1
00:02:08,045 --> 00:02:10,756
Which came first...

2
00:02:10,881 --> 00:02:12,883
the chicken or the egg?

3
00:02:16,887 --> 00:02:19,181
Did the universe
have a beginning...

4
00:02:19,306 --> 00:02:22,392
and if so,
what happened before then?

5
00:02:26,772 --> 00:02:29,733
Where did the universe
come from...

6
00:02:29,858 --> 00:02:31,985
and where is it going?

7
00:03:03,767 --> 00:03:07,062
Luck. Luck. Well...

8
00:03:07,187 --> 00:03:09,773
we have been very lucky...

9
00:03:09,898 --> 00:03:13,026
I mean, my family
and Stephen and everybody.

10
00:03:13,151 --> 00:03:16,113
You have your disasters,
but the point is that we have survived.

11
00:03:16,280 --> 00:03:18,615
Everybody has disasters,
and yet some people disappear...

12
00:03:18,782 --> 00:03:20,617
and are never seen again.

13
00:03:32,963 --> 00:03:35,757
Flying bombs are very alarming.

14
00:03:35,883 --> 00:03:37,926
They came buzzing over...

15
00:03:38,051 --> 00:03:39,970
and then they would cut out.

16
00:03:41,805 --> 00:03:44,600
And when you heard the bang,
you knew it wasn't you...

17
00:03:44,725 --> 00:03:47,019
so you went back
to your meal or whatever.

18
00:03:47,144 --> 00:03:50,147
But one did fall
quite close to our house...

19
00:03:50,272 --> 00:03:52,691
and it blew
the back windows out...

20
00:03:52,816 --> 00:03:56,320
so that the glass was sticking dagger
points all out of the opposite wall.

21
00:03:59,656 --> 00:04:01,825
When Stephen was born,
we decided...

22
00:04:01,992 --> 00:04:04,369
he'd better be born in Oxford.

23
00:04:04,494 --> 00:04:06,663
So while I was staying
in the hospital...

24
00:04:07,706 --> 00:04:10,334
I went to Blackwell's
in Oxford...

25
00:04:10,459 --> 00:04:13,462
and I bought
an astronomical atlas.

26
00:04:14,922 --> 00:04:17,382
One of my sisters-in-law said...

27
00:04:17,508 --> 00:04:20,344
"This is a very prophetic thing
for you to have done."

28
00:04:26,350 --> 00:04:28,477
How real is time?

29
00:04:29,853 --> 00:04:32,439
Will it ever come to an end?

30
00:04:35,859 --> 00:04:37,986
Where does the difference...

31
00:04:38,111 --> 00:04:41,198
between the past
and the future come from?

32
00:04:43,367 --> 00:04:45,702
Why do we remember the past...

33
00:04:45,869 --> 00:04:47,955
but not the future?

34
00:04:52,543 --> 00:04:54,378
I can remember the day...

35
00:04:54,545 --> 00:04:58,507
when we traveled through London
and the blackout was over.

36
00:05:02,344 --> 00:05:05,347
And the trains,
instead of being shut in...

37
00:05:05,472 --> 00:05:08,016
by blinds so that you
just traveled in a train...

38
00:05:08,141 --> 00:05:10,227
we were coming over
one of the bridges...

39
00:05:10,394 --> 00:05:13,730
and all the lights...
well, such lights as were left...

40
00:05:13,897 --> 00:05:17,192
were on in London, but it was also
a completely starry night...

41
00:05:17,317 --> 00:05:20,112
and you could see the light.
It was beautiful.

42
00:05:24,533 --> 00:05:29,079
I remember we all used to lie on the grass,
looking straight up through a telescope...

43
00:05:29,246 --> 00:05:32,416
and seeing the wonders
of the stars.

44
00:05:32,541 --> 00:05:36,086
Stephen always had
a strong sense of wonder...

45
00:05:36,253 --> 00:05:39,423
and I could see that
the stars would draw him...

46
00:05:39,590 --> 00:05:41,508
and further than the stars.

47
00:05:44,219 --> 00:05:47,055
I was born exactly 300 years...

48
00:05:47,181 --> 00:05:49,600
after the death of Galileo.

49
00:05:52,519 --> 00:05:56,273
I estimate that
about 200,000 other babies...

50
00:05:56,440 --> 00:05:58,901
were also born that day.

51
00:06:01,278 --> 00:06:03,405
I don't know
whether any of them...

52
00:06:03,530 --> 00:06:05,782
was later interested
in astronomy.

53
00:06:09,494 --> 00:06:11,371
My first memory is of Isobel...

54
00:06:11,496 --> 00:06:14,291
pushing a rather antiquated...

55
00:06:14,416 --> 00:06:17,127
carriage-built pram
along North Road...

56
00:06:17,294 --> 00:06:19,796
with Stephen and Mary in it...

57
00:06:19,922 --> 00:06:22,424
sort of looking very large...

58
00:06:22,549 --> 00:06:26,720
because they had large heads and pink
cheeks, and they were very noticeable.

59
00:06:26,845 --> 00:06:30,140
They all looked different
from ordinary people.

60
00:06:32,100 --> 00:06:35,896
I can remember visiting
the Hawking home...

61
00:06:36,021 --> 00:06:37,814
oh, several times.

62
00:06:38,065 --> 00:06:41,693
It was the sort of place where,
if invited to stay to supper...

63
00:06:41,818 --> 00:06:43,862
you might, uh...

64
00:06:43,987 --> 00:06:46,198
be allowed to have
your conversation with Stephen...

65
00:06:46,323 --> 00:06:49,117
but the rest of the family
would be sitting...

66
00:06:49,243 --> 00:06:51,453
at the table reading a book...

67
00:06:51,578 --> 00:06:55,082
a behavior which was not really
approved of in my circle...

68
00:06:55,207 --> 00:06:57,251
but which was tolerated
from the Hawkings...

69
00:06:57,376 --> 00:06:59,545
because they were
recognized to be...

70
00:06:59,670 --> 00:07:03,090
very eccentric,
highly intelligent...

71
00:07:03,215 --> 00:07:05,217
very clever people...

72
00:07:05,342 --> 00:07:08,011
but still a bit odd.

73
00:07:09,429 --> 00:07:13,475
My impression of the Hawking family
was that they were all like that...

74
00:07:13,600 --> 00:07:15,853
except for Stephen,
who seemed to be...

75
00:07:16,019 --> 00:07:18,105
the only normal member
of the family.

76
00:07:20,899 --> 00:07:23,485
Stephen used to reckon
he knew, I think it was...

77
00:07:23,610 --> 00:07:27,155
11 ways of getting into the house,
and I could only find ten.

78
00:07:28,532 --> 00:07:30,951
I'm not sure where the other way was.

79
00:07:32,452 --> 00:07:36,331
On the north side of the house
was a bicycle shed.

80
00:07:36,456 --> 00:07:39,960
It had a door at the front
and a door at the back.

81
00:07:40,085 --> 00:07:43,964
Above that, there was a window
into the L-shaped room...

82
00:07:45,507 --> 00:07:48,677
and at the front you could get
sort of around the corner...

83
00:07:48,802 --> 00:07:51,221
onto the roof...

84
00:07:51,346 --> 00:07:54,057
and from that level...

85
00:07:54,183 --> 00:07:56,226
you could get
onto the main roof.

86
00:07:57,728 --> 00:07:59,479
I think one of the ways...

87
00:07:59,605 --> 00:08:01,899
Stephen could get in
was on the main roof.

88
00:08:04,985 --> 00:08:08,030
As I say, he was
a much better climber than I was.

89
00:08:10,532 --> 00:08:13,118
I still didn't know
what the 11th one was.

90
00:08:17,247 --> 00:08:19,750
Before the 20th century...

91
00:08:19,875 --> 00:08:24,004
it was thought that the universe
had existed forever...

92
00:08:24,129 --> 00:08:27,758
or had been created
at some time in the past...

93
00:08:27,925 --> 00:08:30,761
more or less
as we observe it today.

94
00:08:32,971 --> 00:08:36,099
People found comfort
in the thought...

95
00:08:36,225 --> 00:08:39,061
that even though
they may grow old and die...

96
00:08:39,186 --> 00:08:42,648
the universe was eternal
and unchanging.

97
00:08:45,192 --> 00:08:48,779
I gave up playing games
with Stephen...

98
00:08:50,113 --> 00:08:53,992
oh, when he was ill that time
when he was about 12...

99
00:08:54,117 --> 00:08:56,870
because he started
taking games terribly seriously.

100
00:08:57,955 --> 00:09:00,791
We had Monopoly...

101
00:09:00,916 --> 00:09:02,918
and first of all...

102
00:09:03,043 --> 00:09:07,005
the Monopoly board sprang
railways going across it...

103
00:09:07,130 --> 00:09:09,299
to add to the complications...

104
00:09:09,466 --> 00:09:12,261
and then Monopoly
just wasn't adaptable enough.

105
00:09:12,386 --> 00:09:15,264
He ended up with a fearful game
called Dynasty...

106
00:09:16,390 --> 00:09:19,601
which, as far as I can make out...
I never played it...

107
00:09:19,726 --> 00:09:22,813
went on forever because
there was no way of ending it.

108
00:09:23,272 --> 00:09:26,817
It was almost a substitute for living,
as far as I could make out.

109
00:09:26,984 --> 00:09:29,486
It took hours
and hours and hours.

110
00:09:29,903 --> 00:09:31,947
I thought it was
a perfectly terrible game.

111
00:09:32,072 --> 00:09:34,825
I couldn't imagine anyone
getting taken up with that.

112
00:09:34,950 --> 00:09:37,744
But Stephen always had
a very complicated mind...

113
00:09:37,870 --> 00:09:39,705
and I felt
as much as anything...

114
00:09:39,830 --> 00:09:42,332
it was the complication of it
that appealed to him.

115
00:09:44,418 --> 00:09:47,671
When I was in high school,
I learned that light...

116
00:09:47,796 --> 00:09:51,175
from distant galaxies
was shifted to the red.

117
00:09:53,093 --> 00:09:56,513
This meant that they were
moving away from us...

118
00:09:56,638 --> 00:09:58,974
and that the universe
was expanding.

119
00:10:00,350 --> 00:10:02,519
But I didn't believe it.

120
00:10:06,023 --> 00:10:10,194
A static universe seemed
much more natural.

121
00:10:11,570 --> 00:10:13,655
It could have existed...

122
00:10:13,780 --> 00:10:17,034
and could continue to exist forever.

123
00:10:20,621 --> 00:10:23,040
We were discussing
the possibility...

124
00:10:23,165 --> 00:10:26,126
of the spontaneous
generation of life...

125
00:10:26,251 --> 00:10:29,713
and I think
that Stephen made a remark...

126
00:10:29,838 --> 00:10:32,132
which indicated not only
that he'd thought of this...

127
00:10:32,257 --> 00:10:34,676
but he'd even also...

128
00:10:34,801 --> 00:10:37,012
come across some calculations...

129
00:10:37,137 --> 00:10:39,890
as to how long it might take.

130
00:10:40,307 --> 00:10:42,684
At that time,
I think I made a comment...

131
00:10:42,809 --> 00:10:45,395
to one of my friends,
John McClenahan...

132
00:10:45,562 --> 00:10:48,106
"I think that Stephen...

133
00:10:48,232 --> 00:10:50,651
will turn out to be
unusually capable."

134
00:10:50,776 --> 00:10:53,278
I don't think I put it
in quite those words...

135
00:10:53,403 --> 00:10:55,489
but I made
some such remark to him...

136
00:10:55,614 --> 00:10:58,408
and he disagreed.

137
00:10:58,534 --> 00:11:01,161
And so we made
a bet on the subject.

138
00:11:01,286 --> 00:11:03,247
In our childish way, we bet...

139
00:11:03,372 --> 00:11:06,041
a bag of sweets on the issue.

140
00:11:06,375 --> 00:11:10,587
And incidentally, I reckon
that my bet has come correct...

141
00:11:10,754 --> 00:11:12,965
and I think
I'm entitled to payment...

142
00:11:13,090 --> 00:11:15,843
which has not yet been made.

143
00:11:19,096 --> 00:11:21,431
The expansion of the universe...

144
00:11:21,557 --> 00:11:23,767
suggested the possibility...

145
00:11:23,934 --> 00:11:26,019
that the universe
had a beginning...

146
00:11:26,144 --> 00:11:28,438
at some time in the past.

147
00:11:30,399 --> 00:11:34,611
The point at which the universe
may have started out...

148
00:11:34,736 --> 00:11:37,322
became known as the Big Bang.

149
00:11:45,080 --> 00:11:47,791
The first year
he was at St. Albans School...

150
00:11:47,916 --> 00:11:52,379
he came, I think,
third from the bottom.

151
00:11:52,504 --> 00:11:54,506
I said, "Well, Stephen..."

152
00:11:54,631 --> 00:11:57,968
do you really have to be
as far down as that?"

153
00:11:58,093 --> 00:11:59,970
And he said, "Well..."

154
00:12:00,137 --> 00:12:02,598
a lot of other people
didn't do much better."

155
00:12:02,723 --> 00:12:04,808
He was quite unconcerned.

156
00:12:06,810 --> 00:12:08,979
Somehow he was
always recognized...

157
00:12:09,104 --> 00:12:10,981
as being very bright...

158
00:12:12,149 --> 00:12:15,819
and in fact they gave him
the Divinity Prize one year.

159
00:12:15,944 --> 00:12:19,156
That was not surprising because
his father used to read him...

160
00:12:19,323 --> 00:12:21,366
Bible stories
from a very early age...

161
00:12:21,491 --> 00:12:23,660
and he knew them all
very well...

162
00:12:23,785 --> 00:12:26,330
and he was quite well-versed
in religious things...

163
00:12:26,497 --> 00:12:30,250
although I don't think he makes
a great deal of practice of it now.

164
00:12:30,584 --> 00:12:33,337
Everybody
used to argue theology.

165
00:12:34,671 --> 00:12:37,841
That's a good, safe subject.

166
00:12:37,966 --> 00:12:40,761
You don't need any facts or...

167
00:12:40,886 --> 00:12:43,347
distracting things like that.

168
00:12:43,680 --> 00:12:46,141
If you go in for arguing...

169
00:12:48,018 --> 00:12:52,314
you know, debating... you can
quite happily debate about anything...

170
00:12:52,439 --> 00:12:54,775
including theology...

171
00:12:54,900 --> 00:12:57,653
and the existence
or otherwise of God.

172
00:13:00,864 --> 00:13:02,866
And then someone gets bored...

173
00:13:03,033 --> 00:13:06,203
or Journey Into Space comes on,
or something like that...

174
00:13:06,328 --> 00:13:09,289
and the argument breaks up.

175
00:13:11,416 --> 00:13:13,544
In an unchanging universe...

176
00:13:13,669 --> 00:13:17,256
one can imagine
that God created the universe...

177
00:13:17,381 --> 00:13:20,884
at literally any time
in the past.

178
00:13:21,969 --> 00:13:24,221
On the other hand...

179
00:13:24,388 --> 00:13:26,723
if the universe is expanding...

180
00:13:26,890 --> 00:13:29,101
there may be physical reasons...

181
00:13:29,226 --> 00:13:31,854
why there had to be a beginning.

182
00:13:33,397 --> 00:13:37,234
An expanding universe
does not preclude a creator...

183
00:13:37,359 --> 00:13:39,236
but it does place limits...

184
00:13:39,361 --> 00:13:42,781
on when he might have
carried out his job.

185
00:13:46,910 --> 00:13:49,621
When the family went to India...

186
00:13:49,746 --> 00:13:53,250
it was arranged that Stephen should
come and live with us for a year.

187
00:13:54,418 --> 00:13:56,753
He decided it would be nice...

188
00:13:56,879 --> 00:13:59,256
that we should have...

189
00:13:59,423 --> 00:14:01,800
Scottish dancing in the evening.

190
00:14:01,925 --> 00:14:04,678
Mind you, this was
quite an ordinary house...

191
00:14:04,803 --> 00:14:07,973
but we had rather a lot of room
and a large hall...

192
00:14:08,098 --> 00:14:11,768
and so we bought some records...

193
00:14:11,935 --> 00:14:15,814
and a book about what to do...

194
00:14:15,939 --> 00:14:18,775
and Stephen took charge.

195
00:14:18,942 --> 00:14:22,821
And he insisted
you put on a jacket and a tie.

196
00:14:22,946 --> 00:14:27,451
And then he was
the master of the proceedings.

197
00:14:27,576 --> 00:14:29,786
And Stephen took it
very seriously.

198
00:14:29,953 --> 00:14:32,289
But then he liked dancing,
you see?

199
00:14:35,792 --> 00:14:39,129
There were
four physicists in my year...

200
00:14:39,254 --> 00:14:41,131
Gordon Berry...

201
00:14:41,256 --> 00:14:43,133
Richard Bryan...

202
00:14:43,258 --> 00:14:45,135
Stephen...

203
00:14:45,260 --> 00:14:47,095
myself.

204
00:14:48,639 --> 00:14:51,892
I first remember Stephen...

205
00:14:52,017 --> 00:14:55,854
on an occasion when Gordon and I
went up after dinner to his room...

206
00:14:55,979 --> 00:14:59,316
to try to find him.

207
00:14:59,483 --> 00:15:01,318
And Stephen was up there...

208
00:15:01,485 --> 00:15:03,820
with a crate of beer...

209
00:15:03,946 --> 00:15:06,156
slowly drinking
his way through it.

210
00:15:07,241 --> 00:15:10,953
He was only 17.
He couldn't legally go into a pub.

211
00:15:11,078 --> 00:15:13,956
He'd gone up to Oxford
ridiculously early.

212
00:15:19,127 --> 00:15:22,130
We used to have
what we called a gathering net.

213
00:15:23,715 --> 00:15:27,427
We used to organize a beer party
and various things like that...

214
00:15:27,553 --> 00:15:30,722
to gather all these... collar
as many freshman as we could get...

215
00:15:30,848 --> 00:15:32,891
to get them to join
the Boat Club.

216
00:15:33,016 --> 00:15:36,186
And that's how
we collected him, you see?

217
00:15:42,860 --> 00:15:45,654
But the question always
with Stephen was...

218
00:15:46,738 --> 00:15:49,241
"Should we make him
the cox of the first eight...

219
00:15:49,366 --> 00:15:52,035
or the second eight?"

220
00:15:52,161 --> 00:15:55,664
Well, coxes can be
adventurous...

221
00:15:55,789 --> 00:15:59,459
and some coxes can be
very steady people.

222
00:15:59,585 --> 00:16:02,671
He was rather
an adventurous type.

223
00:16:04,214 --> 00:16:06,717
You never knew quite
what he was going to do...

224
00:16:06,884 --> 00:16:08,802
when he went out with the crew.

225
00:16:13,891 --> 00:16:17,644
I think he used to bring his work
with him into the boat sometimes.

226
00:16:17,769 --> 00:16:19,980
His sort of thinking gear
was going...

227
00:16:20,105 --> 00:16:22,566
on different levels.

228
00:16:24,651 --> 00:16:29,072
We were asked
to read chapter 10...

229
00:16:29,239 --> 00:16:32,075
in a book called
Electricity and Magnetism...

230
00:16:32,242 --> 00:16:34,745
by Bleaney and Bleaney,
an unlikely combination...

231
00:16:34,912 --> 00:16:36,997
a husband-and-wife team...

232
00:16:37,122 --> 00:16:40,375
and at the end of that chapter,
there were 13 questions...

233
00:16:40,501 --> 00:16:44,004
all of them
final honors questions.

234
00:16:44,129 --> 00:16:48,467
I discovered very rapidly
that I couldn't do any of them.

235
00:16:48,592 --> 00:16:50,886
Richard and I worked together
for the week...

236
00:16:51,011 --> 00:16:53,597
and we managed to do
11/2 questions...

237
00:16:53,764 --> 00:16:55,682
which we felt very proud of.

238
00:16:55,807 --> 00:16:57,768
Gordon refused all assistance...

239
00:16:57,893 --> 00:17:01,146
and managed to do one
all by himself.

240
00:17:01,271 --> 00:17:04,024
Stephen, as always,
hadn't even started...

241
00:17:04,149 --> 00:17:08,278
but the next morning,
he went up to his rooms at 9:00...

242
00:17:09,488 --> 00:17:12,824
and we came back about 12:00,
maybe five past 12:00...

243
00:17:12,950 --> 00:17:17,037
and down came Stephen, and we were
in the college gateway, the lodge.

244
00:17:17,162 --> 00:17:20,791
"Ah, Hawking," I said, "how many
have you managed to do, then?"

245
00:17:20,958 --> 00:17:24,795
"Well," he said, "I've only had time
to do the first ten."

246
00:17:26,129 --> 00:17:30,425
I think at that point we realized that
it's not just we weren't in the same street.

247
00:17:30,551 --> 00:17:32,636
We weren't on the same planet.

248
00:17:36,431 --> 00:17:38,475
I once calculated...

249
00:17:38,600 --> 00:17:41,603
that I did
about 1,000 hours' work...

250
00:17:41,728 --> 00:17:45,148
in the three years
I was at Oxford...

251
00:17:45,315 --> 00:17:47,985
an average of an hour a day.

252
00:17:48,944 --> 00:17:51,697
I am not proud
of this lack of work.

253
00:17:51,822 --> 00:17:55,158
I am just describing
my attitude at the time...

254
00:17:56,451 --> 00:18:00,455
an attitude that nothing
was worth making an effort for.

255
00:18:04,042 --> 00:18:07,796
He used to produce his work
every week for tutorial...

256
00:18:07,921 --> 00:18:11,175
and, as he never
kept any notes...

257
00:18:11,341 --> 00:18:13,927
or papers
or that sort of thing...

258
00:18:14,052 --> 00:18:18,515
on leaving my room, he would normally
throw it in my wastepaper basket.

259
00:18:18,640 --> 00:18:22,853
And when he was with
other undergraduates at the tutorial...

260
00:18:23,020 --> 00:18:25,522
and they saw this happen,
they were absolutely horrified...

261
00:18:25,647 --> 00:18:29,067
'cause they thought, he did
this work in probably half an hour...

262
00:18:29,193 --> 00:18:33,697
If they could have done it in a year, they
wouldn't have thrown it in the wastepaper basket.

263
00:18:33,864 --> 00:18:36,283
They would've put it
in a frame on their walls.

264
00:18:37,951 --> 00:18:40,204
Because of my lack of work...

265
00:18:40,370 --> 00:18:43,332
I had planned
to get through the final exam...

266
00:18:43,457 --> 00:18:46,668
by doing problems
in theoretical physics...

267
00:18:46,793 --> 00:18:51,548
and avoiding any questions
that required factual knowledge.

268
00:18:53,467 --> 00:18:55,844
I didn't do very well.

269
00:18:57,387 --> 00:19:01,975
I was on the borderline between
a first-and second-class degree...

270
00:19:02,100 --> 00:19:06,522
and I had to be interviewed
to determine which I should get.

271
00:19:08,148 --> 00:19:11,318
They asked me
about my future plans.

272
00:19:12,778 --> 00:19:16,240
I replied,
if they gave me a first...

273
00:19:16,365 --> 00:19:18,534
I would go to Cambridge.

274
00:19:20,118 --> 00:19:22,412
If I only got a second...

275
00:19:22,579 --> 00:19:24,915
I would stay in Oxford.

276
00:19:26,625 --> 00:19:28,752
They gave me a first.

277
00:19:35,509 --> 00:19:38,637
I drove Stephen
and his young brother...

278
00:19:38,762 --> 00:19:41,181
out to Woburn Park...

279
00:19:41,306 --> 00:19:43,308
and he climbed a tree.

280
00:19:43,433 --> 00:19:46,103
He was testing himself out, I think.
I didn't realize.

281
00:19:46,228 --> 00:19:48,063
He did manage to climb a tree...

282
00:19:48,188 --> 00:19:51,233
and go along a branch of it
and get himself down.

283
00:19:51,358 --> 00:19:54,820
I think he began to notice
that his hands...

284
00:19:54,945 --> 00:19:57,573
were less useful
than they had been...

285
00:19:57,698 --> 00:19:59,616
but he didn't tell us.

286
00:20:02,369 --> 00:20:04,872
Univ has these square staircases...

287
00:20:04,997 --> 00:20:07,666
which are round
but they're square.

288
00:20:07,791 --> 00:20:10,711
It was just coming down
from one of the rooms.

289
00:20:10,836 --> 00:20:14,381
Steve actually fell on the stairs
coming downstairs...

290
00:20:14,506 --> 00:20:17,759
and kind of bounced
all the way down to the bottom.

291
00:20:17,885 --> 00:20:22,222
I don't know if he lost consciousness,
but he lost his memory.

292
00:20:23,640 --> 00:20:27,019
We took him to either my room
or someone's room.

293
00:20:27,144 --> 00:20:29,605
The first question of course
was, "Who am I?"

294
00:20:29,730 --> 00:20:32,149
We told him,
"You're Steve Hawking."

295
00:20:32,274 --> 00:20:36,737
Right away he would ask again,
"Who am I?"

296
00:20:36,862 --> 00:20:38,614
"Steve Hawking."

297
00:20:38,739 --> 00:20:42,534
Then, after a couple of minutes,
he remembered he was Steve Hawking.

298
00:20:42,659 --> 00:20:45,871
Then we'd say, "Do you remember
going down to the bar..."

299
00:20:45,996 --> 00:20:48,332
and having a drink
on Sunday night?"

300
00:20:48,499 --> 00:20:51,919
Or, "Do you remember coxing
on the river on Monday?"

301
00:20:52,044 --> 00:20:54,421
And his memory
came back gradually...

302
00:20:54,546 --> 00:20:58,133
until he could remember the previous
day's events, and then the previous hour...

303
00:20:58,258 --> 00:21:02,179
and by the end of the two hours,
he could remember everything.

304
00:21:02,304 --> 00:21:04,598
The question was,
"Well, maybe you've lost...

305
00:21:04,723 --> 00:21:06,683
some of your mind
because of this."

306
00:21:06,808 --> 00:21:10,979
And so Steve decided,
"Well, I'll take the Mensa test."

307
00:21:11,104 --> 00:21:13,065
We said,
"Of course you'll get in."

308
00:21:13,190 --> 00:21:16,777
But he came back delighted
he was able to get into Mensa.

309
00:21:16,902 --> 00:21:18,862
Absolutely delighted.

310
00:21:29,873 --> 00:21:31,959
I felt that there were two areas...

311
00:21:32,084 --> 00:21:34,253
of theoretical physics...

312
00:21:34,378 --> 00:21:36,547
I might study at Cambridge.

313
00:21:38,757 --> 00:21:43,136
One was cosmology,
the study of the very large.

314
00:21:45,848 --> 00:21:49,685
The other was
elementary particles...

315
00:21:49,810 --> 00:21:52,396
the study of the very small.

316
00:21:54,064 --> 00:21:56,859
However, I thought
elementary particles...

317
00:21:56,984 --> 00:21:58,652
were less attractive...

318
00:21:58,777 --> 00:22:01,822
because there was
no proper theory.

319
00:22:03,115 --> 00:22:04,867
All they could do...

320
00:22:04,992 --> 00:22:08,078
was arrange
the particles in families...

321
00:22:08,245 --> 00:22:10,164
like in botany.

322
00:22:12,916 --> 00:22:15,669
In cosmology,
on the other hand...

323
00:22:15,794 --> 00:22:18,589
there was
a well-defined theory...

324
00:22:18,755 --> 00:22:22,050
Einstein's general theory
of relativity.

325
00:22:29,057 --> 00:22:31,268
It was a very cold year...

326
00:22:33,020 --> 00:22:37,691
and the ice
on Verulamium Pond...

327
00:22:37,816 --> 00:22:40,277
it was frozen there...

328
00:22:40,444 --> 00:22:43,697
and we all went skating.

329
00:22:43,822 --> 00:22:46,366
And Stephen managed
to skate fairly well...

330
00:22:46,492 --> 00:22:48,952
but then, he and I
were close together.

331
00:22:49,119 --> 00:22:51,163
He wasn't skating
in a very advanced way...

332
00:22:51,288 --> 00:22:54,166
but nor was I,
if it comes to that.

333
00:22:54,291 --> 00:22:56,001
He fell...

334
00:22:56,126 --> 00:22:58,295
and he couldn't get up.

335
00:22:59,505 --> 00:23:03,091
So I took him to a caf�
to warm up...

336
00:23:03,217 --> 00:23:05,719
and he told me then
all about it.

337
00:23:07,179 --> 00:23:09,515
And it was diagnosed.

338
00:23:10,891 --> 00:23:13,936
I insisted on going
to see his doctor...

339
00:23:14,061 --> 00:23:17,314
because it seemed to me
however long you're going to live...

340
00:23:17,481 --> 00:23:19,775
there's probably something
someone can do about it...

341
00:23:19,900 --> 00:23:22,861
at least anyhow to make
things easier for people.

342
00:23:22,986 --> 00:23:25,405
I won't mention
the doctor's name...

343
00:23:25,531 --> 00:23:29,201
but I got to see him
at the London Clinic.

344
00:23:29,326 --> 00:23:32,996
He was rather surprised that I should
bother to come 'round to see him.

345
00:23:33,121 --> 00:23:35,749
After all, I was only
Stephen's mother.

346
00:23:35,874 --> 00:23:39,837
He was quite nice. He agreed
to see me in a rather grand way.

347
00:23:39,962 --> 00:23:41,964
And he said,
"Yes, it's all very sad.

348
00:23:42,089 --> 00:23:44,967
Brilliant young man cut off
in the prime of his youth."

349
00:23:45,092 --> 00:23:47,594
But of course I said,
"What can we do?"

350
00:23:47,719 --> 00:23:49,638
What can we do to sort of...

351
00:23:49,763 --> 00:23:51,849
Can we get physiotherapy?

352
00:23:51,974 --> 00:23:55,185
"Can we get anything like that
that will help in any way?"

353
00:23:55,352 --> 00:23:57,396
He said, "Well, actually, no."

354
00:23:57,521 --> 00:24:00,524
There's nothing I can do, really.
More or less, that's it."

355
00:24:04,194 --> 00:24:07,406
Shortly after my 21st birthday...

356
00:24:07,531 --> 00:24:10,367
I went into hospital for tests.

357
00:24:12,661 --> 00:24:15,497
They took a muscle sample
from my arm...

358
00:24:15,622 --> 00:24:17,583
stuck electrodes into me...

359
00:24:17,708 --> 00:24:21,712
and injected some radiopaque
fluid into my spine...

360
00:24:21,879 --> 00:24:24,715
and watched it going
up and down with X-rays...

361
00:24:24,882 --> 00:24:27,009
as they tilted the bed.

362
00:24:29,136 --> 00:24:32,598
I was diagnosed as having ALS...

363
00:24:32,723 --> 00:24:35,642
amyotrophic lateral sclerosis...

364
00:24:35,767 --> 00:24:40,105
or motor neuron disease,
as it is also known.

365
00:24:41,690 --> 00:24:44,067
The doctors
could offer no cure...

366
00:24:44,234 --> 00:24:47,654
and gave me 21/2 years to live.

367
00:24:57,706 --> 00:25:00,918
I went into the graduates'
common room...

368
00:25:01,084 --> 00:25:03,754
looking, really, for someone
to have lunch with.

369
00:25:03,921 --> 00:25:07,132
There was nobody around that
I particularly wished to have lunch with...

370
00:25:07,257 --> 00:25:09,051
and then Stephen walked
through the door.

371
00:25:09,176 --> 00:25:12,763
I don't know what he was doing at Oxford.
I've certainly forgotten now.

372
00:25:12,888 --> 00:25:16,433
And so Stephen
generously went off...

373
00:25:16,558 --> 00:25:18,519
to buy the drinks...

374
00:25:18,644 --> 00:25:20,938
and brought them
and put them on the table.

375
00:25:21,063 --> 00:25:23,357
And as he put his pint
of beer down...

376
00:25:23,482 --> 00:25:25,275
he spilled it.

377
00:25:25,400 --> 00:25:27,611
I sort of said genially...

378
00:25:27,778 --> 00:25:31,073
"Oh, heavens.
Drinking at this time of day!"

379
00:25:31,198 --> 00:25:35,619
He then told me he'd been
in Addenbrooke's for three weeks...

380
00:25:35,786 --> 00:25:38,121
and they'd done
a whole series of tests...

381
00:25:38,247 --> 00:25:40,916
and they'd decided...

382
00:25:41,041 --> 00:25:42,960
what was wrong with him.

383
00:25:43,085 --> 00:25:47,005
And he told me
very straight and flat...

384
00:25:47,130 --> 00:25:49,716
that he was gradually
going to lose...

385
00:25:49,842 --> 00:25:52,386
the use of his body...

386
00:25:52,511 --> 00:25:54,888
that eventually...

387
00:25:55,013 --> 00:25:58,141
only his heart and his lungs...

388
00:25:58,308 --> 00:26:01,687
would still be operating,
and his brain...

389
00:26:01,812 --> 00:26:03,897
and that they'd told him that...

390
00:26:04,022 --> 00:26:08,277
eventually he would essentially
have the body of a cabbage...

391
00:26:08,402 --> 00:26:11,780
but his mind would still be
in perfect working order...

392
00:26:11,905 --> 00:26:15,492
and he would be unable to communicate
with the rest of the world.

393
00:26:18,829 --> 00:26:22,040
My dreams at that time
were rather disturbed.

394
00:26:24,126 --> 00:26:27,004
Before my condition
had been diagnosed...

395
00:26:27,129 --> 00:26:29,840
I had been very bored with life.

396
00:26:31,592 --> 00:26:35,179
There had not seemed to be
anything worth doing.

397
00:26:37,389 --> 00:26:40,350
But shortly after
I came out of hospital...

398
00:26:40,517 --> 00:26:44,104
I dreamt that I was
going to be executed.

399
00:26:45,355 --> 00:26:48,984
I suddenly realized there were
a lot of worthwhile things...

400
00:26:49,109 --> 00:26:52,029
I could do if I were reprieved.

401
00:26:58,702 --> 00:27:03,040
I knew perfectly well
that he had no faith...

402
00:27:03,165 --> 00:27:04,833
and...

403
00:27:05,876 --> 00:27:08,337
to me, that made it
the more difficult...

404
00:27:08,462 --> 00:27:11,215
because you must ask yourself,
"Why me?

405
00:27:11,381 --> 00:27:14,551
Why this? Why now?"

406
00:27:14,718 --> 00:27:18,138
But he just totally,
flatly accepted...

407
00:27:18,263 --> 00:27:20,807
that this was what was going
to happen to him.

408
00:27:20,933 --> 00:27:24,978
As far as I can gather, at that point
he started to do some work.

409
00:27:26,897 --> 00:27:29,775
At first, there did not
seem much point...

410
00:27:29,900 --> 00:27:31,944
in working at my research...

411
00:27:32,069 --> 00:27:34,821
because I didn't expect
to live long enough...

412
00:27:34,947 --> 00:27:37,908
to finish my PhD.

413
00:27:39,117 --> 00:27:41,662
However, as time went by...

414
00:27:41,787 --> 00:27:44,248
the disease seemed to slow down.

415
00:27:46,250 --> 00:27:49,586
I began to understand
general relativity...

416
00:27:49,753 --> 00:27:52,005
and made progress with my work.

417
00:27:54,174 --> 00:27:56,718
But what really made
a difference was...

418
00:27:56,844 --> 00:28:01,098
I had got engaged
to a girl called Jane Wilde.

419
00:28:02,724 --> 00:28:05,602
This gave me
something to live for...

420
00:28:05,769 --> 00:28:08,605
but it also meant
I had to get a job...

421
00:28:08,772 --> 00:28:11,024
if we were to get married.

422
00:28:13,068 --> 00:28:16,446
Stephen was already ill.
Jane knew it.

423
00:28:16,572 --> 00:28:20,409
And it was another instance
of Stephen's luck, you know...

424
00:28:20,534 --> 00:28:23,245
meeting the right person
at the right time...

425
00:28:23,370 --> 00:28:28,542
because Stephen was
very, very badly depressed...

426
00:28:28,667 --> 00:28:32,171
and he wasn't very much inclined
to go on with his work.

427
00:28:32,296 --> 00:28:34,631
He'd been told
he's only got 21/2 years.

428
00:28:34,756 --> 00:28:36,800
What can you do in that time?

429
00:28:36,967 --> 00:28:40,679
But meeting Jane really
put him on his mettle...

430
00:28:40,804 --> 00:28:42,806
and he started to work.

431
00:28:45,601 --> 00:28:47,686
I wanted to understand...

432
00:28:47,811 --> 00:28:49,813
how the universe began.

433
00:28:52,065 --> 00:28:54,943
Einstein's theory
of general relativity...

434
00:28:55,068 --> 00:28:57,946
showed that the universe
was expanding.

435
00:28:59,490 --> 00:29:02,993
But there was no answer
to the crucial question...

436
00:29:03,160 --> 00:29:05,704
"Must there have been
a Big Bang...

437
00:29:05,829 --> 00:29:07,789
a beginning to time?"

438
00:29:09,833 --> 00:29:12,961
Then, in my third year
at Cambridge...

439
00:29:13,086 --> 00:29:15,714
Roger Penrose made
his discovery...

440
00:29:15,839 --> 00:29:18,467
about the death of stars.

441
00:29:19,927 --> 00:29:23,680
I remember talking to this friend,
Ivor Robinson...

442
00:29:23,805 --> 00:29:27,142
and we were having
this animated conversation...

443
00:29:27,267 --> 00:29:30,479
and then we had
to cross a road...

444
00:29:30,604 --> 00:29:33,524
and as we crossed the road,
of course, the conversation stopped...

445
00:29:33,649 --> 00:29:35,651
and then we got
to the other side.

446
00:29:35,776 --> 00:29:38,403
Evidently, I had some idea
crossing the road...

447
00:29:38,529 --> 00:29:42,533
but then the conversation started up, and
it got completely blotted out of my mind.

448
00:29:42,658 --> 00:29:46,703
It was only later,
after my friend had gone home...

449
00:29:46,829 --> 00:29:51,291
and I began to have
this strange feeling of elation...

450
00:29:51,416 --> 00:29:53,252
feeling wonderful.

451
00:29:53,377 --> 00:29:57,714
I couldn't figure out why I should feel
like that, so I went back over the day...

452
00:29:57,840 --> 00:30:01,051
thinking all possible things which might
have contributed to such a feeling...

453
00:30:01,176 --> 00:30:04,054
and then gradually
I unearthed this thought...

454
00:30:04,179 --> 00:30:06,181
which I'd had
while crossing the street.

455
00:30:06,598 --> 00:30:09,393
Penrose announced this result...

456
00:30:09,560 --> 00:30:12,271
that when stars
collapse indefinitely...

457
00:30:12,396 --> 00:30:14,439
they will become singular...

458
00:30:14,565 --> 00:30:17,943
as long as some
very broad conditions are satisfied...

459
00:30:18,068 --> 00:30:20,821
that everybody would have
regarded as reasonable.

460
00:30:20,946 --> 00:30:23,615
And I remember Stephen Hawking,
who was then approaching...

461
00:30:23,740 --> 00:30:26,201
his third year
as a research student, saying...

462
00:30:26,326 --> 00:30:28,412
"What very interesting results."

463
00:30:28,579 --> 00:30:30,706
I wonder whether
they could be adapted...

464
00:30:30,831 --> 00:30:33,625
"to understanding
the origin of the universe."

465
00:30:33,750 --> 00:30:37,296
And what he had in mind, you see,
was that if, just mentally...

466
00:30:37,421 --> 00:30:39,464
you reverse the sense of time...

467
00:30:39,590 --> 00:30:42,801
you can think of the expanding
universe as a collapsing system.

468
00:30:42,926 --> 00:30:45,888
It's a bit like
a very giant star collapsing.

469
00:30:47,097 --> 00:30:49,057
Roger Penrose proved...

470
00:30:49,183 --> 00:30:53,395
that a dying star,
collapsing under its own gravity...

471
00:30:53,520 --> 00:30:57,191
eventually shrinks
to a singularity...

472
00:30:57,316 --> 00:31:01,778
a point of infinite density
and zero size.

473
00:31:04,615 --> 00:31:08,452
I realized that if I reversed
the direction of time...

474
00:31:08,577 --> 00:31:11,622
so that the collapse
became an expansion...

475
00:31:11,747 --> 00:31:13,582
I could prove that...

476
00:31:13,707 --> 00:31:15,792
the universe had a beginning.

477
00:31:19,505 --> 00:31:21,381
But my proof...

478
00:31:21,507 --> 00:31:25,135
based on Einstein's theory
of general relativity...

479
00:31:25,260 --> 00:31:28,639
also showed that
we cannot understand...

480
00:31:28,764 --> 00:31:31,141
how the universe began...

481
00:31:32,309 --> 00:31:36,438
because it showed
that all scientific theories...

482
00:31:36,563 --> 00:31:39,983
including
general relativity itself...

483
00:31:40,108 --> 00:31:43,737
break down
at the beginning of the universe.

484
00:31:55,332 --> 00:31:57,167
We had this meeting...

485
00:31:57,334 --> 00:32:00,337
at the Institute of Space Physics
in New York.

486
00:32:00,462 --> 00:32:03,382
I said, "Before we reach
a final conclusion..."

487
00:32:03,507 --> 00:32:06,218
we ought
to throw into the pot...

488
00:32:06,343 --> 00:32:08,387
still another object...

489
00:32:08,512 --> 00:32:12,766
a gravitationally
completely collapsed object.

490
00:32:12,891 --> 00:32:15,018
Well, after you've used
the phrase...

491
00:32:15,143 --> 00:32:19,690
"a gravitationally completely
collapsed object" ten times...

492
00:32:19,815 --> 00:32:22,901
you conclude you've got
to get a better name.

493
00:32:23,026 --> 00:32:25,154
So that's when I switched...

494
00:32:25,279 --> 00:32:27,531
to the word "black hole".

495
00:32:27,990 --> 00:32:31,410
The word "black hole," which John
Wheeler coined, suddenly caught on.

496
00:32:31,535 --> 00:32:34,788
Everybody adopted it,
and from then on...

497
00:32:34,913 --> 00:32:37,749
people around the world...
in Moscow...

498
00:32:37,875 --> 00:32:40,335
in America...

499
00:32:40,460 --> 00:32:42,337
in England and elsewhere...

500
00:32:42,462 --> 00:32:45,340
could know they were speaking
about the same thing.

501
00:32:45,465 --> 00:32:48,552
And not only that,
but suddenly...

502
00:32:48,677 --> 00:32:51,430
the whole range of concepts
got through to the general public...

503
00:32:51,555 --> 00:32:54,474
and even science-fiction writers
all of a sudden...

504
00:32:54,600 --> 00:32:56,560
could talk about it.

505
00:32:58,061 --> 00:33:00,480
Tonight, my friends...

506
00:33:00,606 --> 00:33:04,276
we stand on the brink
of a feat unparalleled...

507
00:33:04,401 --> 00:33:06,445
in space exploration.

508
00:33:07,613 --> 00:33:09,740
If the data
on my returning probe ship...

509
00:33:09,907 --> 00:33:12,284
matches my computerized
calculations...

510
00:33:12,409 --> 00:33:16,038
I will travel where no man
has dared to go.

511
00:33:17,247 --> 00:33:19,541
Into the black hole?

512
00:33:19,666 --> 00:33:21,251
In...

513
00:33:22,419 --> 00:33:24,087
through...

514
00:33:25,380 --> 00:33:27,257
and beyond.

515
00:33:29,009 --> 00:33:31,136
Why, that's crazy!

516
00:33:31,261 --> 00:33:33,764
Ha! Impossible!

517
00:33:36,433 --> 00:33:38,936
As a massive star contracts...

518
00:33:39,061 --> 00:33:41,480
its gravity becomes so strong...

519
00:33:41,605 --> 00:33:44,441
that light can no longer escape.

520
00:33:46,360 --> 00:33:49,571
The region from which
nothing can escape...

521
00:33:49,696 --> 00:33:52,115
is called a black hole...

522
00:33:52,241 --> 00:33:55,536
and its boundary is called
the event horizon.

523
00:33:58,247 --> 00:34:00,958
One might say
of the event horizon...

524
00:34:01,124 --> 00:34:04,044
what Dante said
of the entrance to hell...

525
00:34:05,587 --> 00:34:09,216
"Abandon all hope,
ye who enter here."

526
00:34:13,762 --> 00:34:16,139
I was once asked to actually...

527
00:34:16,306 --> 00:34:18,475
be an adjudicator...

528
00:34:18,642 --> 00:34:22,479
on an essay
of which the subject was...

529
00:34:22,604 --> 00:34:25,315
"How to fall through
a black hole and live."

530
00:34:25,440 --> 00:34:28,527
Now, the problem I had
was that I wouldn't know...

531
00:34:28,652 --> 00:34:30,654
how to give out the prize...

532
00:34:30,821 --> 00:34:34,158
because if I said,
"That looks like a good essay"...

533
00:34:34,283 --> 00:34:37,161
the only real way
of showing this was right...

534
00:34:37,327 --> 00:34:41,248
was to actually follow it,
to do the experiment and fall in.

535
00:34:41,373 --> 00:34:43,333
But then, having fallen in...

536
00:34:43,500 --> 00:34:46,587
I would assume taking the person
who wrote the essay with you...

537
00:34:46,712 --> 00:34:49,923
the question would be,
how do you tell the rest of the world?

538
00:34:50,048 --> 00:34:52,634
Do you take the prize in
that you give to them...

539
00:34:52,759 --> 00:34:55,429
and what do they do with it
when they get to the center?

540
00:34:56,513 --> 00:34:58,640
Believe me...

541
00:34:58,765 --> 00:35:01,685
I've been waiting a long time
for someone like you...

542
00:35:01,810 --> 00:35:03,687
to record this moment.

543
00:35:03,812 --> 00:35:06,440
Thank you, Doctor.

544
00:35:06,565 --> 00:35:08,275
Then I'm ready.

545
00:35:09,693 --> 00:35:13,405
Ready to embark
on man's greatest journey.

546
00:35:13,530 --> 00:35:15,741
Certainly his riskiest.

547
00:35:15,866 --> 00:35:18,869
The risk is incidental
compared to...

548
00:35:18,994 --> 00:35:23,081
the possibility to possess
the great truth of the unknown.

549
00:35:23,207 --> 00:35:25,375
There...

550
00:35:25,501 --> 00:35:28,378
long-cherished laws of nature...

551
00:35:28,545 --> 00:35:30,672
simply do not apply.

552
00:35:30,797 --> 00:35:32,466
They vanish.

553
00:35:33,550 --> 00:35:35,719
And life?

554
00:35:37,179 --> 00:35:38,847
Life?

555
00:35:41,558 --> 00:35:43,477
Life forever.

556
00:36:08,252 --> 00:36:10,712
If you were watching an astronaut...

557
00:36:10,838 --> 00:36:14,007
foolhardy enough
to jump into a black hole...

558
00:36:14,132 --> 00:36:16,677
at some time on his watch...

559
00:36:16,802 --> 00:36:18,846
say, 12:00...

560
00:36:18,971 --> 00:36:21,598
he would cross
the event horizon...

561
00:36:21,723 --> 00:36:23,976
and enter the black hole.

562
00:36:25,727 --> 00:36:28,605
But no matter
how long you waited...

563
00:36:28,730 --> 00:36:33,443
you would never see
the astronaut's watch reach 12:00.

564
00:36:34,778 --> 00:36:37,114
Instead, each second
on the watch...

565
00:36:37,281 --> 00:36:40,033
would appear to take
longer and longer...

566
00:36:40,159 --> 00:36:42,828
until the last second
before midnight...

567
00:36:42,953 --> 00:36:45,080
would take forever.

568
00:36:46,665 --> 00:36:49,626
Thus, by jumping
into a black hole...

569
00:36:49,793 --> 00:36:53,463
one could ensure that
one's image lasted forever.

570
00:36:55,132 --> 00:36:57,885
But the picture
would fade very rapidly...

571
00:36:58,010 --> 00:37:01,972
and grow so dim
that no one could see it.

572
00:37:05,893 --> 00:37:08,437
As somebody disappears
into a black hole...

573
00:37:08,562 --> 00:37:11,481
as seen from the outside,
it looks as though...

574
00:37:11,648 --> 00:37:15,652
time actually slows down,
and the person who's moving...

575
00:37:15,819 --> 00:37:18,155
at least he's thinking
he's moving...

576
00:37:18,280 --> 00:37:21,116
he's perhaps talking
in his spaceship at a normal rate...

577
00:37:21,241 --> 00:37:24,161
seems to slow down
and ends up being frozen...

578
00:37:24,328 --> 00:37:26,997
in a particular position...

579
00:37:27,122 --> 00:37:29,875
as seen by somebody
watching him from the outside.

580
00:37:30,000 --> 00:37:33,295
And as seen from the outside,
you never see what happens after that.

581
00:37:40,010 --> 00:37:43,222
The astronaut
wouldn't notice anything special...

582
00:37:43,347 --> 00:37:46,433
when his watch
reached midnight...

583
00:37:46,558 --> 00:37:49,102
and he crossed
the event horizon...

584
00:37:49,228 --> 00:37:51,271
into the black hole...

585
00:37:53,023 --> 00:37:57,194
until, of course,
he approached the singularity...

586
00:37:57,319 --> 00:37:59,696
and was crushed into spaghetti.

587
00:38:06,787 --> 00:38:09,122
One can fall
through this event horizon...

588
00:38:09,248 --> 00:38:12,042
without feeling anything,
without noticing it.

589
00:38:12,167 --> 00:38:15,587
After about a week of falling,
one begins to feel the pinch...

590
00:38:15,712 --> 00:38:18,382
and one extends
longer and longer...

591
00:38:18,507 --> 00:38:20,676
and gets slightly thinner.

592
00:38:20,801 --> 00:38:24,429
And, of course,
one begins to get squeezed...

593
00:38:24,555 --> 00:38:27,558
until one gets
very long and very thin...

594
00:38:27,724 --> 00:38:29,893
and rather nasty.

595
00:38:30,018 --> 00:38:34,314
By the end of two weeks, one's fallen right
into the center and is, of course, dead.

596
00:38:35,065 --> 00:38:37,901
Before you lose sight
of the outer world...

597
00:38:38,026 --> 00:38:41,196
you would see things happening
and see them at a greater rate...

598
00:38:41,321 --> 00:38:43,907
so that it would look like
a firework display.

599
00:38:44,324 --> 00:38:47,411
The frustration would be that,
although you would be able to see...

600
00:38:47,536 --> 00:38:50,581
everything that happens in the future,
it would be going so fast...

601
00:38:50,747 --> 00:38:54,251
that from a scientific point of view,
you'd have no time to analyze it.

602
00:38:54,376 --> 00:38:56,420
You wouldn't be able
to take it in.

603
00:38:56,545 --> 00:38:58,714
Eventually things
would be going off so fast...

604
00:38:58,839 --> 00:39:01,633
and it would be so explosive
that you yourself would be...

605
00:39:01,758 --> 00:39:05,220
destroyed by the explosion,
and that would be the end.

606
00:39:05,345 --> 00:39:09,099
But it would be a very exciting way
to end one's life.

607
00:39:09,266 --> 00:39:12,644
It would be the way
I would choose if I had the choice.

608
00:39:15,939 --> 00:39:18,734
In the long history of the universe...

609
00:39:18,859 --> 00:39:22,529
many stars must have burned up
their nuclear fuel...

610
00:39:22,654 --> 00:39:25,115
and collapsed in on themselves.

611
00:39:27,242 --> 00:39:30,162
The number of black holes
may be greater...

612
00:39:30,287 --> 00:39:32,664
than the number
of visible stars...

613
00:39:32,789 --> 00:39:35,375
which totals about
a hundred thousand million...

614
00:39:35,501 --> 00:39:37,461
in our galaxy alone.

615
00:39:39,963 --> 00:39:42,132
We also have evidence...

616
00:39:42,257 --> 00:39:45,219
that there is
a very large black hole...

617
00:39:45,344 --> 00:39:48,305
at the center of our own galaxy.

618
00:39:54,937 --> 00:39:58,232
Friends ask me,
"Well, if a black hole is black...

619
00:39:58,357 --> 00:40:00,359
how can you see it?"

620
00:40:00,484 --> 00:40:04,112
And I say,
"Have you ever been to a ball?"

621
00:40:04,238 --> 00:40:06,573
Have you ever watched
the young men...

622
00:40:06,698 --> 00:40:10,202
dressed in their black
evening tuxedos...

623
00:40:10,327 --> 00:40:12,496
and the girls
in their white dresses...

624
00:40:12,621 --> 00:40:15,666
whirling around,
held in each other's arms...

625
00:40:15,791 --> 00:40:17,793
and the lights turned low...

626
00:40:17,918 --> 00:40:20,504
and all you can see
is the girls?

627
00:40:20,629 --> 00:40:23,549
Well, the girl is
the ordinary star...

628
00:40:23,674 --> 00:40:26,593
and the boy is the black hole.

629
00:40:26,718 --> 00:40:30,806
You can't see the black hole
any more than you can see the boy...

630
00:40:30,931 --> 00:40:34,643
but the girl going around
gives you convincing evidence...

631
00:40:34,768 --> 00:40:38,689
"there must be something there
holding her in orbit."

632
00:40:40,983 --> 00:40:45,696
One evening, shortly after
the birth of my daughter, Lucy...

633
00:40:45,863 --> 00:40:48,657
I started to think
about black holes...

634
00:40:48,782 --> 00:40:50,868
as I was getting into bed.

635
00:40:53,453 --> 00:40:57,332
My disability makes this
rather a slow process...

636
00:40:57,457 --> 00:41:00,669
so I had plenty of time.

637
00:41:00,794 --> 00:41:03,672
Suddenly I realized...

638
00:41:03,797 --> 00:41:06,300
that the area
of the event horizon...

639
00:41:06,425 --> 00:41:09,094
must always increase with time.

640
00:41:11,430 --> 00:41:14,933
The increase in the area
of the event horizon...

641
00:41:15,058 --> 00:41:18,228
was very reminiscent
of a quantity called entropy...

642
00:41:18,395 --> 00:41:22,107
which measures the degree
of disorder of a system.

643
00:41:23,317 --> 00:41:25,944
It is a matter
of common experience...

644
00:41:26,069 --> 00:41:29,323
that disorder tends
to increase with time...

645
00:41:29,448 --> 00:41:32,117
if things are left
to themselves.

646
00:41:35,871 --> 00:41:40,292
Jacob Bekenstein
came into the office one day.

647
00:41:40,417 --> 00:41:42,544
"Jacob," I said...

648
00:41:42,669 --> 00:41:44,713
"It always troubles me..."

649
00:41:44,838 --> 00:41:48,050
when I put a hot teacup
next to a cold teacup.

650
00:41:48,175 --> 00:41:51,678
I've increased, by letting heat
flow from one to the other...

651
00:41:51,803 --> 00:41:54,056
the amount of disorder
in the universe.

652
00:41:54,181 --> 00:41:57,726
But Jacob,
if a black hole swims by...

653
00:41:57,851 --> 00:42:01,230
and I drop
both teacups into this...

654
00:42:01,355 --> 00:42:04,900
"I've concealed the evidence
of my crime, have I not?"

655
00:42:06,902 --> 00:42:10,072
Bekenstein's a man
of great integrity...

656
00:42:10,197 --> 00:42:13,492
and he looked troubled,
and he came back to me later...

657
00:42:13,617 --> 00:42:15,911
and he said,
"No, you have not..."

658
00:42:16,036 --> 00:42:18,747
concealed the evidence
of your crime.

659
00:42:18,872 --> 00:42:22,417
"The black hole records
what's happened to you."

660
00:42:22,543 --> 00:42:26,338
Stephen Hawking
read the paper...

661
00:42:26,463 --> 00:42:29,967
in which Bekenstein
announced this result...

662
00:42:30,092 --> 00:42:32,094
thought it was preposterous...

663
00:42:32,219 --> 00:42:34,805
and decided to prove
it was wrong.

664
00:42:38,809 --> 00:42:42,646
My discoveries led
Jacob Bekenstein to suggest...

665
00:42:42,813 --> 00:42:44,940
that the area
of the event horizon...

666
00:42:45,065 --> 00:42:49,319
actually was the entropy
of a black hole.

667
00:42:50,612 --> 00:42:52,823
But there was one fatal flaw...

668
00:42:52,948 --> 00:42:55,159
in Bekenstein's idea:

669
00:42:56,577 --> 00:42:58,996
If black holes
have an entropy...

670
00:42:59,163 --> 00:43:01,665
they ought to have
a temperature.

671
00:43:04,001 --> 00:43:06,086
And if they have
a temperature...

672
00:43:06,211 --> 00:43:08,797
they ought
to give off radiation.

673
00:43:10,883 --> 00:43:13,343
But how could they
give off radiation...

674
00:43:13,468 --> 00:43:16,722
if nothing can escape
from a black hole?

675
00:43:20,726 --> 00:43:22,477
As it turned out...

676
00:43:22,603 --> 00:43:25,189
Bekenstein
was basically correct...

677
00:43:25,314 --> 00:43:28,192
though in a manner
far more surprising...

678
00:43:28,358 --> 00:43:32,154
than he or anyone else
had expected.

679
00:43:36,283 --> 00:43:39,286
As he gradually lost
the use of his hands...

680
00:43:39,411 --> 00:43:44,041
he had to start developing...

681
00:43:44,208 --> 00:43:47,044
carefully choosing
research projects...

682
00:43:47,169 --> 00:43:50,380
that could be tackled
and solved...

683
00:43:50,547 --> 00:43:54,801
through geometrical arguments
that he could do pictorially in his head.

684
00:43:54,927 --> 00:43:59,348
And he developed a very powerful
set of tools nobody else really had.

685
00:43:59,640 --> 00:44:03,268
So in some sense,
when you lose one set of tools...

686
00:44:03,393 --> 00:44:05,771
you may develop other tools,
but the new tools...

687
00:44:05,896 --> 00:44:08,774
are amenable to different kinds
of problems than the old tools.

688
00:44:08,899 --> 00:44:12,194
And if you're the only master
in the world of these new tools...

689
00:44:12,319 --> 00:44:15,739
that means certain kinds of problems
you can solve and nobody else can.

690
00:44:17,574 --> 00:44:20,577
My work up to 1973...

691
00:44:20,744 --> 00:44:22,996
was in general relativity...

692
00:44:23,121 --> 00:44:27,334
and was summarized in a book
I wrote with George Ellis called...

693
00:44:27,459 --> 00:44:30,379
The Large Scale Structure
of Space-Time.

694
00:44:33,006 --> 00:44:37,219
Even then, it was difficult
for me to write things down...

695
00:44:38,971 --> 00:44:42,516
so I tended to think
in pictures and diagrams...

696
00:44:42,641 --> 00:44:45,102
that I could visualize
in my head.

697
00:45:20,053 --> 00:45:22,514
I remember
visiting Stephen and Jane...

698
00:45:22,639 --> 00:45:24,850
at their home in Cambridge.

699
00:45:24,975 --> 00:45:27,936
After supper in the evening...

700
00:45:28,061 --> 00:45:31,231
when it was time
for Stephen to go to bed...

701
00:45:31,356 --> 00:45:35,068
Jane insisted and Stephen acquiesced...
I guess this was standard...

702
00:45:35,194 --> 00:45:37,154
that Stephen make his way up...

703
00:45:37,321 --> 00:45:40,574
I've forgotten whether it was
one flight of stairs or two... alone...

704
00:45:40,699 --> 00:45:43,494
and this was a period
when he could no longer walk.

705
00:45:43,660 --> 00:45:47,289
The way he got up the stairs was,
he grabbed hold of the pillars...

706
00:45:47,414 --> 00:45:50,501
that support the banister
and pulled him up with the strength...

707
00:45:50,626 --> 00:45:53,629
pulled himself up the stairs
with the strength of his own arms...

708
00:45:53,754 --> 00:45:55,672
dragging himself up...

709
00:45:55,797 --> 00:45:58,509
from the ground floor
up to the second story...

710
00:45:58,675 --> 00:46:02,346
in a long, arduous effort.

711
00:46:02,471 --> 00:46:05,265
Jane explained that...

712
00:46:05,390 --> 00:46:08,060
this was an important part
of his physical therapy...

713
00:46:08,185 --> 00:46:12,272
to maintain his coordination...

714
00:46:12,397 --> 00:46:15,818
and strength
as long as possible.

715
00:46:15,943 --> 00:46:18,445
At first it was
sort of heartrending...

716
00:46:18,570 --> 00:46:22,199
to watch what appeared to be the agony
of pulling himself up the stairs...

717
00:46:22,324 --> 00:46:26,036
until I understood
it's just part of life...

718
00:46:26,203 --> 00:46:28,622
pulling himself up
the stairs like that.

719
00:46:32,793 --> 00:46:35,712
General relativity
is what is called...

720
00:46:35,838 --> 00:46:37,756
a classical theory.

721
00:46:39,550 --> 00:46:42,052
It predicts
a single definite path...

722
00:46:42,219 --> 00:46:44,137
for each particle.

723
00:46:45,806 --> 00:46:48,308
But according
to quantum mechanics...

724
00:46:48,433 --> 00:46:51,728
there is an element
of chance or uncertainty.

725
00:46:53,814 --> 00:46:56,900
A particle does not have...

726
00:46:57,025 --> 00:47:01,405
just a single path
through space and time.

727
00:47:02,281 --> 00:47:05,742
Instead, there is
an uncertainty principle...

728
00:47:05,909 --> 00:47:09,079
according to which
both the exact position...

729
00:47:09,204 --> 00:47:13,041
and velocity of a particle
can never be known.

730
00:47:19,506 --> 00:47:22,134
I began investigating...

731
00:47:22,259 --> 00:47:25,262
the effect quantum mechanics
might have...

732
00:47:25,387 --> 00:47:28,724
on particles near a black hole.

733
00:47:28,849 --> 00:47:31,727
I found that particles
could escape...

734
00:47:31,852 --> 00:47:33,896
from a black hole...

735
00:47:34,021 --> 00:47:38,066
that black holes
are not completely black.

736
00:47:38,192 --> 00:47:41,403
At first I didn't believe it.

737
00:47:42,613 --> 00:47:45,657
But when I redid
the calculations...

738
00:47:45,782 --> 00:47:49,745
I couldn't get
the effect to go away.

739
00:47:49,870 --> 00:47:53,707
I met Martin Rees, and he was
shaking with excitement...

740
00:47:53,832 --> 00:47:56,168
and he said, "Have you heard?
Have you heard..."

741
00:47:56,293 --> 00:47:58,003
what Stephen has discovered?

742
00:47:58,128 --> 00:48:00,048
"Everything is different!
Everything is changed!"

743
00:48:00,088 --> 00:48:03,634
I was still unsure of my discovery...

744
00:48:03,759 --> 00:48:06,970
so I only told
a few colleagues...

745
00:48:07,095 --> 00:48:10,724
but word soon spread.

746
00:48:10,849 --> 00:48:14,269
Roger Penrose
phoned up on my birthday.

747
00:48:15,521 --> 00:48:18,982
He was very excited
and went on so long...

748
00:48:19,149 --> 00:48:22,486
that my birthday dinner
got quite cold.

749
00:48:24,154 --> 00:48:27,616
It was a great pity,
because it was goose...

750
00:48:27,741 --> 00:48:30,911
which I'm very fond of.

751
00:48:31,036 --> 00:48:34,790
To me it's a miracle, 'cause it's
a complicated and messy calculation.

752
00:48:34,915 --> 00:48:37,835
We can now do these things
very much better...

753
00:48:37,960 --> 00:48:40,212
and it's more transparent
what happens.

754
00:48:40,337 --> 00:48:43,507
But out of this messy calculation,
he showed that black holes...

755
00:48:43,632 --> 00:48:45,926
aren't black with this
quantum mechanical effect.

756
00:48:46,051 --> 00:48:48,178
There was a residual radiation.

757
00:48:48,345 --> 00:48:50,347
Stephen came to a meeting...

758
00:48:50,472 --> 00:48:52,057
and people were flabbergasted.

759
00:48:52,182 --> 00:48:54,685
I remember someone saying,
"You must be wrong, Stephen.

760
00:48:54,852 --> 00:48:56,687
I don't believe a word of it."

761
00:48:57,020 --> 00:48:59,606
I once said
that I was unhappy...

762
00:48:59,731 --> 00:49:03,861
with the explanation given in terms
of negative energy particles being created.

763
00:49:04,153 --> 00:49:07,030
But I feel this is part
of the controversy of science.

764
00:49:07,197 --> 00:49:11,201
You must have the give and take,
and I'm delighted to be a part of that.

765
00:49:11,368 --> 00:49:13,370
That's what makes it fun.

766
00:49:13,495 --> 00:49:16,206
If you all sat down and said,
"Oh, lovely"...

767
00:49:16,331 --> 00:49:18,709
when you do have
niggling questions in your mind...

768
00:49:18,876 --> 00:49:21,003
that's not doing
a service to science.

769
00:49:21,128 --> 00:49:24,047
But I was not antagonistic
to it in any way...

770
00:49:24,214 --> 00:49:27,384
except for that one time
when I questioned.

771
00:49:29,052 --> 00:49:31,138
I finally convinced myself...

772
00:49:31,263 --> 00:49:33,223
that black holes radiate...

773
00:49:33,348 --> 00:49:37,019
when I found a mechanism
through which this could happen.

774
00:49:38,395 --> 00:49:41,398
According
to quantum mechanics...

775
00:49:41,523 --> 00:49:44,443
space is filled
with virtual particles...

776
00:49:44,568 --> 00:49:46,445
and antiparticles...

777
00:49:46,570 --> 00:49:49,698
that are constantly
materializing in pairs...

778
00:49:49,823 --> 00:49:52,910
separating,
coming together again...

779
00:49:53,076 --> 00:49:55,329
and annihilating each other.

780
00:49:58,499 --> 00:50:01,084
In the presence
of a black hole...

781
00:50:01,251 --> 00:50:04,046
one member of a pair
of virtual particles...

782
00:50:04,171 --> 00:50:06,131
may fall into the hole...

783
00:50:06,256 --> 00:50:08,842
leaving the other member
without a partner...

784
00:50:08,967 --> 00:50:11,136
with which to annihilate.

785
00:50:12,679 --> 00:50:16,517
The forsaken particle
appears to be radiation...

786
00:50:16,642 --> 00:50:18,852
emitted by the black hole.

787
00:50:23,106 --> 00:50:26,985
And so black holes
are not eternal.

788
00:50:29,571 --> 00:50:32,950
They evaporate away
at an increasing rate...

789
00:50:33,075 --> 00:50:37,079
until they vanish
in a gigantic explosion.

790
00:50:40,207 --> 00:50:44,545
Quantum mechanics has allowed
particles and radiation...

791
00:50:44,670 --> 00:50:47,714
to escape
from the ultimate prison...

792
00:50:47,840 --> 00:50:50,217
a black hole.

793
00:50:52,302 --> 00:50:55,597
Einstein never accepted
quantum mechanics...

794
00:50:55,722 --> 00:50:59,101
because of its element
of chance and uncertainty.

795
00:51:00,644 --> 00:51:04,439
He said,
"God does not play dice."

796
00:51:05,774 --> 00:51:09,486
It seems that Einstein
was doubly wrong.

797
00:51:12,197 --> 00:51:14,867
The quantum effects
of black holes...

798
00:51:14,992 --> 00:51:18,537
suggest that not only
does God play dice...

799
00:51:18,662 --> 00:51:20,664
he sometimes throws them...

800
00:51:20,831 --> 00:51:23,000
where they cannot be seen.

801
00:51:24,626 --> 00:51:26,879
He says himself...

802
00:51:27,004 --> 00:51:28,922
that, uh...

803
00:51:29,047 --> 00:51:32,593
he wouldn't have got to where he is
if he hadn't been ill.

804
00:51:32,718 --> 00:51:34,595
And I think
that's quite possible...

805
00:51:34,720 --> 00:51:37,055
because it's like Johnson said:

806
00:51:37,181 --> 00:51:39,766
The knowledge you're to be
hanged in the morning...

807
00:51:39,892 --> 00:51:41,768
concentrates
the mind wonderfully.

808
00:51:41,894 --> 00:51:44,188
And he has concentrated
on this in a way...

809
00:51:44,354 --> 00:51:47,357
I don't think he would have,
because he took a great interest...

810
00:51:47,524 --> 00:51:49,359
in a lot of things in life...

811
00:51:49,485 --> 00:51:52,529
and I don't know that he'd have
applied himself the same way...

812
00:51:52,654 --> 00:51:56,909
if he'd been able to get around
as he used to do, so in a way...

813
00:51:57,034 --> 00:52:00,704
No, I can't think anyone's lucky
having an illness like that, even so.

814
00:52:00,829 --> 00:52:05,375
But it's less bad luck for him
than it would be for some people...

815
00:52:05,501 --> 00:52:08,545
because he can so much
live in his head.

816
00:52:08,962 --> 00:52:11,965
When I lived with the Hawking family,
I would usually get up...

817
00:52:12,090 --> 00:52:14,885
around 7:15 or 7:30
and take a shower...

818
00:52:15,010 --> 00:52:18,013
and then read in my Bible some
in the morning and pray...

819
00:52:18,138 --> 00:52:20,933
and then go down at 8:15
to get Stephen up.

820
00:52:21,058 --> 00:52:25,062
And at breakfast I would often tell him
what I'd been reading in the Bible...

821
00:52:25,229 --> 00:52:28,774
hoping that this would eventually
have some influence.

822
00:52:28,899 --> 00:52:31,443
So then we would go into work...

823
00:52:31,568 --> 00:52:35,155
and usually we'd go in and see
if there were any scientific papers...

824
00:52:35,280 --> 00:52:37,282
that people sent out.

825
00:52:37,407 --> 00:52:41,787
I did discover that despite Hawking's
great brilliance, he does read quite slowly.

826
00:52:41,912 --> 00:52:44,706
I could read
about twice as fast as he.

827
00:52:44,832 --> 00:52:48,085
But of course he would have
to read to remember it...

828
00:52:48,252 --> 00:52:52,047
because it would be very difficult
for him to go back and access the thing...

829
00:52:52,172 --> 00:52:54,925
whereas I could skim the paper
rather quickly and see...

830
00:52:55,050 --> 00:52:56,760
"Is there something
interesting in this?"

831
00:52:56,885 --> 00:53:01,098
If I wanted to work on it,
I could pick the thing up and look at it.

832
00:53:02,182 --> 00:53:04,476
Black hole radiation...

833
00:53:04,601 --> 00:53:07,771
has shown us
that gravitational collapse...

834
00:53:07,938 --> 00:53:10,774
is not as final
as we once thought.

835
00:53:12,693 --> 00:53:15,988
If an astronaut falls
into a black hole...

836
00:53:16,113 --> 00:53:19,491
he will be returned
to the rest of the universe...

837
00:53:19,616 --> 00:53:22,452
in the form of radiation.

838
00:53:23,620 --> 00:53:25,455
Thus, in a sense...

839
00:53:25,581 --> 00:53:28,041
the astronaut will be recycled.

840
00:53:30,335 --> 00:53:34,381
However, it would be
a poor sort of immortality...

841
00:53:34,506 --> 00:53:37,551
because any personal
concept of time...

842
00:53:37,676 --> 00:53:41,013
would come to an end
as he is torn apart...

843
00:53:41,138 --> 00:53:43,098
inside the black hole.

844
00:53:46,351 --> 00:53:48,228
All that would survive...

845
00:53:48,353 --> 00:53:51,148
would be his mass, or energy.

846
00:53:56,820 --> 00:53:59,156
One year,
the Hawkings took me along...

847
00:53:59,281 --> 00:54:02,117
when we went
to a cottage in Wales...

848
00:54:02,242 --> 00:54:03,785
near the River Wye...

849
00:54:03,911 --> 00:54:06,330
and this cottage
was up a hill...

850
00:54:06,455 --> 00:54:09,750
and there was a bit of...

851
00:54:09,875 --> 00:54:13,337
a paved little sidewalk
that went up to the cottage...

852
00:54:13,504 --> 00:54:16,048
which I had not been up,
and of course...

853
00:54:16,173 --> 00:54:19,843
I wanted to do it in the least
number of trips I could imagine...

854
00:54:19,968 --> 00:54:22,137
so we put Stephen's batteries
under his chair...

855
00:54:22,262 --> 00:54:25,423
his wheelchair has space for batteries...
and put extra batteries under there...

856
00:54:25,516 --> 00:54:27,809
which Stephen didn't realize
that I'd put under there...

857
00:54:27,935 --> 00:54:30,437
so he didn't realize his wheelchair
was as heavily laden.

858
00:54:30,854 --> 00:54:34,650
Stephen got quite a bit ahead of me,
and he was turning the corner...

859
00:54:34,775 --> 00:54:37,861
to go around to his house,
but that was on a slope...

860
00:54:38,028 --> 00:54:41,782
so I looked up, and I noticed Stephen's
wheelchair slowly tipping backward.

861
00:54:41,907 --> 00:54:45,702
Of course,
I was about ten meters away...

862
00:54:45,869 --> 00:54:49,373
and tried to run up there,
but I was not able to get there...

863
00:54:49,498 --> 00:54:53,043
rapidly enough before he toppled
backward into the bushes.

864
00:54:53,168 --> 00:54:55,963
So it was
a bit of a shocking sight...

865
00:54:56,088 --> 00:54:58,382
to see this master of gravity
getting overcome...

866
00:54:58,507 --> 00:55:01,385
by the weak gravitational
force of Earth.

867
00:55:02,302 --> 00:55:06,640
One of the worst things for me would be
having people there all the time.

868
00:55:06,765 --> 00:55:09,017
Never alone.
I couldn't bear that.

869
00:55:09,142 --> 00:55:12,396
And yet he finds things funny...

870
00:55:12,521 --> 00:55:16,275
and he enjoys life and he goes
dashing about all over the place...

871
00:55:16,400 --> 00:55:18,235
and I think this is tremendous.

872
00:55:18,402 --> 00:55:20,779
But it's a sort of courage
I haven't got...

873
00:55:20,904 --> 00:55:24,658
and his father hadn't got it,
and we cannot but admire it...

874
00:55:24,783 --> 00:55:27,995
but wonder how on earth
he got it, really.

875
00:55:28,328 --> 00:55:30,455
There must have been
50 people there...

876
00:55:30,581 --> 00:55:33,333
and I was standing off
in a corner...

877
00:55:33,458 --> 00:55:36,628
sort of watching quietly...

878
00:55:36,753 --> 00:55:38,755
for a few minutes, relaxing...

879
00:55:38,922 --> 00:55:41,633
and Stephen was over there,
not far from me.

880
00:55:41,758 --> 00:55:44,052
Jane walked over to Stephen
and looked at him.

881
00:55:44,178 --> 00:55:46,680
He was sitting there
with his head in his lap...

882
00:55:46,805 --> 00:55:49,433
like only Stephen can put
his head in his lap.

883
00:55:49,558 --> 00:55:52,019
And Jane said to Stephen...

884
00:55:52,144 --> 00:55:55,272
"You look miserable, Stephen.
Sit up straight."

885
00:55:55,439 --> 00:55:57,232
Some of your guests
don't understand...

886
00:55:57,357 --> 00:55:59,902
that you're thinking about physics
and having a wonderful time.

887
00:56:00,027 --> 00:56:03,530
"It looks like you're in pain.
Sit up and go talk to your guests."

888
00:56:05,782 --> 00:56:07,784
In 1979...

889
00:56:07,951 --> 00:56:12,039
I was elected
Lucasian Professor of Mathematics.

890
00:56:13,916 --> 00:56:18,712
This is the same chair
once held by Isaac Newton.

891
00:56:20,422 --> 00:56:24,718
They have a big book
which every university teaching officer...

892
00:56:24,843 --> 00:56:26,929
is supposed to sign.

893
00:56:28,430 --> 00:56:32,059
After I had been Lucasian Professor
for about a year...

894
00:56:32,184 --> 00:56:34,770
they realized I had never signed.

895
00:56:36,855 --> 00:56:39,483
So they brought the book
to my office...

896
00:56:39,608 --> 00:56:42,444
and I signed
with some difficulty.

897
00:56:44,196 --> 00:56:47,825
That was the last time
I signed my name.

898
00:56:59,294 --> 00:57:02,881
My interest in the origin
and fate of the universe...

899
00:57:03,006 --> 00:57:05,217
was reawakened
when I attended...

900
00:57:05,342 --> 00:57:08,804
a conference on cosmology
in the Vatican.

901
00:57:10,931 --> 00:57:13,183
Afterwards, we were granted...

902
00:57:13,308 --> 00:57:16,228
an audience with the pope.

903
00:57:16,353 --> 00:57:18,939
He told us
that it was all right...

904
00:57:19,064 --> 00:57:21,650
to study the evolution
of the universe...

905
00:57:21,775 --> 00:57:24,319
after the Big Bang...

906
00:57:24,444 --> 00:57:28,031
but we should not inquire
into the Big Bang itself...

907
00:57:28,198 --> 00:57:31,118
because that was
the moment of creation...

908
00:57:31,243 --> 00:57:33,996
and therefore the work of God.

909
00:57:36,331 --> 00:57:39,209
I was glad
that he did not know...

910
00:57:39,376 --> 00:57:42,796
the subject of the talk
I had just given...

911
00:57:44,590 --> 00:57:48,635
the possibility that the universe
had no beginning...

912
00:57:48,760 --> 00:57:51,054
no moment of creation.

913
00:57:56,560 --> 00:58:00,355
There were theories in the early '70s...
the first type of creation theories...

914
00:58:00,481 --> 00:58:04,318
where the people concerned started off
with a fixed, external space and time...

915
00:58:04,443 --> 00:58:06,570
which for eternity was empty...

916
00:58:06,737 --> 00:58:09,740
and then suddenly, for some
unknown reason, the universe nucleates...

917
00:58:09,865 --> 00:58:12,743
at a particular point
and then, bang, it blows apart.

918
00:58:12,868 --> 00:58:16,538
But the trouble is that when space
and time appear in the classical theory...

919
00:58:16,663 --> 00:58:20,083
that actual point itself
is a singular point in the mathematics.

920
00:58:20,209 --> 00:58:22,169
Mathematics breaks down,
and so...

921
00:58:22,294 --> 00:58:25,088
you cannot use that
to give you a creation theory.

922
00:58:27,007 --> 00:58:29,092
If one goes back in time...

923
00:58:29,218 --> 00:58:32,596
one comes
to the Big Bang singularity...

924
00:58:32,721 --> 00:58:35,599
where the laws
of physics break down.

925
00:58:37,392 --> 00:58:40,145
But there's
another direction of time...

926
00:58:40,270 --> 00:58:44,650
that one can go in
which avoids the singularity.

927
00:58:46,485 --> 00:58:50,781
This is called
the imaginary direction of time.

928
00:58:52,324 --> 00:58:54,451
In imaginary time...

929
00:58:54,618 --> 00:58:57,538
there need not be
any singularities...

930
00:58:57,663 --> 00:59:01,500
which form a beginning
or end to time.

931
00:59:04,878 --> 00:59:08,006
When you come to imaginary time,
you have this rather peculiar possibility...

932
00:59:08,131 --> 00:59:10,300
of having a "now," as it were...

933
00:59:10,467 --> 00:59:12,636
without necessarily having
a sort of a chain...

934
00:59:12,761 --> 00:59:15,973
of past moments.

935
00:59:16,139 --> 00:59:19,935
If we start where we are at the moment
and start running backwards in time...

936
00:59:20,060 --> 00:59:22,521
then for a long time,
things work perfectly normally.

937
00:59:22,646 --> 00:59:25,524
But as you begin to get
further and further back towards...

938
00:59:25,649 --> 00:59:28,819
what would be the origin point
in the conventional real-time picture...

939
00:59:28,986 --> 00:59:31,905
you'd find that
the nature of time changes...

940
00:59:32,030 --> 00:59:35,617
that the imaginary component
becomes more and more prominent...

941
00:59:35,742 --> 00:59:39,121
until what ought to have been the
singular point in the classical theory...

942
00:59:39,246 --> 00:59:41,582
gets smoothed away,
and you have this beautiful picture...

943
00:59:41,707 --> 00:59:44,501
of these bowls where the creation
of the universe is pictures...

944
00:59:44,626 --> 00:59:47,504
of where we are now,
and a smooth bowl of the past...

945
00:59:47,629 --> 00:59:50,757
where there's no initial point,
just a sort of smooth shape.

946
00:59:59,266 --> 01:00:02,478
So long as the universe
had a beginning...

947
01:00:02,603 --> 01:00:05,689
we could suppose
it had a creator.

948
01:00:07,316 --> 01:00:11,153
But if the universe
is completely self-contained...

949
01:00:11,278 --> 01:00:13,822
having no boundary or edge...

950
01:00:15,199 --> 01:00:18,827
it would neither be
created nor destroyed.

951
01:00:18,952 --> 01:00:21,705
It would simply be.

952
01:00:24,374 --> 01:00:27,544
What place, then, for a creator?

953
01:00:31,882 --> 01:00:34,384
All you can really say
is that the universe is...

954
01:00:34,479 --> 01:00:36,599
because it's a self-consistent
mathematical structure.

955
01:00:36,637 --> 01:00:39,681
There's no past because,
unlike the creation-as-a-point scenario...

956
01:00:39,806 --> 01:00:41,850
there's nothing for it
to be created in.

957
01:00:41,975 --> 01:00:45,354
So to say it's created from nothing
is a bit of a misnomer.

958
01:00:45,479 --> 01:00:47,481
It's a misleading use
of the word "nothing".

959
01:00:47,606 --> 01:00:52,152
It's not just that there was empty space in which the
universe appeared, which you might call "nothing".

960
01:00:52,277 --> 01:00:55,572
There was really nothing at all,
because there wasn't even a creation event.

961
01:00:55,739 --> 01:00:59,493
The use of a past tense in a verb
becomes inappropriate in these theories.

962
01:00:59,618 --> 01:01:02,913
Unfortunately, tenses were set up when
people believed in real time, of course...

963
01:01:03,038 --> 01:01:06,917
and we don't yet have a linguistic form
to describe tenses in imaginary time.

964
01:01:07,334 --> 01:01:11,547
The word "time" was not
handed down from heaven...

965
01:01:11,672 --> 01:01:13,799
as a gift from on high.

966
01:01:13,924 --> 01:01:16,969
The idea of time is a word...

967
01:01:17,094 --> 01:01:19,263
invented by man...

968
01:01:19,429 --> 01:01:22,057
and if it has puzzlements
connected with it...

969
01:01:22,182 --> 01:01:24,768
whose fault is it?
It's our fault.

970
01:01:27,980 --> 01:01:29,982
Where does the difference...

971
01:01:30,107 --> 01:01:32,776
between the past and the future
come from?

972
01:01:35,112 --> 01:01:38,073
The laws of science
do not distinguish...

973
01:01:38,198 --> 01:01:40,534
between the past and the future.

974
01:01:41,994 --> 01:01:44,621
Yet there is a big difference...

975
01:01:44,788 --> 01:01:48,458
between the past and future
in ordinary life.

976
01:01:54,923 --> 01:01:58,385
You may see a cup of tea
fall off a table...

977
01:01:58,510 --> 01:02:01,638
and break into pieces
on the floor...

978
01:02:01,763 --> 01:02:05,517
but you will never see the cup
gather itself back together...

979
01:02:05,642 --> 01:02:08,020
and jump back on the table.

980
01:02:11,106 --> 01:02:14,109
The increase of disorder,
or entropy...

981
01:02:14,234 --> 01:02:17,779
is what distinguishes
the past from the future...

982
01:02:17,905 --> 01:02:20,407
giving a direction to time.

983
01:02:26,663 --> 01:02:28,999
He fell ill in Switzerland.

984
01:02:29,166 --> 01:02:32,294
When he came back,
he was on a ventilator.

985
01:02:32,419 --> 01:02:35,547
Because he's on a ventilator,
you've got a tube down your throat...

986
01:02:35,672 --> 01:02:38,008
and therefore you can't speak,
just for that reason.

987
01:02:38,550 --> 01:02:41,386
For that period, which may
have been a couple of months...

988
01:02:41,512 --> 01:02:46,183
I spent probably one in two nights,
one in three nights, at the hospital...

989
01:02:46,308 --> 01:02:49,728
because when he was
in hospital...

990
01:02:49,853 --> 01:02:52,022
he couldn't communicate
with the nurses.

991
01:02:52,189 --> 01:02:54,525
It's not just like
being seriously ill...

992
01:02:54,650 --> 01:02:58,278
but you're in a position where the nurses
couldn't understand what Stephen wanted.

993
01:02:58,403 --> 01:03:01,365
If Stephen was uncomfortable,
they couldn't tell why.

994
01:03:04,159 --> 01:03:06,411
Before I caught pneumonia...

995
01:03:06,537 --> 01:03:09,331
my speech had been getting
more slurred...

996
01:03:09,456 --> 01:03:13,001
so that only a few people
who knew me well...

997
01:03:13,126 --> 01:03:15,045
could understand me.

998
01:03:16,547 --> 01:03:19,049
But at least
I could communicate.

999
01:03:21,385 --> 01:03:23,387
I wrote scientific papers...

1000
01:03:23,512 --> 01:03:25,889
by dictating to a secretary...

1001
01:03:26,056 --> 01:03:28,892
and I gave seminars
through an interpreter.

1002
01:03:30,060 --> 01:03:33,021
And then,
a tracheostomy operation...

1003
01:03:33,147 --> 01:03:36,400
removed my ability
to speak altogether.

1004
01:03:40,320 --> 01:03:43,615
After a long time...
well, it seemed like a long time...

1005
01:03:43,740 --> 01:03:46,410
somebody came up
with this brilliant gadget.

1006
01:03:46,535 --> 01:03:49,246
They didn't have it
at the Cambridge hospital.

1007
01:03:49,413 --> 01:03:51,415
They got it
from somewhere in London.

1008
01:03:51,540 --> 01:03:55,294
This was high technology... how you can
communicate with a person with no voice.

1009
01:03:55,419 --> 01:03:59,173
It's a plastic piece of Perspex
about so big...

1010
01:03:59,298 --> 01:04:03,760
and you've got the letters of the alphabet
arranged like that, and a hole in the middle.

1011
01:04:03,927 --> 01:04:06,430
You hold it up between you
and the other person.

1012
01:04:06,555 --> 01:04:10,476
They look at a letter, and you can see
which letter they're looking at...

1013
01:04:10,601 --> 01:04:13,228
most of the time.
Sometimes you can't be sure.

1014
01:04:13,353 --> 01:04:16,607
So you would get the patient
to spell out what they wanted.

1015
01:04:16,773 --> 01:04:19,610
So each letter...
they have to look to pick out the A.

1016
01:04:19,776 --> 01:04:22,779
You say, "A?" Did you get it right?
It's like a guessing game.

1017
01:04:45,010 --> 01:04:49,389
Stephen wasn't willing to accept
that he wasn't going to speak again...

1018
01:04:49,515 --> 01:04:51,683
and he thought
he would be giving in...

1019
01:04:51,809 --> 01:04:55,646
by trying to find a method
of communicating other than speech.

1020
01:04:56,063 --> 01:04:59,817
I remember
I went in one evening...

1021
01:04:59,983 --> 01:05:02,653
and this was the first time
that he asked...

1022
01:05:02,820 --> 01:05:05,364
to be gotten out of bed
to use the computer.

1023
01:05:05,489 --> 01:05:09,117
Sometimes they'd sit him up
so he wasn't lying in bed all the time...

1024
01:05:09,243 --> 01:05:12,496
as you do with a patient,
but this time when I turned up...

1025
01:05:12,663 --> 01:05:15,457
he asked the nurse,
could he be gotten out of bed...

1026
01:05:16,792 --> 01:05:19,086
so he could use the computer,
and he did.

1027
01:05:19,211 --> 01:05:22,422
I remember the first thing he typed
on there after saying hello...

1028
01:05:22,548 --> 01:05:25,425
Stephen's always very polite
about things like that...

1029
01:05:25,551 --> 01:05:29,346
was, "Will you help me
finish my book?"

1030
01:05:35,060 --> 01:05:37,771
A computer expert in California...

1031
01:05:37,896 --> 01:05:39,898
heard of my plight...

1032
01:05:40,023 --> 01:05:42,359
and sent me
a computer program...

1033
01:05:42,526 --> 01:05:44,319
called Equalizer.

1034
01:05:46,405 --> 01:05:48,907
This allowed me to select words...

1035
01:05:49,032 --> 01:05:52,035
from a series of menus
on a screen...

1036
01:05:52,161 --> 01:05:54,997
by pressing a switch in my hand.

1037
01:05:59,042 --> 01:06:03,297
These words could then be sent
to a speech synthesizer...

1038
01:06:03,422 --> 01:06:05,799
attached to my wheelchair.

1039
01:06:08,093 --> 01:06:10,095
Much to my surprise...

1040
01:06:10,220 --> 01:06:12,890
I found I was able
to communicate...

1041
01:06:13,056 --> 01:06:15,058
much better than before.

1042
01:06:18,562 --> 01:06:21,607
When eventually
he went home from hospital...

1043
01:06:21,732 --> 01:06:24,651
he was told he needed 24-hour nursing,
and everyone was saying...

1044
01:06:24,776 --> 01:06:27,362
"How is he going
to go in and do work?

1045
01:06:27,488 --> 01:06:30,908
Is he going to trail around
with nurses after him in the office?"

1046
01:06:31,074 --> 01:06:33,076
And of course he did.

1047
01:06:33,202 --> 01:06:36,705
They talked originally of him
working at home...

1048
01:06:36,830 --> 01:06:39,082
which he wasn't happy with.

1049
01:06:40,792 --> 01:06:44,171
And so, after a period
of recuperation at home...

1050
01:06:44,296 --> 01:06:46,757
he just decided
to go back into the office.

1051
01:06:46,924 --> 01:06:50,135
And he'd make the trip
from his house to the office...

1052
01:06:50,260 --> 01:06:53,055
which is, I don't know,
half a mile in his wheelchair...

1053
01:06:53,180 --> 01:06:54,932
with a nurse walking
along with him.

1054
01:06:55,098 --> 01:06:57,851
This is at the time
when he was still driving around...

1055
01:06:57,976 --> 01:06:59,895
with the bag
and the nasal drip...

1056
01:07:00,020 --> 01:07:03,941
going into the department,
working, going back home.

1057
01:07:07,778 --> 01:07:10,280
I began to wonder what would happen...

1058
01:07:10,447 --> 01:07:13,200
when the universe
stopped expanding...

1059
01:07:13,325 --> 01:07:15,702
and began to contract.

1060
01:07:17,204 --> 01:07:19,456
Would we see broken cups...

1061
01:07:19,581 --> 01:07:22,251
gather themselves together
off the floor...

1062
01:07:22,376 --> 01:07:25,003
and jump back onto the table?

1063
01:07:27,297 --> 01:07:30,801
Would we be able
to remember tomorrow's prices...

1064
01:07:30,968 --> 01:07:34,054
and make a fortune
off the stock market?

1065
01:07:36,390 --> 01:07:38,267
It seemed to me...

1066
01:07:38,392 --> 01:07:41,562
the universe had to return
to a smooth and ordered state...

1067
01:07:41,687 --> 01:07:43,647
when it recollapsed.

1068
01:07:46,483 --> 01:07:49,736
If this were so,
time would go backwards...

1069
01:07:49,862 --> 01:07:52,656
when the universe
began to collapse.

1070
01:07:54,992 --> 01:07:59,163
People in the contracting phase
would live their lives backward.

1071
01:07:59,288 --> 01:08:01,832
They would die
before they were born...

1072
01:08:01,957 --> 01:08:05,544
and get younger
as the universe got small again.

1073
01:08:06,795 --> 01:08:10,174
Eventually, they would
return to the womb.

1074
01:08:13,427 --> 01:08:15,929
He gave me
my first problem to do.

1075
01:08:17,681 --> 01:08:20,267
He asked me to look
at this mathematical problem.

1076
01:08:20,392 --> 01:08:23,270
Usually when he gives a problem,
he has a good idea...

1077
01:08:23,395 --> 01:08:25,439
of what the answer should be.

1078
01:08:25,564 --> 01:08:29,109
I went to look at it,
and it took me a few months...

1079
01:08:29,234 --> 01:08:33,280
to understand what it was about, and I
came back and said, "I get this answer."

1080
01:08:33,405 --> 01:08:36,867
And he said to me,
"No, that is not what I expected."

1081
01:08:37,034 --> 01:08:41,079
I said, "That's what I get." So I went
to the blackboard, explained what it was.

1082
01:08:41,205 --> 01:08:45,000
He said, "Did you think about that
particular case?" I said, "No, I didn't."

1083
01:08:45,125 --> 01:08:47,169
So I went back...

1084
01:08:47,294 --> 01:08:50,005
and I calculated
what he'd talked to me about.

1085
01:08:50,130 --> 01:08:54,259
I came back a few weeks after, and I
said, "Stephen, I don't get this thing."

1086
01:08:54,384 --> 01:08:57,513
I still get the same answer
I had originally."

1087
01:08:57,638 --> 01:09:00,307
So he said to me,
"No, no, no, no.

1088
01:09:00,432 --> 01:09:02,434
This doesn't work.
Did you think about that?"

1089
01:09:02,559 --> 01:09:05,229
I said, "Oh, no. I'd forgotten
about that particular case."

1090
01:09:05,354 --> 01:09:08,690
So I went back to the drawing board
and started calculating again...

1091
01:09:08,816 --> 01:09:10,818
and again I got the same answer.

1092
01:09:10,943 --> 01:09:14,988
So I went back to see Stephen, and
this dragged on for two or three months.

1093
01:09:16,573 --> 01:09:18,867
Finally he said to me...

1094
01:09:18,992 --> 01:09:21,245
"Maybe one of your approximations
is not valid."

1095
01:09:23,038 --> 01:09:26,583
So me and a colleague decided
to do the thing with computers.

1096
01:09:26,708 --> 01:09:29,837
This takes a lot of time
to write the programs...

1097
01:09:29,962 --> 01:09:31,713
and to be sure
the program was correct.

1098
01:09:31,839 --> 01:09:35,425
We get the answer, and it was still
the way I'd said before...

1099
01:09:35,551 --> 01:09:39,763
and not the way Stephen said, so we went
to see Stephen and said, "See? Again."

1100
01:09:43,767 --> 01:09:45,811
I had made a mistake.

1101
01:09:48,188 --> 01:09:52,109
I had been using
too simple a model of the universe.

1102
01:09:54,444 --> 01:09:56,405
Time will not reverse direction...

1103
01:09:56,530 --> 01:09:59,449
when the universe
begins to contract.

1104
01:10:02,953 --> 01:10:05,831
People will continue
to get older...

1105
01:10:05,956 --> 01:10:10,127
so it is no good waiting
until the universe recollapses...

1106
01:10:10,252 --> 01:10:12,296
to return to our youth.

1107
01:10:28,437 --> 01:10:31,231
Einstein once
asked the question...

1108
01:10:31,356 --> 01:10:33,650
"How much choice did God have...

1109
01:10:33,817 --> 01:10:36,278
in constructing the universe?"

1110
01:10:38,489 --> 01:10:43,243
If my proposal that the universe
has no boundary is correct...

1111
01:10:43,368 --> 01:10:45,496
he had no freedom at all...

1112
01:10:45,621 --> 01:10:48,207
to choose
how the universe began.

1113
01:10:50,167 --> 01:10:52,586
He would only have had
the freedom...

1114
01:10:52,711 --> 01:10:55,672
to choose the laws
the universe obeyed.

1115
01:10:57,633 --> 01:10:59,885
This, however,
may not have been...

1116
01:11:00,010 --> 01:11:02,262
all that much of a choice.

1117
01:11:04,097 --> 01:11:07,643
There may well be
only one unified theory...

1118
01:11:07,768 --> 01:11:10,479
that allows for the existence
of structures...

1119
01:11:10,604 --> 01:11:13,357
as complicated
as human beings...

1120
01:11:13,524 --> 01:11:17,110
who can investigate
the laws of the universe...

1121
01:11:17,236 --> 01:11:19,822
and ask about the nature of God.

1122
01:11:27,955 --> 01:11:30,999
I don't know how clear-cut
these experiments are...

1123
01:11:31,124 --> 01:11:35,295
but there are experiments that have been
done on the timing of consciousness...

1124
01:11:35,420 --> 01:11:38,382
and they seem to lead
to a very odd picture...

1125
01:11:38,549 --> 01:11:41,343
which doesn't even quite
make consistent sense.

1126
01:11:41,468 --> 01:11:43,554
Whether refinement
of these experiments...

1127
01:11:43,720 --> 01:11:46,557
might get rid of this kind
of anomaly I'm not sure...

1128
01:11:46,682 --> 01:11:50,561
but it does look a little as though there
is something very odd about consciousness...

1129
01:11:50,727 --> 01:11:54,314
and somehow almost as though
the future affects the past in some way...

1130
01:11:54,439 --> 01:11:57,943
over a very tiny, limited scale,
but something maybe of the order...

1131
01:11:58,068 --> 01:12:00,028
of a reasonable
fraction of a second.

1132
01:12:00,362 --> 01:12:02,406
And there's no reason
to believe...

1133
01:12:02,531 --> 01:12:05,284
that one's
conscious experience...

1134
01:12:05,409 --> 01:12:08,328
shouldn't be part
of somebody else's...

1135
01:12:08,453 --> 01:12:10,247
at some other stage.

1136
01:12:10,414 --> 01:12:13,709
I don't know if it's fair to say
what happens after one dies...

1137
01:12:13,834 --> 01:12:16,003
but it's a plausible picture...

1138
01:12:16,128 --> 01:12:17,921
that you could be
somebody else...

1139
01:12:18,046 --> 01:12:22,050
and that somebody else could be somebody
that lived in the past, not in the future.

1140
01:12:25,387 --> 01:12:29,516
Even if there is only
one possible unified theory...

1141
01:12:29,641 --> 01:12:32,895
that is just a set
of rules and equations...

1142
01:12:34,480 --> 01:12:37,858
what is it that breathes fire
into the equations...

1143
01:12:37,983 --> 01:12:41,487
and makes a universe
for them to describe?

1144
01:12:43,447 --> 01:12:47,743
Why does the universe
go to all the bother of existing?

1145
01:12:49,953 --> 01:12:52,623
Is the unified theory
so compelling...

1146
01:12:52,748 --> 01:12:55,792
that it brings about
its own existence?

1147
01:12:57,127 --> 01:12:59,379
Or does it need a creator?

1148
01:13:00,672 --> 01:13:02,549
And, if so...

1149
01:13:02,674 --> 01:13:04,635
who created him?

1150
01:13:13,727 --> 01:13:17,022
I think I would say
that the universe has a purpose.

1151
01:13:17,147 --> 01:13:20,317
It's not somehow
just there by chance.

1152
01:13:20,442 --> 01:13:23,111
I think it's... Yeah.

1153
01:13:23,237 --> 01:13:25,697
So...

1154
01:13:25,823 --> 01:13:28,283
it's... it's...

1155
01:13:28,408 --> 01:13:31,662
Some people, I think, take the view
that the universe is just there...

1156
01:13:31,829 --> 01:13:35,290
and it sort of runs and runs,
and it just sort of computes...

1157
01:13:35,415 --> 01:13:38,627
and we happen somehow by accident
to find ourselves in this thing.

1158
01:13:38,752 --> 01:13:41,797
But I don't think
that's a very fruitful...

1159
01:13:41,922 --> 01:13:45,342
or helpful way
of looking at the universe.

1160
01:13:45,467 --> 01:13:48,345
I think that there is something
much deeper about it.

1161
01:13:50,681 --> 01:13:54,560
In real time,
the time in which we live...

1162
01:13:54,685 --> 01:13:58,647
the universe has
two possible destinies:

1163
01:13:58,772 --> 01:14:02,442
It may continue
to expand forever...

1164
01:14:04,236 --> 01:14:07,406
or it may recollapse
and come to an end...

1165
01:14:07,531 --> 01:14:09,491
at the Big Crunch.

1166
01:14:11,326 --> 01:14:14,246
It would be rather like
the Big Bang...

1167
01:14:14,371 --> 01:14:16,373
but in reverse.

1168
01:14:18,292 --> 01:14:22,212
I now believe that the universe
will come to an end...

1169
01:14:22,379 --> 01:14:24,506
at the Big Crunch.

1170
01:14:25,632 --> 01:14:28,719
I do, however,
have certain advantages...

1171
01:14:28,844 --> 01:14:31,388
over many other
prophets of doom.

1172
01:14:33,765 --> 01:14:37,227
Whatever happens
ten billion years from now...

1173
01:14:37,352 --> 01:14:41,106
I don't expect to be around
to be proved wrong.

1174
01:14:43,817 --> 01:14:48,280
Of all the pictures
that I know...

1175
01:14:48,405 --> 01:14:51,241
the simplest of any cosmology...

1176
01:14:51,366 --> 01:14:54,578
is that in which
the universe is closed...

1177
01:14:54,745 --> 01:14:56,872
has a finite lifetime...

1178
01:14:56,997 --> 01:15:00,250
and collapses
with the same kind of collapse...

1179
01:15:00,375 --> 01:15:02,252
that a black hole does.

1180
01:15:04,546 --> 01:15:06,882
If it should turn out
that indeed...

1181
01:15:07,007 --> 01:15:10,093
the universe
is limited in its life...

1182
01:15:12,262 --> 01:15:15,432
how is that different
from the life...

1183
01:15:15,599 --> 01:15:17,434
of each one of us?

1184
01:15:27,277 --> 01:15:29,780
On the evening
of Tuesday, March 5th...

1185
01:15:29,905 --> 01:15:32,366
at about 10:45...

1186
01:15:32,491 --> 01:15:35,452
I was returning
to my flat in Pinehurst.

1187
01:15:37,955 --> 01:15:39,873
It was dark and raining.

1188
01:15:41,667 --> 01:15:43,794
I came up to Grange Road...

1189
01:15:43,961 --> 01:15:46,255
and saw
headlights approaching...

1190
01:15:46,380 --> 01:15:49,132
but judged that they were
far enough away...

1191
01:15:49,258 --> 01:15:51,343
that I could cross safely.

1192
01:15:54,138 --> 01:15:57,683
The vehicle must have been
traveling very fast...

1193
01:15:57,808 --> 01:16:01,395
for when I got just past
the middle of the road...

1194
01:16:01,520 --> 01:16:04,273
my nurse screamed, "Look out!"

1195
01:16:06,692 --> 01:16:08,986
I heard tires skidding...

1196
01:16:09,111 --> 01:16:12,906
and my wheelchair was struck
a tremendous blow in the back.

1197
01:16:14,992 --> 01:16:16,869
I ended up in the road...

1198
01:16:16,994 --> 01:16:20,372
with my legs over the remains
of the wheelchair.

1199
01:16:22,166 --> 01:16:25,127
The accident destroyed
my wheelchair...

1200
01:16:25,252 --> 01:16:27,671
and damaged
my computer system...

1201
01:16:27,796 --> 01:16:29,715
with which I communicate.

1202
01:16:32,217 --> 01:16:35,846
I required 13 stitches
in my head...

1203
01:16:37,514 --> 01:16:42,019
but I was able to go back to work
several days later.

1204
01:16:47,274 --> 01:16:50,861
The memories I have
are very much...

1205
01:16:51,028 --> 01:16:52,905
kind of...

1206
01:16:53,030 --> 01:16:55,991
visual pictures
of what Stephen was...

1207
01:16:56,116 --> 01:17:00,287
of seeing Stephen
in certain situations.

1208
01:17:00,412 --> 01:17:03,415
He was always moving.

1209
01:17:03,540 --> 01:17:05,209
Always.

1210
01:17:05,334 --> 01:17:07,294
Well, hardly ever still.

1211
01:17:08,378 --> 01:17:12,716
It was the same thing
about his face and gesture...

1212
01:17:12,841 --> 01:17:15,135
which he used a great deal,
I should say...

1213
01:17:15,260 --> 01:17:18,013
but it's only memory.

1214
01:17:19,306 --> 01:17:22,017
I found some photographs
recently...

1215
01:17:22,142 --> 01:17:25,729
which reminded me
of the general look of everybody...

1216
01:17:25,854 --> 01:17:29,817
and I must say Stephen looked
very much like he does now...

1217
01:17:31,068 --> 01:17:34,029
if one thinks of him like that.

1218
01:17:40,536 --> 01:17:43,664
He does believe
very intensely...

1219
01:17:43,789 --> 01:17:49,336
in the almost infinite
possibility of the human mind.

1220
01:17:49,711 --> 01:17:51,964
You have to find out
what you can't know...

1221
01:17:52,089 --> 01:17:54,091
before you know you can't,
don't you?

1222
01:17:54,258 --> 01:17:58,595
So I don't think that thought
should be restricted at all.

1223
01:17:58,762 --> 01:18:02,933
Why shouldn't you go on
thinking about the unthinkable?

1224
01:18:03,058 --> 01:18:05,102
Somebody's
got to start sometime.

1225
01:18:05,269 --> 01:18:08,689
Think how many things
were unthinkable a century ago...

1226
01:18:08,814 --> 01:18:10,858
and yet people
have thought them.

1227
01:18:10,983 --> 01:18:13,193
And often they also seemed
quite unpractical.

1228
01:18:14,695 --> 01:18:17,364
Not all the things
Stephen says probably...

1229
01:18:17,489 --> 01:18:19,658
are to be taken as gospel truth.

1230
01:18:19,783 --> 01:18:22,244
He's a searcher.
He's looking for things.

1231
01:18:22,369 --> 01:18:26,123
And sometimes he probably
talks nonsense. Well, don't we all?

1232
01:18:26,290 --> 01:18:28,500
But the point is...

1233
01:18:29,626 --> 01:18:31,920
people must think.

1234
01:18:32,045 --> 01:18:33,922
People must go on thinking.

1235
01:18:34,047 --> 01:18:37,468
They must try to extend
the boundaries of knowledge...

1236
01:18:37,593 --> 01:18:40,095
and they don't sometimes
even know where to start.

1237
01:18:41,972 --> 01:18:45,100
You don't know where
the boundaries are, do you?

1238
01:18:45,225 --> 01:18:48,479
You don't know what
your taking-off point is.

1239
01:18:57,571 --> 01:19:01,325
If we do discover
a complete theory of the universe...

1240
01:19:01,450 --> 01:19:03,660
it should in time
be understandable...

1241
01:19:03,827 --> 01:19:06,580
in broad principle
by everyone...

1242
01:19:06,705 --> 01:19:09,249
not just a few scientists.

1243
01:19:14,004 --> 01:19:15,964
Then we shall all...

1244
01:19:16,089 --> 01:19:20,511
philosophers, scientists,
and just ordinary people...

1245
01:19:20,677 --> 01:19:24,848
be able to take part
in the discussion of why it is...

1246
01:19:25,015 --> 01:19:28,519
that we and the universe exist.

1247
01:19:32,064 --> 01:19:34,858
If we find the answer to that...

1248
01:19:34,983 --> 01:19:37,236
it would be
the ultimate triumph...

1249
01:19:37,361 --> 01:19:39,321
of human reason...

1250
01:19:42,366 --> 01:19:45,035
for then we would know...

1251
01:19:45,160 --> 01:19:47,538
the mind of God.