Cosmic Queries Unleashed: Gravitons, Expanding Universes & the Weight of Space Travel

WEBVTT

0
00:00:00.400 --> 00:00:02.200
Andrew Dunkley: Hello again. Thanks for joining us. This is a

1
00:00:02.200 --> 00:00:05.120
Q and A edition of Space Nuts. We talk

2
00:00:05.120 --> 00:00:07.720
astronomy, space science, and answer

3
00:00:07.720 --> 00:00:10.280
audience questions. Well, maybe we won't do

4
00:00:10.280 --> 00:00:12.000
one of those three things today. I don't

5
00:00:12.000 --> 00:00:14.160
know. We'll see how it goes. Uh, we've got a

6
00:00:14.160 --> 00:00:16.060
lot of questions to get through today. Um,

7
00:00:16.060 --> 00:00:17.920
Fred Watson reckons some of these are very,

8
00:00:17.920 --> 00:00:20.240
very tricky, so we'll see how it all pans

9
00:00:20.240 --> 00:00:23.000
out. Um, a question about the expanding

10
00:00:23.000 --> 00:00:25.820
universe. Never had one of those before. Uh,

11
00:00:25.820 --> 00:00:28.510
a question about gravitons. Never had one of

12
00:00:28.510 --> 00:00:31.470
those before. Yes, we have. Uh, photons

13
00:00:31.710 --> 00:00:34.710
and weight shift. That's all coming up on

14
00:00:34.710 --> 00:00:37.310
this edition of space nuts. 15

15
00:00:37.390 --> 00:00:37.950
seconds.

16
00:00:37.950 --> 00:00:40.278
Professor Fred Watson: Guidance is internal. 10,

17
00:00:40.422 --> 00:00:43.310
9. Ignition sequence start.

18
00:00:43.549 --> 00:00:46.357
Space nuts. 5, 4, 3. 2. 1, 2,

19
00:00:46.428 --> 00:00:49.230
3, 4, 5, 5, 4, 3, 2, 1.

20
00:00:49.310 --> 00:00:52.070
Andrew Dunkley: Space nuts. Astronauts report it feels

21
00:00:52.070 --> 00:00:54.990
good. And joining us once more to

22
00:00:54.990 --> 00:00:57.850
unravel all of that, or maybe ravel it

23
00:00:57.850 --> 00:00:59.370
up even more, is Professor Fred Watson

24
00:00:59.370 --> 00:01:00.970
Watson, astronomer at, uh, large. Hello,

25
00:01:00.970 --> 00:01:01.330
Fred Watson.

26
00:01:01.650 --> 00:01:04.650
Professor Fred Watson: Hello, Andrew. I do feel pretty ravelled at

27
00:01:04.650 --> 00:01:05.010
the moment.

28
00:01:05.010 --> 00:01:07.770
Andrew Dunkley: Yeah, look, we have got some tricky

29
00:01:07.770 --> 00:01:10.750
questions, but before we get to those, uh,

30
00:01:10.750 --> 00:01:13.210
we've received a note from Rennie in

31
00:01:13.210 --> 00:01:13.970
California.

32
00:01:13.990 --> 00:01:16.490
Uh, Rennie quite regularly sends questions

33
00:01:16.490 --> 00:01:18.850
into us, but he sent us a really lovely note

34
00:01:19.010 --> 00:01:22.010
which I want to share. Uh, he says no

35
00:01:22.010 --> 00:01:24.570
questions today, just to thank you. I try to

36
00:01:24.570 --> 00:01:26.930
absorb as much information as I can listening

37
00:01:26.930 --> 00:01:28.970
to your podcast. And when I'm engaged in a

38
00:01:28.970 --> 00:01:31.070
convers conversation with my two grandsons

39
00:01:31.070 --> 00:01:33.870
aged 15 and 12, I try to excite

40
00:01:33.870 --> 00:01:36.430
them and get them to think about our place in

41
00:01:36.430 --> 00:01:39.270
the universe and how it behaves. Now it's

42
00:01:39.270 --> 00:01:41.670
paying off with the announcement that my

43
00:01:41.670 --> 00:01:44.390
older grandson wants to carry on in college

44
00:01:44.390 --> 00:01:47.150
with some form of education in astronomy

45
00:01:47.310 --> 00:01:50.310
or particle physics. Thank you for paying

46
00:01:50.310 --> 00:01:52.630
it forward, Renny. Isn't that lovely?

47
00:01:52.630 --> 00:01:54.510
Professor Fred Watson: Yeah, that's great. Absolutely great.

48
00:01:54.920 --> 00:01:56.990
Andrew Dunkley: Uh, I love it when we get feedback from

49
00:01:56.990 --> 00:01:59.730
people that, that become inspired

50
00:02:00.450 --> 00:02:01.330
despite us.

51
00:02:04.130 --> 00:02:05.410
No, I mean, it's fantastic.

52
00:02:05.410 --> 00:02:05.690
Professor Fred Watson: It is.

53
00:02:05.690 --> 00:02:07.730
Andrew Dunkley: I'm really, really pleased. Really pleased.

54
00:02:07.730 --> 00:02:10.010
So, um, pass on our regards, Rennie, to your

55
00:02:10.010 --> 00:02:12.250
boys or, uh, your grandsons, um, and wish

56
00:02:12.250 --> 00:02:14.850
them well and. Yeah, look, just.

57
00:02:15.410 --> 00:02:17.490
I do the same thing with my grandson and

58
00:02:17.570 --> 00:02:20.050
three granddaughters. Um, I talk to them

59
00:02:20.370 --> 00:02:22.090
whenever there's something interesting to

60
00:02:22.090 --> 00:02:24.490
talk about, and there usually is, uh, in the

61
00:02:24.490 --> 00:02:27.330
astronomical world. And, um, I show

62
00:02:27.330 --> 00:02:29.870
them the images I take with the Telesco, and

63
00:02:29.870 --> 00:02:32.150
I've even had them outside looking up at the

64
00:02:32.150 --> 00:02:35.110
moon. And, um, yeah, it's captivating. Once,

65
00:02:35.110 --> 00:02:37.310
once they, you know, once you can convince

66
00:02:37.310 --> 00:02:38.590
them to actually get outside.

67
00:02:39.690 --> 00:02:42.430
Um, you know, the universe is their

68
00:02:42.430 --> 00:02:45.070
oyster. It's, uh, it's good

69
00:02:45.070 --> 00:02:47.390
stuff. So lovely to hear from you, Rennie.

70
00:02:47.390 --> 00:02:49.150
And that is really fabulous news.

71
00:02:50.110 --> 00:02:51.510
Are you ready for your first question,

72
00:02:51.510 --> 00:02:51.950
Fred Watson?

73
00:02:53.230 --> 00:02:55.590
Professor Fred Watson: Well, after a. Yes. After a build up like

74
00:02:55.590 --> 00:02:56.910
that, I guess we've got to tackle them,

75
00:02:56.910 --> 00:02:57.390
haven't we?

76
00:02:57.450 --> 00:02:58.670
Andrew Dunkley: Uh, we probably should.

77
00:02:58.830 --> 00:03:00.510
Professor Fred Watson: You're right, in a way. You know, the

78
00:03:00.510 --> 00:03:02.410
ultimate notes, I guess,

79
00:03:03.450 --> 00:03:06.370
is to provide that little bit of perhaps

80
00:03:06.370 --> 00:03:09.130
inspiration that might lead people to do

81
00:03:09.130 --> 00:03:11.330
things that might one day change the world.

82
00:03:11.330 --> 00:03:12.010
Who knows?

83
00:03:12.250 --> 00:03:14.530
Andrew Dunkley: Yep, you just don't know. You just don't

84
00:03:14.530 --> 00:03:17.530
know. Maybe that's our lot in life is to just

85
00:03:18.410 --> 00:03:20.770
try to inspire, uh, just a handful of people

86
00:03:20.770 --> 00:03:23.290
to pick up the baton, Fred Watson. Who knows?

87
00:03:24.570 --> 00:03:27.290
All right, question one. It's like a test,

88
00:03:27.290 --> 00:03:27.850
isn't it?

89
00:03:27.930 --> 00:03:30.430
Question one. Uh, if space is

90
00:03:30.430 --> 00:03:32.430
expanding faster than the speed of light,

91
00:03:32.910 --> 00:03:35.470
then in millions or billions of years from

92
00:03:35.470 --> 00:03:38.110
now, will our night sky be completely black

93
00:03:38.590 --> 00:03:41.000
or a completely black void? Um,

94
00:03:41.860 --> 00:03:44.789
uh, or completely black, devoid of

95
00:03:44.789 --> 00:03:47.750
all light except our local solar system. That

96
00:03:47.750 --> 00:03:50.470
comes from Clint. Uh, this is

97
00:03:50.470 --> 00:03:53.310
something that has come up occasionally and I

98
00:03:53.310 --> 00:03:55.990
think even in one of our most recent

99
00:03:55.990 --> 00:03:58.390
episodes, we were talking about the expansion

100
00:03:58.390 --> 00:04:00.670
of the universe and its significance. And,

101
00:04:00.810 --> 00:04:02.930
and I think in our Q and A episode, someone

102
00:04:02.930 --> 00:04:04.890
asked about the expansion of the universe.

103
00:04:05.680 --> 00:04:07.850
Um, so here it is again.

104
00:04:08.820 --> 00:04:11.460
Um, we are, ah,

105
00:04:11.460 --> 00:04:13.970
expanding, and it's

106
00:04:13.970 --> 00:04:16.090
expanding at an accelerating rate. Although

107
00:04:16.090 --> 00:04:17.970
it's debatable whether or not that

108
00:04:17.970 --> 00:04:20.890
acceleration is actually as m. Significant

109
00:04:20.970 --> 00:04:23.690
as it was. That is a

110
00:04:23.690 --> 00:04:26.450
separate debate. Um, but I think it's pretty

111
00:04:26.450 --> 00:04:29.410
clear that in the long distant future

112
00:04:29.410 --> 00:04:32.280
of this universe, it will become a black

113
00:04:32.280 --> 00:04:33.200
void, won't it?

114
00:04:34.380 --> 00:04:37.280
Professor Fred Watson: Uh, yes. So the answer to Clint's question

115
00:04:37.280 --> 00:04:37.920
is yes.

116
00:04:38.240 --> 00:04:39.200
Andrew Dunkley: Okay, question

117
00:04:41.120 --> 00:04:43.980
Professor Fred Watson: no. Exactly. As you said, um,

118
00:04:43.980 --> 00:04:46.960
if you've got, um. So

119
00:04:47.840 --> 00:04:50.200
when you say the universe is expanding more

120
00:04:50.200 --> 00:04:52.080
than the speed of light, you've got to be a

121
00:04:52.080 --> 00:04:54.080
bit specific because really what you're

122
00:04:54.080 --> 00:04:57.050
talking about is objects within

123
00:04:57.050 --> 00:04:59.970
the universe which are being carried along by

124
00:04:59.970 --> 00:05:02.650
the expansion of the universe. And so,

125
00:05:03.020 --> 00:05:05.530
uh, there will be, at a certain

126
00:05:05.530 --> 00:05:07.770
distance from us now,

127
00:05:08.410 --> 00:05:10.970
objects whose, what we call the recession

128
00:05:10.970 --> 00:05:13.210
velocity is faster than the speed of light,

129
00:05:13.690 --> 00:05:16.610
but they're actually, they're beyond

130
00:05:16.610 --> 00:05:18.450
the wall that we can't see beyond anyway,

131
00:05:18.450 --> 00:05:20.410
which is the cosmic microwave background

132
00:05:20.410 --> 00:05:22.610
radiation. But you can imagine as the

133
00:05:22.610 --> 00:05:25.530
expansion continues to accelerate, and you're

134
00:05:25.530 --> 00:05:27.330
right, it is still thought to be

135
00:05:27.330 --> 00:05:29.690
accelerating. We just don't quite know

136
00:05:29.690 --> 00:05:31.770
whether that acceleration is a constant.

137
00:05:31.770 --> 00:05:34.770
That's the thing you were alluding

138
00:05:34.770 --> 00:05:37.290
to because there's some evidence that

139
00:05:37.370 --> 00:05:39.690
maybe the acceleration is reducing,

140
00:05:40.250 --> 00:05:42.490
but nevertheless it's still accelerating. So

141
00:05:42.490 --> 00:05:45.050
it's still getting bigger, faster, uh, all

142
00:05:45.050 --> 00:05:47.450
the time. And so what that would do,

143
00:05:48.500 --> 00:05:51.280
um, you can, you can sort of

144
00:05:51.280 --> 00:05:53.560
imagine in your head what this situation

145
00:05:53.560 --> 00:05:55.680
would lead to. It means that the,

146
00:05:56.960 --> 00:05:59.600
the, the sort of black horizon, the horizon

147
00:05:59.920 --> 00:06:02.320
which is where light can never get to you

148
00:06:02.320 --> 00:06:04.440
because it's being carried away. The objects

149
00:06:04.440 --> 00:06:05.920
are being carried away faster than the speed

150
00:06:05.920 --> 00:06:08.400
of light. That black horizon will, will

151
00:06:08.400 --> 00:06:11.200
approach, um, it'll get nearer

152
00:06:11.200 --> 00:06:14.040
as the universe's expansion continues to

153
00:06:14.040 --> 00:06:16.720
accelerate. So eventually you can imagine

154
00:06:16.720 --> 00:06:19.590
that maybe you would see just

155
00:06:19.590 --> 00:06:22.130
the other galaxies in the Local Group, uh,

156
00:06:22.130 --> 00:06:24.670
which is Andromeda and the, uh, triangular

157
00:06:24.830 --> 00:06:27.470
whirlpool galaxy and things like that. But

158
00:06:27.470 --> 00:06:29.630
eventually, yeah, it might just be

159
00:06:30.430 --> 00:06:33.120
objects in our own solar system, uh,

160
00:06:33.310 --> 00:06:36.030
which makes astronomy a little bit of a.

161
00:06:36.270 --> 00:06:38.910
Boring. Yeah.

162
00:06:38.910 --> 00:06:39.350
Yeah.

163
00:06:39.350 --> 00:06:41.230
Andrew Dunkley: Well, let's go see what we can find. Oh,

164
00:06:41.230 --> 00:06:41.870
there's the moon.

165
00:06:41.950 --> 00:06:43.950
Professor Fred Watson: Yeah. Yeah. Oh, wait, it's gone.

166
00:06:46.630 --> 00:06:48.070
Andrew Dunkley: Well, it's moving away from us too.

167
00:06:48.070 --> 00:06:50.430
Professor Fred Watson: So it is rather slower than the speed of

168
00:06:50.430 --> 00:06:52.630
light. Yeah. Six centimetres a year.

169
00:06:52.710 --> 00:06:54.550
Andrew Dunkley: I can't imagine this is going to happen in an

170
00:06:54.550 --> 00:06:55.590
awful hurry, Fred Watson.

171
00:06:55.590 --> 00:06:58.030
Professor Fred Watson: No, it's not. It's very, very long way down

172
00:06:58.030 --> 00:06:59.350
the track. And of course, from our

173
00:06:59.350 --> 00:07:01.490
perspective here on, ah, Earth, long, uh,

174
00:07:01.750 --> 00:07:04.630
before anything like that takes place,

175
00:07:04.790 --> 00:07:07.710
um, we'll have been

176
00:07:07.710 --> 00:07:09.870
confronted by the expansion of the sun

177
00:07:09.870 --> 00:07:12.470
itself, um, as it turns into

178
00:07:12.710 --> 00:07:13.830
a red giant star.

179
00:07:14.340 --> 00:07:16.740
Andrew Dunkley: Yeah. Who knows where we'll be in the

180
00:07:16.740 --> 00:07:19.700
universe by then. We might have moved out

181
00:07:19.700 --> 00:07:21.580
into other parts of the galaxy by then if

182
00:07:21.580 --> 00:07:24.540
we've managed, um, to find some kind of

183
00:07:24.540 --> 00:07:27.380
propulsion system or learn how to fold

184
00:07:27.380 --> 00:07:29.610
space or whatever it is you need to do. Uh,

185
00:07:29.700 --> 00:07:32.700
maybe develop wormholes and be able

186
00:07:32.700 --> 00:07:34.100
to travel mega distances.

187
00:07:34.420 --> 00:07:37.220
Professor Fred Watson: Yeah. Fast. You're the person, you're the

188
00:07:37.220 --> 00:07:39.060
science fiction writer. You've got to tell us

189
00:07:39.060 --> 00:07:40.260
what it is we're going to do.

190
00:07:40.560 --> 00:07:43.300
Andrew Dunkley: Uh, I'm working, um, uh, on

191
00:07:44.100 --> 00:07:46.220
warp, uh, warp travel at the moment.

192
00:07:46.220 --> 00:07:46.780
Professor Fred Watson: Oh, good.

193
00:07:47.020 --> 00:07:49.500
Andrew Dunkley: In m. My. In my novels. So,

194
00:07:49.660 --> 00:07:52.420
yeah, I'm doing the final editing at this

195
00:07:52.420 --> 00:07:55.020
stage and it's, uh, it's the most horrible

196
00:07:55.020 --> 00:07:55.340
job.

197
00:07:56.540 --> 00:07:57.780
Professor Fred Watson: It is, isn't it? Yeah.

198
00:07:57.780 --> 00:07:59.020
Andrew Dunkley: Especially writing's fun.

199
00:07:59.100 --> 00:07:59.540
Professor Fred Watson: Yeah.

200
00:07:59.540 --> 00:08:01.340
Andrew Dunkley: But then you've got to fix all your blunders

201
00:08:01.340 --> 00:08:04.180
and you don't realise how really hopeless you

202
00:08:04.180 --> 00:08:05.060
are until you have

203
00:08:05.060 --> 00:08:07.420
Professor Fred Watson: to edit your own stuff.

204
00:08:07.580 --> 00:08:10.180
Andrew Dunkley: Yeah, yeah. I'd pay someone, but I can't

205
00:08:10.180 --> 00:08:13.140
afford it. It's not a, it's not a cheap

206
00:08:13.140 --> 00:08:15.800
thing to get Done book editing. Um,

207
00:08:16.040 --> 00:08:18.880
but anyway, uh, so the basic

208
00:08:18.880 --> 00:08:21.200
answer to Clint's question is yes, it's going

209
00:08:21.200 --> 00:08:24.120
to happen. Uh, there will be complete black

210
00:08:24.360 --> 00:08:26.520
nothingness, um,

211
00:08:27.400 --> 00:08:29.600
in a matter of about three weeks time, or

212
00:08:29.600 --> 00:08:31.400
could be three gazillion years time.

213
00:08:31.640 --> 00:08:32.840
Professor Fred Watson: I think the latter's more likely.

214
00:08:32.840 --> 00:08:35.760
Andrew Dunkley: More likely the latter. Thank you, Clint.

215
00:08:35.760 --> 00:08:36.840
Great to hear from you.

216
00:08:37.320 --> 00:08:39.400
Our next question comes from

217
00:08:40.200 --> 00:08:42.120
somebody whose name I forgot to write down.

218
00:08:42.260 --> 00:08:44.640
Uh, no, it didn't. It comes from, uh, Alan.

219
00:08:44.640 --> 00:08:47.080
Now, this is a pretty big question, so I'll

220
00:08:47.080 --> 00:08:48.900
just go straight through it and we can figure

221
00:08:48.900 --> 00:08:51.860
all out the rest out later. Uh, I know you

222
00:08:51.860 --> 00:08:54.660
want audio questions, but you know how they

223
00:08:54.660 --> 00:08:57.420
say you have a face made for radio? I've got

224
00:08:57.420 --> 00:09:00.300
one of those. Well, uh, I have a voice made

225
00:09:00.300 --> 00:09:03.220
for text. That's very

226
00:09:03.220 --> 00:09:05.820
good. I, um, hope it's not true. Uh, I

227
00:09:05.820 --> 00:09:08.100
discovered space nuts more than a year ago

228
00:09:08.260 --> 00:09:10.460
and have listened to your entire back

229
00:09:10.460 --> 00:09:11.140
catalogue.

230
00:09:11.300 --> 00:09:11.780
Professor Fred Watson: Wow.

231
00:09:12.740 --> 00:09:15.700
Andrew Dunkley: Wow. Get a job. No. Fantastic. Thank

232
00:09:15.700 --> 00:09:18.380
you. Uh, still listening and have not lost my

233
00:09:18.380 --> 00:09:19.060
mind yet.

234
00:09:19.360 --> 00:09:19.680
Professor Fred Watson: Wow.

235
00:09:20.000 --> 00:09:20.720
Andrew Dunkley: That's a record.

236
00:09:21.210 --> 00:09:22.920
Uh, here's something that's been bothering me

237
00:09:22.920 --> 00:09:25.520
for, uh, some months. Some physicists

238
00:09:25.600 --> 00:09:28.360
don't believe relativity, uh, when it says

239
00:09:28.360 --> 00:09:30.640
that gravity is not a force. Also, they

240
00:09:30.640 --> 00:09:32.560
believe that all forces are conveyed by

241
00:09:32.560 --> 00:09:35.440
particles. To unify gravity with other

242
00:09:35.440 --> 00:09:38.240
forces, they postulate the graviton to be

243
00:09:38.240 --> 00:09:41.000
that particle for gravity. It's said that

244
00:09:41.000 --> 00:09:42.800
nothing escapes a black hole, but actually

245
00:09:42.800 --> 00:09:45.440
gravity does. If gravitons exist

246
00:09:46.380 --> 00:09:49.100
and convey the force of gravity, then they

247
00:09:49.100 --> 00:09:51.500
escape black holes. So they are not affected

248
00:09:51.500 --> 00:09:54.500
by gravity. That means they do not affect

249
00:09:54.500 --> 00:09:57.100
each other. We know gravity does affect all

250
00:09:57.100 --> 00:09:59.500
massive particles and photons, massless

251
00:09:59.500 --> 00:10:01.779
particles that convey the electromagnetic

252
00:10:01.779 --> 00:10:04.340
force. I don't know if gravitons affect other

253
00:10:04.340 --> 00:10:06.820
massless particles. This is the interesting

254
00:10:06.820 --> 00:10:09.700
part. If f equals gm 1 m

255
00:10:09.700 --> 00:10:12.220
2 divided by d squared is

256
00:10:12.380 --> 00:10:15.140
the complete calculation for the force

257
00:10:15.140 --> 00:10:17.500
of gravity, no modifications introduced by

258
00:10:17.720 --> 00:10:20.040
relativity or quantum physics, then gravitons

259
00:10:20.040 --> 00:10:23.040
are not affected by anything. So gravitons

260
00:10:23.040 --> 00:10:25.880
affect every particle except gravitons and

261
00:10:25.880 --> 00:10:28.760
are not affected by anything. So is

262
00:10:28.760 --> 00:10:30.840
an asymmetry that breaks

263
00:10:32.280 --> 00:10:34.520
conservation, uh, of energy and momentum. My

264
00:10:34.520 --> 00:10:37.480
question is. Here it is. Why do some

265
00:10:37.480 --> 00:10:39.720
physicists still believe in

266
00:10:40.040 --> 00:10:42.600
gravitons? That comes from Alan in San

267
00:10:42.600 --> 00:10:45.000
Antonio, Texas. Boy, Alan, you've put a lot

268
00:10:45.000 --> 00:10:46.840
of thought into that. You really have.

269
00:10:47.000 --> 00:10:49.120
Professor Fred Watson: Yeah. And these are questions that are right

270
00:10:49.120 --> 00:10:51.900
on money as well. Yeah. Uh, especially the

271
00:10:51.900 --> 00:10:54.300
last one. Why do physicists believe in

272
00:10:54.300 --> 00:10:56.100
gravitons? I think most physicists probably

273
00:10:56.100 --> 00:10:58.340
do. Uh, Alan, because

274
00:10:58.560 --> 00:11:01.020
um, we know that gravity is a fundamental

275
00:11:01.020 --> 00:11:03.420
force and all the other fundamental forces

276
00:11:03.420 --> 00:11:05.780
have their subatomic particles,

277
00:11:06.290 --> 00:11:09.060
uh, which are basically

278
00:11:09.930 --> 00:11:12.890
um, um,

279
00:11:13.300 --> 00:11:16.060
particles that can. That sort of what we

280
00:11:16.060 --> 00:11:18.580
call, we call them bosons. They're what, they

281
00:11:18.580 --> 00:11:21.300
carry a field in a way. And the field is

282
00:11:21.920 --> 00:11:24.550
another way of looking at how a uh,

283
00:11:24.680 --> 00:11:27.560
force works. I didn't

284
00:11:27.560 --> 00:11:30.400
phrase that very well, but uh, that's why

285
00:11:30.480 --> 00:11:33.080
some physicists believe in gravitons. We've

286
00:11:33.080 --> 00:11:35.920
never found them. We don't have a particle

287
00:11:35.920 --> 00:11:38.680
physics theory of gravity. Uh, so we don't

288
00:11:38.680 --> 00:11:40.320
know that they exist. But I think most

289
00:11:40.400 --> 00:11:43.040
physicists would assume that they exist.

290
00:11:44.160 --> 00:11:46.880
And so uh, that

291
00:11:46.880 --> 00:11:49.760
first um, conundrum

292
00:11:51.120 --> 00:11:52.640
that you mentioned,

293
00:11:53.840 --> 00:11:56.160
if nothing escapes a black hole, well,

294
00:11:56.160 --> 00:11:58.800
gravity does. And so if

295
00:11:58.800 --> 00:12:00.760
gravitons exist and convey the force of

296
00:12:00.760 --> 00:12:03.000
gravity, then they escape black holes. So

297
00:12:03.000 --> 00:12:05.240
they're not affected by gravity. That means

298
00:12:05.240 --> 00:12:08.240
they do not affect each other. But in

299
00:12:08.240 --> 00:12:10.720
fact, um, uh,

300
00:12:11.200 --> 00:12:14.000
the bottom line with black holes it's

301
00:12:14.000 --> 00:12:16.910
quite complicated. Uh, but you

302
00:12:17.230 --> 00:12:19.870
don't have gravitons escaping

303
00:12:20.510 --> 00:12:22.970
from the black hole. Uh,

304
00:12:23.390 --> 00:12:26.190
the way people who know a lot more about

305
00:12:26.190 --> 00:12:28.510
these things than me, uh, the way they

306
00:12:28.510 --> 00:12:31.390
envisage this is that the gravitational

307
00:12:31.390 --> 00:12:34.230
field of the black hole is a kind

308
00:12:34.230 --> 00:12:37.190
of fossilised one that was

309
00:12:37.190 --> 00:12:39.870
established before the collapse

310
00:12:40.590 --> 00:12:43.280
into uh, a black hole.

311
00:12:44.000 --> 00:12:46.800
Or, and here's another way of looking at it.

312
00:12:49.120 --> 00:12:51.680
This really, you're gonna think, um, Alan,

313
00:12:51.680 --> 00:12:54.120
this is a cop out, but this is the way the

314
00:12:54.120 --> 00:12:57.120
physicists see it. Uh, the,

315
00:12:57.200 --> 00:12:59.280
the gravitational field of black hole

316
00:12:59.600 --> 00:13:02.400
basically uh, includes

317
00:13:02.400 --> 00:13:04.560
something called virtual gravitons.

318
00:13:05.650 --> 00:13:08.320
Uh, and so that sort of ties in with the fact

319
00:13:08.320 --> 00:13:10.800
that the, the gravitational field is a

320
00:13:10.800 --> 00:13:13.080
fossilised footprint, if I can put it that

321
00:13:13.080 --> 00:13:15.940
way. Um, the

322
00:13:16.020 --> 00:13:18.740
virtual gravitons, uh, are an

323
00:13:18.740 --> 00:13:21.380
embodiment of that, but they don't

324
00:13:21.460 --> 00:13:23.900
necessarily obey the

325
00:13:23.900 --> 00:13:25.860
normal laws of physics.

326
00:13:28.020 --> 00:13:28.420
So

327
00:13:30.870 --> 00:13:31.490
uh,

328
00:13:34.100 --> 00:13:36.820
basically what you've got here, and

329
00:13:37.540 --> 00:13:40.250
I think, um, the

330
00:13:40.250 --> 00:13:42.690
physicists who look at this problem probably

331
00:13:42.690 --> 00:13:45.490
just automatically drop into the two

332
00:13:45.490 --> 00:13:48.290
camps of relativist people who

333
00:13:48.290 --> 00:13:51.090
are ah, experts in general relativity. That's

334
00:13:51.090 --> 00:13:53.130
Einstein's theory of gravity that says, yes,

335
00:13:53.470 --> 00:13:56.130
um, gravity is not a force, it's just a

336
00:13:56.130 --> 00:13:58.930
distortion of space. Uh, and the quantum

337
00:13:58.930 --> 00:14:01.730
mechanics people who look at it from the

338
00:14:01.730 --> 00:14:04.490
perspective of gravitons.

339
00:14:05.400 --> 00:14:08.170
Um, and so yeah, the virtual particles,

340
00:14:08.800 --> 00:14:11.770
uh, the quantum mechanics

341
00:14:11.850 --> 00:14:13.930
person's answer to this,

342
00:14:15.180 --> 00:14:17.970
uh, they're basically

343
00:14:17.970 --> 00:14:20.849
just mathematical constructs, uh, in a

344
00:14:20.849 --> 00:14:23.570
quantum field. And so they don't have to

345
00:14:23.570 --> 00:14:26.410
obey speed limits or anything like that, or

346
00:14:26.410 --> 00:14:28.370
even don't have to worry about the event

347
00:14:28.370 --> 00:14:31.050
horizon so they can continually

348
00:14:32.000 --> 00:14:34.840
basically, uh, keep the gravitational force

349
00:14:34.840 --> 00:14:37.600
there without actually being

350
00:14:37.600 --> 00:14:40.480
trapped by it. I think that's the way

351
00:14:40.560 --> 00:14:42.240
physicists look at it.

352
00:14:43.250 --> 00:14:46.000
Andrew Dunkley: Uh, all that says to me is

353
00:14:48.480 --> 00:14:50.440
something. It's still a big mystery. There

354
00:14:50.440 --> 00:14:52.400
are so many different theories behind

355
00:14:52.400 --> 00:14:55.360
gravity, and we really don't know what it is.

356
00:14:56.560 --> 00:14:58.200
We know what it is, but we don't know why it

357
00:14:58.200 --> 00:14:58.480
is.

358
00:14:58.880 --> 00:15:01.640
Professor Fred Watson: Well, no. So all we know about

359
00:15:01.640 --> 00:15:04.470
gravity is the way it behaves. Um,

360
00:15:04.700 --> 00:15:07.500
we really don't know what it is. And in a

361
00:15:07.500 --> 00:15:10.300
way, Alan's question is well posed

362
00:15:10.300 --> 00:15:13.060
because it could end up that it's something

363
00:15:13.060 --> 00:15:14.860
different and there aren't gravitons.

364
00:15:15.650 --> 00:15:18.300
Um, and, uh, that's why we haven't found

365
00:15:18.300 --> 00:15:21.110
them, because they're not there. Um,

366
00:15:22.620 --> 00:15:24.620
it's fascinating. I mean, in a sense,

367
00:15:25.550 --> 00:15:28.180
uh, gravitons are along the same line as the

368
00:15:28.180 --> 00:15:31.020
hypothetical dark matter particles. We know,

369
00:15:31.810 --> 00:15:34.730
um, dark matter is real. We know it's

370
00:15:34.730 --> 00:15:37.370
there. Uh, we assume it's subatomic

371
00:15:37.370 --> 00:15:40.250
particles. We've seen some recent works. Uh,

372
00:15:40.330 --> 00:15:42.810
work. Sorry. We've seen some recent work that

373
00:15:42.810 --> 00:15:45.570
suggests perhaps they're not, um,

374
00:15:45.570 --> 00:15:47.770
perhaps it's not subatomic particles, but

375
00:15:47.770 --> 00:15:49.650
primordial black holes, which can be very

376
00:15:49.650 --> 00:15:52.610
small and very difficult to detect. Uh, which

377
00:15:52.610 --> 00:15:55.210
takes us back to the, um, macho

378
00:15:55.210 --> 00:15:57.530
theory. Massive compact halo objects, the

379
00:15:57.610 --> 00:16:00.330
macho theory of dark matter, as distinct from

380
00:16:00.330 --> 00:16:01.930
the WIMP theory, the weakly interacting

381
00:16:01.930 --> 00:16:04.670
massive particles. I

382
00:16:04.670 --> 00:16:07.190
think gravitons almost fall into the same

383
00:16:07.190 --> 00:16:10.110
boat as dark matter particles in the sense

384
00:16:10.110 --> 00:16:12.630
that we haven't detected them. We hypothesise

385
00:16:12.630 --> 00:16:14.310
that they're there. We've built constructs

386
00:16:14.310 --> 00:16:17.310
like virtual gravitons that allow us to do

387
00:16:17.310 --> 00:16:19.680
that without going completely mad. Um,

388
00:16:19.989 --> 00:16:22.790
but, uh, at the moment, still, I think,

389
00:16:23.110 --> 00:16:25.310
uh, the door is wide open for all kinds of

390
00:16:25.310 --> 00:16:27.470
new ideas that might change our view

391
00:16:27.470 --> 00:16:27.990
completely.

392
00:16:28.470 --> 00:16:31.230
Andrew Dunkley: Yeah, I guess the day we crack it will

393
00:16:31.230 --> 00:16:33.470
go, uh. Yeah, I should have thought of that.

394
00:16:35.070 --> 00:16:37.230
Professor Fred Watson: Exactly. Well, Alan's already thought of it.

395
00:16:37.470 --> 00:16:37.950
Andrew Dunkley: Yeah.

396
00:16:38.270 --> 00:16:40.790
Professor Fred Watson: Yeah. In terms of, you know, what, what the

397
00:16:40.790 --> 00:16:43.110
conundrums are and why it is. Why it's so

398
00:16:43.110 --> 00:16:44.910
difficult. Yeah, it's a great question.

399
00:16:45.070 --> 00:16:47.070
Andrew Dunkley: I guess the question that comes from that is,

400
00:16:47.070 --> 00:16:49.670
does it have to be a particle? And the answer

401
00:16:49.670 --> 00:16:52.390
is no. Um, it doesn't, uh, have to be

402
00:16:52.390 --> 00:16:54.150
just because everything else is made of

403
00:16:54.150 --> 00:16:55.870
particles. So.

404
00:16:56.750 --> 00:16:58.500
Professor Fred Watson: Yes, that's right. I mean, it's.

405
00:16:59.610 --> 00:17:01.530
So what's called the standard model of

406
00:17:01.690 --> 00:17:04.090
subatomic particles is this

407
00:17:04.490 --> 00:17:07.410
group of 17 particles which we don't

408
00:17:07.410 --> 00:17:09.210
think can be broken down into Anything

409
00:17:09.210 --> 00:17:10.410
smaller. That's why they're called

410
00:17:10.410 --> 00:17:13.130
fundamental, um, and

411
00:17:13.210 --> 00:17:15.670
they account. Among them are, uh,

412
00:17:16.970 --> 00:17:19.130
the force, um, particles,

413
00:17:19.910 --> 00:17:22.770
um, electromagnetic, strong

414
00:17:22.770 --> 00:17:24.750
and weak nuclear forces, um,

415
00:17:26.670 --> 00:17:29.580
uh, which we know about. Gravity is just

416
00:17:29.580 --> 00:17:32.460
assumed to be, uh, a fundamental force

417
00:17:32.460 --> 00:17:34.340
with its fundamental particle because it

418
00:17:34.340 --> 00:17:37.220
behaves in every other way. It behaves like

419
00:17:37.220 --> 00:17:39.500
the other ones do. Uh, but we just haven't

420
00:17:39.500 --> 00:17:41.820
managed to pinpoint the particle itself.

421
00:17:43.020 --> 00:17:43.740
There you go.

422
00:17:43.770 --> 00:17:46.740
Andrew Dunkley: Ah, Alan, you've kind of, um, put

423
00:17:46.740 --> 00:17:49.220
your thumb on one of the big mysteries of the

424
00:17:49.220 --> 00:17:52.050
universe and expected us to have an answer.

425
00:17:53.590 --> 00:17:56.370
Uh, no, it's just

426
00:17:56.530 --> 00:17:59.090
one of those great big, um, question marks in

427
00:17:59.090 --> 00:18:00.810
space. If you look up, you can see a giant

428
00:18:00.810 --> 00:18:03.650
question mark in space. That's gravity.

429
00:18:04.770 --> 00:18:06.130
Professor Fred Watson: That's right, yeah.

430
00:18:06.250 --> 00:18:08.970
Andrew Dunkley: Uh, whether or not there are gravitons, the

431
00:18:08.970 --> 00:18:11.690
debate remains. Thank, uh, you, Alan, for the

432
00:18:11.690 --> 00:18:14.210
question. This is Space Nuts Andrew Dunkley

433
00:18:14.210 --> 00:18:16.290
here with Professor Fred Watson Watson.

434
00:18:18.410 --> 00:18:20.290
Professor Fred Watson: I believe that this nation should commit

435
00:18:20.290 --> 00:18:22.490
Andrew Dunkley: itself to achieving the goal

436
00:18:23.130 --> 00:18:26.090
before this decade is out, of landing a

437
00:18:26.090 --> 00:18:26.250
man

438
00:18:26.250 --> 00:18:28.610
Professor Fred Watson: on the moon and returning him safely to the

439
00:18:28.610 --> 00:18:28.930
Earth.

440
00:18:28.930 --> 00:18:30.730
Andrew Dunkley: Beast nuts, Fred Watson.

441
00:18:30.730 --> 00:18:33.590
Our next question comes from, uh,

442
00:18:33.609 --> 00:18:35.770
somebody else who's thinking particles. I

443
00:18:35.770 --> 00:18:38.250
spend a lot of time thinking about

444
00:18:38.570 --> 00:18:41.370
photons and have, uh, so many questions about

445
00:18:41.370 --> 00:18:44.370
them. Uh, you know, I know

446
00:18:44.370 --> 00:18:46.770
this about Misty because, um, she's always

447
00:18:46.770 --> 00:18:48.610
walking around with a light bulb above her

448
00:18:48.610 --> 00:18:50.790
head. So that explains that,

449
00:18:51.210 --> 00:18:53.670
um, photons are really weird to understand.

450
00:18:54.470 --> 00:18:56.790
I'm curious to know if there are any

451
00:18:56.790 --> 00:18:59.590
fundamental particles that do not have a

452
00:18:59.590 --> 00:19:02.550
wave function. And then is it possible

453
00:19:02.550 --> 00:19:05.350
to detect a particle or photon that does not

454
00:19:05.350 --> 00:19:08.070
have any properties of a wave?

455
00:19:08.790 --> 00:19:10.750
And the last part of the question. Is it

456
00:19:10.750 --> 00:19:13.030
possible for a photon or particle to have

457
00:19:13.030 --> 00:19:15.310
such a long wavelength that we don't have a

458
00:19:15.310 --> 00:19:17.650
detector big enough to pick it up? That's,

459
00:19:17.650 --> 00:19:19.630
uh, from Misty in Pennsylvania, one of our

460
00:19:19.630 --> 00:19:21.970
administrators on the Facebook PODC Ask

461
00:19:21.970 --> 00:19:24.970
Group. So, um, uh, thank you, Misty,

462
00:19:24.970 --> 00:19:26.570
for sending in a question. Nice to hear from

463
00:19:26.570 --> 00:19:28.690
you and beautiful part of the world,

464
00:19:28.690 --> 00:19:30.970
Pennsylvania. Got to drive through that last

465
00:19:30.970 --> 00:19:33.890
year. And, uh, yeah, it is

466
00:19:33.890 --> 00:19:36.850
absolutely lovely in summer. Don't

467
00:19:36.850 --> 00:19:38.130
think I want to be there in winter.

468
00:19:41.250 --> 00:19:44.000
Nevertheless. Okay, so, um,

469
00:19:44.770 --> 00:19:47.770
photons. Yeah. What can we talk? What

470
00:19:47.770 --> 00:19:50.610
can you tell us about? Are there any

471
00:19:50.610 --> 00:19:52.410
particles that don't have wavelengths? That's

472
00:19:52.410 --> 00:19:53.790
an interest question.

473
00:19:53.790 --> 00:19:56.710
Professor Fred Watson: Yes. So that's M, more or less what

474
00:19:56.710 --> 00:19:59.230
it amounts to. So we see

475
00:19:59.470 --> 00:20:01.790
in quantum mechanics, uh,

476
00:20:02.190 --> 00:20:04.910
we see this fundamental thing that particles,

477
00:20:05.670 --> 00:20:08.590
m, uh, display the properties

478
00:20:08.590 --> 00:20:11.510
both of a particle and a wave. And so we

479
00:20:11.510 --> 00:20:14.350
call it a wave function. And as

480
00:20:14.350 --> 00:20:16.950
I understand it, and I Think, uh, quantum

481
00:20:16.950 --> 00:20:19.310
mechanics backs, uh, this up.

482
00:20:19.910 --> 00:20:22.860
Uh, there are no fundamental particles

483
00:20:23.020 --> 00:20:26.020
that don't have a wave function, so they

484
00:20:26.020 --> 00:20:28.860
all exhibit this wave particle

485
00:20:28.940 --> 00:20:29.660
duality.

486
00:20:30.570 --> 00:20:30.600
Andrew Dunkley: Um,

487
00:20:35.900 --> 00:20:36.960
Professor Fred Watson: It is, uh,

488
00:20:38.940 --> 00:20:41.100
I guess, you know, the way that,

489
00:20:41.150 --> 00:20:43.900
um, particle physicists think about

490
00:20:43.900 --> 00:20:46.780
these things are uh, a little bit different

491
00:20:47.610 --> 00:20:50.530
from the way we might interpret it. So when I

492
00:20:50.530 --> 00:20:52.890
think of the wave particle duality,

493
00:20:53.450 --> 00:20:55.850
my mind immediately goes to the photon,

494
00:20:56.550 --> 00:20:59.450
um, which, um, Misty's already mentioned.

495
00:21:00.030 --> 00:21:02.170
Uh, yes, we understand

496
00:21:03.210 --> 00:21:05.770
photons as particles because we see the

497
00:21:05.770 --> 00:21:08.530
photoelectric effect, which insists that

498
00:21:08.530 --> 00:21:10.330
they've got to be particles because you get

499
00:21:10.490 --> 00:21:13.010
basically quantized amounts of energy out of

500
00:21:13.010 --> 00:21:15.850
them. But then when I think about the waves,

501
00:21:15.930 --> 00:21:18.570
I think about things like polarisation,

502
00:21:19.130 --> 00:21:21.350
uh, where you've got waves that are

503
00:21:21.590 --> 00:21:23.270
oscillating in different directions. I think

504
00:21:23.270 --> 00:21:24.790
we talked about that a couple of episodes

505
00:21:24.790 --> 00:21:27.390
ago, we did, in the mapping of the magnetic

506
00:21:27.390 --> 00:21:30.350
fields of the galaxy of the universe. Um, and

507
00:21:30.350 --> 00:21:32.750
so I always think about waves vibrating

508
00:21:32.750 --> 00:21:34.710
through a median. But,

509
00:21:35.010 --> 00:21:37.910
um, the physicists

510
00:21:38.710 --> 00:21:41.350
kind of combine those two ideas

511
00:21:42.790 --> 00:21:45.590
and, uh, think in terms of, uh, something

512
00:21:45.990 --> 00:21:48.310
it's usually called quantized

513
00:21:48.470 --> 00:21:50.630
excitations of underlying

514
00:21:51.010 --> 00:21:53.090
fields. So

515
00:21:53.570 --> 00:21:56.510
that's to say that, um,

516
00:21:56.610 --> 00:21:59.490
it kind of mixes both relativity and

517
00:21:59.890 --> 00:22:02.610
quantum physics here because the

518
00:22:02.610 --> 00:22:04.850
underlying field is what?

519
00:22:05.530 --> 00:22:08.290
Um, it's the sort of,

520
00:22:08.370 --> 00:22:10.090
if I can put it that way, the background

521
00:22:10.090 --> 00:22:13.010
canvas on which the information

522
00:22:13.330 --> 00:22:16.050
is superimposed and the particle

523
00:22:16.450 --> 00:22:19.170
is a bit of that background canvas that is

524
00:22:19.250 --> 00:22:22.090
excited to vibrate and

525
00:22:22.170 --> 00:22:24.770
give you a wave, but it's

526
00:22:24.770 --> 00:22:27.370
excited in a way that is quantized. That

527
00:22:27.370 --> 00:22:30.210
means there isn't an

528
00:22:30.210 --> 00:22:33.210
infinite number of different excitations

529
00:22:33.290 --> 00:22:34.890
that can be set up.

530
00:22:36.570 --> 00:22:39.450
They're specific numbers,

531
00:22:39.450 --> 00:22:41.770
which means you get specific wavelengths

532
00:22:42.090 --> 00:22:44.930
from the excitation. So it is all a

533
00:22:44.930 --> 00:22:46.660
mix of, of

534
00:22:47.460 --> 00:22:50.340
particles and waves, but it kind of brings

535
00:22:50.340 --> 00:22:52.940
it together and once you think of it in those

536
00:22:52.940 --> 00:22:54.820
terms, uh, then

537
00:22:56.100 --> 00:22:58.140
it becomes clear that you can't have a

538
00:22:58.140 --> 00:23:00.580
particle without its wave function.

539
00:23:00.980 --> 00:23:03.380
Andrew Dunkley: Which kind of writes off her second question.

540
00:23:03.380 --> 00:23:06.140
If there's, um, a long enough wavelength that

541
00:23:06.140 --> 00:23:07.940
we haven't got the equipment to detect it.

542
00:23:08.450 --> 00:23:10.260
Professor Fred Watson: Um, no, I don't think it does

543
00:23:11.380 --> 00:23:13.910
because I think, um,

544
00:23:14.970 --> 00:23:17.970
I mean we, you know, we. In, in

545
00:23:17.970 --> 00:23:20.410
a way the ultra low

546
00:23:20.410 --> 00:23:23.050
frequency radio waves are a bit like that,

547
00:23:23.730 --> 00:23:26.090
uh, because they are,

548
00:23:27.210 --> 00:23:29.009
uh. Some of them have got a wavelength bigger

549
00:23:29.009 --> 00:23:31.890
than the Earth. And

550
00:23:31.890 --> 00:23:34.050
so how do you detect that? Well, you've got

551
00:23:34.050 --> 00:23:36.090
to have a spacecraft that's got the other end

552
00:23:36.090 --> 00:23:38.850
of the aerial on it, you know, that sort of

553
00:23:38.850 --> 00:23:41.130
thing. Um, there's also,

554
00:23:42.530 --> 00:23:45.450
uh. What was I going to say,

555
00:23:45.630 --> 00:23:48.290
um, yeah, we know that there are

556
00:23:48.290 --> 00:23:50.970
gravitational waves that have got

557
00:23:51.290 --> 00:23:54.080
wavelengths measured in light years. Uh,

558
00:23:54.410 --> 00:23:56.650
I think the gravitational

559
00:23:57.690 --> 00:24:00.450
properties of the Big Bang. So the

560
00:24:00.450 --> 00:24:02.290
gravitational waves that were set up by the

561
00:24:02.290 --> 00:24:05.210
Big Bang are extremely long

562
00:24:05.290 --> 00:24:07.370
wavelength. I think I've got that the right

563
00:24:07.370 --> 00:24:10.000
way around. Um,

564
00:24:10.080 --> 00:24:12.840
it's so, uh. And we, you know, there are

565
00:24:12.840 --> 00:24:15.760
ones that we don't have normal,

566
00:24:16.160 --> 00:24:18.720
everyday ways of detecting them. There are

567
00:24:18.720 --> 00:24:20.520
subtleties because you expect some of these

568
00:24:20.520 --> 00:24:22.720
waves to be polarised. And that, I think,

569
00:24:22.720 --> 00:24:24.999
gives you an insight into it. But, yeah,

570
00:24:24.999 --> 00:24:27.920
it's, uh. Look, it is a good question.

571
00:24:28.600 --> 00:24:31.400
Uh, and I, uh, think, um, once again,

572
00:24:31.400 --> 00:24:34.360
mist is thinking outside the box. Uh,

573
00:24:34.360 --> 00:24:36.960
no particles without their wave

574
00:24:36.960 --> 00:24:39.480
function, because a particle is an

575
00:24:39.480 --> 00:24:42.260
excitation of the underlying field, a

576
00:24:42.260 --> 00:24:44.540
quantized excitation of the underlying field.

577
00:24:45.020 --> 00:24:47.740
Andrew Dunkley: So it is possible we cannot detect certain

578
00:24:47.740 --> 00:24:49.620
wavelengths because they're too big, but they

579
00:24:49.620 --> 00:24:50.300
still exist.

580
00:24:50.540 --> 00:24:51.780
Professor Fred Watson: I think that's right, yes.

581
00:24:51.780 --> 00:24:54.060
Andrew Dunkley: Yeah. All right. What about gravitons? Do you

582
00:24:54.060 --> 00:24:55.380
reckon they have a wavelength?

583
00:24:55.380 --> 00:24:57.700
Professor Fred Watson: Well, yes, they do. That's the thing. Um, if

584
00:24:57.700 --> 00:24:59.630
they exist, yes. Uh, because, um,

585
00:25:01.030 --> 00:25:03.980
uh, we've got gravitational waves. So the

586
00:25:03.980 --> 00:25:06.100
wave particle duality works both ways. If

587
00:25:06.100 --> 00:25:07.580
you've got a wave, you've got a particle.

588
00:25:07.900 --> 00:25:10.780
Andrew Dunkley: There you go. Uh, good one. Thanks,

589
00:25:10.780 --> 00:25:13.220
Misty. Hope all is well in Pennsylvania.

590
00:25:16.100 --> 00:25:18.420
Three, two, one.

591
00:25:18.980 --> 00:25:20.260
Professor Fred Watson: Space nuts.

592
00:25:20.500 --> 00:25:23.380
Andrew Dunkley: And our final question, uh, comes from

593
00:25:23.380 --> 00:25:25.380
another one of our regular contributors,

594
00:25:25.380 --> 00:25:28.140
Casey in Colorado. What does it feel

595
00:25:28.140 --> 00:25:30.740
like to go from weightlessness to normal

596
00:25:30.740 --> 00:25:33.060
gravity for astronauts when returning to

597
00:25:33.060 --> 00:25:36.030
Earth? I think it would depend

598
00:25:36.030 --> 00:25:38.940
on how long you've been up there and, uh,

599
00:25:38.940 --> 00:25:40.470
whether or not you've actually bothered to

600
00:25:40.470 --> 00:25:41.470
use the treadmill.

601
00:25:43.230 --> 00:25:45.030
Professor Fred Watson: Well, that's right. The treadmill is all

602
00:25:45.030 --> 00:25:46.750
about keeping up your muscle strength.

603
00:25:46.910 --> 00:25:49.070
Andrew Dunkley: Exactly. Um, because once you're out there,

604
00:25:49.310 --> 00:25:51.900
your muscles immediately start to wither. Uh,

605
00:25:52.390 --> 00:25:52.910
they do.

606
00:25:52.910 --> 00:25:55.390
Professor Fred Watson: And you don't really have anything against

607
00:25:55.390 --> 00:25:58.230
which to push to keep them,

608
00:25:58.230 --> 00:26:00.060
you know, keep them going, other than the.

609
00:26:00.530 --> 00:26:02.450
The, um, torture equipment that

610
00:26:03.490 --> 00:26:06.010
NASA and Roscosmos provide on their space

611
00:26:06.010 --> 00:26:06.530
station.

612
00:26:06.530 --> 00:26:08.890
Andrew Dunkley: I think on Space Lab, they didn't have a

613
00:26:08.890 --> 00:26:10.850
treadmill. They had a running track that ran

614
00:26:10.850 --> 00:26:13.810
around the inside of

615
00:26:14.850 --> 00:26:17.850
wall of, uh, Skylab, I think. And

616
00:26:17.850 --> 00:26:20.690
so I've seen footage of astronauts actually

617
00:26:20.690 --> 00:26:23.090
running in a circle around the

618
00:26:23.410 --> 00:26:25.250
interior of Skylab.

619
00:26:25.570 --> 00:26:28.250
Professor Fred Watson: So they're keeping themselves, um, running

620
00:26:28.250 --> 00:26:30.290
just by the centrifugal force that they're

621
00:26:30.370 --> 00:26:32.990
setting up. Yeah, yeah, yeah. That's

622
00:26:32.990 --> 00:26:34.570
interesting. I didn't know that. That's, uh.

623
00:26:34.630 --> 00:26:37.270
Andrew Dunkley: Yeah, I'm sure that if you had online, you'd

624
00:26:37.270 --> 00:26:40.030
find Footage of it. I. I strongly remember

625
00:26:40.030 --> 00:26:42.430
that M. I saw it on the news one day and

626
00:26:42.430 --> 00:26:44.510
thought, wow, how did they do that? Well,

627
00:26:44.510 --> 00:26:45.620
there's no gravity, duh. Uh,

628
00:26:47.470 --> 00:26:49.230
Professor Fred Watson: yeah. Um,

629
00:26:50.350 --> 00:26:53.350
wasn't there something like that in 2001 A

630
00:26:53.350 --> 00:26:55.070
Space Odyssey? I think there was. Could have

631
00:26:55.070 --> 00:26:55.270
been.

632
00:26:55.270 --> 00:26:58.030
Andrew Dunkley: I think I watched that very recently.

633
00:26:58.110 --> 00:27:00.150
I just thought I really wanted to watch it

634
00:27:00.150 --> 00:27:02.500
again. But, um, I fell asleep. But

635
00:27:02.980 --> 00:27:04.860
it's very late. Judy had gone to bed, and I

636
00:27:04.860 --> 00:27:07.730
thought, oh, I might just start this. Uh,

637
00:27:07.730 --> 00:27:08.900
yeah, I was gone.

638
00:27:11.420 --> 00:27:13.860
Um, what was the question? Oh, uh, what's the

639
00:27:13.940 --> 00:27:16.620
feel like? I also remember seeing

640
00:27:16.620 --> 00:27:19.460
footage of cosmonauts, uh, coming back

641
00:27:19.460 --> 00:27:22.180
from very long haul time in space.

642
00:27:23.220 --> 00:27:25.580
And they'd get them out of the capsule once

643
00:27:25.580 --> 00:27:27.420
they came back to Earth and they couldn't

644
00:27:27.420 --> 00:27:27.820
stand up.

645
00:27:27.820 --> 00:27:29.740
Professor Fred Watson: Couldn't stand up. Yeah. I've seen similar

646
00:27:29.740 --> 00:27:32.740
things and. Well, you know, even with the

647
00:27:32.740 --> 00:27:34.960
exercise that the Artemis II crew

648
00:27:35.520 --> 00:27:38.240
were doing, they were a little bit wobbly

649
00:27:38.320 --> 00:27:40.920
when they got out of the spacecraft. And we

650
00:27:40.920 --> 00:27:43.920
all saw them going across the deck of the,

651
00:27:44.280 --> 00:27:46.820
uh, recovery ship. Uh,

652
00:27:47.280 --> 00:27:49.239
so I think how wobbly you are probably

653
00:27:49.239 --> 00:27:51.120
depends on just how much effort you've put

654
00:27:51.120 --> 00:27:53.720
into keeping up your muscle strength. So I

655
00:27:53.720 --> 00:27:56.480
think that's the key thing that Casey

656
00:27:57.360 --> 00:28:00.280
might be thinking of. Um, exactly. As

657
00:28:00.280 --> 00:28:02.600
you've said, your muscles go to waste very

658
00:28:02.600 --> 00:28:05.100
quickly. Uh, and if you. You don't

659
00:28:05.100 --> 00:28:06.740
exercise, then you're going to be in big

660
00:28:06.740 --> 00:28:08.780
trouble. You simply would not be able to

661
00:28:08.780 --> 00:28:11.700
walk. Um, so quite a

662
00:28:11.700 --> 00:28:14.140
significant, uh, thing. Ah. Which would also,

663
00:28:14.140 --> 00:28:16.180
of course, depend on how long you've been in

664
00:28:16.180 --> 00:28:17.580
space, how long you've been weightless.

665
00:28:17.820 --> 00:28:20.259
Andrew Dunkley: And the other thing they might suffer from is

666
00:28:20.259 --> 00:28:23.100
fatigue because they have

667
00:28:23.100 --> 00:28:26.060
to work so much harder to achieve the same

668
00:28:26.940 --> 00:28:29.180
mobility as they were used to. When they had

669
00:28:29.180 --> 00:28:32.120
full muscle strength, they'd get

670
00:28:32.120 --> 00:28:34.600
very tired very fast. I think,

671
00:28:35.560 --> 00:28:37.560
all jokes aside, I think the,

672
00:28:38.130 --> 00:28:39.880
um, everyday person,

673
00:28:41.300 --> 00:28:43.340
uh, who's been through, um,

674
00:28:43.480 --> 00:28:46.200
immunotherapy or some

675
00:28:46.200 --> 00:28:49.120
form of, um, um, um,

676
00:28:49.400 --> 00:28:51.620
inhibitor for, um,

677
00:28:53.080 --> 00:28:56.080
testosterone, for example, for cancer

678
00:28:56.080 --> 00:28:58.990
treatment or something like that, that

679
00:28:58.990 --> 00:29:01.110
has the same effect on your muscles. Muscle

680
00:29:01.110 --> 00:29:03.550
wastage. When you stop producing testosterone

681
00:29:04.510 --> 00:29:06.590
as a male, your muscles

682
00:29:07.550 --> 00:29:09.350
actually do fade away. And you've got to do

683
00:29:09.350 --> 00:29:12.270
exercise to keep. Like astronauts, you've got

684
00:29:12.270 --> 00:29:14.190
to keep your exercise up to keep your muscles

685
00:29:14.190 --> 00:29:17.070
in trim, but it

686
00:29:17.070 --> 00:29:20.030
does slow you down. Um, and case in

687
00:29:20.030 --> 00:29:22.230
point, I did have that sort of treatment for

688
00:29:22.230 --> 00:29:24.590
my prostate cancer. And for six months

689
00:29:25.660 --> 00:29:28.180
I went into basically the

690
00:29:28.180 --> 00:29:30.460
equivalent to menopause. I had muscle

691
00:29:30.460 --> 00:29:32.980
wastage. Um, I kept up my

692
00:29:32.980 --> 00:29:35.740
exercise, but it wasn't enough. And I

693
00:29:35.980 --> 00:29:38.060
had a situation where I'd go out and play

694
00:29:38.060 --> 00:29:40.899
golf. I lost 40 yards on

695
00:29:40.899 --> 00:29:43.460
shots simply because my muscles had wasted

696
00:29:43.460 --> 00:29:46.180
away. And it's probably taken a year to get

697
00:29:46.180 --> 00:29:46.780
it all back.

698
00:29:47.100 --> 00:29:47.740
Professor Fred Watson: Yeah, interesting.

699
00:29:48.620 --> 00:29:51.580
Andrew Dunkley: Yeah. Um, it would be the same effect for an

700
00:29:51.580 --> 00:29:53.780
astronaut on it. Exactly the same. Different,

701
00:29:53.860 --> 00:29:56.100
different, you know, different mechanism.

702
00:29:56.180 --> 00:29:58.100
Mechanism, but same effect.

703
00:29:59.010 --> 00:30:01.900
Um, and. And yet the

704
00:30:01.900 --> 00:30:03.500
other thing that they'd probably have to deal

705
00:30:03.500 --> 00:30:05.140
with is some, some of them have very

706
00:30:05.700 --> 00:30:08.660
significant health effects from, from

707
00:30:08.660 --> 00:30:10.700
being in zero G and you come back to Earth.

708
00:30:10.700 --> 00:30:13.620
Like we had a, um, didn't. Wasn't there an

709
00:30:13.620 --> 00:30:15.700
astronaut recently who was temporarily

710
00:30:15.700 --> 00:30:18.500
blinded from,

711
00:30:18.500 --> 00:30:21.260
from zero G? And there's all sorts of

712
00:30:21.260 --> 00:30:24.260
things that um, they can suffer from. And

713
00:30:24.660 --> 00:30:26.140
a lot of the time when they come back to

714
00:30:26.140 --> 00:30:28.540
Earth, it does fix itself because you're back

715
00:30:28.540 --> 00:30:31.340
in your normal environment. But when you're

716
00:30:31.340 --> 00:30:33.420
out there orbiting or going to the moon and

717
00:30:33.420 --> 00:30:36.100
back, it is not a human environment.

718
00:30:36.980 --> 00:30:39.500
Professor Fred Watson: That's not normal. Yeah, so it was an

719
00:30:39.500 --> 00:30:42.100
evacuation the uh, beginning of the year, I

720
00:30:42.100 --> 00:30:44.060
think it was, that we only really found out a

721
00:30:44.060 --> 00:30:46.900
few snippets about not very long ago.

722
00:30:47.780 --> 00:30:49.700
And I can't remember what the details were

723
00:30:50.260 --> 00:30:52.480
because my brain's atrophy because of

724
00:30:54.720 --> 00:30:55.440
old age.

725
00:30:56.320 --> 00:30:59.320
Andrew Dunkley: Yes, indeed. But, uh, there

726
00:30:59.320 --> 00:31:02.030
would be various levels of, um,

727
00:31:02.030 --> 00:31:04.320
dysfunction as a consequence of spending time

728
00:31:04.320 --> 00:31:07.280
in space. It would be a

729
00:31:07.840 --> 00:31:10.480
person to person variable.

730
00:31:10.790 --> 00:31:13.480
Um, it's not a one size

731
00:31:13.480 --> 00:31:15.800
fits all situation. Some people who'd come

732
00:31:15.800 --> 00:31:18.600
back probably not feel anything. But if, um,

733
00:31:18.800 --> 00:31:20.840
if you're up there long enough. Yeah, it's

734
00:31:20.840 --> 00:31:22.400
going to have a big impact on you.

735
00:31:22.400 --> 00:31:23.440
Professor Fred Watson: Yes, indeed.

736
00:31:24.240 --> 00:31:26.400
Andrew Dunkley: Thank you so much for the question, Kasey. I

737
00:31:26.400 --> 00:31:29.120
hope we covered it

738
00:31:29.360 --> 00:31:32.240
reasonably well. Um, anyway,

739
00:31:32.290 --> 00:31:34.960
uh, in the not too distant future, I'm pretty

740
00:31:34.960 --> 00:31:36.600
sure there'll be so many people going in and

741
00:31:36.600 --> 00:31:38.600
out of space, they'll come up with ways of

742
00:31:38.600 --> 00:31:41.520
dealing with it. Who knows? And

743
00:31:41.520 --> 00:31:42.960
I think that brings us to the end.

744
00:31:42.960 --> 00:31:44.720
Don't forget, if you've got, uh, questions

745
00:31:44.720 --> 00:31:47.360
for us or observations or comments or

746
00:31:47.360 --> 00:31:49.200
whatever you like, you can go to our website,

747
00:31:49.820 --> 00:31:51.940
send it to us in a text or audio

748
00:31:51.940 --> 00:31:53.344
format@spacenuts

749
00:31:53.656 --> 00:31:55.300
IO or

750
00:31:55.300 --> 00:31:58.060
spacenutspodcast.com

751
00:31:58.460 --> 00:32:01.220
and just click on the little ama button at

752
00:32:01.220 --> 00:32:04.060
the top that stands for Ask me Anything. And

753
00:32:04.930 --> 00:32:07.420
um, you can send it through. Don't forget to

754
00:32:07.500 --> 00:32:09.980
tell us who you are or where you're from.

755
00:32:11.420 --> 00:32:13.140
And Fred Watson, that's it. Thanks so much

756
00:32:13.140 --> 00:32:15.500
for answering those. That was a tough batch

757
00:32:15.500 --> 00:32:15.820
today.

758
00:32:17.500 --> 00:32:19.380
Professor Fred Watson: Great questions though. Well done. To all our

759
00:32:19.380 --> 00:32:22.200
listeners for what they do in terms

760
00:32:22.200 --> 00:32:24.520
of, uh, thinking through a lot of these

761
00:32:24.520 --> 00:32:25.480
issues. It's great.

762
00:32:25.960 --> 00:32:27.520
Andrew Dunkley: Very good. All right, we'll catch you real

763
00:32:27.520 --> 00:32:28.640
soon. Fred Watson, thanks so much.

764
00:32:28.640 --> 00:32:30.040
Professor Fred Watson: Looking forward to it. Thanks, Andrew.

765
00:32:30.200 --> 00:32:32.000
Andrew Dunkley: Professor Fred Watson Watson, astronomer at

766
00:32:32.000 --> 00:32:34.240
large. And thanks to Huw in the studio, who

767
00:32:34.240 --> 00:32:35.980
couldn't be with us today because, um,

768
00:32:36.920 --> 00:32:39.560
there was, um, so much going on with

769
00:32:39.560 --> 00:32:41.960
gravitons and weightlessness, he just

770
00:32:42.360 --> 00:32:45.120
decided to float away. And from me,

771
00:32:45.120 --> 00:32:46.440
Andrew Dunkley. Thanks for your company.

772
00:32:46.440 --> 00:32:47.840
We'll catch you on the next episode of

773
00:32:47.840 --> 00:32:48.710
SpaceNuts real soon.

774
00:32:48.860 --> 00:32:49.020
Professor Fred Watson: Soon.

775
00:32:49.020 --> 00:32:51.940
Andrew Dunkley: Bye. Bye. You've been listening

776
00:32:51.940 --> 00:32:53.660
to the Space Nuts podcast,

777
00:32:55.260 --> 00:32:58.060
available at Apple Podcasts, Spotify,

778
00:32:58.220 --> 00:33:00.980
iHeartRadio or your favourite podcast

779
00:33:00.980 --> 00:33:02.700
player. You can also stream on

780
00:33:02.700 --> 00:33:04.380
demand@bytes.com.

781
00:33:04.700 --> 00:33:06.780
Professor Fred Watson: this has been another quality podcast

782
00:33:06.780 --> 00:33:08.860
production from bytes.com.