Theia's True Origins, 40,000 Asteroids & Enceladus’ Organic Mystery

WEBVTT

0
00:00:00.000 --> 00:00:02.160
Andrew Dunkley: Hi there. Thanks for joining us on Space

1
00:00:02.160 --> 00:00:04.160
Nuts, where we talk astronomy and space

2
00:00:04.160 --> 00:00:06.720
science. My name is Andrew Dunkley. Great to

3
00:00:06.720 --> 00:00:09.680
have your company. Coming up on this episode,

4
00:00:09.840 --> 00:00:12.640
uh, a new study from the Max Planck Institute

5
00:00:12.640 --> 00:00:14.920
shedding some new light on the theia, uh,

6
00:00:14.960 --> 00:00:17.600
Earth relationship, which might surprise you.

7
00:00:18.000 --> 00:00:19.840
And just when you thought it was safe to go

8
00:00:19.840 --> 00:00:22.400
back, uh, to sleep at night. 40,000

9
00:00:22.560 --> 00:00:25.560
new near earth asteroids have been

10
00:00:25.560 --> 00:00:28.270
discovered. Only 40,000? And they're all

11
00:00:28.270 --> 00:00:30.310
coming our way. No, they're not. Uh, the

12
00:00:30.310 --> 00:00:32.790
search for life just got another, um,

13
00:00:33.270 --> 00:00:36.230
a bit closer. Thanks uh, to some Cassini

14
00:00:36.230 --> 00:00:38.870
data. And 3i atlas still

15
00:00:38.950 --> 00:00:41.190
making the news. We'll talk about all of that

16
00:00:41.190 --> 00:00:44.150
on this episode of space nuts. 15

17
00:00:44.230 --> 00:00:44.870
seconds.

18
00:00:44.870 --> 00:00:47.640
Professor Fred Watson: Guidance is internal. 10, 9,

19
00:00:47.640 --> 00:00:50.150
uh, ignition sequence start.

20
00:00:50.310 --> 00:00:51.054
Space nuts.

21
00:00:51.131 --> 00:00:54.117
5, 4, 3, 2, 1, 2, 3, 4,

22
00:00:54.194 --> 00:00:56.070
5, 5, 4, 3, 2,.

23
00:00:56.150 --> 00:00:57.350
Andrew Dunkley: Space nuts.

24
00:00:57.350 --> 00:00:59.030
Professor Fred Watson: Astronauts report it feels.

25
00:01:00.050 --> 00:01:01.970
Andrew Dunkley: And we rolled out the red carpet because.

26
00:01:01.970 --> 00:01:04.490
He's back. It's Professor Fred Watson,

27
00:01:04.490 --> 00:01:06.210
astronomer at large. Hello, Fred.

28
00:01:06.770 --> 00:01:08.770
Professor Fred Watson: Hi, Andrew. I'm actually looking for the red

29
00:01:08.770 --> 00:01:09.210
carpet.

30
00:01:09.210 --> 00:01:12.170
Andrew Dunkley: Yeah, I rolled it back up again. It's had

31
00:01:12.170 --> 00:01:13.330
a few moth holes in it.

32
00:01:14.770 --> 00:01:16.770
Professor Fred Watson: Yeah, but, yeah, it's glad to hear it. Good.

33
00:01:17.730 --> 00:01:20.450
And you too. And, um, well, we've missed you.

34
00:01:20.450 --> 00:01:22.690
No, wait a minute. No, you've missed one or

35
00:01:22.690 --> 00:01:23.010
the other.

36
00:01:23.010 --> 00:01:25.400
Andrew Dunkley: Yes, we did have a few people starting to,

37
00:01:25.400 --> 00:01:28.260
um. I found in radio, if you're away for

38
00:01:28.260 --> 00:01:30.300
more than about three or four weeks, people

39
00:01:30.300 --> 00:01:33.060
started ringing the station and emailing to

40
00:01:33.060 --> 00:01:35.860
say, where's Joe Bloggs? Or where's. You

41
00:01:35.860 --> 00:01:37.980
know, this started happening with you, Fred?

42
00:01:37.980 --> 00:01:38.380
So.

43
00:01:38.460 --> 00:01:39.820
Professor Fred Watson: Oh, seriously, where's Fred?

44
00:01:39.820 --> 00:01:41.420
Andrew Dunkley: Where's Fred? What's going on with Fred? What

45
00:01:41.420 --> 00:01:44.260
happened to Fred? Uh, and funnily enough,

46
00:01:44.260 --> 00:01:46.380
I was able to say, yeah, I don't know.

47
00:01:48.460 --> 00:01:51.060
Professor Fred Watson: We haven't seen him for weeks. He's just

48
00:01:51.060 --> 00:01:51.740
disappeared.

49
00:01:51.980 --> 00:01:53.740
Andrew Dunkley: But no, he's back. He's back.

50
00:01:54.140 --> 00:01:56.500
So where did you go? What was the. Give us

51
00:01:56.500 --> 00:01:59.280
the. Give us the precede version of your

52
00:01:59.280 --> 00:02:00.440
seven weeks away.

53
00:02:01.480 --> 00:02:04.000
Professor Fred Watson: Three weeks, um, leading one of Marnie's

54
00:02:04.000 --> 00:02:06.760
tours, uh, which, uh, is the third

55
00:02:06.840 --> 00:02:09.090
big one we've done this year, actually. Um,

56
00:02:09.160 --> 00:02:11.840
after the Arctic in January and

57
00:02:11.840 --> 00:02:14.240
February. And then it was, uh, Western

58
00:02:14.240 --> 00:02:16.200
Australia in the middle of the year. And then

59
00:02:16.200 --> 00:02:18.680
this time we went to Japan. Uh, so we had a

60
00:02:18.680 --> 00:02:21.240
tour that took in interesting, uh, places

61
00:02:21.240 --> 00:02:23.560
like Osaka and Kyoto and

62
00:02:23.640 --> 00:02:26.640
Tokyo. And, um, Marnie and I actually made

63
00:02:26.640 --> 00:02:29.200
a side trip down to Hiroshima, which is a

64
00:02:29.200 --> 00:02:31.220
place I've always wanted to visit and I'm

65
00:02:31.220 --> 00:02:34.140
very glad I did. Very sobering place to

66
00:02:34.140 --> 00:02:37.060
be. Uh, But a welcoming city as well.

67
00:02:37.410 --> 00:02:39.980
Um, it was a pleasure to be there. Uh, and

68
00:02:39.980 --> 00:02:42.340
then, um, we wound up actually in Hokkaido,

69
00:02:42.340 --> 00:02:45.020
right in the north of Japan, where it was

70
00:02:45.020 --> 00:02:47.940
essentially coming onto winter. Uh, they get

71
00:02:47.940 --> 00:02:50.260
lots and lots of snow up there. It's a lot

72
00:02:50.340 --> 00:02:52.380
similar to, um, the Arctic, even though it's

73
00:02:52.380 --> 00:02:55.340
at a much lower latitude. Um, yeah, that was

74
00:02:55.340 --> 00:02:57.140
all fun. So we came back, we had four nights

75
00:02:57.140 --> 00:02:59.700
in Sydney, at home in our own bed, do the

76
00:02:59.700 --> 00:03:01.610
washing, and then off again to a conference.

77
00:03:01.680 --> 00:03:03.880
Conference on dark skies in County Mayo in

78
00:03:03.880 --> 00:03:06.560
Ireland. Uh, we were in Ireland for about a

79
00:03:06.560 --> 00:03:08.040
week, a little bit more than a week. We did

80
00:03:08.040 --> 00:03:10.880
some touring down in the South. We blew

81
00:03:10.880 --> 00:03:12.880
a kiss to the Blarney Stone.

82
00:03:12.880 --> 00:03:13.270
Andrew Dunkley: I did.

83
00:03:13.270 --> 00:03:16.160
Professor Fred Watson: Uh. Yeah, I wasn't game to

84
00:03:16.160 --> 00:03:17.799
kiss the Blarney Stone because you have to be

85
00:03:17.799 --> 00:03:18.400
upside down.

86
00:03:18.720 --> 00:03:19.160
Andrew Dunkley: Yeah.

87
00:03:19.160 --> 00:03:20.480
Professor Fred Watson: Doesn't suit me at all.

88
00:03:20.640 --> 00:03:21.680
Andrew Dunkley: We didn't do that either.

89
00:03:22.240 --> 00:03:24.310
Professor Fred Watson: No. So we blew it a kiss, which is, uh,

90
00:03:24.310 --> 00:03:25.840
enough, apparently, to get the gift of the

91
00:03:25.840 --> 00:03:28.200
gab. And then, uh, in fact, Blarney was a

92
00:03:28.200 --> 00:03:29.720
delightful place. It was the one sunny

93
00:03:29.720 --> 00:03:32.430
afternoon we had in, um. And it was

94
00:03:32.430 --> 00:03:34.630
lovely. Such an amazing castle. And the

95
00:03:34.630 --> 00:03:37.510
grounds are picture perfect. Uh, then we went

96
00:03:37.510 --> 00:03:40.310
over to Scotland, spent some time with my two

97
00:03:40.310 --> 00:03:42.790
daughters, had a great time with them. Took a

98
00:03:42.790 --> 00:03:45.550
weekend out. Uh, we all beetled off to St.

99
00:03:45.550 --> 00:03:47.990
Andrews, where I was educated. A, uh, town

100
00:03:47.990 --> 00:03:49.710
that's very close to my heart. We had a great

101
00:03:49.710 --> 00:03:51.230
time there. Uh, didn't do any golf. I'm

102
00:03:51.230 --> 00:03:53.470
sorry. But we did walk past the old course

103
00:03:53.470 --> 00:03:56.350
and thought of you with your golf clubs and

104
00:03:56.350 --> 00:03:58.030
that they don't float and things like that.

105
00:04:00.510 --> 00:04:03.250
And then after that, we, um, took the

106
00:04:03.250 --> 00:04:05.250
train down to Birmingham from Edinburgh, and

107
00:04:05.250 --> 00:04:07.250
that was pleasant. And at Birmingham, we got

108
00:04:07.250 --> 00:04:09.650
on a plane and went to Cyprus, uh, in the

109
00:04:09.650 --> 00:04:11.730
eastern end of the Mediterranean. And we

110
00:04:11.730 --> 00:04:13.810
actually had a holiday, six nights.

111
00:04:13.810 --> 00:04:15.730
Andrew Dunkley: And you found an observatory, a brand new one

112
00:04:15.730 --> 00:04:16.570
called Troodos.

113
00:04:16.970 --> 00:04:19.490
Professor Fred Watson: Troodos Observatory. Yes, we did. Marnie had

114
00:04:19.490 --> 00:04:20.690
checked it out, as she does with these

115
00:04:20.690 --> 00:04:23.130
things. And so we made a pilgrimage up into

116
00:04:23.130 --> 00:04:25.410
the hills. Not very far from the highest

117
00:04:25.410 --> 00:04:27.290
point in the island, actually, Mount Olympus.

118
00:04:27.680 --> 00:04:29.760
Uh, but, uh, it's got its own little

119
00:04:29.760 --> 00:04:32.040
mountain, has, uh. Uh, the Troodos

120
00:04:32.040 --> 00:04:34.000
Observatory. Uh, we went up there. We went

121
00:04:34.000 --> 00:04:36.600
completely unannounced. They just had a tour

122
00:04:36.600 --> 00:04:38.840
group through. So there were two coaches

123
00:04:38.840 --> 00:04:41.160
which were just about to set off down this

124
00:04:41.880 --> 00:04:43.960
road that was slightly narrower than a coach.

125
00:04:44.520 --> 00:04:47.440
Ah, and an angle of 45 degrees. Uh, if

126
00:04:47.440 --> 00:04:49.560
we'd been, um, you know, if we'd Been half an

127
00:04:49.560 --> 00:04:51.360
hour later, we'd have probably not been able

128
00:04:51.360 --> 00:04:53.280
to get there because these damn, um, coaches

129
00:04:53.280 --> 00:04:55.600
going by. But when we arrived, um,

130
00:04:56.250 --> 00:04:57.770
you know, they just got rid of all the coach

131
00:04:57.930 --> 00:04:59.610
party, and we turned up and said, we're

132
00:04:59.610 --> 00:05:01.810
astronomers. Can, uh, we have a look? And

133
00:05:01.810 --> 00:05:03.250
they said, oh, no, no, you'll have to wait

134
00:05:03.250 --> 00:05:05.690
till the next tour. Uh, but we managed to get

135
00:05:05.690 --> 00:05:07.650
hold of the events manager who said, yeah,

136
00:05:07.650 --> 00:05:09.570
come in, let's talk about what we do. And all

137
00:05:09.570 --> 00:05:11.570
the rest of it. Had a great time. So that was

138
00:05:11.570 --> 00:05:14.050
very, very nice. Uh, and if she's a Space

139
00:05:14.050 --> 00:05:16.170
Nuts listener, um,

140
00:05:16.890 --> 00:05:19.130
nice to have met you, I think it was. Irena

141
00:05:19.130 --> 00:05:22.090
was her name. Greek version of that. And then

142
00:05:22.090 --> 00:05:24.530
came home, uh, and we came home last week and

143
00:05:24.530 --> 00:05:25.770
we're now jet lagged.

144
00:05:25.850 --> 00:05:27.930
Andrew Dunkley: Yeah, it's hard to get over jet lag. I think

145
00:05:27.930 --> 00:05:30.330
it's. It's an age thing, Fred. We take you.

146
00:05:30.330 --> 00:05:32.930
Professor Fred Watson: Could be. Except, um, my other half is a lot

147
00:05:32.930 --> 00:05:34.890
younger than I am and she's jet lagged too.

148
00:05:35.850 --> 00:05:38.250
Andrew Dunkley: Just goes a bit territory. Yeah.

149
00:05:38.250 --> 00:05:40.370
Well, I've got a golf story for you while

150
00:05:40.370 --> 00:05:42.330
you're away. I won it. I won a championship.

151
00:05:42.730 --> 00:05:45.690
Professor Fred Watson: You did? Yes. Well done. So it

152
00:05:45.690 --> 00:05:47.570
was, um, 17 years between.

153
00:05:47.570 --> 00:05:50.540
Andrew Dunkley: M. Ah, uh, well, no, I came, uh,

154
00:05:50.540 --> 00:05:53.540
in the state championship, So I came third

155
00:05:53.620 --> 00:05:56.030
on handicaps and top, uh,

156
00:05:56.340 --> 00:05:59.060
10. I finished ninth, I think, in the state

157
00:05:59.060 --> 00:06:00.800
championship. But then we had our own, um,

158
00:06:01.060 --> 00:06:03.100
championship at Dubbo Golf Club the other

159
00:06:03.100 --> 00:06:05.070
day, and I managed to win one of those. So,

160
00:06:05.070 --> 00:06:07.500
uh, that's very good. And then today, just

161
00:06:07.500 --> 00:06:10.340
before this, I played in the Pro Am because

162
00:06:10.340 --> 00:06:12.820
we're hosting the New South Wales Women's

163
00:06:12.820 --> 00:06:15.820
Open qualifying event. So. Played with

164
00:06:15.820 --> 00:06:18.130
a young lass from Melbourne. Her name is

165
00:06:18.290 --> 00:06:20.610
Piper. Um, Piper.

166
00:06:21.570 --> 00:06:24.280
Oh, I've gone blank. Um,

167
00:06:24.930 --> 00:06:27.170
anyway, come back to me, lovely, uh, young

168
00:06:27.170 --> 00:06:30.130
lady hits a really mean ball and wishing

169
00:06:30.130 --> 00:06:31.890
her well, hope she makes it to the New South

170
00:06:31.890 --> 00:06:34.490
Wales Open. And, um, I'll be watching her

171
00:06:34.490 --> 00:06:36.370
career closely, so. Very good.

172
00:06:37.170 --> 00:06:37.970
Professor Fred Watson: She beat you.

173
00:06:38.290 --> 00:06:40.930
Andrew Dunkley: Oh, uh, gosh, yes. Oh, uh, yes, well, it was

174
00:06:40.930 --> 00:06:42.570
a teams event today, so we were technically

175
00:06:42.570 --> 00:06:44.770
playing together, but she out drove Smoke

176
00:06:45.100 --> 00:06:47.460
Miles. Yes, Chicken Head is interesting. It

177
00:06:47.460 --> 00:06:50.340
is a long way, but, uh, just a pleasure. Just

178
00:06:50.340 --> 00:06:53.340
a delight. We had a good day. We

179
00:06:53.340 --> 00:06:54.940
should get down to it, Fred.

180
00:06:55.100 --> 00:06:56.980
Professor Fred Watson: Yeah, we should. Yes. We're not here to talk

181
00:06:56.980 --> 00:06:59.140
about golf, are we? Although, no, it doesn't

182
00:06:59.140 --> 00:06:59.740
seem that way.

183
00:06:59.820 --> 00:07:00.700
Andrew Dunkley: Not for a change.

184
00:07:01.170 --> 00:07:04.100
Um, our first story takes us back four

185
00:07:04.100 --> 00:07:06.140
and a half billion years when our neighboring

186
00:07:06.140 --> 00:07:09.020
world, known as Thea, smashed into

187
00:07:09.020 --> 00:07:11.380
Us and all hell broke loose, literally and

188
00:07:11.380 --> 00:07:14.300
figuratively. But, uh, a new study has

189
00:07:14.380 --> 00:07:16.300
just, uh, been released from the Max Planck

190
00:07:16.300 --> 00:07:18.480
Institute Institute that's uh, shed a bit of

191
00:07:18.480 --> 00:07:21.470
new light on the thea Earth relationship. Uh,

192
00:07:21.640 --> 00:07:24.480
it doesn't sound like this was what

193
00:07:24.480 --> 00:07:26.400
we originally thought. Just some m. Random

194
00:07:26.400 --> 00:07:27.960
thing coming in and hitting us.

195
00:07:29.080 --> 00:07:31.400
There's more to the story now.

196
00:07:32.200 --> 00:07:34.800
Professor Fred Watson: There is, yes. Um, sorry Andrew, you broke up

197
00:07:34.800 --> 00:07:36.850
there, but I think I know what you said. Uh,

198
00:07:37.630 --> 00:07:40.440
um, the story of Theia, of course, this has

199
00:07:40.440 --> 00:07:43.280
been the principal theory, uh, for the

200
00:07:43.280 --> 00:07:45.320
origin of the Moon for at least the last 60

201
00:07:45.320 --> 00:07:47.840
years. Uh, when the Apollo astronauts brought

202
00:07:47.840 --> 00:07:50.770
back, what was it, 380 kg of lunar

203
00:07:50.770 --> 00:07:52.970
rock and soil, which is still being analyzed.

204
00:07:53.680 --> 00:07:56.090
Um, so, uh, Theia is the

205
00:07:56.410 --> 00:07:59.220
hypothesized planet, uh,

206
00:07:59.770 --> 00:08:01.970
perhaps protoplanet is a better word because

207
00:08:01.970 --> 00:08:04.050
this was at a time when the solar system was

208
00:08:04.050 --> 00:08:06.650
still in its infancy 4 1/2 billion years ago.

209
00:08:07.450 --> 00:08:10.370
And this object, uh, basically clouted the

210
00:08:10.370 --> 00:08:13.370
Earth. Uh, and uh, we think that what

211
00:08:13.370 --> 00:08:15.770
happened in the aftermath of that collision

212
00:08:16.350 --> 00:08:19.110
was a cloud of debris raised from the surface

213
00:08:19.110 --> 00:08:21.230
of the Earth, went into orbit around the

214
00:08:21.230 --> 00:08:22.950
Earth and eventually coalesced to form the

215
00:08:22.950 --> 00:08:25.940
Moon. And so we've um,

216
00:08:25.950 --> 00:08:28.550
had puzzles which you and I have spoken about

217
00:08:28.550 --> 00:08:31.230
a number of times as to why it is.

218
00:08:32.189 --> 00:08:34.590
Well, let me step back a bit. The first

219
00:08:34.670 --> 00:08:37.590
theory was that because this is

220
00:08:37.590 --> 00:08:40.390
a smaller object hitting a bigger object, so

221
00:08:40.390 --> 00:08:42.070
theories thought to have been half the size

222
00:08:42.070 --> 00:08:44.780
of the Earth to get the dynamics right, um,

223
00:08:45.460 --> 00:08:47.980
the Earth's the bigger planet. Uh, what you

224
00:08:47.980 --> 00:08:50.580
would expect is that the debris cloud

225
00:08:50.660 --> 00:08:53.380
raised from the Earth when the collision

226
00:08:53.380 --> 00:08:55.380
happened would be mostly made of Theia

227
00:08:55.380 --> 00:08:57.700
material. Um, and

228
00:08:58.100 --> 00:09:00.420
that's been a puzzle for a long time because

229
00:09:01.220 --> 00:09:04.100
most of the lunar rocks and soil

230
00:09:04.340 --> 00:09:07.340
have the same isotopic signature

231
00:09:07.340 --> 00:09:09.940
which we've talked about before as well, the

232
00:09:09.940 --> 00:09:12.140
same isotopic signature as the Earth. They're

233
00:09:12.140 --> 00:09:15.140
identical, uh, to the Earth's rocks. And so

234
00:09:15.140 --> 00:09:17.840
that was seen as a puzzle about probably five

235
00:09:17.840 --> 00:09:19.640
years ago or so. We did cover it on space

236
00:09:19.640 --> 00:09:22.140
notes. Some Japanese researchers, um,

237
00:09:22.400 --> 00:09:24.160
figured out that if the Earth were still

238
00:09:24.160 --> 00:09:26.680
effectively molten at that time, if it was

239
00:09:26.680 --> 00:09:29.200
still a magma world when the collision

240
00:09:29.200 --> 00:09:32.160
happened, then you'd get, um, a moon that

241
00:09:32.160 --> 00:09:34.160
was formed largely of Earth

242
00:09:34.480 --> 00:09:37.360
compounds. So, um, what has

243
00:09:37.360 --> 00:09:40.160
now happened is that, um, a close

244
00:09:40.160 --> 00:09:43.120
examination has been made and as you write

245
00:09:43.120 --> 00:09:45.500
it, the Max Planck Institute for Solar System

246
00:09:45.500 --> 00:09:47.180
Research, along with the University of

247
00:09:47.180 --> 00:09:50.180
Chicago, um, they've really honed

248
00:09:50.180 --> 00:09:52.310
in on um,

249
00:09:53.060 --> 00:09:55.980
the exact, uh, details of

250
00:09:55.980 --> 00:09:58.900
the isotopes in rocks from the, uh, Earth,

251
00:09:59.140 --> 00:10:01.980
the Moon and meteorites, because they're part

252
00:10:01.980 --> 00:10:04.820
of the story too. And it's not just

253
00:10:05.140 --> 00:10:07.260
the sort of isotopes that have been looked at

254
00:10:07.260 --> 00:10:09.380
before. These are, uh, iron, chromium,

255
00:10:09.380 --> 00:10:11.600
molybdenum, molybdenum, ah,

256
00:10:11.640 --> 00:10:14.360
zirconium, all these,

257
00:10:14.440 --> 00:10:17.240
um, chemical elements. Their isotope

258
00:10:17.240 --> 00:10:20.120
data have been analyzed to

259
00:10:20.120 --> 00:10:23.080
look again at, uh, what we find, because,

260
00:10:23.480 --> 00:10:26.480
yes, we still find that the Earth and the

261
00:10:26.480 --> 00:10:29.320
Moon have very similar isotopic mixes.

262
00:10:29.680 --> 00:10:32.680
Uh, but then you can identify

263
00:10:32.920 --> 00:10:35.320
some slight differences that are

264
00:10:35.320 --> 00:10:38.120
attributed to be isotopes that have come

265
00:10:38.570 --> 00:10:41.530
from Theia itself. So they can tease out

266
00:10:41.850 --> 00:10:44.770
what was Theia and what was Earth. And it

267
00:10:44.770 --> 00:10:47.530
turns out that when you do that, you still

268
00:10:47.530 --> 00:10:50.010
get a similar picture, that the

269
00:10:50.090 --> 00:10:52.570
isotope ratios, uh, on

270
00:10:52.570 --> 00:10:55.370
Theia were probably very similar to what

271
00:10:55.370 --> 00:10:58.010
they are on Earth. Um, and

272
00:10:58.170 --> 00:10:59.290
that is

273
00:11:01.130 --> 00:11:03.850
symptomatic, if I can put it that way, of

274
00:11:04.840 --> 00:11:07.320
the Earth and Theia being born

275
00:11:07.560 --> 00:11:10.520
close together. And the reason why we think

276
00:11:10.520 --> 00:11:12.680
that is that when you look at the solar

277
00:11:12.680 --> 00:11:15.680
system, you find that these isotope ratios

278
00:11:15.680 --> 00:11:18.640
change depending on how far out you are from

279
00:11:18.640 --> 00:11:21.640
the Sun. So if you've got two planets

280
00:11:21.800 --> 00:11:24.440
with very similar isotope ratios, then

281
00:11:24.600 --> 00:11:27.440
what you can deduce from that is

282
00:11:27.440 --> 00:11:29.880
that they were orbiting the sun close

283
00:11:29.880 --> 00:11:32.360
together. And that makes complete sense

284
00:11:32.360 --> 00:11:34.200
because eventually they run into one another.

285
00:11:34.760 --> 00:11:37.750
Um, but what the outcome of this research

286
00:11:37.830 --> 00:11:40.830
is is that, uh, Theia was not just

287
00:11:40.830 --> 00:11:42.990
a random object that ran into the Earth in

288
00:11:42.990 --> 00:11:45.550
the early solar system. It was actually, if

289
00:11:45.550 --> 00:11:48.070
not a companion of Earth, but something in a

290
00:11:48.070 --> 00:11:50.590
very similar orbit. So, you know, maybe we

291
00:11:50.590 --> 00:11:53.550
had Mercury, Venus, Theia, uh, Earth, Mars as

292
00:11:53.550 --> 00:11:56.550
the rocky planets. Um, although that order,

293
00:11:56.550 --> 00:11:58.390
you know, I've made that up, but that's the

294
00:11:58.390 --> 00:12:00.870
kind of thing it's bringing, bringing

295
00:12:00.870 --> 00:12:03.430
Theia into the picture as something that

296
00:12:03.430 --> 00:12:05.830
would have been maybe, had it not collided

297
00:12:05.830 --> 00:12:08.250
with the Earth, it would have, uh, the ninth

298
00:12:08.250 --> 00:12:10.410
planet, uh, in the inner part of the solar

299
00:12:10.410 --> 00:12:13.210
system. So, uh, a very nice piece of work,

300
00:12:13.210 --> 00:12:15.330
some very, very careful studies there that I

301
00:12:15.330 --> 00:12:17.450
think has raised a lot of, um, interest in

302
00:12:17.450 --> 00:12:20.330
the planetary, uh, science

303
00:12:20.330 --> 00:12:20.690
community.

304
00:12:21.090 --> 00:12:23.680
Andrew Dunkley: Yeah, I suppose that sort of, uh,

305
00:12:23.680 --> 00:12:26.010
confirms that it was part of the solar system

306
00:12:26.010 --> 00:12:28.010
and not just some random thing passing

307
00:12:28.010 --> 00:12:30.530
through, knocking us over in the process.

308
00:12:31.090 --> 00:12:34.020
Professor Fred Watson: That's right, yeah. And, um, I should just

309
00:12:34.020 --> 00:12:36.780
explain how the Theia remnants have

310
00:12:36.780 --> 00:12:39.620
been. The Theia isotopes have been

311
00:12:39.620 --> 00:12:41.220
determined, and it's by looking at things

312
00:12:41.220 --> 00:12:42.980
that we find in the crust of the, uh, Earth,

313
00:12:43.540 --> 00:12:46.060
because we know that the heavy elements would

314
00:12:46.060 --> 00:12:48.340
have already sunk to the. To the center of

315
00:12:48.340 --> 00:12:50.740
the Earth when that collision happened. So

316
00:12:50.740 --> 00:12:52.260
when we think fine things like these

317
00:12:52.660 --> 00:12:55.620
molybdenum, iron, zirconium, things

318
00:12:55.620 --> 00:12:58.620
of that sort, um, we can infer

319
00:12:58.620 --> 00:13:00.660
that some of that actually came from Thee

320
00:13:00.660 --> 00:13:03.620
itself. And that's how the similarity

321
00:13:03.620 --> 00:13:06.140
has been deduced, along with looking at

322
00:13:06.140 --> 00:13:08.670
meteorite samples too. So you're right. Um,

323
00:13:09.740 --> 00:13:12.220
it is not something that's come from

324
00:13:12.540 --> 00:13:15.020
another solar system like our current visitor

325
00:13:15.020 --> 00:13:17.740
3i atlas. Uh, it's

326
00:13:17.740 --> 00:13:20.260
definitely a homegrown planet that, uh, we

327
00:13:20.260 --> 00:13:21.100
collided with.

328
00:13:21.420 --> 00:13:23.620
Andrew Dunkley: Okay. And now it's sort of a. Well, it's not

329
00:13:23.620 --> 00:13:25.740
a part of us. There's bits and pieces of it,

330
00:13:25.740 --> 00:13:28.220
but most, um, of it, it's sort of vanquished

331
00:13:28.220 --> 00:13:30.140
into the never never, didn't it?

332
00:13:30.740 --> 00:13:32.400
Professor Fred Watson: Yeah, a lot of it would have done. But, um,

333
00:13:32.420 --> 00:13:34.180
some of it's in the moon, some of it's on the

334
00:13:34.180 --> 00:13:34.820
Earth as well.

335
00:13:35.060 --> 00:13:35.540
Andrew Dunkley: Yeah.

336
00:13:35.620 --> 00:13:36.180
Professor Fred Watson: All right.

337
00:13:36.500 --> 00:13:39.260
Andrew Dunkley: So, yes, some new information from the

338
00:13:39.260 --> 00:13:41.940
Max Planck Institute about, uh, theia

339
00:13:42.420 --> 00:13:44.340
being a part of the inner solar system. If

340
00:13:44.340 --> 00:13:46.020
you'd like to read about that, uh, there's a

341
00:13:46.020 --> 00:13:46.579
really great

342
00:13:46.579 --> 00:13:49.220
article@scienceblog.com

343
00:13:49.780 --> 00:13:51.700
this is space Nuts with Andrew Dunkley and

344
00:13:51.700 --> 00:13:52.420
Professor Fred.

345
00:13:56.980 --> 00:13:57.940
Space Nuts.

346
00:13:58.380 --> 00:14:00.300
Uh, now to some really good news, Fred.

347
00:14:00.380 --> 00:14:03.180
40,000 near Earth asteroids have been

348
00:14:03.180 --> 00:14:05.940
discovered. Is that all? Is that all I could

349
00:14:05.940 --> 00:14:06.300
find?

350
00:14:07.180 --> 00:14:10.180
Professor Fred Watson: Well, yeah, I mean, for a long time

351
00:14:10.180 --> 00:14:12.780
we've known 39,999.

352
00:14:14.490 --> 00:14:16.660
Um, maybe not for very long because we're

353
00:14:16.660 --> 00:14:18.900
discovering asteroids at a very prolific rate

354
00:14:18.900 --> 00:14:20.700
at the moment. And that comes about because

355
00:14:20.700 --> 00:14:22.740
we've got such good technology discovering

356
00:14:22.740 --> 00:14:25.340
them. Um, and so, yes, this is a

357
00:14:25.340 --> 00:14:27.380
milestone that's been celebrated by esa, the

358
00:14:27.380 --> 00:14:28.700
European Space Agency.

359
00:14:29.070 --> 00:14:29.300
Andrew Dunkley: Uh.

360
00:14:31.160 --> 00:14:33.640
Professor Fred Watson: So they've put out a press release saying

361
00:14:33.880 --> 00:14:36.650
40,000 near Earth asteroids discovered. Uh,

362
00:14:36.650 --> 00:14:38.640
what do we mean by a near Earth asteroid?

363
00:14:38.640 --> 00:14:41.080
It's one that approaches within about

364
00:14:41.160 --> 00:14:43.880
45 million kilometers of

365
00:14:44.040 --> 00:14:47.000
the Earth. Uh, and that's nearly a third

366
00:14:47.000 --> 00:14:49.920
of the distance to the sun. So when you

367
00:14:49.920 --> 00:14:52.560
say near, it's a fairly

368
00:14:52.560 --> 00:14:55.480
relative term. It's one, uh, with objects

369
00:14:55.480 --> 00:14:57.800
that can get within that distance of Earth.

370
00:14:58.200 --> 00:15:00.240
Then there's another subset of those, though,

371
00:15:00.240 --> 00:15:02.560
that we tend to call PHAs,

372
00:15:02.960 --> 00:15:05.280
potentially hazardous asteroids.

373
00:15:05.900 --> 00:15:08.400
Uh, and, um, there are something like. I

374
00:15:08.400 --> 00:15:09.760
think if I remember rightly, it's about two

375
00:15:09.760 --> 00:15:12.120
and a half thousand of those. And they're the

376
00:15:12.120 --> 00:15:14.480
ones whose orbits cross the orbit of the

377
00:15:14.480 --> 00:15:16.960
Earth. Um, and so they are potentially

378
00:15:16.960 --> 00:15:18.760
hazardous. And they're the ones that we keep

379
00:15:18.760 --> 00:15:20.840
an eye on all the time, uh,

380
00:15:21.200 --> 00:15:23.680
monitoring where they are, uh, and

381
00:15:24.320 --> 00:15:27.040
checking forward, uh, in computers.

382
00:15:27.200 --> 00:15:29.160
Once we know their orbits, checking forward

383
00:15:29.160 --> 00:15:31.160
as to whether there's any likelihood of

384
00:15:31.160 --> 00:15:33.380
collision. The good news is is that there's

385
00:15:33.380 --> 00:15:35.780
not. Uh, over the next hundred years or so

386
00:15:35.780 --> 00:15:38.540
we've got a fairly clean sweep of things.

387
00:15:38.620 --> 00:15:40.940
At least things bigger than about 140

388
00:15:41.340 --> 00:15:44.220
meters across and they can be very dangerous.

389
00:15:44.780 --> 00:15:47.100
They could be city destroyers or even state

390
00:15:47.100 --> 00:15:50.020
destroyers. So um, keeping an eye on

391
00:15:50.020 --> 00:15:52.580
those is important. Uh, and I think the

392
00:15:52.580 --> 00:15:55.580
reason why ESA has highlighted this is

393
00:15:55.580 --> 00:15:58.540
because it does highlight the whole regime

394
00:15:58.540 --> 00:16:01.340
of planetary defense. Uh, that's a very

395
00:16:01.340 --> 00:16:04.220
active area in astronomy and um,

396
00:16:04.360 --> 00:16:06.630
m actually almost civil defense as well. It's

397
00:16:06.630 --> 00:16:08.830
not just astronomy that is concerned with

398
00:16:08.830 --> 00:16:11.150
that. I think I probably mentioned before

399
00:16:11.150 --> 00:16:13.190
when I was at the IAU a couple of years ago,

400
00:16:13.750 --> 00:16:16.330
I actually got myself into a meeting uh,

401
00:16:16.330 --> 00:16:18.870
which was the Planetary Defense Agency,

402
00:16:19.830 --> 00:16:22.590
uh talking about uh, their next activities

403
00:16:22.590 --> 00:16:25.160
which included uh, um,

404
00:16:25.510 --> 00:16:28.350
a mock threatened uh, planetary asteroid

405
00:16:28.350 --> 00:16:30.830
impact and how all the services would deal

406
00:16:30.830 --> 00:16:33.430
with that. And from the astronomers

407
00:16:33.510 --> 00:16:36.160
right to the, the people who get the fire

408
00:16:36.160 --> 00:16:38.200
engines out to put out the fires and things

409
00:16:38.200 --> 00:16:40.240
of that sort. It's a very interesting thing

410
00:16:40.240 --> 00:16:42.640
to watch. So uh, what it did was

411
00:16:42.880 --> 00:16:45.200
reassured me that we're in quite good hands.

412
00:16:45.610 --> 00:16:48.320
Uh but yeah, the bottom line, 40 uh, thousand

413
00:16:48.480 --> 00:16:51.360
near Earth asteroids known. Uh, the

414
00:16:51.360 --> 00:16:53.450
good news is always that the big ones which

415
00:16:53.450 --> 00:16:55.240
uh, are the most dangerous ones, they're the

416
00:16:55.240 --> 00:16:58.200
easiest to find. And we think we know pretty

417
00:16:58.200 --> 00:17:01.120
well all of the asteroids bigger

418
00:17:01.120 --> 00:17:03.280
than a uh, kilometer which would be

419
00:17:03.750 --> 00:17:06.700
um, dinosaur killers, they would wipe out,

420
00:17:06.700 --> 00:17:09.020
you know, there'd be mass extinction objects.

421
00:17:09.350 --> 00:17:12.300
Uh, we think one of those hits the earth

422
00:17:12.460 --> 00:17:15.350
roughly every 200 million years. It's uh,

423
00:17:15.460 --> 00:17:18.220
66 million years ago since the last one did,

424
00:17:18.220 --> 00:17:20.740
which was, was the one that wiped out we, the

425
00:17:20.740 --> 00:17:23.460
dinosaurs. Um, since then though we've

426
00:17:23.460 --> 00:17:25.860
learned a lot about, not only about asteroids

427
00:17:25.860 --> 00:17:28.860
but about how we might deflect uh an

428
00:17:28.860 --> 00:17:31.660
asteroid if uh, if there was

429
00:17:31.660 --> 00:17:33.340
one that could be shown to be on a collision

430
00:17:33.340 --> 00:17:35.940
course with Earth. And you and I have talked

431
00:17:35.940 --> 00:17:38.660
at length and with great enthusiasm about the

432
00:17:38.660 --> 00:17:41.420
dart mission back in 2022 and the double

433
00:17:41.420 --> 00:17:44.370
asteroid redirection test, a uh,

434
00:17:44.460 --> 00:17:47.180
really well put together experiment by NASA

435
00:17:47.420 --> 00:17:50.420
which succeeded uh, in changing the

436
00:17:50.420 --> 00:17:52.860
orbit of a little world called Dimorphos.

437
00:17:53.220 --> 00:17:56.060
Uh, and that's great news because we know

438
00:17:56.060 --> 00:17:58.500
that it's now possible to do that. And just

439
00:17:58.500 --> 00:18:01.370
as a postscript to this story, um, ESA

440
00:18:01.760 --> 00:18:04.520
currently has a spacecraft called Hera H E R

441
00:18:04.520 --> 00:18:07.280
A on um, its way to Dimorphos

442
00:18:07.520 --> 00:18:10.240
to check out what the result of that impact

443
00:18:10.320 --> 00:18:12.240
was. It's going to study that little world,

444
00:18:12.640 --> 00:18:15.640
look at the debris that was raised by the

445
00:18:15.640 --> 00:18:18.480
impact, get uh, a much better idea of whether

446
00:18:19.120 --> 00:18:21.160
it really is just a rubble pile, which we

447
00:18:21.160 --> 00:18:24.080
think it probably is, and just uh, learn more

448
00:18:24.080 --> 00:18:26.940
about what an impact by uh,

449
00:18:27.120 --> 00:18:29.800
a spacecraft does to an asteroid. Because

450
00:18:29.800 --> 00:18:31.880
that's the key thing. If we're going to have

451
00:18:31.880 --> 00:18:34.060
to save ourselves one day by, by doing this.

452
00:18:34.220 --> 00:18:36.300
We want to know as much about it as possible.

453
00:18:36.540 --> 00:18:38.940
And if I remember rightly, Hera will reach

454
00:18:39.020 --> 00:18:41.300
Dimorphous. I think it's late next year. I

455
00:18:41.300 --> 00:18:42.700
think it's towards the end of next year.

456
00:18:43.340 --> 00:18:46.220
Andrew Dunkley: Very exciting. Yeah, nice to get a follow up

457
00:18:46.220 --> 00:18:49.020
on that story too. Yeah. Um, and of course

458
00:18:49.020 --> 00:18:51.860
this is not the end of finding these kinds of

459
00:18:51.860 --> 00:18:54.420
things because, uh, the Vera C. Rubin

460
00:18:54.420 --> 00:18:55.500
Observatory in Chile,

461
00:18:57.100 --> 00:18:59.340
it's not its primary role, but it will be

462
00:19:00.000 --> 00:19:02.840
looking for other, um, Near Earth

463
00:19:02.840 --> 00:19:05.520
objects. And they expect it to find

464
00:19:05.520 --> 00:19:06.880
tens of thousands of them.

465
00:19:06.880 --> 00:19:09.280
Professor Fred Watson: Absolutely, that's right. By this time next

466
00:19:09.280 --> 00:19:11.600
year we might be Talking about, uh, 80,000 or

467
00:19:11.600 --> 00:19:14.200
100,000 near Earth asteroids

468
00:19:14.200 --> 00:19:16.560
discovered. And of course again that's a good

469
00:19:16.560 --> 00:19:18.400
news story because as soon as you discover

470
00:19:18.400 --> 00:19:20.360
one of these things, first thing you do is

471
00:19:20.360 --> 00:19:23.240
put its orbital elements into the computer

472
00:19:23.240 --> 00:19:26.000
grind away, look at its trajectory in the

473
00:19:26.000 --> 00:19:28.720
future. And that is all done automatically.

474
00:19:28.720 --> 00:19:31.610
And if there is a need, uh, the system will

475
00:19:31.610 --> 00:19:33.690
raise alerts that there could be a collision,

476
00:19:34.130 --> 00:19:36.810
uh, in a certain window in the future. So

477
00:19:37.070 --> 00:19:39.890
um, that whole process is really part of

478
00:19:39.890 --> 00:19:41.650
planetary defense. It's what's safeguarding

479
00:19:41.650 --> 00:19:43.050
us from the asteroid hazard.

480
00:19:43.370 --> 00:19:46.250
Andrew Dunkley: Yeah, yeah. Um, I read a

481
00:19:46.250 --> 00:19:48.570
story the other day, I think Vera C. Rubin,

482
00:19:48.630 --> 00:19:51.370
um, had had it took its first

483
00:19:51.370 --> 00:19:53.610
picture, first light. I think they refer to

484
00:19:53.610 --> 00:19:55.690
it as in, was it June or July this year?

485
00:19:56.010 --> 00:19:57.330
Professor Fred Watson: Yeah, I think it's about then.

486
00:19:57.330 --> 00:20:00.190
Andrew Dunkley: Yeah, yeah. Uh, so we're almost at

487
00:20:00.190 --> 00:20:02.950
the pointy end of that, um, observatory

488
00:20:02.950 --> 00:20:03.910
kicking into action.

489
00:20:04.310 --> 00:20:06.110
Professor Fred Watson: That's right. If I remember rightly, I might

490
00:20:06.110 --> 00:20:07.630
have these figures slightly wrong, but it was

491
00:20:07.630 --> 00:20:10.110
something like. Was it a 10 hour set of

492
00:20:10.110 --> 00:20:11.790
observations they took and they discovered

493
00:20:11.790 --> 00:20:13.989
more than a thousand asteroids in that

494
00:20:13.990 --> 00:20:16.070
period. So imagine what it's going to be

495
00:20:16.070 --> 00:20:18.870
like. This thing looks at the entire southern

496
00:20:18.870 --> 00:20:21.310
sky every three nights. That's incredibly

497
00:20:21.310 --> 00:20:23.270
remarkable. Yeah, it's quite, yeah.

498
00:20:23.310 --> 00:20:26.290
Andrew Dunkley: Um, like we, we were so blessed to be able to

499
00:20:26.290 --> 00:20:28.920
get so much information out of, um.

500
00:20:30.850 --> 00:20:33.770
My brain's not working today. Um, the

501
00:20:33.770 --> 00:20:35.890
other observatory, the one that's out on in

502
00:20:35.890 --> 00:20:37.210
the L2.

503
00:20:37.210 --> 00:20:39.210
Professor Fred Watson: Oh yeah, you mean the James Webb Telescope.

504
00:20:39.210 --> 00:20:40.930
Andrew Dunkley: James Webb. Gosh, why Couldn't I think of

505
00:20:40.930 --> 00:20:43.810
that? But, um, working side by

506
00:20:43.810 --> 00:20:45.930
side with VC Rubin, this is just going to

507
00:20:45.930 --> 00:20:47.250
open up a whole new.

508
00:20:47.970 --> 00:20:50.930
Professor Fred Watson: Yep, that's right. At least a new registry of

509
00:20:50.930 --> 00:20:52.670
new discoveries. Yeah, yeah. Very, very

510
00:20:52.670 --> 00:20:53.110
exciting.

511
00:20:54.230 --> 00:20:56.550
Andrew Dunkley: If you would like to read about those 40,000

512
00:20:56.630 --> 00:20:59.350
Near Earth Objects, if you

513
00:20:59.350 --> 00:21:01.310
really, you know, you can go to a horror

514
00:21:01.310 --> 00:21:03.660
movie instead, probably much more fun. But,

515
00:21:03.660 --> 00:21:06.110
um, 40,000 near earth objects, you can do

516
00:21:06.110 --> 00:21:08.550
that through the European Space Agency

517
00:21:08.550 --> 00:21:08.870
website.

518
00:21:11.590 --> 00:21:13.990
Professor Fred Watson: Okay. We checked all four systems and being

519
00:21:13.990 --> 00:21:15.430
with a girl space nats.

520
00:21:15.910 --> 00:21:17.990
Andrew Dunkley: Now this, this is a story that really excites

521
00:21:17.990 --> 00:21:20.400
me because, because, um, we've talked about

522
00:21:20.400 --> 00:21:23.150
this so many times, but, um,

523
00:21:23.320 --> 00:21:26.200
this story I saw pop up last weekend

524
00:21:26.440 --> 00:21:29.240
and we have been talking so much

525
00:21:29.240 --> 00:21:30.840
about the potential for life

526
00:21:31.640 --> 00:21:34.479
elsewhere. Haven't found it yet, but the

527
00:21:34.479 --> 00:21:37.040
signs are starting to build, particularly

528
00:21:37.040 --> 00:21:39.720
within our own solar system. And

529
00:21:40.040 --> 00:21:41.480
this particular story

530
00:21:42.920 --> 00:21:45.920
is one again where we have taken a bit of

531
00:21:45.920 --> 00:21:48.330
old data and reanalyzed it.

532
00:21:49.040 --> 00:21:51.040
And this involves the Cassini

533
00:21:51.520 --> 00:21:53.920
mission, uh, which has been taking

534
00:21:54.160 --> 00:21:56.960
samples of the eruptions

535
00:21:57.360 --> 00:22:00.120
from Enceladus. And what they've

536
00:22:00.120 --> 00:22:02.540
discovered is very, very, uh,

537
00:22:02.640 --> 00:22:03.200
exciting.

538
00:22:04.399 --> 00:22:06.960
Professor Fred Watson: It is, uh, that's right. And uh, yes,

539
00:22:06.960 --> 00:22:09.840
Cassini, you know, uh, was active, if I

540
00:22:09.840 --> 00:22:12.640
remember rightly, between 2000

541
00:22:13.040 --> 00:22:15.960
and I think. Was it 2004? Yes,

542
00:22:15.960 --> 00:22:18.960
and 2017. So that was the period when

543
00:22:19.200 --> 00:22:22.180
Cassini collecting its data. And as you've

544
00:22:22.180 --> 00:22:24.860
just said, we're still learning things from

545
00:22:24.860 --> 00:22:27.260
those data. Uh, and in particular

546
00:22:27.900 --> 00:22:30.780
what has been identified is some

547
00:22:30.780 --> 00:22:33.260
previously unknown organic

548
00:22:33.340 --> 00:22:35.940
chemicals in the ice grains that

549
00:22:35.940 --> 00:22:38.540
Cassini flew through, which are

550
00:22:38.540 --> 00:22:40.860
erupting, as you said, from the ice

551
00:22:40.940 --> 00:22:43.670
geysers near the southern, uh,

552
00:22:43.670 --> 00:22:46.300
pole, the south pole of enceladus, that

553
00:22:46.300 --> 00:22:49.180
little 500 kilometer diameter world which

554
00:22:49.180 --> 00:22:51.800
is, uh, one of Saturn's moons with the

555
00:22:51.800 --> 00:22:53.840
structure that we think is fairly common out

556
00:22:53.840 --> 00:22:56.720
in that part of the solar system. Ah, a rocky

557
00:22:56.720 --> 00:22:59.200
body overlaying with a liquid ocean

558
00:22:59.360 --> 00:23:01.760
with ice on top of that. And the pressure of

559
00:23:01.760 --> 00:23:03.920
the ice is what's keeping that ocean liquid,

560
00:23:03.920 --> 00:23:06.840
along with the squeezing and squashing of the

561
00:23:06.840 --> 00:23:09.600
rocky part of the body by the,

562
00:23:09.890 --> 00:23:12.280
uh, tidal forces exerted by the giant planet

563
00:23:12.280 --> 00:23:14.960
Saturn, uh, next door. And Saturn, by the

564
00:23:14.960 --> 00:23:17.320
way, um, we've just gone through its ring

565
00:23:17.320 --> 00:23:19.230
plane. So Saturn. If you looked at Saturn

566
00:23:19.230 --> 00:23:21.510
through a telescope tonight or anytime within

567
00:23:21.510 --> 00:23:23.070
the next couple of weeks, you won't see any

568
00:23:23.070 --> 00:23:25.230
sign of the rings because we're the edge onto

569
00:23:25.230 --> 00:23:25.470
us.

570
00:23:25.470 --> 00:23:26.430
Andrew Dunkley: Oh, okay.

571
00:23:26.430 --> 00:23:29.190
Professor Fred Watson: Yep. Just a little aside there. Um, so,

572
00:23:29.730 --> 00:23:31.830
uh, what has happened is

573
00:23:32.390 --> 00:23:35.350
that, uh, we've known about

574
00:23:35.430 --> 00:23:38.390
these organic chemicals in

575
00:23:38.390 --> 00:23:41.390
Ice grains, which we know come

576
00:23:41.390 --> 00:23:43.910
from Enceladus because they actually

577
00:23:43.990 --> 00:23:46.810
feed into the outer ring of Saturn,

578
00:23:46.810 --> 00:23:48.410
something called the E ring, which is a very

579
00:23:48.410 --> 00:23:51.130
diffuse ring. And we know that the

580
00:23:51.210 --> 00:23:53.250
material in that ring, the ice crystals in

581
00:23:53.250 --> 00:23:56.010
that E ring, actually come from the south

582
00:23:56.010 --> 00:23:59.010
pole of Enceladus. And those

583
00:23:59.010 --> 00:24:02.010
have been well analyzed, um, by Cassini

584
00:24:02.010 --> 00:24:05.010
and also by other observations. And

585
00:24:05.010 --> 00:24:07.410
so it was known that there were organics in

586
00:24:07.410 --> 00:24:09.770
there. But the question was

587
00:24:10.170 --> 00:24:12.720
these ice crystals may have been in

588
00:24:12.720 --> 00:24:14.520
orbit, they may have been in space for

589
00:24:14.520 --> 00:24:16.760
centuries. And so their

590
00:24:17.480 --> 00:24:19.960
chemical structure might well have been

591
00:24:20.440 --> 00:24:23.280
modified first of all by the sun's

592
00:24:23.280 --> 00:24:25.960
ultraviolet radiation, which tends to change

593
00:24:25.960 --> 00:24:28.800
chemistry. Uh, and the solar

594
00:24:28.800 --> 00:24:30.880
wind, the wind of subatomic particles that

595
00:24:30.880 --> 00:24:33.680
comes from the sun, that too can change the

596
00:24:33.680 --> 00:24:35.620
chemistry of particles, uh,

597
00:24:36.440 --> 00:24:39.000
grains of, um, ice

598
00:24:39.720 --> 00:24:42.480
with their organics on them, the organic

599
00:24:42.480 --> 00:24:44.460
chemicals, uh, it can, can change their

600
00:24:44.460 --> 00:24:46.820
chemistry. And so there was always a question

601
00:24:47.300 --> 00:24:50.060
whether these quite complex organic

602
00:24:50.060 --> 00:24:52.940
chemicals that were identified, uh, in

603
00:24:52.940 --> 00:24:55.940
the E ring, uh, whether they are

604
00:24:55.940 --> 00:24:58.740
telling you that that's how the

605
00:24:58.740 --> 00:25:00.820
ice crystals were when they came, when they

606
00:25:00.820 --> 00:25:03.300
were spat out from M. Cassini's south

607
00:25:03.300 --> 00:25:06.100
pole, um, it puts doubt on it.

608
00:25:06.180 --> 00:25:08.980
And so what this new analysis

609
00:25:08.980 --> 00:25:11.770
does is looks back to one of the

610
00:25:11.770 --> 00:25:14.650
fly throughs of, uh, Cassini

611
00:25:14.650 --> 00:25:16.810
through the ice plumes back in

612
00:25:16.810 --> 00:25:19.570
2008. Uh, Cassini

613
00:25:19.570 --> 00:25:21.930
flew through the plume at about, um, 18

614
00:25:21.930 --> 00:25:24.690
kilometers per second at Ah, a height of

615
00:25:24.690 --> 00:25:27.410
about 20 kilometers above the surface of

616
00:25:27.410 --> 00:25:29.770
Cassini. And so the

617
00:25:30.170 --> 00:25:32.410
ice crystals that it passed through,

618
00:25:33.280 --> 00:25:36.010
um, only a few minutes earlier were actually

619
00:25:36.010 --> 00:25:38.330
water in the ocean of

620
00:25:38.490 --> 00:25:41.130
Enceladus. So these are fresh

621
00:25:41.450 --> 00:25:44.250
crystals of ice straight from the ocean. In

622
00:25:44.250 --> 00:25:45.250
other words, they're, you know, they're

623
00:25:45.250 --> 00:25:48.050
effectively samples of the ocean water. And

624
00:25:48.050 --> 00:25:50.850
what they've succeeded in showing, uh, what

625
00:25:50.850 --> 00:25:52.690
the scientists who've done this succeeded in

626
00:25:52.690 --> 00:25:55.330
showing is that the chemistry is still there.

627
00:25:55.330 --> 00:25:58.010
The, the organic, the complex organics

628
00:25:58.330 --> 00:26:00.490
are uh, there in this fresh

629
00:26:01.080 --> 00:26:03.120
ocean spray, as they call it. I love that

630
00:26:03.120 --> 00:26:05.880
idea. It's an ocean spray, uh, but it's ice

631
00:26:05.880 --> 00:26:08.840
crystals and there's a whole, you

632
00:26:08.840 --> 00:26:11.560
know, a whole list of um, things

633
00:26:11.640 --> 00:26:14.600
like esters, aromatics, heteroatom

634
00:26:14.600 --> 00:26:17.040
bearing organics. These are chemical terms

635
00:26:17.040 --> 00:26:19.840
that, um, I'm not that familiar with

636
00:26:19.840 --> 00:26:22.360
because chemistry was not my strong point.

637
00:26:22.940 --> 00:26:25.520
Uh, but these chemicals are, ah, yes, they

638
00:26:25.520 --> 00:26:27.800
are there in the ocean of Enceladus.

639
00:26:28.280 --> 00:26:31.040
And what that has done is raised

640
00:26:31.200 --> 00:26:33.520
again the possibility that living organisms

641
00:26:33.520 --> 00:26:36.480
might exist in that ocean. Uh, and that

642
00:26:36.640 --> 00:26:39.080
because these chemicals are, as we keep on

643
00:26:39.080 --> 00:26:42.080
saying, the building blocks of life uh, so

644
00:26:42.160 --> 00:26:44.160
just maybe there's something swimming around

645
00:26:44.160 --> 00:26:46.520
in the ocean of Enceladus that we are yet to

646
00:26:46.520 --> 00:26:46.960
discover.

647
00:26:47.600 --> 00:26:49.720
Andrew Dunkley: Yes. And wouldn't it be exciting? And, uh,

648
00:26:49.840 --> 00:26:52.360
hopefully in the not too distant future we'll

649
00:26:52.360 --> 00:26:54.690
be able to confirm it. Um,

650
00:26:55.280 --> 00:26:56.920
I think people are starting to get very

651
00:26:56.920 --> 00:26:58.720
confident about the possibility, though.

652
00:26:59.210 --> 00:26:59.490
Professor Fred Watson: Yep.

653
00:26:59.490 --> 00:27:02.450
Andrew Dunkley: Yeah, that's right. Fingers crossed. But, uh,

654
00:27:02.450 --> 00:27:04.170
yeah, the signs are starting to really build.

655
00:27:04.170 --> 00:27:06.730
And even though it'll be

656
00:27:06.890 --> 00:27:09.050
probably one of the most exciting things ever

657
00:27:09.050 --> 00:27:11.850
discovered, should we succeed in finding

658
00:27:11.850 --> 00:27:14.410
evidence of life elsewhere, we

659
00:27:14.650 --> 00:27:17.050
also probably shouldn't be surprised because

660
00:27:17.770 --> 00:27:20.770
water, we now know is prolific

661
00:27:20.770 --> 00:27:23.510
throughout the universe. We know there are,

662
00:27:23.510 --> 00:27:26.490
uh, probably exoplanets orbiting almost

663
00:27:26.490 --> 00:27:29.430
every star in the universe. Stands to

664
00:27:29.430 --> 00:27:32.230
reason that somewhere, somewhere out there,

665
00:27:32.390 --> 00:27:34.950
there's. There's got to be some form of life,

666
00:27:34.950 --> 00:27:37.510
even if it's only microbial, but.

667
00:27:38.150 --> 00:27:41.150
Professor Fred Watson: Or krill. Krill would be

668
00:27:41.150 --> 00:27:43.670
exciting. Green slime is what we're likely to

669
00:27:43.670 --> 00:27:46.150
find. I think green slime. Green slime will

670
00:27:46.150 --> 00:27:49.150
do. Green slime would do it. That's right. It

671
00:27:49.150 --> 00:27:49.710
would indeed.

672
00:27:49.710 --> 00:27:51.990
Andrew Dunkley: Indeed. If you'd like to read up on that

673
00:27:51.990 --> 00:27:54.710
story about the latest from Enceladus,

674
00:27:55.030 --> 00:27:57.350
you can find it in the journal Nature

675
00:27:57.430 --> 00:27:58.310
Astronomy.

676
00:28:01.190 --> 00:28:02.230
Space Butts.

677
00:28:02.790 --> 00:28:05.150
One last story in this episode, Fred, and

678
00:28:05.150 --> 00:28:07.990
it's a bit of an update on 3i Atlas the

679
00:28:07.990 --> 00:28:10.630
XO comet that is currently,

680
00:28:11.030 --> 00:28:13.790
um, doing its thing. It's doing whatever it

681
00:28:13.790 --> 00:28:16.200
wants, really. Um, but, um,

682
00:28:16.550 --> 00:28:19.190
it's, uh. It's. It's sort of reappeared. And

683
00:28:19.190 --> 00:28:21.030
they're getting some great pictures of it,

684
00:28:21.030 --> 00:28:23.840
not only from Earth, but from Mars. And,

685
00:28:24.670 --> 00:28:27.600
um. Some of these photos are extraordinary.

686
00:28:28.400 --> 00:28:30.640
Professor Fred Watson: Yes, they are. When you look at them, they're

687
00:28:30.880 --> 00:28:32.800
a little bit underwhelming until you realize

688
00:28:32.800 --> 00:28:35.640
that they've been taken by telescopes not on

689
00:28:35.640 --> 00:28:38.440
Earth, but, um, in one case on the surface of

690
00:28:38.440 --> 00:28:41.200
Mars. But, um. Uh, also, uh, from

691
00:28:41.200 --> 00:28:44.160
Mars orbit. Uh, and there's a little bit of

692
00:28:44.160 --> 00:28:46.400
a story to this because these images were

693
00:28:46.400 --> 00:28:49.210
taken, um, when, um,

694
00:28:50.160 --> 00:28:52.990
the interstellar comet 3I Atlas uh,

695
00:28:53.120 --> 00:28:56.060
made its closest passage, uh,

696
00:28:56.960 --> 00:28:59.840
closest flyby of Mars, basically, uh, 30

697
00:28:59.840 --> 00:29:02.120
million kilometers of Mars. That's quite a

698
00:29:02.120 --> 00:29:04.560
close approach compared with, um, the

699
00:29:04.560 --> 00:29:07.280
distances that we are from it on

700
00:29:07.280 --> 00:29:09.680
Earth. Uh, and that took place

701
00:29:10.080 --> 00:29:12.640
actually nearly two months ago, uh, in early

702
00:29:12.640 --> 00:29:15.480
October. Um, but what's held up the

703
00:29:15.480 --> 00:29:18.460
release of the, uh, of the images, uh,

704
00:29:18.460 --> 00:29:21.240
is the US Um government shutdown, which,

705
00:29:21.240 --> 00:29:24.040
yeah, prevented these images being

706
00:29:24.280 --> 00:29:25.000
situated.

707
00:29:25.320 --> 00:29:27.960
Andrew Dunkley: He spoke about that at length. Oh, getting

708
00:29:27.960 --> 00:29:29.040
back previous episode.

709
00:29:29.040 --> 00:29:31.320
Professor Fred Watson: So, yeah, I think, yes, we're pretty.

710
00:29:31.320 --> 00:29:34.200
Andrew Dunkley: Well squared away on the issue um, but he

711
00:29:34.200 --> 00:29:36.800
had colleagues that was so badly affected by

712
00:29:36.800 --> 00:29:39.800
that because, yes, the, um, you know, well,

713
00:29:39.800 --> 00:29:42.160
basically no income for as long as the

714
00:29:42.160 --> 00:29:43.040
shutdown existed.

715
00:29:43.040 --> 00:29:44.760
Professor Fred Watson: It's very, very difficult situation.

716
00:29:44.760 --> 00:29:47.710
Andrew Dunkley: But, yeah, so we, we know why

717
00:29:47.710 --> 00:29:49.710
NASA couldn't do anything at the time.

718
00:29:50.110 --> 00:29:52.190
Professor Fred Watson: Yeah, so that's right.

719
00:29:52.800 --> 00:29:55.670
Um, but we now have these images revealed now

720
00:29:55.670 --> 00:29:57.630
that things are up and running again. And

721
00:29:57.710 --> 00:30:00.190
perhaps the best one has come

722
00:30:00.350 --> 00:30:02.830
from the, um, HiRise

723
00:30:03.470 --> 00:30:06.110
camera on board Mars Reconnaissance Orbiter.

724
00:30:06.590 --> 00:30:09.590
And that's quite a detailed image of Comet

725
00:30:09.590 --> 00:30:12.550
3I Atlas with its short

726
00:30:12.550 --> 00:30:15.550
tail and its coma. That's the region around

727
00:30:15.550 --> 00:30:18.310
the nucleus where, uh, material is outgassing

728
00:30:18.310 --> 00:30:21.260
and, and um, shining because of, um,

729
00:30:21.260 --> 00:30:22.570
excitation by the sun.

730
00:30:24.650 --> 00:30:27.130
There's some interesting images from,

731
00:30:27.650 --> 00:30:30.490
uh, the Maven, uh, spacecraft

732
00:30:30.490 --> 00:30:33.370
as well, which, uh, has cameras on looking

733
00:30:33.370 --> 00:30:35.610
in the ultraviolet. And in fact it's got a

734
00:30:35.610 --> 00:30:38.450
spectrometer on that allows you to, uh, split

735
00:30:38.450 --> 00:30:41.200
the light up into its component colors. Uh,

736
00:30:41.610 --> 00:30:44.250
so we see the glow of hydrogen actually from,

737
00:30:44.790 --> 00:30:47.720
uh, from 3i Atlas, uh, photographed by the

738
00:30:47.720 --> 00:30:50.200
Maven spacecraft

739
00:30:50.200 --> 00:30:52.930
cameras and the Mastcam camera, uh,

740
00:30:53.520 --> 00:30:56.520
on the, uh, it's Mastcam

741
00:30:56.520 --> 00:30:59.240
Z, it's called on Perseverance on the

742
00:30:59.240 --> 00:31:01.600
surface of Mars, actually managed to capture

743
00:31:01.920 --> 00:31:04.720
a very, very faint image, uh, of

744
00:31:04.870 --> 00:31:07.720
uh, three Eye Atlas against a background of

745
00:31:07.720 --> 00:31:10.090
stars. It's faint because that's. That

746
00:31:10.330 --> 00:31:13.090
mastcam was never designed to do

747
00:31:13.090 --> 00:31:15.890
astronomy. It's all designed to navigate on

748
00:31:15.890 --> 00:31:18.010
the surface of Mars. But yet it's managed to

749
00:31:18.010 --> 00:31:20.450
catch a picture, uh, by being pointed

750
00:31:20.450 --> 00:31:23.090
upwards, obviously, uh, at this

751
00:31:23.090 --> 00:31:25.929
celestial visitor. So the hope is that as

752
00:31:25.929 --> 00:31:28.490
these images are analyzed, Andrew, we'll find

753
00:31:28.490 --> 00:31:31.330
out more about 3i Atlas, maybe even to

754
00:31:31.330 --> 00:31:34.050
get a good measurement of how big its nucleus

755
00:31:34.050 --> 00:31:36.970
is, the icy component that gives rise to

756
00:31:37.690 --> 00:31:40.460
all this luminosity. Um, the last

757
00:31:40.460 --> 00:31:42.580
I heard was that the thinking was it was in

758
00:31:42.580 --> 00:31:45.340
the region of 20 km across, which is large

759
00:31:45.340 --> 00:31:47.780
for a comet nucleus. Uh, but I think the jury

760
00:31:47.780 --> 00:31:50.300
is probably still out on that. Um, might find

761
00:31:50.300 --> 00:31:51.580
more from these measurements.

762
00:31:52.060 --> 00:31:54.700
Andrew Dunkley: So how much longer will 3i Atlas be

763
00:31:54.780 --> 00:31:55.980
in our vicinity?

764
00:31:58.460 --> 00:32:00.620
Professor Fred Watson: Quite a while. Uh, it's not. You know,

765
00:32:02.300 --> 00:32:04.860
I, um, think it passes closest to Earth

766
00:32:05.350 --> 00:32:07.790
this month, if I remember rightly. Um, and

767
00:32:07.790 --> 00:32:10.670
then we'll be receding. Uh, it has passed

768
00:32:10.670 --> 00:32:12.910
its closest to the sun, and so it certainly

769
00:32:12.910 --> 00:32:14.510
brightened up when it did that, which is what

770
00:32:14.510 --> 00:32:17.230
you expect as it leaves the

771
00:32:17.230 --> 00:32:19.910
solar system. We'll continue to track it with

772
00:32:20.150 --> 00:32:22.030
the world's big telescopes. Probably the

773
00:32:22.030 --> 00:32:23.990
James Webb will have a few more looks at it.

774
00:32:24.330 --> 00:32:27.190
Uh, and so, um, I Think we're going to

775
00:32:27.190 --> 00:32:28.950
be observing it for several months yet.

776
00:32:29.670 --> 00:32:31.990
Andrew Dunkley: Very good. All right. Keeps making the news.

777
00:32:31.990 --> 00:32:34.790
And uh, I mean it's one of those

778
00:32:34.790 --> 00:32:37.460
things like, like this is only one of a

779
00:32:37.460 --> 00:32:40.140
handful of these things that we've

780
00:32:40.140 --> 00:32:42.380
found, but it's starting to look like this is

781
00:32:42.380 --> 00:32:43.780
not an uncommon thread.

782
00:32:44.580 --> 00:32:47.180
Professor Fred Watson: That's right. And I think once again harking

783
00:32:47.180 --> 00:32:49.620
back to the Vera C. Rubin telescope, we're

784
00:32:49.620 --> 00:32:51.499
going to find more of these. Uh, when that

785
00:32:51.499 --> 00:32:53.060
telescope comes online we're probably going

786
00:32:53.060 --> 00:32:55.500
to have, you know, we've got three known

787
00:32:55.500 --> 00:32:57.820
interstellar objects now. It'll probably be

788
00:32:57.820 --> 00:33:00.580
20 by middle of next year. Who

789
00:33:00.580 --> 00:33:03.200
knows, it'll be quite extraordinary indeed.

790
00:33:03.280 --> 00:33:05.760
Andrew Dunkley: All right, uh, you can read more about the

791
00:33:05.870 --> 00:33:08.498
uh, images that have been taken of 3i

792
00:33:08.582 --> 00:33:10.920
Atlas and you can see them too at the

793
00:33:10.920 --> 00:33:13.440
universetoday.com website.

794
00:33:14.560 --> 00:33:17.080
Fred, that brings us to the end. Thank you so

795
00:33:17.080 --> 00:33:17.360
much.

796
00:33:17.920 --> 00:33:20.690
Professor Fred Watson: It's been a pleasure. Andrew. Um, uh, uh,

797
00:33:20.800 --> 00:33:23.520
I've forgotten how much I miss uh, my

798
00:33:23.520 --> 00:33:25.720
weekly dose of spacenauts. So it's good to be

799
00:33:25.720 --> 00:33:26.560
talking again.

800
00:33:26.720 --> 00:33:29.560
Andrew Dunkley: It's good to have you back. Um, thank you for

801
00:33:29.560 --> 00:33:30.320
deciding to return

802
00:33:32.650 --> 00:33:34.810
even without the red carpet. Oh and by the

803
00:33:34.810 --> 00:33:36.530
way, that golfer uh, I played with today,

804
00:33:36.530 --> 00:33:39.010
Piper Stubbs from Melbourne. Oh good, Stubbs.

805
00:33:39.010 --> 00:33:39.930
Professor Fred Watson: Look up the name.

806
00:33:40.010 --> 00:33:42.810
Andrew Dunkley: She uh, she studied um, at

807
00:33:43.050 --> 00:33:44.770
college uh, in the United States and played

808
00:33:44.770 --> 00:33:47.610
collegiate golf over there. Ah, she's

809
00:33:47.610 --> 00:33:50.410
finished now and she qualified um, as a,

810
00:33:50.650 --> 00:33:52.610
in political science. So.

811
00:33:52.610 --> 00:33:53.210
Professor Fred Watson: Very good.

812
00:33:53.450 --> 00:33:56.250
Andrew Dunkley: Yeah, uh, quite a bright young lady.

813
00:33:56.560 --> 00:33:59.010
Uh, and um, thanks to Huw in the studio.

814
00:33:59.010 --> 00:34:00.570
Although he couldn't be with us today because

815
00:34:00.570 --> 00:34:03.070
he heard there were 40,000 near of asteroids

816
00:34:03.070 --> 00:34:05.350
discovered. So he built himself a bunker.

817
00:34:05.830 --> 00:34:08.300
He won't come out. And um,

818
00:34:09.350 --> 00:34:11.830
and uh, by the way, if you would like to

819
00:34:11.830 --> 00:34:14.270
become a patron, um, by all means, jump on

820
00:34:14.270 --> 00:34:17.150
our website and, and find uh, out uh, all

821
00:34:17.150 --> 00:34:19.150
about it. I uh, know it's uh, there are

822
00:34:19.150 --> 00:34:21.590
difficult times and we would never expect you

823
00:34:22.150 --> 00:34:24.950
to um, to, to spend money to listen to us.

824
00:34:24.950 --> 00:34:27.630
It's a, it's a free podcast but people choose

825
00:34:27.630 --> 00:34:30.590
to and there are multiple options these

826
00:34:30.590 --> 00:34:32.960
days. So if you want to become a patron, uh,

827
00:34:33.110 --> 00:34:36.050
you'll get commercial free edition of the

828
00:34:36.050 --> 00:34:38.770
podcast. So um, uh, if you'd prefer to be

829
00:34:38.770 --> 00:34:40.330
commercial free, this is the way to do it.

830
00:34:40.330 --> 00:34:42.690
You can do it through Patreon, Supercast,

831
00:34:42.930 --> 00:34:45.930
Spreaker and Apple podcasts. They

832
00:34:45.930 --> 00:34:48.930
all do um, various uh, uh, payment

833
00:34:48.930 --> 00:34:51.090
options if that's your thing. If it's not,

834
00:34:51.330 --> 00:34:54.010
just forget everything I just said and don't

835
00:34:54.010 --> 00:34:55.650
forget to visit us online while you're there.

836
00:34:55.650 --> 00:34:58.090
Or the, uh, or the Facebook group. Uh, the

837
00:34:58.090 --> 00:35:00.370
podcast group on Facebook. Uh, very active.

838
00:35:00.370 --> 00:35:02.100
And you can talk to each other about. About

839
00:35:02.100 --> 00:35:04.260
anything you like to do with space and

840
00:35:04.340 --> 00:35:07.140
astronomy. That's it for this episode.

841
00:35:07.140 --> 00:35:09.780
Join us again soon when we do a Q A episode.

842
00:35:09.940 --> 00:35:12.700
Um, and, and looking forward to having you

843
00:35:12.700 --> 00:35:15.140
join us then from me, Andrew Dunkley. Until

844
00:35:15.140 --> 00:35:15.700
next time.

845
00:35:16.100 --> 00:35:16.460
Professor Fred Watson: Bye.

846
00:35:16.460 --> 00:35:19.420
Andrew Dunkley: Bye. You'll be listening to the

847
00:35:19.420 --> 00:35:20.820
Space Nuts podcast,

848
00:35:22.340 --> 00:35:25.140
available at Apple Podcasts, Spotify,

849
00:35:25.300 --> 00:35:27.630
iHeartRadio, or your favorite favorite

850
00:35:27.630 --> 00:35:29.790
podcast player. You can also stream on

851
00:35:29.790 --> 00:35:32.790
demand@bytes.com. um, this has been another

852
00:35:32.790 --> 00:35:35.470
quality podcast production from bytes.

853
00:35:35.630 --> 00:35:35.910
Professor Fred Watson: Com. Um.