1
00:00:33,580 --> 00:00:36,140
THE UNIVERSE WAS BORN TO DIE.
2
00:00:36,140 --> 00:00:40,550
BUT HOW AND WHEN
WILL IT ALL END?
3
00:00:40,550 --> 00:00:42,380
THAT'S THE REASON
I BECAME A COSMOLOGIST.
4
00:00:42,380 --> 00:00:44,120
I WANTED TO BE THE FIRST PERSON
THAT WOULD KNOW
5
00:00:44,120 --> 00:00:46,090
HOW THE UNIVERSE WOULD END.
6
00:00:46,090 --> 00:00:49,860
TWO COSMIC HEAVYWEIGHTS
WRESTLE FOR CONTROL.
7
00:00:49,860 --> 00:00:52,360
THE WINNER SEALS OUR FATE.
8
00:00:52,360 --> 00:00:55,160
THE TUG OF WAR IS GRAVITY,
9
00:00:55,160 --> 00:00:56,830
WHICH IS TRYING
TO SHRINK IT DOWN,
10
00:00:56,830 --> 00:00:59,630
AND THE EXPANSION OF SPACE
AND TIME ITSELF.
11
00:00:59,630 --> 00:01:01,970
WILL GRAVITY TRIUMPH?
12
00:01:01,970 --> 00:01:05,140
THE UNIVERSE WILL GET SMALLER
AND SMALLER, HOTTER AND HOTTER.
13
00:01:05,140 --> 00:01:08,140
OR WILL EXPANSION
GET THE UPPER HAND?
14
00:01:08,140 --> 00:01:12,110
EVEN THE ELECTRONS AROUND
YOUR ATOMS WILL BE RIPPED APART.
15
00:01:12,110 --> 00:01:13,580
THE END IS COMING,
16
00:01:13,580 --> 00:01:17,120
AND IT COULD BE
SOONER THAN YOU THINK.
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00:01:21,420 --> 00:01:24,420
-- Captions by VITAC --
www.vitac.com
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CAPTIONS PAID FOR BY
DISCOVERY COMMUNICATIONS
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THE UNIVERSE IS EVERYTHING
20
00:01:33,570 --> 00:01:37,270
ALL SPACE, ALL TIME, ALL MATTER.
21
00:01:39,540 --> 00:01:42,510
THE EARTH IS A SPECK
BY COMPARISON,
22
00:01:42,510 --> 00:01:47,080
A GRAIN OF ROCK ORBITING JUST
ONE OF THE 200 BILLION STARS
23
00:01:47,080 --> 00:01:50,150
IN OUR HOME GALAXY,
THE MILKY WAY.
24
00:01:53,460 --> 00:01:57,260
IN TURN, THIS ENORMOUS STRUCTURE
IS JUST A DROP
25
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IN AN OCEAN OF GALAXIES
THAT STRETCH
26
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FOR 90 BILLION LIGHT YEARS.
27
00:02:04,500 --> 00:02:06,600
AND ALL OF THIS,
28
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FROM THE BIGGEST GALAXY
TO THE SMALLEST ATOM,
29
00:02:10,770 --> 00:02:12,980
WILL ONE DAY DIE.
30
00:02:14,810 --> 00:02:17,210
WE DON'T SEE EVIDENCE
OF ANYTHING BEING ETERNAL.
31
00:02:17,210 --> 00:02:18,910
ETERNITY DOESN'T EXIST.
32
00:02:18,910 --> 00:02:21,180
EVEN SPACE AND TIME
WILL COME TO AN END.
33
00:02:22,520 --> 00:02:26,460
THE UNIVERSE HAS BEEN
EXPANDING SINCE ITS BIRTH,
34
00:02:26,460 --> 00:02:30,630
GRADUALLY BURNING THROUGH
THE FUEL THAT LIGHTS ITS STARS.
35
00:02:30,630 --> 00:02:33,630
BUT WHAT HAPPENS
WHEN THE FUEL RUNS OUT?
36
00:02:33,630 --> 00:02:36,130
WILL IT ALL JUST FADE AWAY?
37
00:02:36,130 --> 00:02:38,540
STARS DIE OUT,
USE UP THEIR NUCLEAR FUEL.
38
00:02:38,540 --> 00:02:41,140
WE HAVE AN EMPTY, COLD,
DESOLATE UNIVERSE.
39
00:02:41,140 --> 00:02:43,210
JUST DEAD REMNANTS OF STARS --
40
00:02:43,210 --> 00:02:45,310
BLACK HOLES, NEUTRON STARS.
41
00:02:45,310 --> 00:02:46,840
EVENTUALLY, THEY DECAY AWAY,
42
00:02:46,840 --> 00:02:49,780
AND YOU'RE LEFT WITH A THIN HAZE
OF VERY LOW ENERGY LIGHT.
43
00:02:49,780 --> 00:02:51,110
THAT'S IT.
44
00:02:51,120 --> 00:02:52,880
WE USED TO THINK THE UNIVERSE
45
00:02:52,880 --> 00:02:55,650
WOULD CRUISE GENTLY
INTO OLD AGE.
46
00:02:55,650 --> 00:02:57,750
BUT OVER THE PAST FEW DECADES,
47
00:02:57,760 --> 00:03:01,220
ASTRONOMERS HAVE
REVEALED A VERY DIFFERENT
48
00:03:01,230 --> 00:03:02,990
AND DISTURBING PICTURE.
49
00:03:02,990 --> 00:03:05,930
THE UNIVERSE ISN'T CRUISING.
50
00:03:05,930 --> 00:03:07,760
IT'S FIGHTING FOR ITS LIFE.
51
00:03:07,760 --> 00:03:10,030
IT MAY SEEM PEACEFUL HERE
ON EARTH ON A NICE, SUNNY DAY,
52
00:03:10,030 --> 00:03:11,870
BUT IN FACT, ABOVE US
AND ALL AROUND US,
53
00:03:11,870 --> 00:03:15,000
THROUGHOUT THE UNIVERSE,
A BATTLE IS RAGING,
54
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AND IT HAS RAGED
SINCE THE BEGINNING OF TIME.
55
00:03:17,910 --> 00:03:21,480
TWO DEADLY FORCES
GRAPPLE FOR CONTROL.
56
00:03:21,480 --> 00:03:26,020
THE FIRST, EXPANSION,
PULLS GALAXIES APART,
57
00:03:26,020 --> 00:03:29,050
COOLING THE UNIVERSE
AND THREATENING IT
58
00:03:29,050 --> 00:03:32,120
WITH A FROZEN EXTINCTION.
59
00:03:32,120 --> 00:03:36,660
THE SECOND, GRAVITY, TRIES TO
CRUSH EVERYTHING BACK TOGETHER,
60
00:03:36,660 --> 00:03:40,500
ANNIHILATING THE UNIVERSE
IN A DENSE BALL OF FIRE.
61
00:03:43,070 --> 00:03:46,670
WILL GRAVITY OR EXPANSION WIN?
62
00:03:46,670 --> 00:03:48,710
OR WILL IT END IN A TIE?
63
00:03:48,710 --> 00:03:52,510
THESE TWO COLOSSAL FORCES
YIELD THREE ENDGAMES.
64
00:03:53,110 --> 00:03:55,180
ONE IS THE BIG FREEZE.
65
00:03:55,180 --> 00:03:58,150
EXPANSION WINS, AND THE UNIVERSE
JUST EXPANDS FOREVER.
66
00:03:58,150 --> 00:04:00,750
THE SECOND IS THAT THERE IS
A DELICATE BALANCE
67
00:04:00,750 --> 00:04:02,020
BETWEEN THE EXPANSION
68
00:04:02,020 --> 00:04:03,690
AND THE AMOUNT OF GRAVITATIONAL
ATTRACTION,
69
00:04:03,690 --> 00:04:05,790
AND THE UNIVERSE GETS
TO A PARTICULAR SIZE,
70
00:04:05,790 --> 00:04:07,260
AND IT PRETTY MUCH STAYS THERE.
71
00:04:07,260 --> 00:04:08,930
AND THE THIRD OUTCOME IS THAT
72
00:04:08,930 --> 00:04:10,760
THE GRAVITATIONAL
ATTRACTION WINS,
73
00:04:10,760 --> 00:04:12,400
AND THE EXPANSION STOPS,
74
00:04:12,400 --> 00:04:14,130
AND THE UNIVERSE
BEGINS TO GET SMALLER
75
00:04:14,130 --> 00:04:17,300
UNTIL, EVENTUALLY,
IT GOES BACK TO A BIG CRUNCH.
76
00:04:19,510 --> 00:04:21,840
SO FAR,
THE UNIVERSE SEEMS BALANCED
77
00:04:21,840 --> 00:04:25,780
ON A TIGHTROPE BETWEEN
EXPANSION AND CONTRACTION.
78
00:04:25,780 --> 00:04:29,180
BUT WILL IT KEEP ITS EQUILIBRIUM
UNTIL IT RUNS OUT OF STEAM,
79
00:04:29,180 --> 00:04:31,990
OR WILL SOMETHING
TIP THE BALANCE?
80
00:04:34,020 --> 00:04:36,960
I DON'T THINK THERE'S
ANY BIGGER QUESTION THAN,
81
00:04:36,960 --> 00:04:39,190
WHERE IS THE UNIVERSE GOING?
82
00:04:39,190 --> 00:04:42,730
TO PREDICT THE FUTURE,
COSMOLOGISTS HAVE ALWAYS LOOKED
83
00:04:42,730 --> 00:04:46,930
TO THE PAST, BACK TO
THE BEGINNING OF EXPANSION,
84
00:04:46,930 --> 00:04:51,710
THE BEGINNING OF GRAVITY,
THE BEGINNING OF EVERYTHING.
85
00:04:54,310 --> 00:04:59,280
13.8 BILLION YEARS AGO,
AN INFINITELY DENSE,
86
00:04:59,280 --> 00:05:03,980
HOT SPECK IGNITES
AND SUDDENLY EXPANDS OUTWARD --
87
00:05:03,980 --> 00:05:05,990
THE BIG BANG.
88
00:05:07,520 --> 00:05:11,090
ALL ENERGY, ALL SPACE,
AND ALL MATTER...
89
00:05:12,830 --> 00:05:15,860
...THE BUILDING BLOCKS OF
THE UNIVERSE WE SEE TODAY,
90
00:05:15,860 --> 00:05:18,330
ARE CREATED AND SET IN MOTION.
91
00:05:19,330 --> 00:05:21,570
THINK OF IT.
92
00:05:21,570 --> 00:05:23,870
EVERYTHING YOU SEE AROUND US
93
00:05:23,870 --> 00:05:28,510
CONCENTRATED INTO A PRIMORDIAL
FIREBALL THAT EXPLODED,
94
00:05:28,510 --> 00:05:31,310
SENDING ALL THE GALAXIES
INTO MOTION.
95
00:05:35,380 --> 00:05:39,050
THAT OUTWARD BLAST,
THE BIRTH OF EXPANSION,
96
00:05:39,050 --> 00:05:41,720
IS STILL GOING ON TODAY.
97
00:05:41,720 --> 00:05:45,130
WITHOUT IT, WE WOULDN'T HAVE
A UNIVERSE BIG ENOUGH
98
00:05:45,130 --> 00:05:47,930
FOR STARS
AND GALAXIES TO EXIST IN.
99
00:05:47,930 --> 00:05:51,200
EXPANSION IS AN ASTONISHING
FORCE OF NATURE.
100
00:05:51,200 --> 00:05:55,500
IT WORKS BY INFLATING
THE FABRIC OF SPACE-TIME.
101
00:05:55,500 --> 00:05:59,170
SPACE BETWEEN GALAXIES EXPANDS,
102
00:05:59,180 --> 00:06:01,480
AND IT PUSHES
THE GALAXIES APART.
103
00:06:01,480 --> 00:06:06,580
SPACE CARRIES OBJECTS WITH IT
LIKE A SURFER ON A WAVE.
104
00:06:06,580 --> 00:06:08,980
IT'S GOING ON
IN EVERY PART OF SPACE.
105
00:06:08,990 --> 00:06:10,650
EVEN INSIDE YOUR BODY RIGHT NOW,
106
00:06:10,650 --> 00:06:12,590
THERE'S A PRESSURE
FOR SPACE TO EXPAND.
107
00:06:13,460 --> 00:06:16,490
EXPANSION GENERATED
THE VAST, MOVING STAGE
108
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ON WHICH TODAY'S UNIVERSE
PLAYS OUT.
109
00:06:19,130 --> 00:06:22,030
BUT LEFT UNCHECKED,
IT COULD HAVE BEEN A FORCE
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FOR UTTER ANNIHILATION.
111
00:06:24,170 --> 00:06:26,400
IF THE UNIVERSE HAD
BEEN EXPANDING MUCH FASTER,
112
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IT WOULD HAVE EMPTIED OUT
SO FAST,
113
00:06:28,170 --> 00:06:30,440
YOU WOULDN'T HAVE HAD TIME
TO MAKE GALAXIES,
114
00:06:30,440 --> 00:06:31,580
PLANETS, PEOPLE.
115
00:06:34,240 --> 00:06:35,850
THE FACT
THAT WE'RE HERE
116
00:06:35,850 --> 00:06:38,420
MEANS THAT SOMETHING MUST HAVE
PUT ON THE BRAKES.
117
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IT WAS, OF COURSE,
OUR UNIVERSAL GLUE -- GRAVITY.
118
00:06:43,020 --> 00:06:46,490
GRAVITY AND MATTER
GO HAND IN HAND.
119
00:06:46,490 --> 00:06:49,390
THE MORE MASSIVE THE OBJECT,
120
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THE MORE PULL IT EXERTS
ON EVERYTHING AROUND IT.
121
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IT DRAWS ATOM TO ATOM,
PARTICLE TO PARTICLE...
122
00:06:58,800 --> 00:07:04,110
...BUILDING STARS, NEBULAS,
123
00:07:04,110 --> 00:07:06,440
GALAXIES --
124
00:07:06,440 --> 00:07:10,580
THE HARDWARE OF THE UNIVERSE
WE SEE TODAY.
125
00:07:10,580 --> 00:07:13,420
BUT GRAVITY
IS A DOUBLE-EDGED SWORD.
126
00:07:13,420 --> 00:07:16,320
TOO MUCH, AND THE EARLY UNIVERSE
WOULD NEVER HAVE GOTTEN
127
00:07:16,320 --> 00:07:18,490
OUT OF THE STARTING BLOCKS.
128
00:07:18,490 --> 00:07:20,520
IF IT HAD BEEN
EXPANDING MORE SLOWLY,
129
00:07:20,520 --> 00:07:22,790
IT WOULD HAVE RE-COLLAPSED
INTO ANOTHER SINGULARITY.
130
00:07:22,790 --> 00:07:25,560
AND AGAIN, YOU WOULDN'T HAVE HAD
THE TIME TO MAKE GALAXIES,
131
00:07:25,560 --> 00:07:27,360
PLANETS, OR PEOPLE.
132
00:07:27,370 --> 00:07:29,000
SO WE LIVE IN THE GOLDILOCKS
UNIVERSE.
133
00:07:29,000 --> 00:07:31,130
WE LIVE IN THE UNIVERSE
THAT LASTS LONG ENOUGH
134
00:07:31,140 --> 00:07:33,640
THAT WE CAN BE HERE,
BUT EXPANDS GENTLY ENOUGH
135
00:07:33,640 --> 00:07:35,570
THAT WE HAVE TIME TO FORM.
136
00:07:38,340 --> 00:07:42,140
THE UNIVERSE HAS
LASTED FOR 13.8 BILLION YEARS,
137
00:07:42,150 --> 00:07:46,120
THANKS TO THE OPPOSING FORCES
OF GRAVITY AND EXPANSION.
138
00:07:46,120 --> 00:07:50,190
BUT JUST HOW STABLE
IS THIS BALANCING ACT?
139
00:07:50,190 --> 00:07:53,690
DOES OUR UNIVERSE HAVE JUST
THE RIGHT AMOUNT OF STUFF IN IT
140
00:07:53,690 --> 00:07:55,790
TO KEEP IT FROM
RUNAWAY EXPANSION
141
00:07:55,790 --> 00:07:57,860
OR CATASTROPHIC COLLAPSE?
142
00:07:58,460 --> 00:08:01,330
IN THE 1920s,
SCIENTISTS DID THE MATH,
143
00:08:01,330 --> 00:08:05,170
AND THE RESULTS WERE
ANYTHING BUT REASSURING.
144
00:08:05,170 --> 00:08:08,410
THE MORE MATTER YOU HAVE,
THE MORE GRAVITY YOU HAVE.
145
00:08:08,410 --> 00:08:11,740
IF YOU HAVE LOTS OF MATTER
IN A VERY DENSE UNIVERSE,
146
00:08:11,740 --> 00:08:14,810
PERHAPS THE UNIVERSE
BEGINS TO RE-COLLAPSE.
147
00:08:14,810 --> 00:08:16,910
OR, IF YOU HAVE
VERY LITTLE MATTER,
148
00:08:16,920 --> 00:08:19,280
THE UNIVERSE WOULD
FREEZE TO DEATH.
149
00:08:19,290 --> 00:08:23,450
SO WHAT IS THE CRITICAL DENSITY,
THE BORDER BETWEEN THE TWO?
150
00:08:23,460 --> 00:08:27,990
IT'S APPROXIMATELY FIVE HYDROGEN
ATOMS PER CUBIC METER.
151
00:08:27,990 --> 00:08:33,400
SO THINK OF A CUBIC YARD,
AND PUT JUST FIVE HYDROGEN ATOMS
152
00:08:33,400 --> 00:08:36,230
INSIDE,
AND THAT IS THE TIPPING POINT.
153
00:08:36,240 --> 00:08:38,370
IF YOU PUT MORE THAN FIVE ATOMS,
154
00:08:38,370 --> 00:08:40,370
THEN THE UNIVERSE WILL
BEGIN TO COLLAPSE.
155
00:08:40,370 --> 00:08:41,910
IF YOU HAVE
LESS THAN FIVE ATOMS,
156
00:08:41,910 --> 00:08:43,510
THEN THE UNIVERSE
JUST KEEPS ON GOING.
157
00:08:44,510 --> 00:08:46,710
IF WE THOUGHT
THE UNIVERSE WAS BALANCED
158
00:08:46,710 --> 00:08:49,880
ON A TIGHTROPE BEFORE,
THE CRITICAL DENSITY QUESTION
159
00:08:49,880 --> 00:08:54,150
SHOWED US THAT THE ROPE
WAS MORE LIKE A RAZOR BLADE.
160
00:08:54,520 --> 00:08:57,460
YET, WHEN ASTRONOMERS TOOK
ADDITIONAL MEASUREMENTS,
161
00:08:57,460 --> 00:08:59,890
THEY LIKED WHAT THEY SAW.
162
00:08:59,890 --> 00:09:03,300
THE UNIVERSE APPEARED TO CONTAIN
JUST THE RIGHT AMOUNT
163
00:09:03,300 --> 00:09:06,230
OF MATTER TO STAY
AT THE CRITICAL DENSITY.
164
00:09:07,370 --> 00:09:09,470
MORE AND MORE,
THE INDIRECT EVIDENCE
165
00:09:09,470 --> 00:09:12,300
AND THE THEORETICAL
ARGUMENTS SUGGESTED
166
00:09:12,310 --> 00:09:15,010
THAT THE UNIVERSE MUST BE
EXACTLY AT THE BOUNDARY
167
00:09:15,010 --> 00:09:16,840
BETWEEN A UNIVERSE
THAT WOULD COLLAPSE
168
00:09:16,840 --> 00:09:19,150
AND ONE THAT
WOULD EXPAND FOREVER,
169
00:09:19,150 --> 00:09:22,780
THAT WE WERE TEETERING
ON THE HAIRY EDGE OF EXPANSION.
170
00:09:22,780 --> 00:09:27,050
THE UNIVERSE SEEMED
SO PERFECTLY BALANCED
171
00:09:27,050 --> 00:09:30,960
THAT IT WOULD HEAD QUIETLY
INTO OLD AGE.
172
00:09:30,960 --> 00:09:34,490
THEN, IN THE 1970s, ASTRONOMERS
MADE AN OBSERVATION
173
00:09:34,490 --> 00:09:36,500
THAT SHOCKED THEM.
174
00:09:36,500 --> 00:09:40,400
THE COSMOS WAS FILLED
WITH INVISIBLE STUFF,
175
00:09:40,400 --> 00:09:45,110
AND ITS GRAVITY COULD CAUSE
A CATASTROPHIC COLLAPSE.
176
00:09:55,520 --> 00:09:58,650
THE UNIVERSE
IS BALANCED ON A TIGHTROPE.
177
00:09:58,650 --> 00:10:02,790
ON EACH SIDE OF THE DROP
LIES AN EARLY DEATH --
178
00:10:02,790 --> 00:10:06,530
A BIG FREEZE, FUELED BY
THE RUNAWAY STRETCHING OF SPACE,
179
00:10:06,530 --> 00:10:12,430
OR A BIG CRUNCH, THE RESULT OF
GRAVITY OVERCOMING EXPANSION.
180
00:10:12,430 --> 00:10:15,900
40 YEARS AGO, SCIENTISTS
BELIEVED WE'D STAY BALANCED
181
00:10:15,900 --> 00:10:19,470
BETWEEN THESE FATES
FOR ETERNITY.
182
00:10:19,480 --> 00:10:21,710
NOW THINGS HAVE CHANGED
TREMENDOUSLY,
183
00:10:21,710 --> 00:10:24,450
BECAUSE WE'VE DISCOVERED
SOMETHING WE NEVER KNEW ABOUT
184
00:10:24,450 --> 00:10:25,250
40 YEARS AGO.
185
00:10:25,850 --> 00:10:30,520
IN THE 1970s,
ASTRONOMERS ARE STUNNED.
186
00:10:30,520 --> 00:10:34,220
SOME UNKNOWN FORM OF MATTER,
INVISIBLE TO TELESCOPES,
187
00:10:34,220 --> 00:10:36,920
DWARFS WHAT WE THOUGHT WAS
OUT THERE,
188
00:10:36,930 --> 00:10:40,700
NOT A FRACTION MORE,
BUT FIVE TIMES MORE.
189
00:10:40,700 --> 00:10:43,870
WE USED TO THINK
THAT GRAVITY CAME FROM STARS
190
00:10:43,870 --> 00:10:46,870
AND OBJECTS YOU CAN SEE --
END OF STORY.
191
00:10:46,870 --> 00:10:50,240
NOW, WE REALIZE THAT THAT NAIVE
PICTURE IS ACTUALLY WRONG.
192
00:10:51,280 --> 00:10:53,580
ASTRONOMERS MAKE
THE DISCOVERY,
193
00:10:53,580 --> 00:10:56,950
STUDYING THE CLOCKWORK
NATURE OF OUR UNIVERSE.
194
00:10:58,350 --> 00:11:01,020
THE HUGE GRAVITY OF THE SUN
HOLDS THE EARTH
195
00:11:01,020 --> 00:11:05,160
AND ALL THE OTHER PLANETS
IN A DELICATE CIRCULAR DANCE.
196
00:11:09,030 --> 00:11:12,560
THE SUN'S MASS CONTROLS
THE SPEED OF THESE ORBITS.
197
00:11:12,560 --> 00:11:15,730
IF IT WERE MORE MASSIVE,
THE PLANETS WOULD ORBIT
198
00:11:15,730 --> 00:11:17,400
MUCH MORE QUICKLY.
199
00:11:17,400 --> 00:11:19,970
AND IF IT WERE SMALLER,
IT WOULD TAKE MUCH LONGER
200
00:11:19,970 --> 00:11:22,610
FOR A PLANET TO COMPLETE
AN ORBIT.
201
00:11:24,810 --> 00:11:28,080
GALAXIES RUN
LIKE CLOCKWORK, TOO.
202
00:11:28,080 --> 00:11:31,350
THE VAST MASS AT THE CENTER
PULLS THE OUTER STARS
203
00:11:31,350 --> 00:11:34,750
INTO CIRCULAR,
PLANET-LIKE ORBITS.
204
00:11:34,750 --> 00:11:37,250
ASTRONOMERS MAKE
PRECISE MEASUREMENTS
205
00:11:37,260 --> 00:11:40,920
OF THESE GALACTIC
ORBITS IN THE 1970s.
206
00:11:40,920 --> 00:11:44,100
THE RESULTS CHANGE EVERYTHING.
207
00:11:45,000 --> 00:11:47,560
THE GALAXIES
WERE SPINNING TOO FAST.
208
00:11:47,570 --> 00:11:49,100
WAY TOO FAST.
209
00:11:52,170 --> 00:11:55,040
EVEN ACCOUNTING FOR
THE SUPERMASSIVE BLACK HOLES
210
00:11:55,040 --> 00:11:59,340
AT THEIR CENTER, NINE-TENTHS
OF THEIR MASS WAS MISSING.
211
00:11:59,340 --> 00:12:02,180
BY RIGHTS,
THE GALAXY SHOULD FLY APART.
212
00:12:02,180 --> 00:12:04,350
BY RIGHTS, THE EARTH
SHOULD HAVE BEEN FLUNG
213
00:12:04,350 --> 00:12:07,320
INTO INTERGALACTIC SPACE
BILLIONS OF YEARS AGO.
214
00:12:07,320 --> 00:12:10,520
WE SHOULD HAVE NO
MILKY WAY GALAXY, AND YET,
215
00:12:10,520 --> 00:12:12,260
OUR UNIVERSE IS
FULL OF GALAXIES.
216
00:12:16,330 --> 00:12:19,260
AN IMMENSE
ADDITIONAL SOURCE OF GRAVITY
217
00:12:19,260 --> 00:12:22,170
MUST BE HOLDING GALAXIES
TOGETHER.
218
00:12:22,170 --> 00:12:25,400
BUT NO MATTER WHERE ASTRONOMERS
POINT THEIR TELESCOPES,
219
00:12:25,400 --> 00:12:27,340
THEY SEE NOTHING.
220
00:12:27,340 --> 00:12:30,870
NOT A GLIMMER, NOT A SHADOW.
221
00:12:30,880 --> 00:12:35,750
WHATEVER THIS NEW STUFF IS,
IT DOESN'T EMIT LIGHT,
222
00:12:35,750 --> 00:12:39,380
REFLECT LIGHT,
OR EVEN BLOCK LIGHT.
223
00:12:39,380 --> 00:12:42,290
THEY CALL IT DARK MATTER.
224
00:12:42,320 --> 00:12:45,660
WHAT WE'VE LEARNED IS THAT MOST
OF THE MATTER IN THE UNIVERSE
225
00:12:45,660 --> 00:12:48,300
IS NOT ORDINARY STUFF.
IT'S NOT ATOMS.
226
00:12:48,300 --> 00:12:51,100
IT'S NOT PARTICLES WE'VE YET
DETECTED IN ANY EXPERIMENT
227
00:12:51,100 --> 00:12:52,800
DONE HERE ON EARTH.
228
00:12:52,800 --> 00:12:55,440
IT'S SOME NEW KIND OF PARTICLE
THAT WE CALL THE DARK MATTER.
229
00:12:58,570 --> 00:13:00,470
DARK MATTER FILLS THE UNIVERSE,
230
00:13:00,470 --> 00:13:03,580
OUTSTRIPPING NORMAL MATTER
BY 5-TO-1.
231
00:13:07,180 --> 00:13:11,680
VAST FILAMENTS SPREAD OUT
THROUGHOUT THE COSMOS,
232
00:13:11,690 --> 00:13:16,160
AND BRIGHT GALAXIES CLUSTER
WHERE DARK MATTER IS THICKEST.
233
00:13:18,490 --> 00:13:22,830
DARK MATTER PROVIDES
THE SCAFFOLDING THAT UNDERLIES
234
00:13:22,830 --> 00:13:25,700
HOW THE MATTER IN THE UNIVERSE
STRUCTURES ITSELF,
235
00:13:25,700 --> 00:13:27,600
WHERE IT GOES,
AND WHAT IT DOES.
236
00:13:28,470 --> 00:13:30,400
SO,
DARK MATTER DICTATED
237
00:13:30,410 --> 00:13:33,970
HOW THE UNIVERSE UNFOLDED.
238
00:13:33,970 --> 00:13:36,110
IT SEEMS AS IF
OUT OF THE HOT BIG BANG,
239
00:13:36,110 --> 00:13:39,750
DARK MATTER CONDENSED FIRST,
BEFORE ATOMS,
240
00:13:39,750 --> 00:13:42,720
AND DARK MATTER BEGAN
TO BECOME CLUMPY.
241
00:13:42,720 --> 00:13:45,920
THE CLUMPINESS THEN BEGAN
TO ATTRACT ATOMS
242
00:13:45,920 --> 00:13:49,620
AS THEY WERE FORMED LATER,
AND THAT FORMED GALAXIES.
243
00:13:49,620 --> 00:13:51,660
AND IN SOME SENSE,
THE DARK MATTER THEREFORE
244
00:13:51,660 --> 00:13:55,260
PROVIDES KIND OF A WOMB THAT
ALLOWS THE BIRTH OF OUR GALAXY.
245
00:13:58,500 --> 00:14:01,670
DARK MATTER HOLDS
THE UNIVERSE TOGETHER,
246
00:14:01,670 --> 00:14:04,140
BUT IT ALSO THREATENS
TO DESTROY IT.
247
00:14:06,970 --> 00:14:07,670
ONE OF THE MOST
AMAZING DISCOVERIES
248
00:14:07,670 --> 00:14:10,110
OF THE PAST FEW DECADES
IS DARK MATTER,
249
00:14:10,110 --> 00:14:12,080
THE FACT THAT THERE'S MUCH MORE
MATTER IN THE UNIVERSE
250
00:14:12,080 --> 00:14:13,550
THAN WE WERE AWARE OF.
251
00:14:13,550 --> 00:14:16,050
AND ALL OF THAT MATTER
HAS A LOT OF GRAVITY.
252
00:14:16,050 --> 00:14:18,180
SO ALL THIS NEW MATTER,
ALL THIS NEW GRAVITY
253
00:14:18,190 --> 00:14:20,590
MUST BE SLOWING DOWN
THE EXPANSION OF THE UNIVERSE.
254
00:14:21,360 --> 00:14:24,290
DARK MATTER MAY EVEN
TIP THE COSMIC SCALES
255
00:14:24,290 --> 00:14:26,290
IN FAVOR OF GRAVITY,
256
00:14:26,290 --> 00:14:30,060
DEFEATING EXPANSION
AND PULLING THE ENTIRE UNIVERSE
257
00:14:30,060 --> 00:14:32,670
TOWARDS A DEATH BY FIRE.
258
00:14:32,670 --> 00:14:35,470
IT'S CALLED THE BIG CRUNCH,
259
00:14:35,470 --> 00:14:37,840
AND THIS IS HOW
IT WOULD PLAY OUT.
260
00:14:39,540 --> 00:14:43,880
FOR A FRACTION OF A SECOND,
THE UNIVERSE STALLS,
261
00:14:43,880 --> 00:14:47,620
POISED BETWEEN
EXPANSION AND CONTRACTION.
262
00:14:47,620 --> 00:14:51,720
THEN, GRAVITY KICKS OFF
A CATACLYSM.
263
00:14:51,720 --> 00:14:54,190
WHEN YOU LOOKED OUT,
THE VERY FIRST THINGS
264
00:14:54,190 --> 00:14:56,120
AS IT BEGAN TO TURN AROUND
THAT YOU BEGAN TO SEE
265
00:14:56,130 --> 00:14:58,760
IS THAT GALAXIES, INSTEAD OF
MOVING AWAY FROM US ON AVERAGE,
266
00:14:58,760 --> 00:15:01,260
WOULD BEGIN TO BE MOVING TOWARDS
US ON AVERAGE.
267
00:15:02,400 --> 00:15:05,370
THE WHOLE UNIVERSE WOULD LOOK
LIKE IT WAS COMING TO GET US.
268
00:15:07,170 --> 00:15:09,770
AS SPACE
CONTRACTS FURTHER,
269
00:15:09,770 --> 00:15:13,610
THE DENSITY OF MATTER INCREASES,
GRAVITY GETS STRONGER,
270
00:15:13,610 --> 00:15:18,780
TEMPERATURES SOAR
AS THE CRUNCH GATHERS MOMENTUM.
271
00:15:18,780 --> 00:15:21,120
GALAXIES BEGIN TO COLLIDE,
272
00:15:21,120 --> 00:15:24,090
GAS CLOUDS BEGIN TO COLLIDE,
273
00:15:24,090 --> 00:15:27,190
PLANETS SLAM INTO THE EARTH.
274
00:15:30,960 --> 00:15:34,530
BLACK HOLES WILL EXECUTE A DEATH
DANCE AROUND EACH OTHER.
275
00:15:34,530 --> 00:15:37,970
TEMPERATURES, OF COURSE,
WILL CONTINUE TO SKYROCKET.
276
00:15:37,970 --> 00:15:41,810
MATTER, SPACE,
AND TIME IMPLODE
277
00:15:41,810 --> 00:15:44,740
UNTIL EVERYTHING IN THE UNIVERSE
IS COMPRESSED
278
00:15:44,740 --> 00:15:50,580
INTO A TINY SPECK OF INFINITE
MASS, HEAT, AND PRESSURE.
279
00:15:50,580 --> 00:15:53,350
FOR THE LAST STAGES
OF THE BIG CRUNCH,
280
00:15:53,350 --> 00:15:56,550
GALAXIES WILL COLLIDE
AND FORM A PRIMORDIAL ATOM.
281
00:15:56,550 --> 00:16:00,920
AND THEN, LIFE AS WE KNOW IT
WILL BE IMPOSSIBLE.
282
00:16:00,930 --> 00:16:03,360
WE'RE BACK
TO WHERE IT ALL BEGAN,
283
00:16:03,360 --> 00:16:04,500
BACK AT THE BIG BANG.
284
00:16:05,300 --> 00:16:09,030
THE UNIVERSE THAT WE LIVE IN
WILL CEASE TO EXIST.
285
00:16:12,600 --> 00:16:18,340
BUT SOME BELIEVE A BIG CRUNCH
COULD HERALD A NEW BEGINNING.
286
00:16:18,340 --> 00:16:20,680
WE DON'T KNOW WHAT THE END POINT
OF A BIG CRUNCH WOULD BE,
287
00:16:20,680 --> 00:16:23,410
BECAUSE THE LAWS OF PHYSICS
BREAK DOWN.
288
00:16:23,410 --> 00:16:26,880
IT'S POSSIBLE, AND INDEED,
PHILOSOPHICALLY VERY PLEASANT,
289
00:16:26,890 --> 00:16:31,120
TO IMAGINE THAT THAT CRUNCH
WOULD SOMEHOW END UP EVOLVING
290
00:16:31,120 --> 00:16:34,420
INTO AN EXPANSION AGAIN, AND YOU
COULD HAVE A CYCLIC UNIVERSE
291
00:16:34,420 --> 00:16:35,960
WHICH GOES ON FOREVER.
292
00:16:35,960 --> 00:16:39,700
PERHAPS AT THAT POINT, WE WILL
RECREATE ANOTHER BIG BANG.
293
00:16:43,640 --> 00:16:46,000
IT'S CONCEIVABLE THAT AS
EVERYTHING COMES TOGETHER
294
00:16:46,000 --> 00:16:49,540
IN THE CRUNCH, SOMETHING SORT OF
KEEPS IT FROM JUST CONTINUING
295
00:16:49,540 --> 00:16:53,210
AND PUSHES OUT IN A HOT,
DENSE, SMOOTH STATE,
296
00:16:53,210 --> 00:16:55,910
AND FROM THE OTHER SIDE,
IT LOOKS LIKE A BIG BANG,
297
00:16:55,910 --> 00:16:57,650
AND A NEW UNIVERSE HAS BEEN
CREATED.
298
00:16:57,650 --> 00:17:00,520
OUR BIG BANG MIGHT HAVE BEEN
SOMEONE ELSE'S BIG CRUNCH.
299
00:17:00,520 --> 00:17:02,820
BUT JUST WHEN
SCIENTISTS CAME TO TERMS
300
00:17:02,820 --> 00:17:06,290
WITH DARK MATTER'S BIG CRUNCH,
THE UNIVERSE THREW THEM
301
00:17:06,290 --> 00:17:08,690
ANOTHER, EVEN BIGGER CURVE.
302
00:17:08,690 --> 00:17:13,230
SOME GHOSTLY FORCE SEEMED TO BE
SENDING US HURTLING TOWARD
303
00:17:13,230 --> 00:17:15,330
A COMPLETELY DIFFERENT DEATH.
304
00:17:15,330 --> 00:17:18,140
MY POSTDOCTORAL
SCHOLAR SHOWED ME THE RESULTS.
305
00:17:18,140 --> 00:17:19,310
I NEARLY FELL OFF MY CHAIR.
306
00:17:29,450 --> 00:17:31,790
GRAVITY AND EXPANSION
BATTLE FOR CONTROL
307
00:17:31,790 --> 00:17:35,260
OF OUR UNIVERSE
FOR 14 BILLION YEARS...
308
00:17:39,430 --> 00:17:43,860
...EXPANSION
PUSHING IT OUTWARDS,
309
00:17:43,860 --> 00:17:46,470
GRAVITY PULLING IT IN.
310
00:17:47,970 --> 00:17:50,070
WITH DARK MATTER IN ITS CORNER,
311
00:17:50,070 --> 00:17:52,570
GRAVITY SEEMS TO BE
THE INEVITABLE WINNER.
312
00:17:52,570 --> 00:17:57,140
THE EXTRA MASS WILL DRAG
THE UNIVERSE INTO A BIG CRUNCH,
313
00:17:57,140 --> 00:17:59,180
UNTIL A STUNNING DISCOVERY
314
00:17:59,180 --> 00:18:03,690
REVOLUTIONIZES OUR UNDERSTANDING
OF THE UNIVERSE.
315
00:18:06,020 --> 00:18:10,960
AROUND 1990, TWO TEAMS OF
RESEARCHERS DECIDED TO MEASURE
316
00:18:10,960 --> 00:18:13,030
THE EXPANSION HISTORY
OF THE UNIVERSE
317
00:18:13,030 --> 00:18:16,130
TO DETERMINE WHETHER
IT'S BEEN SLOWING DOWN SO MUCH
318
00:18:16,130 --> 00:18:18,370
THAT IT'LL EVENTUALLY HAVE
A BIG CRUNCH,
319
00:18:18,370 --> 00:18:20,900
OR WHETHER IT HASN'T BEEN
SLOWING DOWN MUCH
320
00:18:20,900 --> 00:18:22,870
AND WILL ETERNALLY EXPAND.
321
00:18:22,870 --> 00:18:27,370
ASTRONOMER ALEX FILIPPENKO
WAS ON ONE TEAM.
322
00:18:27,370 --> 00:18:29,980
SAUL PERLMUTTER LED THE OTHER.
323
00:18:29,980 --> 00:18:33,010
WE REALIZED THAT IT WAS POSSIBLE
FOR THE FIRST TIME
324
00:18:33,010 --> 00:18:36,680
TO GO AND ACTUALLY MAKE
A DIRECT MEASUREMENT
325
00:18:36,680 --> 00:18:39,190
OF HOW MUCH THE UNIVERSE HAD
BEEN SLOWING DOWN IN THE PAST.
326
00:18:39,390 --> 00:18:40,920
BOTH TEAMS WANT
TO MEASURE
327
00:18:40,920 --> 00:18:43,220
THE SPEED OF DISTANT GALAXIES.
328
00:18:43,220 --> 00:18:47,100
BUT BECAUSE THE GALAXIES ARE
TOO DIM AND TOO FAR AWAY,
329
00:18:47,100 --> 00:18:49,130
THEY LOOK FOR SOMETHING
BRIGHTER.
330
00:18:54,040 --> 00:18:58,510
BILLIONS OF LIGHT YEARS
FROM EARTH, A STAR DETONATES.
331
00:18:58,510 --> 00:19:01,180
THIS IS A SUPERNOVA,
332
00:19:01,180 --> 00:19:05,180
A DYING STAR'S
BRILLIANT FINAL GASP.
333
00:19:05,180 --> 00:19:09,120
IT BURNS BRIGHTLY, 5 BILLION
TIMES BRIGHTER THAN THE SUN,
334
00:19:09,120 --> 00:19:11,790
BUT BRIEFLY.
335
00:19:11,790 --> 00:19:13,950
PERLMUTTER AND FILIPPENKO
HAVE A WINDOW
336
00:19:13,960 --> 00:19:16,520
OF JUST ONE OR TWO WEEKS
TO MEASURE
337
00:19:16,520 --> 00:19:19,830
HOW MUCH THE GALAXY IT SITS IN
IS SLOWING DOWN
338
00:19:19,830 --> 00:19:22,100
AS IT MOVES AWAY FROM US.
339
00:19:26,200 --> 00:19:29,440
THE TEAMS LOOK FOR SUPERNOVAS
FOR EIGHT YEARS.
340
00:19:29,440 --> 00:19:35,250
THEY MEASURE 42, AND THE RESULTS
SEEM IMPOSSIBLE.
341
00:19:35,250 --> 00:19:37,850
WE PLOTTED THE POINTS
ON THE GRAPHS,
342
00:19:37,850 --> 00:19:40,580
AND...IT DIDN'T MAKE ANY SENSE.
343
00:19:40,580 --> 00:19:42,450
THEY WERE NOT SLOWING DOWN
AT ALL.
344
00:19:42,450 --> 00:19:44,390
THEY WERE ACTUALLY SPEEDING UP.
345
00:19:45,560 --> 00:19:49,160
WHAT BOTH GROUPS FOUND
STUNNED THE WORLD.
346
00:19:49,160 --> 00:19:52,000
IN THE LAST 4 OR 5 BILLION
YEARS,
347
00:19:52,000 --> 00:19:56,160
THE UNIVERSE HAS ACTUALLY BEEN
SPEEDING UP IN ITS EXPANSION.
348
00:19:56,170 --> 00:19:58,000
AN ACCELERATING UNIVERSE,
349
00:19:58,000 --> 00:20:01,970
PROPELLED BY SOMETHING
MYSTERIOUS.
350
00:20:01,970 --> 00:20:04,440
FOR SO LONG, WE'VE BEEN ARGUING
WHETHER THE UNIVERSE WOULD
351
00:20:04,440 --> 00:20:07,280
EXPAND FOREVER OR COLLAPSE
BACK IN ON ITSELF,
352
00:20:07,280 --> 00:20:09,650
BUT NOBODY THOUGHT
THE ANSWER WAS GOING TO BE
353
00:20:09,650 --> 00:20:11,950
THAT THE UNIVERSE WAS
ACCELERATING,
354
00:20:11,950 --> 00:20:13,750
GOING FASTER AND FASTER
ALL THE TIME.
355
00:20:15,320 --> 00:20:18,690
THE ACCELERATION
BEWILDERS THE SCIENTISTS.
356
00:20:18,690 --> 00:20:21,790
IT SEEMS TO DEFY
THE LAWS OF PHYSICS.
357
00:20:21,790 --> 00:20:24,060
IMAGINE I'VE GOT A BASEBALL
358
00:20:24,060 --> 00:20:25,730
AND I THROW IT STRAIGHT UP.
359
00:20:25,730 --> 00:20:28,530
AND INSTEAD OF SLOWING DOWN
ONCE IT LEAVES MY HAND,
360
00:20:28,530 --> 00:20:30,370
WHICH IS WHAT
NORMALLY IT WILL DO,
361
00:20:30,370 --> 00:20:32,240
IT BEGINS TO SLOW DOWN AT FIRST,
362
00:20:32,240 --> 00:20:34,140
BUT THEN IT STARTS
SPEEDING AWAY.
363
00:20:34,140 --> 00:20:35,770
SOMEHOW, IT'S GETTING ENERGY.
364
00:20:35,780 --> 00:20:41,250
THE NEW ENERGY SEEMED
TO BE COMING FROM NOTHING,
365
00:20:41,250 --> 00:20:43,480
THE VACUUM OF SPACE.
366
00:20:43,480 --> 00:20:47,250
THE WORD "VACUUM" TO A SCIENTIST
MEANS COMPLETELY EMPTY SPACE,
367
00:20:47,250 --> 00:20:49,850
NO PARTICLES THERE AT ALL,
NO TEMPERATURE,
368
00:20:49,850 --> 00:20:51,450
NO ENERGY TO SPEAK OF.
369
00:20:51,460 --> 00:20:54,760
BUT THERE'S AN INTRINSIC ENERGY
IN SPACE AND TIME.
370
00:20:54,760 --> 00:20:58,460
EMPTY SPACE HAS ENERGY,
AND THAT ENERGY PRODUCES
371
00:20:58,460 --> 00:21:01,600
A GRAVITATIONAL REPULSION,
A KIND OF ANTI-GRAVITY.
372
00:21:01,600 --> 00:21:06,040
WITHOUT A CLUE WHAT
THIS FORCE IS OR HOW IT WORKS,
373
00:21:06,040 --> 00:21:11,610
ALL SCIENTISTS CAN DO IS GIVE IT
A NAME -- DARK ENERGY.
374
00:21:11,980 --> 00:21:14,380
WE COULD HAVE CALLED IT
WE-DON'T-KNOW ENERGY.
375
00:21:14,380 --> 00:21:15,850
WE COULD HAVE CALLED IT
ANYTHING.
376
00:21:15,850 --> 00:21:18,250
BUT WE DON'T KNOW WHAT IT IS,
AND DARK OR NOT,
377
00:21:18,250 --> 00:21:20,390
IT'S THE BIGGEST MYSTERY
IN PHYSICS.
378
00:21:23,560 --> 00:21:26,590
NASA CALIBRATES
ITS FINEST SPACE TELESCOPES
379
00:21:26,590 --> 00:21:29,730
TO MEASURE HOW MUCH DARK ENERGY
IS OUT THERE,
380
00:21:29,730 --> 00:21:33,060
AND THE RESULT IS MIND-BLOWING.
381
00:21:33,070 --> 00:21:37,870
IT DOMINATES THE MASS OF
THE UNIVERSE BY NEARLY 3-TO-1.
382
00:21:37,870 --> 00:21:39,540
AND THE MORE SPACE EXPANDS,
383
00:21:39,540 --> 00:21:42,710
THE MORE DARK ENERGY
THERE SEEMS TO BE.
384
00:21:42,710 --> 00:21:45,640
DARK ENERGY IS THE ENERGY
OF NOTHING,
385
00:21:45,640 --> 00:21:47,180
AND IT'S REPULSIVE.
386
00:21:47,180 --> 00:21:50,980
THEREFORE, AS THIS DARK ENERGY
REPELS GALAXIES,
387
00:21:50,980 --> 00:21:52,920
THERE'S MORE OF IT,
THERE'S MORE VACUUM.
388
00:21:52,920 --> 00:21:55,020
AND SO THERE'S MORE REPULSION,
389
00:21:55,020 --> 00:21:57,960
AND PERHAPS THAT'S THE REASON
WHY THE UNIVERSE IS ACCELERATING
390
00:21:57,960 --> 00:22:01,290
RIGHT NOW
RATHER THAN SLOWING DOWN.
391
00:22:01,290 --> 00:22:04,760
DARK ENERGY SEEMS TO
KILL THE BIG CRUNCH THEORY,
392
00:22:04,770 --> 00:22:07,830
BUT SCIENTISTS AREN'T YET SURE
HOW DARK ENERGY,
393
00:22:07,830 --> 00:22:11,370
EXPANSION, AND SPACE
ARE CONNECTED.
394
00:22:11,370 --> 00:22:14,710
IF A VOLUME OF SPACE DOUBLES
IN SIZE,
395
00:22:14,710 --> 00:22:17,610
DOES THE DARK ENERGY
INSIDE IT DOUBLE, TOO?
396
00:22:17,610 --> 00:22:19,710
OR DOES IT INCREASE MORE?
397
00:22:19,710 --> 00:22:23,250
A 1-TO-1 RELATIONSHIP LEADS
TO A STEADY EXPANSION.
398
00:22:23,250 --> 00:22:26,390
THE UNIVERSE ENDS
IN A BIG FREEZE.
399
00:22:26,390 --> 00:22:30,960
BUT IF DARK ENERGY INCREASES
ABOVE AND BEYOND EXPANSION,
400
00:22:30,960 --> 00:22:35,530
A NEW, EVEN MORE TERRIFYING END
AWAITS THE UNIVERSE -- A BIG RIP.
401
00:22:36,330 --> 00:22:40,370
IN A BIG RIP SCENARIO,
THE EXPANSION IS SO GREAT
402
00:22:40,370 --> 00:22:44,570
THAT EVEN THE GALAXIES BEGIN
TO EXPAND INTERNALLY,
403
00:22:44,570 --> 00:22:45,910
WHICH MEANS THAT LITERALLY
404
00:22:45,910 --> 00:22:47,840
OUR BODIES
ARE GOING TO BE RIPPED APART.
405
00:22:49,140 --> 00:22:50,640
SCIENTISTS CALCULATE
406
00:22:50,640 --> 00:22:52,980
JUST HOW THE BIG RIP
WILL PLAY OUT.
407
00:22:55,320 --> 00:22:59,390
ONE BY ONE, THE GALAXIES IN
THE NIGHT SKY WILL BLINK OUT
408
00:22:59,390 --> 00:23:02,350
AS SPACE PULLS THEM AWAY
FROM THE EARTH
409
00:23:02,360 --> 00:23:04,160
FASTER THAN THE SPEED OF LIGHT.
410
00:23:05,860 --> 00:23:10,260
60 MILLION YEARS BEFORE THE END,
DARK ENERGY OVERCOMES GRAVITY
411
00:23:10,270 --> 00:23:13,200
ON SMALLER AND SMALLER SCALES.
412
00:23:13,200 --> 00:23:16,500
FIRST GALAXIES START
TO RIP APART,
413
00:23:16,500 --> 00:23:20,370
THEN INSIDES OF GALAXIES
WILL BEGIN TO RIP APART,
414
00:23:20,370 --> 00:23:23,040
AND THEN SOLAR SYSTEMS WILL
BEGIN TO RIP APART...
415
00:23:25,310 --> 00:23:28,280
THEN PLANETS...
416
00:23:28,280 --> 00:23:33,690
AND THEN ROCKS, PEOPLE, ATOMS.
417
00:23:33,690 --> 00:23:36,990
THE END WILL
BE MERCIFULLY QUICK.
418
00:23:38,290 --> 00:23:40,560
IN THE SPACE OF A FEW MINUTES,
419
00:23:40,560 --> 00:23:44,730
ALL THE STARS AND PLANETS IN THE
UNIVERSE WILL BE DESTROYED,
420
00:23:44,730 --> 00:23:49,500
THEIR REMAINS PULLED APART
INTO EVER-SMALLER PIECES
421
00:23:49,510 --> 00:23:52,170
UNTIL FINALLY,
WHEN THE UNIVERSE HAS
422
00:23:52,180 --> 00:23:53,910
LESS THAN A SECOND TO LIVE,
423
00:23:53,910 --> 00:23:57,380
THE SUBATOMIC PARTICLES
THAT MADE ALL MATTER
424
00:23:57,380 --> 00:23:59,050
WILL BE DESTROYED,
425
00:23:59,050 --> 00:24:02,350
AND ALL THAT REMAINS WILL BE
INDIVIDUAL PHOTONS
426
00:24:02,350 --> 00:24:04,650
BECOMING SCARCER AND SCARCER
427
00:24:04,650 --> 00:24:07,390
AS THE SPACE BETWEEN THEM
EXPANDS.
428
00:24:07,390 --> 00:24:09,860
ALL YOU'RE LEFT WITH IS VERY LOW
ENERGY LIGHT
429
00:24:09,860 --> 00:24:11,330
THAT GETS STRETCHED
AND STRETCHED
430
00:24:11,330 --> 00:24:13,430
UNTIL IT MIGHT AS WELL
NOT EXIST AT ALL.
431
00:24:13,430 --> 00:24:15,430
THE LAST THING TO GO --
432
00:24:15,430 --> 00:24:18,930
THE EMPTY VACUUM
OF SPACE ITSELF.
433
00:24:20,470 --> 00:24:22,970
IT'LL BE PULLING ON THE UNIVERSE
SO HARD,
434
00:24:22,970 --> 00:24:25,880
IT COULD TEAR THE FABRIC
OF THE UNIVERSE APART.
435
00:24:25,880 --> 00:24:29,280
REALITY COULD DISSOLVE.
436
00:24:29,280 --> 00:24:32,620
WILL THE UNIVERSE END
WITH A BIG RIP,
437
00:24:32,620 --> 00:24:34,950
OR A BIG FREEZE?
438
00:24:34,950 --> 00:24:39,420
THE ANSWER IS LOCKED INSIDE
THE MYSTERY OF DARK ENERGY.
439
00:24:39,420 --> 00:24:44,190
SOLVE THAT, AND THE FATE
OF THE UNIVERSE BECOMES CLEAR.
440
00:24:56,080 --> 00:24:58,440
THE END
OF THE UNIVERSE IS COMING.
441
00:24:58,440 --> 00:25:00,610
BUT HOW WILL IT PLAY OUT?
442
00:25:00,610 --> 00:25:04,480
FOR A TIME, A BIG CRUNCH
WAS THE LIKELY ANSWER.
443
00:25:04,480 --> 00:25:08,250
DARK MATTER, THE INVISIBLE BULK
OF THE UNIVERSE,
444
00:25:08,250 --> 00:25:11,560
CAUSES SPACE
TO FALL IN ON ITSELF.
445
00:25:12,830 --> 00:25:17,190
GALAXIES COLLIDE.
PLANET MERGES WITH PLANET.
446
00:25:17,200 --> 00:25:21,970
EVERYTHING BECOMES HOTTER
AND HOTTER, DENSER AND DENSER.
447
00:25:21,970 --> 00:25:24,540
THE UNIVERSE IS LIKE
ONE GIANT STAR.
448
00:25:28,310 --> 00:25:32,340
DARK ENERGY KILLS
THE BIG CRUNCH THEORY.
449
00:25:32,340 --> 00:25:35,480
IT ACTS LIKE ROCKET FUEL
FOR THE EXPANSION OF SPACE
450
00:25:35,480 --> 00:25:37,720
BETWEEN GALAXIES.
451
00:25:37,720 --> 00:25:40,950
THEY'RE NOT JUST COASTING.
THEY'RE GETTING PUSHED OUTWARD.
452
00:25:44,290 --> 00:25:46,490
ONLY TWO POSSIBLE FATES
REMAIN --
453
00:25:46,490 --> 00:25:49,190
A BIG RIP OR A BIG FREEZE.
454
00:25:49,190 --> 00:25:52,100
BOTH SCENARIOS RELY
ON DARK ENERGY.
455
00:25:52,100 --> 00:25:55,030
FOR THE UNIVERSE TO BE TORN
TO SHREDS IN A BIG RIP,
456
00:25:55,030 --> 00:25:58,740
DARK ENERGY MUST INCREASE
EXPONENTIALLY IN THE FUTURE.
457
00:25:58,740 --> 00:26:02,070
BUT A BIG FREEZE REQUIRES
A STEADY INCREASE
458
00:26:02,070 --> 00:26:03,580
IN DARK ENERGY,
459
00:26:03,580 --> 00:26:05,480
PUSHING GALAXIES AWAY
FROM EACH OTHER.
460
00:26:05,580 --> 00:26:08,550
WE CAN'T WRITE THE LAST CHAPTER
OF OUR UNIVERSE
461
00:26:08,550 --> 00:26:12,020
UNTIL WE UNDERSTAND THE NATURE
OF DARK ENERGY.
462
00:26:13,620 --> 00:26:16,490
MAY 2009.
463
00:26:16,490 --> 00:26:20,090
THE EUROPEAN SPACE AGENCY
LAUNCHES THE PLANCK SATELLITE
464
00:26:20,100 --> 00:26:24,000
TO SEARCH FOR THE BIRTH
OF DARK ENERGY.
465
00:26:24,000 --> 00:26:28,470
ITS ULTRA-SENSITIVE TELESCOPE
PEERS THROUGH SPACE AND TIME
466
00:26:28,470 --> 00:26:31,000
BACK THROUGH BILLIONS OF YEARS,
467
00:26:31,000 --> 00:26:35,580
TOWARDS THE BEGINNING OF
EVERYTHING, TO CAPTURE THIS.
468
00:26:35,580 --> 00:26:38,080
THIS IS OUR UNIVERSE
AS IT APPEARED
469
00:26:38,080 --> 00:26:41,010
OVER 13 BILLION YEARS AGO,
470
00:26:41,010 --> 00:26:45,050
380,000 YEARS
AFTER THE BIG BANG.
471
00:26:46,620 --> 00:26:49,220
SO WHAT PLANCK HAS DONE
IS TAKE A PICTURE
472
00:26:49,220 --> 00:26:51,490
OF THE EARLY UNIVERSE
473
00:26:51,490 --> 00:26:54,630
AND TOLD US ABOUT WHAT
THE EARLY UNIVERSE IS LIKE
474
00:26:54,630 --> 00:26:57,060
AND GIVEN US OUR MOST DETAILED
AND ACCURATE PICTURE
475
00:26:57,060 --> 00:26:58,400
OF THAT MOMENT IN TIME.
476
00:26:58,400 --> 00:27:00,830
THE UNIVERSE IN THIS PICTURE
477
00:27:00,830 --> 00:27:05,340
IS A HOT SOUP OF PROTONS,
ELECTRONS, AND PHOTONS.
478
00:27:05,340 --> 00:27:08,410
HYDROGEN ATOMS HAVE JUST STARTED
TO FORM,
479
00:27:08,410 --> 00:27:11,140
AND IT'S THE LIGHT FROM THIS
GENESIS OF MATTER
480
00:27:11,150 --> 00:27:13,010
THAT WE SEE HERE.
481
00:27:15,080 --> 00:27:18,320
BLUE AREAS ARE COLDER.
REDS ARE WARM.
482
00:27:18,450 --> 00:27:20,560
EVENTUALLY, THOSE HOT SPOTS,
483
00:27:20,560 --> 00:27:22,760
THOSE RED SPOTS YOU SEE
IN THE MAP,
484
00:27:22,760 --> 00:27:25,390
ARE GOING TO FORM LARGE
SUPERCLUSTERS
485
00:27:25,390 --> 00:27:29,870
MADE UP OF HUNDREDS OR THOUSANDS
OF GALAXIES.
486
00:27:29,870 --> 00:27:34,000
EACH ONE OF THOSE GALAXIES WILL
CONTAIN BILLIONS OF STARS.
487
00:27:35,640 --> 00:27:37,940
GRAVITY
AND EXPANSION ALONE
488
00:27:37,940 --> 00:27:42,640
APPEAR TO DRIVE THE FORMATION
OF THESE EMBRYONIC GALAXIES.
489
00:27:42,640 --> 00:27:46,910
DARK ENERGY DOESN'T SEEM
TO HAVE SWITCHED ON YET.
490
00:27:46,920 --> 00:27:51,750
SO, WHEN DID DARK ENERGY TAKE
CONTROL OF THE UNIVERSE?
491
00:27:58,260 --> 00:28:01,460
ASTRONOMER BRENDA FRYE
IS PART OF A TEAM
492
00:28:01,460 --> 00:28:04,070
USING MASSIVE
GROUND-BASED TELESCOPES
493
00:28:04,070 --> 00:28:06,870
LIKE THIS ONE AT KITT PEAK,
ARIZONA.
494
00:28:06,870 --> 00:28:11,240
SHE PEERS BACK IN TIME
TO CAPTURE THE UNIVERSE
495
00:28:11,240 --> 00:28:14,140
THROUGH ITS CHILDHOOD
AS IT WAS GROWING.
496
00:28:16,180 --> 00:28:18,750
RIGHT.
SO THIS IS AN ALUMINUM PLATE,
497
00:28:18,750 --> 00:28:22,950
AND INTO THIS PLATE ARE
DRILLED 640 INDIVIDUAL HOLES.
498
00:28:22,950 --> 00:28:26,020
EACH ONE IS PUT AT A VERY
SPECIFIC PLACE ON THE MASK
499
00:28:26,020 --> 00:28:30,090
WHICH WILL CORRESPOND TO ONE
PARTICULAR GALAXY IN THE SKY.
500
00:28:32,460 --> 00:28:34,190
DURING EACH OBSERVATION,
501
00:28:34,200 --> 00:28:38,700
THE LIGHT FROM 640 INDIVIDUAL
GALAXIES IS COLLECTED
502
00:28:38,700 --> 00:28:42,100
USING FIBER OPTIC CABLES.
503
00:28:42,110 --> 00:28:45,570
THE SPEED AND RELATIVE POSITION
OF EACH GALAXY IS MEASURED
504
00:28:45,580 --> 00:28:49,450
TO PINPOINT EXACTLY WHERE IT IS
IN SPACE.
505
00:28:49,550 --> 00:28:52,180
SO FAR, THE TEAM
HAS ACCURATELY MAPPED
506
00:28:52,180 --> 00:28:55,020
AROUND A MILLION GALAXIES
IN 3D,
507
00:28:55,020 --> 00:28:56,890
AND THIS IS WHAT THEY LOOK LIKE.
508
00:28:58,120 --> 00:29:00,760
EACH ONE OF THESE FUZZY PATCHES
509
00:29:00,760 --> 00:29:02,590
IS A FULLY GROWN GALAXY
510
00:29:02,590 --> 00:29:06,630
CONTAINING AROUND
200 BILLION STARS.
511
00:29:06,630 --> 00:29:08,300
THIS IS A VERY BASIC
MEASUREMENT,
512
00:29:08,300 --> 00:29:10,470
AND WE THINK THAT
THIS WILL BE ABLE TO HELP US
513
00:29:10,470 --> 00:29:13,470
TO GET A GRASP INTO THE NATURE
OF DARK ENERGY.
514
00:29:13,470 --> 00:29:17,770
SCIENTISTS COMPARE
THIS ADOLESCENT UNIVERSE
515
00:29:17,770 --> 00:29:19,640
TO ITS BABY PICTURES.
516
00:29:19,640 --> 00:29:21,880
IT SHOWS DARK ENERGY EMERGING
517
00:29:21,880 --> 00:29:25,080
WHEN THE UNIVERSE IS
HALF AS OLD AS IT IS TODAY.
518
00:29:26,350 --> 00:29:29,090
ABOUT 8 BILLION YEARS
AFTER THE BIG BANG,
519
00:29:29,090 --> 00:29:33,320
THIS EXPANSION OF THE UNIVERSE
BEGINS TO ACCELERATE,
520
00:29:33,320 --> 00:29:35,960
AND WE'RE IN THE MIDDLE
OF THIS ACCELERATION.
521
00:29:35,960 --> 00:29:40,660
THE DATA ALSO SHOWS
THAT AS SPACE EXPANDS,
522
00:29:40,670 --> 00:29:45,300
DARK ENERGY
INCREASES IN LOCKSTEP WITH IT.
523
00:29:45,300 --> 00:29:47,640
IF YOU HAD A BOX AND YOU PUT
SOME DARK ENERGY IN IT,
524
00:29:47,640 --> 00:29:49,970
AND THEN YOU WENT AND YOU
WEIGHED THAT BOX...
525
00:29:49,970 --> 00:29:51,880
NOW YOU TAKE THE BOX,
YOU MAKE IT TWICE AS BIG.
526
00:29:51,880 --> 00:29:53,740
YOU DON'T OPEN IT.
YOU DON'T PUT ANYTHING IN IT.
527
00:29:53,740 --> 00:29:56,280
YOU WEIGH IT AGAIN, IT'S GONNA
WEIGH TWICE AS MUCH.
528
00:29:56,280 --> 00:29:58,620
THIS REMARKABLE
OBSERVATION MEANS
529
00:29:58,620 --> 00:30:02,090
THAT WE SHOULD BE SAFE
FROM A BIG RIP.
530
00:30:02,090 --> 00:30:05,520
DARK ENERGY WILL CONTINUE
TO INCREASE GRADUALLY.
531
00:30:05,520 --> 00:30:09,090
THE UNIVERSE IS HEADING
FOR A BIG FREEZE,
532
00:30:09,090 --> 00:30:13,130
AND SCIENTISTS CAN FINALLY
CALCULATE A TIMELINE
533
00:30:13,130 --> 00:30:16,000
FOR THE END OF EVERYTHING.
534
00:30:25,180 --> 00:30:26,710
IT NOW SEEMS
THAT WE LIVE
535
00:30:26,710 --> 00:30:29,350
IN AN ALMOST PERFECT UNIVERSE,
536
00:30:29,350 --> 00:30:32,920
WITH JUST ENOUGH GRAVITY
TO HOLD THE GALAXIES TOGETHER
537
00:30:32,920 --> 00:30:36,820
AND JUST ENOUGH DARK ENERGY
THAT IT WILL EXPAND FOREVER
538
00:30:36,820 --> 00:30:39,460
WITHOUT RIPPING ITSELF
TO SHREDS.
539
00:30:41,400 --> 00:30:46,070
COSMOLOGISTS CAN FINALLY
ENVISION THE END OF IT ALL.
540
00:30:47,400 --> 00:30:49,970
30 YEARS AGO,
IT WAS DEBATABLE.
541
00:30:49,970 --> 00:30:52,840
BUT NOW, IT APPEARS
THAT THE UNIVERSE MOST LIKELY
542
00:30:52,840 --> 00:30:54,410
WILL SUFFER A DEEP FREEZE.
543
00:30:54,410 --> 00:30:57,710
IF YOU LOOK AT THE DATA,
IT STARES OUT AT YOU.
544
00:30:58,880 --> 00:31:00,450
IN A BIG FREEZE,
545
00:31:00,450 --> 00:31:04,580
DARK ENERGY PUSHES GALAXIES
FURTHER AND FURTHER APART,
546
00:31:04,590 --> 00:31:07,460
BUT THEY REMAIN INTACT.
547
00:31:07,490 --> 00:31:11,160
THE STARS INSIDE THEM
FADE AWAY.
548
00:31:11,160 --> 00:31:13,690
EVERY STAR YOU SEE IN THE SKY,
INCLUDING OUR SUN,
549
00:31:13,700 --> 00:31:15,800
IS BURNING THROUGH
ITS NUCLEAR FUEL.
550
00:31:15,800 --> 00:31:19,000
THE GAS WILL RUN OUT,
STARS WILL STOP BEING MADE,
551
00:31:19,000 --> 00:31:22,640
AND THE ONES THAT EXIST ARE IT.
THOSE ARE THE LAST ONES.
552
00:31:27,040 --> 00:31:29,340
A HUNDRED TRILLION
YEARS FROM NOW,
553
00:31:29,340 --> 00:31:33,650
THE BIGGEST STARS WILL BE
THE FIRST TO GO EXTINCT.
554
00:31:33,650 --> 00:31:36,780
BIG STARS BURN BRIGHT
AND DIE HARD.
555
00:31:36,780 --> 00:31:41,220
THE STAR'S CORE COLLAPSES,
556
00:31:41,220 --> 00:31:43,360
UNLEASHING A SUPERNOVA.
557
00:31:44,660 --> 00:31:48,000
THEN GRAVITY CRUSHES
THE DEAD STAR DOWN
558
00:31:48,000 --> 00:31:50,670
TO A SINGLE DENSE SPOT.
559
00:31:50,670 --> 00:31:54,100
THE BRIGHT STAR
IS NOW A BLACK HOLE.
560
00:31:56,470 --> 00:31:59,040
SUN-LIKE STARS GO NEXT.
561
00:32:00,510 --> 00:32:03,110
AS THEIR SUPPLY OF HYDROGEN
RUNS OUT,
562
00:32:03,110 --> 00:32:05,480
THEY SWELL TO A BLOATED FIREBALL
563
00:32:05,480 --> 00:32:08,420
OVER 200 TIMES
THEIR CURRENT SIZE.
564
00:32:14,290 --> 00:32:16,530
AND WHEN THE CORE
HAS NO MORE HYDROGEN,
565
00:32:16,530 --> 00:32:19,800
IT'S GOING TO BLOAT UP
INTO A RED GIANT STAR.
566
00:32:19,800 --> 00:32:22,160
NOW, RED GIANT STARS ARE SO BIG,
THEY WILL ACTUALLY
567
00:32:22,170 --> 00:32:24,170
EAT UP THEIR OWN PLANETS.
568
00:32:24,170 --> 00:32:26,000
WE KNOW OF EXAMPLES
OF RED GIANTS
569
00:32:26,000 --> 00:32:28,070
THAT GO ALL THE WAY OUT
TO WHERE THE ORBIT OF JUPITER IS
570
00:32:28,070 --> 00:32:30,000
IN OUR SOLAR SYSTEM.
571
00:32:30,010 --> 00:32:32,970
ITS FUEL EXHAUSTED,
572
00:32:32,980 --> 00:32:35,680
THE SUN-LIKE STAR
GIVES IN TO GRAVITY
573
00:32:35,680 --> 00:32:37,780
AND SHRINKS TO A WHITE DWARF,
574
00:32:37,780 --> 00:32:39,550
A DENSE BALL OF MATTER
575
00:32:39,550 --> 00:32:42,680
JUST A FEW THOUSAND MILES
IN DIAMETER.
576
00:32:42,680 --> 00:32:46,720
IT WILL GLOW WITH HEAT
FOR A FURTHER 10 BILLION YEARS
577
00:32:46,720 --> 00:32:49,290
BEFORE COOLING TO A BLACK DWARF,
578
00:32:49,290 --> 00:32:54,330
A BALL OF COMPRESSED CARBON,
PERHAPS EVEN DIAMOND.
579
00:32:57,030 --> 00:32:59,370
AS THE BIGGEST STARS DIE,
580
00:32:59,370 --> 00:33:02,910
THE UNIVERSE
WILL SLOWLY TURN RED.
581
00:33:02,910 --> 00:33:04,670
THE BLUE STARS
WILL BLOW UP,
582
00:33:04,670 --> 00:33:06,840
AND THEN THE SLIGHTLY LESS BLUE
STARS WILL BLOW UP,
583
00:33:06,840 --> 00:33:09,210
AND THEN STARS LIKE THE SUN
WILL FADE AWAY AND DIE,
584
00:33:09,210 --> 00:33:11,880
LEAVING JUST THE RED STARS
TO EXIST.
585
00:33:13,450 --> 00:33:15,290
RED STARS
ARE THE SMALLEST
586
00:33:15,290 --> 00:33:17,190
AND COOLEST IN THE UNIVERSE.
587
00:33:17,190 --> 00:33:19,460
THEY BURN THEIR FUEL SLOWLY.
588
00:33:19,460 --> 00:33:22,190
BUT, AFTER ANOTHER
10 TRILLION YEARS,
589
00:33:22,190 --> 00:33:24,600
EVEN THESE SMALLEST
OF DWARF STARS
590
00:33:24,600 --> 00:33:26,860
WILL USE UP THEIR FUEL.
591
00:33:26,870 --> 00:33:30,430
STARS AS WE KNOW THEM
WILL CEASE TO BURN ENERGY,
592
00:33:30,430 --> 00:33:32,900
AND THE NIGHT SKY
WILL TURN BLACK.
593
00:33:32,900 --> 00:33:36,770
BLACK HOLES,
THE CORPSES OF DEAD STARS,
594
00:33:36,780 --> 00:33:41,410
AND COLD CLOUDS OF GAS AND DUST
ARE ALL THAT REMAINS.
595
00:33:43,220 --> 00:33:45,980
THE AGE OF STARS IS OVER.
596
00:33:45,990 --> 00:33:49,720
THE AGE OF BLACK HOLES BEGINS.
597
00:33:49,720 --> 00:33:51,920
BLACK HOLES BECOME
THE FUNDAMENTAL BUILDING BLOCK
598
00:33:51,920 --> 00:33:53,590
OF THE UNIVERSE.
599
00:33:53,590 --> 00:33:55,960
A GALAXY WILL BASICALLY BE
A SUPERMASSIVE BLACK HOLE
600
00:33:55,960 --> 00:33:57,990
IN THE CENTER, WITH SMALLER
BLACK HOLES ORBITING IT.
601
00:33:58,000 --> 00:34:00,530
IN SOME WAYS, IT'S KIND OF
A GHOST UNIVERSE.
602
00:34:00,530 --> 00:34:02,370
IT'S THE CORPSES,
THE ZOMBIE STARS,
603
00:34:02,370 --> 00:34:04,070
THAT WILL TAKE US
INTO THE FUTURE.
604
00:34:04,070 --> 00:34:07,240
ZOMBIE GALAXIES
FILLED WITH BLACK HOLES
605
00:34:07,240 --> 00:34:09,040
CONTINUE TO EVOLVE.
606
00:34:09,040 --> 00:34:12,410
THEY SWEEP UP THE DEAD REMAINS
OF STARS.
607
00:34:12,410 --> 00:34:16,510
BLACK HOLE MERGES
WITH BLACK HOLE.
608
00:34:16,520 --> 00:34:18,620
THEY'LL EAT EACH OTHER
AND THEY'LL GET BIGGER,
609
00:34:18,620 --> 00:34:20,450
AND MAYBE THEY'LL FALL INTO
THE SUPERMASSIVE BLACK HOLE
610
00:34:20,450 --> 00:34:21,920
AND IT'LL GET BIGGER.
611
00:34:21,920 --> 00:34:24,920
THE UNIVERSE WILL STILL BE
AN EXCITING, DYNAMIC PLACE,
612
00:34:24,920 --> 00:34:27,220
IT'S JUST THAT THE TIME SCALES
YOU'RE TALKING ABOUT
613
00:34:27,230 --> 00:34:28,790
ARE NOW TRILLIONS OF YEARS
614
00:34:28,790 --> 00:34:31,500
INSTEAD OF THOUSANDS
OR MILLIONS OF YEARS.
615
00:34:31,500 --> 00:34:35,670
ANY MATERIAL THAT
EVADES THE PULL OF A BLACK HOLE
616
00:34:35,670 --> 00:34:40,940
EVENTUALLY DIES AWAY
AS ITS PROTONS DISINTEGRATE.
617
00:34:40,940 --> 00:34:44,080
A PROTON, ONE OF THE FUNDAMENTAL
BUILDING BLOCKS
618
00:34:44,080 --> 00:34:46,910
OF ATOMIC MATTER,
OF WHAT MAKES US UP,
619
00:34:46,910 --> 00:34:49,410
CAN JUST SPONTANEOUSLY
FALL APART,
620
00:34:49,410 --> 00:34:53,290
AND IT TURNS OUT THIS TAKES
A TREMENDOUSLY LONG TIME.
621
00:34:53,290 --> 00:34:55,390
BUT EVEN THAT WILL GO AWAY.
622
00:34:55,390 --> 00:35:00,460
ALL THAT WILL BE LEFT
IS A SEA OF BLACK HOLES.
623
00:35:00,460 --> 00:35:03,730
SCIENTISTS USED TO THINK
BLACK HOLES WERE IMMORTAL,
624
00:35:03,730 --> 00:35:05,400
BUT EVEN THESE WILL ONE DAY DIE.
625
00:35:05,500 --> 00:35:08,200
NOW WE'RE TALKING ABOUT
TIME SCALES
626
00:35:08,200 --> 00:35:09,870
OF UNIMAGINABLE LENGTH --
627
00:35:09,870 --> 00:35:12,410
QUADRILLIONS OF YEARS
INTO THE FUTURE.
628
00:35:12,510 --> 00:35:13,970
BUT ON THAT TIME SCALE,
629
00:35:13,970 --> 00:35:18,080
EVEN THE BLACK HOLES
BEGIN TO EVAPORATE.
630
00:35:18,080 --> 00:35:20,310
THEY'LL GET SMALLER AND SMALLER
AND SMALLER,
631
00:35:20,310 --> 00:35:22,250
AND THEN, POOF, THEY'LL BE GONE.
632
00:35:22,250 --> 00:35:24,720
THE UNIVERSE WILL END
633
00:35:24,720 --> 00:35:27,550
WHEN THE LAST REMAINING
BLACK HOLE DIES.
634
00:35:27,550 --> 00:35:30,360
AS IT GETS SMALLER,
THE EVAPORATION RATE
635
00:35:30,360 --> 00:35:32,390
INCREASES EXPONENTIALLY.
636
00:35:32,390 --> 00:35:34,590
BEFORE LONG,
IT REACHES A SIZE
637
00:35:34,590 --> 00:35:39,600
A BILLIONTH OF A TRILLIONTH
OF A TRILLIONTH OF AN INCH.
638
00:35:39,600 --> 00:35:43,000
AT THAT INSTANT,
THE LAWS OF PHYSICS BREAK DOWN,
639
00:35:43,000 --> 00:35:47,170
AND THE LAST BLACK HOLE EXPLODES
IN A FLASH OF GAMMA RAYS,
640
00:35:47,170 --> 00:35:49,940
LEAVING NOTHING.
641
00:35:49,940 --> 00:35:53,550
AND IT WILL DIE
IN A SUDDEN BURST OF LIGHT,
642
00:35:53,550 --> 00:35:55,210
THE LAST BURST OF LIGHT
643
00:35:55,220 --> 00:35:57,550
IN THE ENTIRE HISTORY
OF THE UNIVERSE.
644
00:35:58,190 --> 00:36:00,190
THE BIG FREEZE IS COMING.
645
00:36:00,190 --> 00:36:04,490
THE UNIVERSE WILL SUFFER A COLD,
SLOW, DARK DEATH
646
00:36:04,490 --> 00:36:05,860
WHICH WILL PLAY OUT
647
00:36:05,860 --> 00:36:09,600
OVER TRILLIONS UPON TRILLIONS
OF YEARS.
648
00:36:09,600 --> 00:36:13,000
BUT QUANTUM PHYSICS LEAVES
THE DOOR OPEN
649
00:36:13,000 --> 00:36:14,770
FOR AN ALTERNATIVE END,
650
00:36:14,770 --> 00:36:18,210
AN EVENT SO POWERFUL,
SO DESTRUCTIVE,
651
00:36:18,210 --> 00:36:23,910
THAT IT COULD DESTROY EVERYTHING
WE SEE IN THE BLINK OF AN EYE.
652
00:36:23,910 --> 00:36:27,080
AND IT COULD HAPPEN TOMORROW.
653
00:36:36,330 --> 00:36:38,160
THE END OF THE UNIVERSE --
654
00:36:38,160 --> 00:36:39,690
IT'S COMING.
655
00:36:39,690 --> 00:36:43,100
DARK ENERGY ACCELERATES
THE SPACE BETWEEN GALAXIES,
656
00:36:43,100 --> 00:36:46,670
PUSHING EVERYTHING WE SEE
TO A LONG, COLD,
657
00:36:46,670 --> 00:36:49,410
AND VERY SLOW DEATH.
658
00:36:49,410 --> 00:36:53,270
UNLESS, THAT IS, SOMETHING
BIZARRE HAPPENS FIRST.
659
00:36:53,280 --> 00:36:57,080
A MONSTER CALLED
PHASE TRANSITION
660
00:36:57,080 --> 00:36:58,710
IS LURKING IN THE SHADOWS,
661
00:36:58,710 --> 00:37:02,650
AND IT COULD ANNIHILATE
THE FABRIC OF SPACE AND TIME
662
00:37:02,650 --> 00:37:05,750
AT ANY MOMENT.
663
00:37:05,750 --> 00:37:09,520
WHEN WE COOL DOWN WATER,
IT TURNS INTO ICE.
664
00:37:09,530 --> 00:37:11,030
THE PROPERTIES CHANGE.
665
00:37:11,030 --> 00:37:13,230
IF YOU LIVED IN THE WATER,
WHEN IT CHANGED TO ICE,
666
00:37:13,230 --> 00:37:15,060
YOUR WORLD
WOULD BE VERY DIFFERENT.
667
00:37:15,070 --> 00:37:20,270
WATER PHASE CHANGES
INTO ICE WHEN IT LOSES ENERGY.
668
00:37:20,270 --> 00:37:23,310
I ONCE LEFT A WATER
BOTTLE IN MY CAR OVERNIGHT.
669
00:37:23,310 --> 00:37:26,210
IT WAS STILL LIQUID,
BUT THE MOMENT I TOUCHED IT,
670
00:37:26,210 --> 00:37:27,610
THE SLIGHT IMPERFECTION,
671
00:37:27,610 --> 00:37:29,480
THE LITTLE BIT OF ICE
THAT IT FORMED, SPREAD,
672
00:37:29,480 --> 00:37:31,350
POOF, AND FILLED UP
THE WHOLE BOTTLE.
673
00:37:31,350 --> 00:37:34,550
THAT RAPID CHANGE
TO SOMETHING NEW
674
00:37:34,550 --> 00:37:36,720
IS CALLED A PHASE TRANSITION,
675
00:37:36,720 --> 00:37:42,120
AND BIZARRELY, THE SAME THING
COULD HAPPEN TO EMPTY SPACE.
676
00:37:42,120 --> 00:37:44,830
WE'VE REALLY COME TO UNDERSTAND
677
00:37:44,830 --> 00:37:48,030
THAT WE SHOULDN'T TAKE
FOR GRANTED THAT...VACUUM,
678
00:37:48,030 --> 00:37:50,770
WHAT WE CALL NOTHING,
IS ACTUALLY STABLE.
679
00:37:50,770 --> 00:37:53,670
IT COULD BE THAT THE ENERGY
STORED IN EMPTY SPACE
680
00:37:53,670 --> 00:37:56,470
IS JUST WAITING TO BE RELEASED
IN A PHASE TRANSITION.
681
00:37:56,470 --> 00:37:59,610
IF IT IS, THE LAWS OF PHYSICS
WILL CHANGE.
682
00:38:01,480 --> 00:38:05,180
A SPONTANEOUS GLITCH
IN THE FABRIC OF SPACE-TIME
683
00:38:05,180 --> 00:38:09,090
COULD TRIGGER
A PHASE TRANSITION OF SPACE,
684
00:38:09,090 --> 00:38:13,490
A TINY BUBBLE OF NEW UNIVERSE
THAT SPREADS OUT,
685
00:38:13,490 --> 00:38:15,790
OVERWRITING THE OLD.
686
00:38:15,790 --> 00:38:19,460
WE KNOW IT CAN HAPPEN,
BECAUSE IT'S HAPPENED BEFORE.
687
00:38:23,270 --> 00:38:25,270
AT THE MOMENT OF THE BIG BANG,
688
00:38:25,270 --> 00:38:27,340
THE UNIVERSE
THAT'S FIRST CREATED
689
00:38:27,340 --> 00:38:30,710
IS COMPLETELY DIFFERENT
TO THE ONE WE SEE TODAY.
690
00:38:30,710 --> 00:38:33,640
HOT AND WITHOUT FORM,
691
00:38:33,640 --> 00:38:36,250
THERE'S NO MATTER, NO TIME.
692
00:38:36,250 --> 00:38:39,820
THE LAWS OF PHYSICS
ARE DIFFERENT.
693
00:38:39,820 --> 00:38:43,520
SUDDENLY, LESS THAN A TRILLIONTH
OF A SECOND LATER,
694
00:38:43,520 --> 00:38:46,590
A GLITCH TRIGGERS
A PHASE TRANSITION.
695
00:38:46,590 --> 00:38:50,230
A TINY BUBBLE OF THE UNIVERSE
WE LIVE IN TODAY FORMS,
696
00:38:50,230 --> 00:38:52,460
AND IT RACES OUTWARD,
697
00:38:52,460 --> 00:38:54,430
DESTROYING EVERYTHING IT TOUCHES
698
00:38:54,430 --> 00:38:57,600
LIKE ICE
SPREADING THROUGH WATER.
699
00:38:57,600 --> 00:39:01,340
THE ENERGY THAT SPILLS OUT
CREATES THE SPACE AND TIME
700
00:39:01,340 --> 00:39:02,970
THAT WE EXIST IN,
701
00:39:02,970 --> 00:39:07,580
THE BUILDING BLOCKS OF MATTER
AND THE FORCES THAT GOVERN THEM.
702
00:39:07,580 --> 00:39:10,310
ALL THAT ENERGY WAS RELEASED,
PRODUCING ALL THE MATTER
703
00:39:10,320 --> 00:39:12,250
AND RADIATION WE OBSERVE
IN THE UNIVERSE TODAY.
704
00:39:12,450 --> 00:39:15,290
THE OLD UNIVERSE
GIVES UP ITS ENERGY
705
00:39:15,290 --> 00:39:16,920
TO CREATE THE NEW.
706
00:39:16,920 --> 00:39:19,060
BUT IT HOLDS SOME BACK.
707
00:39:19,060 --> 00:39:23,490
THE VACUUM OF SPACE
STILL HAS ENERGY BOUND TO IT.
708
00:39:23,500 --> 00:39:28,030
PERHAPS THIS IS THE DARK ENERGY
WE SEE TODAY.
709
00:39:28,030 --> 00:39:31,340
PHYSICISTS BELIEVE
THAT SOMEDAY IN THE FUTURE,
710
00:39:31,340 --> 00:39:34,840
A BRAND NEW GLITCH IN THE FABRIC
OF SPACE-TIME
711
00:39:34,840 --> 00:39:37,380
MAY TRIGGER ANOTHER
PHASE TRANSITION,
712
00:39:37,380 --> 00:39:40,950
ONE THAT WIPES US
AND EVERYTHING WE SEE
713
00:39:40,950 --> 00:39:42,880
OUT OF EXISTENCE.
714
00:39:42,880 --> 00:39:46,380
THIS IS A WAY TO DESTROY
AN ENTIRE UNIVERSE,
715
00:39:46,390 --> 00:39:48,150
BECAUSE WITHIN YOUR UNIVERSE
716
00:39:48,150 --> 00:39:50,650
ARE THE SEEDS
OF ITS OWN DESTRUCTION.
717
00:39:50,660 --> 00:39:53,630
IT WOULD SPREAD OUT AT THE SPEED
OF LIGHT IN A DEATH BUBBLE,
718
00:39:53,630 --> 00:39:56,590
RUINING ALL THE GALAXIES
AS IT PASSES THROUGH,
719
00:39:56,600 --> 00:39:59,900
AND ULTIMATELY COMPLETELY
DESTROYING OUR UNIVERSE.
720
00:39:59,900 --> 00:40:03,400
NOTHING CAN SURVIVE
THE EXPANDING PHASE TRANSITION.
721
00:40:03,400 --> 00:40:08,210
PLANETS, NEBULAS, GALAXIES --
ALL ARE RIPPED APART
722
00:40:08,210 --> 00:40:10,510
AS THE BOUNDARY
OF THE BUBBLE REACHES THEM.
723
00:40:10,510 --> 00:40:13,750
INSIDE THIS BUBBLE,
PROTONS ARE UNSTABLE,
724
00:40:13,750 --> 00:40:17,580
ATOMS BEGIN TO REARRANGE
IN A NEW FORM OF MATTER.
725
00:40:17,580 --> 00:40:19,620
AS THESE BUBBLES
BEGIN TO EXPAND,
726
00:40:19,620 --> 00:40:22,250
A NEW UNIVERSE IS BEING BORN
727
00:40:22,260 --> 00:40:24,920
IN THE CORPSE
OF THE OLD UNIVERSE,
728
00:40:24,920 --> 00:40:28,260
AND THE BEGINNING
OF A NEW LAW OF PHYSICS.
729
00:40:28,460 --> 00:40:32,100
AND SO, THE EXPANDING UNIVERSE
WE NOW SEE
730
00:40:32,100 --> 00:40:35,540
MAY END IN A PHASE TRANSITION,
BUT WE WON'T KNOW WHAT HIT US,
731
00:40:35,540 --> 00:40:37,470
'CAUSE THE LAWS OF PHYSICS
WILL CHANGE,
732
00:40:37,470 --> 00:40:40,210
AND WE WILL ESSENTIALLY MOST
LIKELY DISAPPEAR
733
00:40:40,210 --> 00:40:41,970
AT THE INSTANT IT HAPPENS.
734
00:40:41,980 --> 00:40:45,640
THIS BUBBLE WILL EXPAND
AT THE SPEED OF LIGHT,
735
00:40:45,650 --> 00:40:47,510
AND AS THE BUBBLE PASSES YOU,
736
00:40:47,520 --> 00:40:50,550
ALL THE ATOMS OF YOUR BODY
REARRANGE THEMSELVES,
737
00:40:50,550 --> 00:40:52,250
AND YOU WOULD NEVER KNOW IT.
738
00:40:52,250 --> 00:40:54,950
YOU WOULD HAVE NO WARNING,
BECAUSE THE BUBBLE ITSELF
739
00:40:54,960 --> 00:40:56,520
IS EXPANDING
AT THE SPEED OF LIGHT.
740
00:40:56,520 --> 00:40:59,130
YOU CAN'T PREDICT PRECISELY
WHEN IT COULD HAPPEN.
741
00:40:59,130 --> 00:41:00,760
YOU ONLY HAVE A PROBABILITY.
742
00:41:00,760 --> 00:41:03,000
SO WHAT YOU REALLY
ARE PREDICTING IS A RATE.
743
00:41:03,000 --> 00:41:06,170
DOES IT HAPPEN ONCE A YEAR?
ONCE EVERY 10 BILLION YEARS?
744
00:41:06,170 --> 00:41:08,400
ONCE EVERY GOOGOL YEARS?
OR WHATEVER.
745
00:41:08,400 --> 00:41:11,700
IT'S VERY POSSIBLE THAT
THESE BUBBLES GET NUCLEATED
746
00:41:11,700 --> 00:41:15,340
AND GROW ABOUT ONCE EVERY
10 OR 20 BILLION YEARS.
747
00:41:15,340 --> 00:41:17,980
SO IT HASN'T HAPPENED YET
BECAUSE WE GOT LUCKY.
748
00:41:17,980 --> 00:41:20,920
IT'S UNLIKELY IT WOULD HAPPEN
THE NEXT YEAR OR THE NEXT DAY,
749
00:41:20,920 --> 00:41:22,980
BUT THE LAWS OF PHYSICS
ABSOLUTELY ALLOW IT.
750
00:41:26,320 --> 00:41:30,590
A PHASE CHANGE
MAY HAPPEN, OR IT MAY NOT.
751
00:41:31,730 --> 00:41:35,870
THE UNIVERSE PLAYS ITS CARDS
CLOSE TO ITS CHEST.
752
00:41:39,700 --> 00:41:42,900
AND, LIKE DARK ENERGY
AND DARK MATTER,
753
00:41:42,910 --> 00:41:44,870
THERE MAY BE MORE SURPRISES
TO COME...
754
00:41:46,680 --> 00:41:51,550
...SURPRISES THAT WILL ONLY
ADD TO THE MYSTERY AND WONDER
755
00:41:51,550 --> 00:41:54,180
OUR UNIVERSE HOLDS FOR US.
756
00:41:57,550 --> 00:41:59,190
WHATEVER THE UNIVERSE
IS UP TO,
757
00:41:59,190 --> 00:42:00,550
WE STILL DON'T KNOW ENOUGH.
758
00:42:00,560 --> 00:42:02,660
WE'RE IN AN AGE OF DISCOVERY
RIGHT NOW.
759
00:42:02,660 --> 00:42:04,560
PERHAPS THERE IS SOMETHING ELSE
OUT THERE
760
00:42:04,560 --> 00:42:05,930
THAT WE DON'T KNOW ABOUT.
761
00:42:05,930 --> 00:42:08,330
SO, I'M NOT GOING TO DRAW
ANY CONCLUSIONS
762
00:42:08,330 --> 00:42:10,030
UNTIL THINGS ARE CONCLUSIVE.
763
00:42:12,730 --> 00:42:15,240
WE DON'T UNDERSTAND
THE NATURE OF DARK ENERGY.
764
00:42:15,240 --> 00:42:18,840
AND WITHOUT THAT UNDERSTANDING,
VIRTUALLY ANYTHING IS POSSIBLE.
765
00:42:18,840 --> 00:42:20,880
THE FUTURE IS STILL UNCERTAIN,
766
00:42:20,880 --> 00:42:23,210
AND THAT MEANS
THERE'S STILL A MYSTERY.
767
00:42:23,210 --> 00:42:26,580
AND FOR ME, THAT'S THE MOST
EXCITING POSSIBILITY OF ALL.