations
for a black hole.
624
00:41:07,540 --> 00:41:10,770
In other words, we could be
inside an event horizon.
625
00:41:10,770 --> 00:41:16,280
Perhaps we are actually living
inside a black hole.
626
00:41:16,280 --> 00:41:19,750
Narrator: Every black hole
might be the origin
627
00:41:19,750 --> 00:41:22,620
Of an entirely separate
universe.
628
00:41:22,620 --> 00:41:23,980
If that's true,
629
00:41:23,990 --> 00:41:28,660
There could be billions
of universes out there...
630
00:41:32,060 --> 00:41:37,430
...Each one
full of stars, planets, life.
631
00:41:37,430 --> 00:41:39,970
Whatever we figure out later,
632
00:41:39,970 --> 00:41:43,900
We know now
that black holes are everywhere.
633
00:41:43,910 --> 00:41:45,140
They're bigger in size
634
00:41:45,140 --> 00:41:47,880
And more critical
to the evolution of the universe
635
00:41:47,880 --> 00:41:50,080
Than we ever imagined.
636
00:42:01,390 --> 00:42:03,320
Dr. Krauss:
Literally, our understanding
637
00:42:03,320 --> 00:42:05,390
Of the universe
that's important around us,
638
00:42:05,390 --> 00:42:07,800
The universe
that's visible to telescopes,
639
00:42:07,800 --> 00:42:09,660
Has been profoundly affected
640
00:42:09,660 --> 00:42:13,100
By our realization
that black holes are everywhere.
641
00:42:16,000 --> 00:42:17,270
Dr. Kaku:
Once upon a time,
642
00:42:17,270 --> 00:42:18,940
People thought
that black-hole physics
643
00:42:18,940 --> 00:42:22,080
Was too fantastic to be true.
644
00:42:22,080 --> 00:42:24,650
And now they are center-stage.
645
00:42:24,650 --> 00:42:26,110
We now know they dominate
646
00:42:26,110 --> 00:42:28,380
The evolution
of the universe itself.
647
00:42:30,290 --> 00:42:31,850
Dr. Plait:
When I was a kid,
648
00:42:31,850 --> 00:42:33,950
Black holes basically played
a part in science fiction.
649
00:42:33,960 --> 00:42:35,490
It was always
something to avoid.
650
00:42:35,490 --> 00:42:37,020
Your spaceship --
651
00:42:37,030 --> 00:42:38,760
You try to get around them
before you get drawn in.
652
00:42:38,760 --> 00:42:40,830
But what we've learned
since then
653
00:42:40,830 --> 00:42:43,060
Is that black holes
play a huge role
654
00:42:43,060 --> 00:42:45,630
And a huge number of roles
in the universe.
655
00:42:48,500 --> 00:42:50,840
It's not an exaggeration to say
656
00:42:50,840 --> 00:42:54,610
That if black holes did not
exist, we wouldn't be here.
657
00:42:54,610 --> 00:42:57,410
We literally owe
our existence to black holes.
658
00:43:01,520 --> 00:43:04,950
Narrator:
The story's not over yet.
659
00:43:04,950 --> 00:43:07,590
There's still
much more to be discovered
660
00:43:07,590 --> 00:43:12,530
About the mysterious objects
called black holes...
661
00:43:12,530 --> 00:43:15,800
The masters of the universe.
662
00:43:15,840 --> 00:43:21,840
Sync by kuniva for addic7ed.com
54144
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