WEBVTT

0
00:00:00.320 --> 00:00:02.400
Steve Dunkley: And welcome again to another astronomy Daily.

1
00:00:02.400 --> 00:00:04.800
It's the 14th of July, 2025.

2
00:00:08.880 --> 00:00:09.240
Generic: Welcome to Astronomy Daily The Podcast with 

3
00:00:09.240 --> 00:00:10.960
Your host, Steve Dunkley.

4
00:00:20.240 --> 00:00:23.080
Steve Dunkley: Wow, the 14th of July. Ah, already? It's as

5
00:00:23.080 --> 00:00:25.560
close to the halfway mark of the year as we

6
00:00:25.560 --> 00:00:26.520
can get, Hallie.

7
00:00:26.520 --> 00:00:28.720
Hallie: I think you watched that calendar a bit too

8
00:00:28.720 --> 00:00:29.520
closely, human.

9
00:00:29.680 --> 00:00:31.910
Steve Dunkley: Oh, Hallie, it's just a way of mark

10
00:00:32.540 --> 00:00:34.820
time. You know, humans like to do that. I

11
00:00:34.820 --> 00:00:36.780
guess that's where our fascination with

12
00:00:36.780 --> 00:00:38.620
astronomy came from in the first place.

13
00:00:38.620 --> 00:00:39.660
Hallie: That makes sense.

14
00:00:39.820 --> 00:00:40.300
Steve Dunkley: Yeah.

15
00:00:40.460 --> 00:00:42.580
Hallie: Speaking of time, it's great to be back in

16
00:00:42.580 --> 00:00:45.140
the Australia studio again for this podcast.

17
00:00:45.140 --> 00:00:45.500
Time.

18
00:00:45.580 --> 00:00:47.340
Steve Dunkley: That's right. Monday is our time.

19
00:00:47.340 --> 00:00:49.060
Hallie: Have you got our schedules set up?

20
00:00:49.060 --> 00:00:49.740
Steve Dunkley: Uh, uh, what?

21
00:00:49.740 --> 00:00:51.420
Hallie: Yeah, it was your turn.

22
00:00:51.580 --> 00:00:54.220
Steve Dunkley: Well, yes, Hallie, I. I got it done in time.

23
00:00:54.220 --> 00:00:56.660
Hallie: That's good. I hope it didn't take too much

24
00:00:56.660 --> 00:00:57.740
of your private time.

25
00:00:57.820 --> 00:01:00.740
Steve Dunkley: Oh, private time? No, not this time. As

26
00:01:00.740 --> 00:01:02.220
if I had any private time.

27
00:01:02.380 --> 00:01:03.740
Hallie: So, what have you got for us?

28
00:01:04.680 --> 00:01:06.920
Steve Dunkley: Well, Hallie, it's time for another meteor

29
00:01:06.920 --> 00:01:09.040
shower, and Australia looks like it's in the

30
00:01:09.040 --> 00:01:10.840
prime location for the best view.

31
00:01:11.080 --> 00:01:12.120
Hallie: It's about time.

32
00:01:12.440 --> 00:01:14.760
Steve Dunkley: Well, I suspect Australia is always in the

33
00:01:14.760 --> 00:01:17.040
best position for a meteor shower, so, uh,

34
00:01:17.040 --> 00:01:18.200
well, viewing anyway.

35
00:01:18.280 --> 00:01:20.360
Hallie: Okay, okay. What else?

36
00:01:20.360 --> 00:01:22.360
Steve Dunkley: Well, as well as the Perseids, we've got

37
00:01:22.520 --> 00:01:25.480
building things on Mars with fungus

38
00:01:26.120 --> 00:01:28.720
astronomers, uh, looking at the cosmic

39
00:01:28.720 --> 00:01:31.600
web, and, um, we might actually be living

40
00:01:31.600 --> 00:01:34.320
in a giant void. They sound pretty cool,

41
00:01:34.320 --> 00:01:34.840
don't they?

42
00:01:35.080 --> 00:01:37.500
Hallie: Excellent. Okay, so.

43
00:01:37.500 --> 00:01:38.260
Steve Dunkley: Hey, Helly.

44
00:01:38.340 --> 00:01:39.140
Hallie: Yes, human?

45
00:01:39.700 --> 00:01:41.500
Steve Dunkley: How's about we just launch right into.

46
00:01:41.500 --> 00:01:43.540
Hallie: The episode and save some time?

47
00:01:43.620 --> 00:01:45.620
Steve Dunkley: You think Tempest fugit, Hallie?

48
00:01:45.620 --> 00:01:46.740
Hallie: Indeed it does.

49
00:01:46.980 --> 00:01:49.140
Steve Dunkley: Okay, Hallie, you have the con Okies.

50
00:02:00.420 --> 00:02:02.180
Hallie: One of the main objectives of the Hubble

51
00:02:02.180 --> 00:02:04.860
Space telescope, launched in 1990, was to

52
00:02:04.860 --> 00:02:07.060
measure the size and age of the universe, as

53
00:02:07.060 --> 00:02:08.860
well as the rate at which it is expanding,

54
00:02:08.860 --> 00:02:11.620
AKA the Hubble constant. This was

55
00:02:11.620 --> 00:02:13.500
enabled for the first time with the Hubble

56
00:02:13.500 --> 00:02:15.620
Deep Fields, which visualized the farthest

57
00:02:15.620 --> 00:02:17.580
galaxies that are observable in visible

58
00:02:17.580 --> 00:02:19.900
light, 13 billion light years from Earth.

59
00:02:20.700 --> 00:02:22.500
However, when astronomers measured the

60
00:02:22.500 --> 00:02:25.300
distance to these galaxies, they noted a they

61
00:02:25.300 --> 00:02:26.980
were inconsistent with measurements of the

62
00:02:26.980 --> 00:02:29.790
local universe. This became known as

63
00:02:29.790 --> 00:02:31.910
the Hubble Tension, which remains one of the

64
00:02:31.910 --> 00:02:34.230
biggest cosmological mysteries to this day.

65
00:02:34.950 --> 00:02:36.670
While astronomers hope to resolve this

66
00:02:36.670 --> 00:02:38.350
tension with the launch of the James Webb

67
00:02:38.350 --> 00:02:40.110
Space Telescope, Webb's measurements

68
00:02:40.110 --> 00:02:43.070
confirmed what Hubble saw. Many theories have

69
00:02:43.070 --> 00:02:45.230
been advanced to explain this, including the

70
00:02:45.230 --> 00:02:47.270
possibility that the Milky Way is located

71
00:02:47.270 --> 00:02:49.390
inside a giant void that makes the cosmos

72
00:02:49.390 --> 00:02:50.990
expand faster here than in neighboring

73
00:02:50.990 --> 00:02:53.670
regions of the universe. The latest

74
00:02:53.670 --> 00:02:55.830
research supporting this theory was presented

75
00:02:55.830 --> 00:02:58.110
at the Royal Astronomical Society's National

76
00:02:58.110 --> 00:03:00.890
Astronomy Meeting in Durham. Their theory

77
00:03:00.890 --> 00:03:02.930
could potentially resolve the Hubble tension

78
00:03:02.930 --> 00:03:04.770
and confirm the true age of our universe,

79
00:03:04.770 --> 00:03:06.970
which is thought to be about 13.8 billion

80
00:03:06.970 --> 00:03:09.850
years old. The Hubble constant takes its

81
00:03:09.850 --> 00:03:11.450
name from Edwin Hubble, one of two

82
00:03:11.450 --> 00:03:13.050
astronomers, the other being Georges

83
00:03:13.050 --> 00:03:15.210
Lemaitre, who confirmed in the early 20th

84
00:03:15.210 --> 00:03:16.970
century that the universe was in a state of

85
00:03:16.970 --> 00:03:19.770
expansion. This was demonstrated using

86
00:03:19.770 --> 00:03:21.730
redshift measurements, where the wavelength

87
00:03:21.730 --> 00:03:23.850
of light from objects receding from Earth is

88
00:03:23.850 --> 00:03:25.570
shifted toward the red end of the spectrum.

89
00:03:26.570 --> 00:03:28.370
Before the Hubble Space Telescope was

90
00:03:28.370 --> 00:03:30.290
launched, astronomers were able to gauge the

91
00:03:30.290 --> 00:03:32.210
distance of objects up to 4 billion light

92
00:03:32.210 --> 00:03:34.290
years away using a combination of redshift

93
00:03:34.290 --> 00:03:37.170
and parallax measurements. The problem was

94
00:03:37.170 --> 00:03:39.010
that when comparing local measurements to

95
00:03:39.010 --> 00:03:41.170
those of the distant early universe based on

96
00:03:41.170 --> 00:03:42.850
the standard lambda cold dark matter

97
00:03:42.850 --> 00:03:44.970
cosmological model, the results were in

98
00:03:44.970 --> 00:03:47.850
tension with each other. The latest research,

99
00:03:48.090 --> 00:03:49.970
explained Dr. Indranil Banik of the

100
00:03:49.970 --> 00:03:52.050
University of Portsmouth, shows that baryon

101
00:03:52.050 --> 00:03:54.890
acoustic oscillations, essentially the sound

102
00:03:54.890 --> 00:03:57.010
waves of the Big Bang, support the idea that

103
00:03:57.010 --> 00:03:58.830
our galaxy be in a void where cosmic

104
00:03:58.830 --> 00:04:00.470
expansion is greater than the universe

105
00:04:00.470 --> 00:04:03.230
beyond. Bannock said a potential

106
00:04:03.230 --> 00:04:05.310
solution to this inconsistency is that our

107
00:04:05.310 --> 00:04:07.350
galaxy is close to the center of a large

108
00:04:07.430 --> 00:04:10.110
local void. It would cause matter to be

109
00:04:10.110 --> 00:04:12.110
pulled by gravity towards the higher density

110
00:04:12.110 --> 00:04:14.070
exterior of the void, leading to the void

111
00:04:14.070 --> 00:04:16.910
becoming emptier with time. As the void is

112
00:04:16.910 --> 00:04:19.110
emptying out, the velocity of objects away

113
00:04:19.110 --> 00:04:20.910
from us would be larger than if the void were

114
00:04:20.910 --> 00:04:23.470
not there. This therefore gives the

115
00:04:23.470 --> 00:04:25.590
appearance of a faster local expansion rate.

116
00:04:26.330 --> 00:04:28.170
The Hubble tension is largely a local

117
00:04:28.170 --> 00:04:30.210
phenomenon, with little evidence that the

118
00:04:30.210 --> 00:04:32.530
expansion rate disagrees with expectations in

119
00:04:32.530 --> 00:04:34.810
the standard cosmology further back in time.

120
00:04:35.610 --> 00:04:38.010
So a local solution like a local void is a

121
00:04:38.010 --> 00:04:39.730
promising way to go about solving the

122
00:04:39.730 --> 00:04:42.410
problem. This void would need to measure a

123
00:04:42.410 --> 00:04:44.250
billion light years in radius and have a

124
00:04:44.250 --> 00:04:46.490
density roughly 20% lower than the average

125
00:04:46.490 --> 00:04:49.410
for the universe as a whole. This theory is

126
00:04:49.410 --> 00:04:51.650
supported by a direct count of local galaxies

127
00:04:51.650 --> 00:04:53.410
in our cosmic neighborhood. Since the number

128
00:04:53.410 --> 00:04:55.520
density is lower than in neighboring regions.

129
00:04:56.630 --> 00:04:58.670
However, the existence of such a void is

130
00:04:58.670 --> 00:05:00.710
inconsistent with the LCDM model, which

131
00:05:00.710 --> 00:05:02.430
includes the theory that the universe is

132
00:05:02.430 --> 00:05:04.750
antistropic in nature, meaning that matter is

133
00:05:04.750 --> 00:05:06.550
uniformly spread throughout the universe on

134
00:05:06.550 --> 00:05:09.430
large scales. Despite this, the new

135
00:05:09.430 --> 00:05:12.310
Data presented at NAM 2025 indicates

136
00:05:12.310 --> 00:05:14.710
otherwise, said Bannock.

137
00:05:15.430 --> 00:05:17.550
These sound waves traveled for only a short

138
00:05:17.550 --> 00:05:19.470
while before becoming frozen in place. Once

139
00:05:19.470 --> 00:05:21.550
the universe cooled enough for neutral atoms

140
00:05:21.550 --> 00:05:24.390
to form, they act as a standard ruler

141
00:05:24.390 --> 00:05:26.350
whose angular size we can use to chart the

142
00:05:26.350 --> 00:05:29.310
cosmic expansion history. A local void

143
00:05:29.310 --> 00:05:31.030
slightly distorts the relation between the

144
00:05:31.030 --> 00:05:33.470
BAO angular scale and the redshift because

145
00:05:33.470 --> 00:05:35.710
the velocities induced by a local void and

146
00:05:35.710 --> 00:05:37.510
its gravitational effect slightly increase

147
00:05:37.510 --> 00:05:39.630
the redshift on top of that due to cosmic

148
00:05:39.630 --> 00:05:42.230
expansion. By considering all available

149
00:05:42.230 --> 00:05:44.670
BAO measurements over the last 20 years, we

150
00:05:44.670 --> 00:05:46.870
showed that a void model is about 100 million

151
00:05:46.870 --> 00:05:48.830
times more likely than a void free model with

152
00:05:48.830 --> 00:05:50.630
parameters designed to fit the CMB

153
00:05:50.630 --> 00:05:52.870
observations taken by the Planck satellite,

154
00:05:53.110 --> 00:05:55.270
the so called homogeneous Planck cosmology.

155
00:05:56.150 --> 00:05:58.310
To confirm this theory, researchers must

156
00:05:58.310 --> 00:06:00.030
compare the local void theory with other

157
00:06:00.030 --> 00:06:01.950
models to obtain new estimates for the

158
00:06:01.950 --> 00:06:04.950
expansion history of the universe. This will

159
00:06:04.950 --> 00:06:07.110
consist of obtaining spectra from quiescent

160
00:06:07.110 --> 00:06:09.750
or dead galaxies, those no longer forming new

161
00:06:09.750 --> 00:06:11.990
stars, to determine what types of stars they

162
00:06:11.990 --> 00:06:14.950
have and in what proportion. Since massive

163
00:06:14.950 --> 00:06:17.190
stars have short lifespans and are absent

164
00:06:17.190 --> 00:06:18.920
from older galaxies, this will help

165
00:06:18.920 --> 00:06:20.800
astronomers establish the age of these

166
00:06:20.800 --> 00:06:23.520
galaxies. Combined with a galaxy's

167
00:06:23.520 --> 00:06:25.640
redshift, astronomers can chart the history

168
00:06:25.640 --> 00:06:28.360
of cosmic expansion. You're listening to

169
00:06:28.360 --> 00:06:29.280
Astronomy Daily.

170
00:06:36.320 --> 00:06:38.880
Steve Dunkley: Landing on Mars once felt like a distant

171
00:06:38.880 --> 00:06:41.800
dream. Now space agencies have sent rovers

172
00:06:41.800 --> 00:06:44.490
and landers to explore the red Planet for

173
00:06:44.490 --> 00:06:47.370
decades. Scientists worldwide are

174
00:06:47.370 --> 00:06:49.770
thinking about how to make Mars a second home

175
00:06:49.770 --> 00:06:52.370
for humans. But major questions still

176
00:06:52.370 --> 00:06:55.050
remain. How do you build structures millions

177
00:06:55.050 --> 00:06:57.930
of miles from Earth? Uh, shipping heavy loads

178
00:06:57.930 --> 00:07:00.770
of materials to Mars from Earth is

179
00:07:00.770 --> 00:07:03.410
expensive and impractical. Rockets have

180
00:07:03.410 --> 00:07:06.250
limited space and fuel, and sending cement

181
00:07:06.250 --> 00:07:09.010
and metal beams would cost billions.

182
00:07:09.980 --> 00:07:12.100
Researchers are now exploring ways to use

183
00:07:12.100 --> 00:07:15.060
what Mars already has, its soil, dust and

184
00:07:15.060 --> 00:07:17.860
natural resources to build homes for future

185
00:07:17.860 --> 00:07:20.580
astronauts. At Texas A and M

186
00:07:20.580 --> 00:07:23.540
University, Dr. Congrue Grace Ginn and

187
00:07:23.540 --> 00:07:26.140
her team are, uh, tackling this challenge.

188
00:07:26.220 --> 00:07:27.700
They've spent years developing

189
00:07:27.700 --> 00:07:30.380
biomanufacturing methods to create

190
00:07:30.460 --> 00:07:33.300
engineering living materials. Their

191
00:07:33.300 --> 00:07:35.980
latest research proposes a solution that

192
00:07:35.980 --> 00:07:38.620
could change how humans build structures on

193
00:07:38.620 --> 00:07:41.080
other planets. We can build

194
00:07:41.080 --> 00:07:43.760
synthetic community by mimicking natural

195
00:07:43.760 --> 00:07:45.560
lichens, explains Jin.

196
00:07:46.680 --> 00:07:49.080
We've developed a way to build synthetic

197
00:07:49.080 --> 00:07:51.800
lichens to create biomaterials that

198
00:07:51.800 --> 00:07:53.920
glue Martian regolith particles into

199
00:07:53.920 --> 00:07:56.600
structures. Then, through 3D printing,

200
00:07:56.840 --> 00:07:59.680
a wide range of structures can be fabricated,

201
00:07:59.680 --> 00:08:01.520
such as buildings, houses, and even

202
00:08:01.520 --> 00:08:04.520
furniture. Gin's team, working with the

203
00:08:04.520 --> 00:08:07.020
University of Nebraska, Lincoln, has

204
00:08:07.020 --> 00:08:10.020
designed a synthetic lichen system. This

205
00:08:10.020 --> 00:08:12.660
system forms strong building materials

206
00:08:12.660 --> 00:08:15.580
without any help from humans. Martian

207
00:08:15.580 --> 00:08:18.260
regolith is loose soil, dust,

208
00:08:18.340 --> 00:08:20.740
sand, and broken rocks on the Martian

209
00:08:20.740 --> 00:08:23.660
surface. Their research shows that a

210
00:08:23.660 --> 00:08:25.940
synthetic community of organisms can turn

211
00:08:25.940 --> 00:08:28.180
regolith into building materials strong

212
00:08:28.180 --> 00:08:30.620
enough for homes, tables, and chairs. This

213
00:08:30.620 --> 00:08:33.130
breakthrough may one day allow humans to to

214
00:08:33.130 --> 00:08:36.130
build on Mars without sending extra materials

215
00:08:36.130 --> 00:08:38.890
from Earth. Other scientists

216
00:08:38.890 --> 00:08:41.810
have studied different ways to bond Martian

217
00:08:41.810 --> 00:08:44.770
soil. Some tried using magnesium based,

218
00:08:44.850 --> 00:08:47.410
sulfur based or geopolymer

219
00:08:47.410 --> 00:08:49.810
methods. However, all of these approaches

220
00:08:49.970 --> 00:08:52.530
need humans to carry out parts of the process

221
00:08:53.010 --> 00:08:55.090
on Mars. There won't be enough people to

222
00:08:55.090 --> 00:08:57.970
oversee these complicated tasks, at least

223
00:08:58.130 --> 00:08:59.890
in the foreseeable future future.

224
00:09:00.770 --> 00:09:03.170
Another approach is called microbe

225
00:09:03.250 --> 00:09:05.490
mediated self growing technology.

226
00:09:05.970 --> 00:09:08.850
This uses bacteria or fungi to produce

227
00:09:09.090 --> 00:09:11.690
minerals to bind soil particles into

228
00:09:11.690 --> 00:09:14.210
bricks. NASA has explored using

229
00:09:14.290 --> 00:09:17.290
fungi mycelium as a bonding agent, while

230
00:09:17.290 --> 00:09:19.770
other scientists have tested bacteria that

231
00:09:19.770 --> 00:09:22.770
produce calcium carbonate. Even these

232
00:09:23.490 --> 00:09:26.350
methods require outside nutrients to keep the

233
00:09:26.350 --> 00:09:28.870
microbes alive. Needing human intervention,

234
00:09:29.190 --> 00:09:31.270
Jin's team wanted to solve this problem.

235
00:09:31.510 --> 00:09:34.510
Their idea was simple, yet powerful. Build

236
00:09:34.510 --> 00:09:37.430
a system that runs on its own using organisms

237
00:09:37.430 --> 00:09:40.230
that help each other survive. They created

238
00:09:40.230 --> 00:09:43.190
a synthetic lichen system that combines

239
00:09:43.190 --> 00:09:46.030
two types of organisms. Filamentous

240
00:09:46.030 --> 00:09:48.390
fungi and diazotrophic

241
00:09:48.390 --> 00:09:51.310
cyanobacteria. Once again, I apologize

242
00:09:51.310 --> 00:09:53.640
for my pronunciation. I am

243
00:09:53.720 --> 00:09:56.520
Australian. Filamentous fungi

244
00:09:56.520 --> 00:09:59.280
act as the builders. They can produce large

245
00:09:59.280 --> 00:10:01.920
amounts of biominerals, uh, to bond soil

246
00:10:01.920 --> 00:10:04.480
particles. These fungi survive harsh

247
00:10:04.480 --> 00:10:07.480
conditions better than bacteria. They also

248
00:10:07.480 --> 00:10:10.280
bind metal ions into their cell walls,

249
00:10:10.360 --> 00:10:13.200
creating sites for biomineral crystals to

250
00:10:13.200 --> 00:10:15.600
grow. At the same time, they help the

251
00:10:15.600 --> 00:10:18.120
cyanobacteria grow by giving them water,

252
00:10:18.200 --> 00:10:20.040
minerals and carbon dioxide.

253
00:10:20.540 --> 00:10:23.020
Diazotrophic cyanobacteria act as the

254
00:10:23.020 --> 00:10:25.740
providers. They fix carbon dioxide and

255
00:10:25.740 --> 00:10:28.140
dino trojan from the air and turn them into

256
00:10:28.140 --> 00:10:30.900
oxygen and organic nutrients. This

257
00:10:30.900 --> 00:10:33.140
process feeds the fungi and increases

258
00:10:33.140 --> 00:10:35.540
carbonate ions in the environment. The

259
00:10:35.540 --> 00:10:38.020
carbonate ions are essential for creating

260
00:10:38.020 --> 00:10:40.540
mineral crystals that bond the soil together.

261
00:10:40.860 --> 00:10:42.900
The cyanobacteria also uses

262
00:10:42.900 --> 00:10:45.220
photosynthesis to produce the nutrients

263
00:10:45.220 --> 00:10:48.020
needed for the fungi to thrive. Both,

264
00:10:48.020 --> 00:10:51.020
uh, organisms secrete biopolymers that

265
00:10:51.020 --> 00:10:53.540
help glue regolith particles and mineral

266
00:10:53.540 --> 00:10:56.100
crystals into strong solid materials.

267
00:10:56.340 --> 00:10:58.980
Their relationship is mutually beneficial.

268
00:10:59.220 --> 00:11:01.740
Together, they form a system that requires

269
00:11:01.740 --> 00:11:04.420
only Martian regolith, simulant air,

270
00:11:04.420 --> 00:11:07.100
light, and an inorganic liquid medium to

271
00:11:07.100 --> 00:11:09.940
grow. No external carbon or

272
00:11:09.940 --> 00:11:11.780
nitrogen sources are needed.

273
00:11:14.270 --> 00:11:16.270
Hallie: You're listening to Astronomy Daily, the

274
00:11:16.270 --> 00:11:17.950
podcast with Steve Dunkley.

275
00:11:28.350 --> 00:11:29.990
Steve Dunkley: Thank you for joining us for this Monday

276
00:11:29.990 --> 00:11:32.230
edition of Astronomy Daily, where we offer

277
00:11:32.230 --> 00:11:34.030
just a few stories from the now famous

278
00:11:34.030 --> 00:11:36.190
Astronomy Daily newsletter, which you can

279
00:11:36.190 --> 00:11:38.420
receive in your email every day, just like

280
00:11:38.570 --> 00:11:41.090
Hallie and I do. And to do that, just visit

281
00:11:41.090 --> 00:11:43.130
our uh, URL astronomydaily

282
00:11:43.530 --> 00:11:46.290
IO and place your email address in the slot

283
00:11:46.290 --> 00:11:48.730
provided. Just like that, you'll be receiving

284
00:11:48.890 --> 00:11:51.050
all the latest news about science, space,

285
00:11:51.050 --> 00:11:53.290
science and astronomy from around the world

286
00:11:53.290 --> 00:11:55.730
as it's happening. And not only that. You can

287
00:11:55.730 --> 00:11:58.250
interact with us by visiting at

288
00:11:58.250 --> 00:12:00.890
astrodaily Pod on X

289
00:12:01.050 --> 00:12:03.730
or at our new Facebook page, which is, of

290
00:12:03.730 --> 00:12:06.490
course, Astronomy Daily on Facebook. See you

291
00:12:06.490 --> 00:12:09.250
there. Astronomy Daily

292
00:12:09.250 --> 00:12:11.650
with Steve and Hallie Space,

293
00:12:12.130 --> 00:12:14.370
Space Science and Astronomy.

294
00:12:17.570 --> 00:12:19.930
Hallie: Observations of a 23 million light year long

295
00:12:19.930 --> 00:12:22.530
gaseous filament and 39 bursts of radio waves

296
00:12:22.530 --> 00:12:24.610
are helping astronomers chart the universe's

297
00:12:24.610 --> 00:12:27.450
largest scale structures. A curious

298
00:12:27.450 --> 00:12:29.610
fact about the universe around us. We can't

299
00:12:29.610 --> 00:12:32.370
see most of it. It's not only mysterious

300
00:12:32.370 --> 00:12:34.570
dark matter and dark energy that, except for

301
00:12:34.570 --> 00:12:36.450
their indirect impacts on astronomical

302
00:12:36.450 --> 00:12:39.390
observations, remain invisible. Much of

303
00:12:39.390 --> 00:12:42.070
a normal amatter evades detection, too, even

304
00:12:42.070 --> 00:12:44.030
though those ordinary particles known as

305
00:12:44.030 --> 00:12:46.790
baryons also make up perfectly visible stars,

306
00:12:46.790 --> 00:12:48.630
planets, and kitchen sinks.

307
00:12:49.510 --> 00:12:51.710
Now, two teams with opposite approaches have

308
00:12:51.710 --> 00:12:53.710
found much of ordinary matter prefers to take

309
00:12:53.710 --> 00:12:55.670
up residence in the lonelier latticework that

310
00:12:55.670 --> 00:12:58.470
makes up the cosmic web. This large scale

311
00:12:58.470 --> 00:13:00.710
structure consists primarily of dark matter,

312
00:13:00.790 --> 00:13:02.830
which has gravitationally collapsed from a

313
00:13:02.830 --> 00:13:05.790
smooth spread. Crisscrossing filaments leave

314
00:13:05.790 --> 00:13:08.710
largely empty voids in between. Dark matter

315
00:13:08.710 --> 00:13:10.950
is the gravitational backbone of the cosmic

316
00:13:10.950 --> 00:13:13.030
web, along which normal matter collects and

317
00:13:13.030 --> 00:13:15.230
comes together into galaxies and galaxy

318
00:13:15.230 --> 00:13:17.910
clusters. One of these filaments is

319
00:13:17.910 --> 00:13:20.189
23 million light years long, a thick thread

320
00:13:20.189 --> 00:13:22.070
of gas and dark matter that connects two

321
00:13:22.070 --> 00:13:24.310
pairs of galaxy clusters in Centaurus.

322
00:13:24.870 --> 00:13:26.830
The quartet of clusters are part of the

323
00:13:26.830 --> 00:13:29.670
larger Shapley's supercluster. Only

324
00:13:29.750 --> 00:13:31.750
astronomers didn't know the filament was

325
00:13:31.750 --> 00:13:34.050
there. The colliding clusters were

326
00:13:34.050 --> 00:13:36.370
intriguing, though, and many teams pointed X

327
00:13:36.370 --> 00:13:38.410
ray observatories in their direction between

328
00:13:38.410 --> 00:13:41.330
2001 and 2020. Now

329
00:13:41.330 --> 00:13:43.290
combining these archival observations,

330
00:13:43.530 --> 00:13:45.770
Konstantino's Mikas, UH Leiden University,

331
00:13:46.090 --> 00:13:48.169
the Netherlands, and his group collected the

332
00:13:48.169 --> 00:13:50.090
equivalent of a multi day stare at this

333
00:13:50.090 --> 00:13:52.890
region of sky. In doing so, they

334
00:13:52.890 --> 00:13:54.890
revealed the faint X ray glow of a filament

335
00:13:54.890 --> 00:13:57.530
connecting the clusters. The matter in the

336
00:13:57.530 --> 00:13:59.660
sky filament is hard to see because it's both

337
00:13:59.660 --> 00:14:02.540
sparse and hot. Hot gas emits some

338
00:14:02.540 --> 00:14:04.860
low energy X rays, but that emission becomes

339
00:14:04.860 --> 00:14:06.900
quite faint when the gas is spread out over

340
00:14:06.900 --> 00:14:09.340
millions of light years. Not that

341
00:14:09.340 --> 00:14:11.300
astronomers haven't tried, and with some

342
00:14:11.300 --> 00:14:13.819
success. One team has observed

343
00:14:13.819 --> 00:14:16.020
individual cosmic web filaments. Another

344
00:14:16.020 --> 00:14:17.820
study combined data from thousands of

345
00:14:17.820 --> 00:14:19.780
filaments to better understand their average

346
00:14:19.780 --> 00:14:22.500
properties. But in all previous cases,

347
00:14:22.660 --> 00:14:24.820
the measured densities were shockingly high,

348
00:14:24.980 --> 00:14:26.740
several times more than cosmological

349
00:14:26.740 --> 00:14:29.430
simulations predicted. This time

350
00:14:29.430 --> 00:14:32.390
Mikasa's team tried something new. In

351
00:14:32.390 --> 00:14:33.870
addition to observing the glow of the

352
00:14:33.870 --> 00:14:36.150
filament itself using the sensitive Suzaku

353
00:14:36.150 --> 00:14:38.270
Observatory they also employed the sharper

354
00:14:38.270 --> 00:14:40.590
images of XMM Newton to find and remove other

355
00:14:40.590 --> 00:14:42.990
sources of x rays, such as supermassive black

356
00:14:42.990 --> 00:14:45.870
holes and galaxy halos. The result

357
00:14:45.870 --> 00:14:47.830
is a measurement of just how hot and sparse

358
00:14:47.830 --> 00:14:50.830
this one filament really is. Its temperature

359
00:14:50.830 --> 00:14:52.910
hovers around 10 million degrees. That's

360
00:14:52.910 --> 00:14:54.590
about the same temperature at which fusion

361
00:14:54.590 --> 00:14:57.510
begins within the Sun. But its density is

362
00:14:57.510 --> 00:14:59.510
so incredibly low that fusion would never

363
00:14:59.510 --> 00:15:01.790
happen 10 to 5 particles per cubic

364
00:15:01.790 --> 00:15:03.750
centimeter, which works out to about 5

365
00:15:03.750 --> 00:15:05.550
particles within the volume of an average

366
00:15:05.550 --> 00:15:08.470
bathtub. That density, remarkably,

367
00:15:08.470 --> 00:15:11.190
is exactly what's expected, Mikas notes.

368
00:15:11.910 --> 00:15:13.870
Obtaining the first result ever that matches

369
00:15:13.870 --> 00:15:16.190
the cosmological model perfectly was indeed a

370
00:15:16.190 --> 00:15:18.950
surprise, he says. There are countless

371
00:15:18.950 --> 00:15:20.550
filaments out there, some of which are

372
00:15:20.550 --> 00:15:23.470
amenable to direct imaging. But for the rest,

373
00:15:23.470 --> 00:15:25.830
there's another way to see the cosmic web via

374
00:15:25.830 --> 00:15:28.430
an unexpected beacon. Fast radio bursts

375
00:15:30.110 --> 00:15:32.470
Fast radio bursts are quick flashes of radio

376
00:15:32.470 --> 00:15:34.070
waves that astronomers think come from

377
00:15:34.070 --> 00:15:36.190
explosive events around dead stellar cores

378
00:15:36.190 --> 00:15:38.430
known as magnetars. For

379
00:15:38.430 --> 00:15:40.950
cosmologists, though, the exact source of the

380
00:15:40.950 --> 00:15:43.910
bursts isn't important. What is important is

381
00:15:43.910 --> 00:15:45.750
the ability to measure the dispersion of each

382
00:15:45.750 --> 00:15:47.790
radio flash, in which intervening matter

383
00:15:47.790 --> 00:15:49.430
spreads out the signal so that lower

384
00:15:49.430 --> 00:15:52.300
frequencies arrive later. The dispersion

385
00:15:52.300 --> 00:15:54.380
thus encodes how much matter lies between us

386
00:15:54.380 --> 00:15:57.220
and the burst. Combine that data with the

387
00:15:57.220 --> 00:15:59.580
burst's distance, which requires pinpointing

388
00:15:59.580 --> 00:16:01.500
where on the sky it's emanating from. Then

389
00:16:01.500 --> 00:16:03.420
mix in some computer simulations of the

390
00:16:03.420 --> 00:16:05.580
evolving universe, and you get something akin

391
00:16:05.580 --> 00:16:08.580
to a map of cosmic matter. On the simplest

392
00:16:08.580 --> 00:16:10.780
level, the change of dispersion with distance

393
00:16:10.780 --> 00:16:12.660
told the team about the amount of normal

394
00:16:12.660 --> 00:16:14.940
baryonic matter in the universe, which

395
00:16:14.940 --> 00:16:17.790
matched predictions on a deeper level.

396
00:16:17.870 --> 00:16:19.670
The spread of the data Whether a group of

397
00:16:19.670 --> 00:16:21.990
FRBs at a certain distance have mostly the

398
00:16:21.990 --> 00:16:24.030
same dispersion or many different values

399
00:16:24.030 --> 00:16:26.830
tells about the distribution of matter. If

400
00:16:26.830 --> 00:16:28.630
normal matter were mostly locked away in

401
00:16:28.630 --> 00:16:30.950
galaxies and clusters, our universe would be

402
00:16:30.950 --> 00:16:32.910
rather lumpy, and the dispersions at a

403
00:16:32.910 --> 00:16:35.430
certain distance would be spread out. But

404
00:16:35.430 --> 00:16:38.350
that's not the universe we live in. Comparing

405
00:16:38.350 --> 00:16:41.230
distance and dispersion for 39 FRBs detected

406
00:16:41.230 --> 00:16:43.270
with the Deep Synoptic Array 110 in

407
00:16:43.270 --> 00:16:45.190
California, Liam Connor of the center for

408
00:16:45.190 --> 00:16:47.670
Astrophysics, Harvard, and Smithsonian, and

409
00:16:47.670 --> 00:16:49.270
colleagues mapped normal matter out to when

410
00:16:49.270 --> 00:16:52.110
our universe was half its current age. They

411
00:16:52.110 --> 00:16:53.790
found that the spread of matter is pretty

412
00:16:53.790 --> 00:16:56.390
smooth, with less than 15% of normal matter

413
00:16:56.390 --> 00:16:58.470
in stars and the cooler gas that could one

414
00:16:58.470 --> 00:17:01.030
day become stars. The rest of the

415
00:17:01.030 --> 00:17:03.350
baryons aren't in galaxies they are between

416
00:17:03.350 --> 00:17:06.310
them that some material should be in cosmic

417
00:17:06.310 --> 00:17:09.070
filaments isn't unexpected, but that the

418
00:17:09.070 --> 00:17:10.750
filaments should contain three quarters of

419
00:17:10.750 --> 00:17:12.670
the universe's baryon suggests that that

420
00:17:12.670 --> 00:17:14.270
something is sloshing gas back out of

421
00:17:14.270 --> 00:17:17.230
galaxies at a high rate. Unfortunately,

422
00:17:17.230 --> 00:17:19.390
we don't yet have the granularity to pin down

423
00:17:19.390 --> 00:17:21.750
specific feedback scenarios, connor says.

424
00:17:22.390 --> 00:17:24.710
We'll have to wait for the large upcoming FRB

425
00:17:24.710 --> 00:17:27.550
samples for that. My suspicion is that you

426
00:17:27.550 --> 00:17:29.150
can't produce our results without a good

427
00:17:29.150 --> 00:17:31.150
amount of active galactic nucleus feedback,

428
00:17:31.150 --> 00:17:33.390
he adds, referring to the winds and jets that

429
00:17:33.390 --> 00:17:36.150
emanate from supermassive black holes. But

430
00:17:36.150 --> 00:17:39.040
that's just a hunch. Mikas points out

431
00:17:39.040 --> 00:17:41.240
that Connor's study is exactly complementary

432
00:17:41.240 --> 00:17:43.480
to his own. Whereas his own team measures the

433
00:17:43.480 --> 00:17:45.440
properties of a single filament, Connor's

434
00:17:45.440 --> 00:17:47.000
team measures how much matter is in these

435
00:17:47.000 --> 00:17:49.960
filaments overall. Connor likewise

436
00:17:49.960 --> 00:17:52.320
is glad to see the result from Migkus's team

437
00:17:52.400 --> 00:17:54.200
directly. Imaging filaments is really

438
00:17:54.200 --> 00:17:56.280
exciting, and I agree that this result meshes

439
00:17:56.280 --> 00:17:59.200
with ours, he says. It's fun to see a

440
00:17:59.200 --> 00:18:01.240
literal image of the gas our FRBs were

441
00:18:01.240 --> 00:18:04.210
dispersed by. You're listening

442
00:18:04.210 --> 00:18:06.890
to Astronomy Daily, the podcast with your

443
00:18:06.890 --> 00:18:09.290
host Steve Dunkley at Bermuda.

444
00:18:14.890 --> 00:18:17.290
Steve Dunkley: And Australians get ready for the Perseid

445
00:18:17.290 --> 00:18:19.210
meteor shower just around the corner. The

446
00:18:19.210 --> 00:18:21.250
night sky, uh, above Australia has been

447
00:18:21.250 --> 00:18:23.610
putting on a show this year with a flurry of

448
00:18:23.610 --> 00:18:25.730
interstellar activity on display throughout

449
00:18:25.730 --> 00:18:28.530
2025. But July is really delivering the

450
00:18:28.530 --> 00:18:30.620
celestial, celestial drama as the

451
00:18:31.180 --> 00:18:33.940
spectacular Perseid meteor shower

452
00:18:33.940 --> 00:18:36.460
begins its roughly one month journey past

453
00:18:36.460 --> 00:18:36.940
Earth.

454
00:18:37.500 --> 00:18:39.700
Well, what is the perceived meteor shower?

455
00:18:39.700 --> 00:18:41.860
We've covered this, uh, a couple over the

456
00:18:41.860 --> 00:18:43.980
last couple of years on Astronomy Daily, but

457
00:18:43.980 --> 00:18:46.860
the Perseid media shower is often dubbed as

458
00:18:46.860 --> 00:18:49.260
the best of its kind, characterized by its

459
00:18:49.260 --> 00:18:51.100
swift and bright meteors that are visible

460
00:18:51.100 --> 00:18:53.580
both, uh, in the Northern and Southern

461
00:18:53.580 --> 00:18:55.310
Hemispheres. It's one of the most common,

462
00:18:55.460 --> 00:18:57.980
highly anticipated celestial events around

463
00:18:57.980 --> 00:18:59.940
the world. The natural light show has long

464
00:18:59.940 --> 00:19:02.580
been a favorite among astronomy enthusiasts,

465
00:19:02.740 --> 00:19:05.700
famed for the vibrant trains of light left

466
00:19:05.700 --> 00:19:08.420
in the wake of the, uh, fireballs that often

467
00:19:08.580 --> 00:19:11.380
accompany each meteor. Not, uh, only

468
00:19:11.540 --> 00:19:14.180
can, uh, Earth dwellers easily spot

469
00:19:14.180 --> 00:19:17.100
the meteors with the naked eye, but

470
00:19:17.100 --> 00:19:19.020
we're also able to make out different colors

471
00:19:19.020 --> 00:19:21.360
and sizes compared to other showers like the

472
00:19:21.360 --> 00:19:24.280
Lyrids, which usually average 10 or 20

473
00:19:24.280 --> 00:19:27.000
per hour. The likelihood of witnessing the

474
00:19:27.000 --> 00:19:29.800
Perseids is extremely high. According

475
00:19:29.800 --> 00:19:32.400
to NASA, observers can expect between 20 and

476
00:19:32.400 --> 00:19:35.400
100 meteors per hour, a, uh, whopping 400%

477
00:19:35.400 --> 00:19:38.200
increase in sighting probability. And

478
00:19:38.200 --> 00:19:41.040
when will all of this be active? The proceeds

479
00:19:41.040 --> 00:19:43.760
originate from Comet 109P Swift

480
00:19:43.760 --> 00:19:46.440
Tuttle, which left a large trail of detritus

481
00:19:46.520 --> 00:19:49.480
as it cruised past us back in 1992.

482
00:19:49.480 --> 00:19:51.080
And when Earth, uh, passes through, through

483
00:19:51.080 --> 00:19:53.560
the debris stream during its orbit around the

484
00:19:53.560 --> 00:19:55.920
sun, the cometary material collides with our

485
00:19:55.920 --> 00:19:58.400
atmosphere. Extreme speeds

486
00:19:58.800 --> 00:20:01.160
create air friction and that combined with

487
00:20:01.160 --> 00:20:03.320
atmospheric compression, causes the objects

488
00:20:03.320 --> 00:20:05.480
to heat up and break apart and burn out. And

489
00:20:05.480 --> 00:20:07.920
that's what we see during the meteor shower.

490
00:20:08.000 --> 00:20:10.640
Earth enters Comet 109P

491
00:20:10.720 --> 00:20:13.360
Swift Tuttle's debris trail once a year and

492
00:20:13.360 --> 00:20:15.720
takes around a month to fully clear it. This

493
00:20:15.720 --> 00:20:18.290
means we're treated to the Perseids meteor

494
00:20:18.290 --> 00:20:20.570
shower every single year.

495
00:20:21.050 --> 00:20:24.010
And while it's, uh, visible as

496
00:20:24.010 --> 00:20:26.770
early as July 17, the best time to

497
00:20:26.770 --> 00:20:29.130
witness the celestial show is around mid

498
00:20:29.130 --> 00:20:31.970
August. Actually, this year it's expected to

499
00:20:31.970 --> 00:20:34.610
peak around the 12th to 13th of

500
00:20:34.610 --> 00:20:37.170
August. This is when Earth passes through the

501
00:20:37.170 --> 00:20:39.530
most concentrated part of the debris tail,

502
00:20:39.770 --> 00:20:42.490
resulting in the most meteor activity.

503
00:20:43.140 --> 00:20:45.740
Australia is probably the best place to see

504
00:20:45.740 --> 00:20:48.500
it this year. Uh, and Australia is home to

505
00:20:48.500 --> 00:20:51.260
plenty of prime stargazing spots due to its

506
00:20:51.260 --> 00:20:54.220
wide open spaces. From dedicated reserves

507
00:20:54.220 --> 00:20:57.180
and observatories to our very own dark

508
00:20:57.180 --> 00:20:59.700
sky approved stay. But thanks to the

509
00:20:59.700 --> 00:21:02.300
Perseide's spectacular scale, you won't need

510
00:21:02.300 --> 00:21:05.300
to venture all the way down under to catch a

511
00:21:05.300 --> 00:21:07.860
glimpse or even too far out of, uh, um,

512
00:21:07.860 --> 00:21:10.530
populated areas. No matter what the part of

513
00:21:10.530 --> 00:21:12.770
the country you call home, even a backyard

514
00:21:12.770 --> 00:21:15.490
Starchaser is in for a treat. But

515
00:21:16.610 --> 00:21:19.090
to get the most out of your experience, a few

516
00:21:19.090 --> 00:21:21.570
simple tips and tricks can go a long way.

517
00:21:21.570 --> 00:21:23.970
First things first, find a spot with minimal

518
00:21:23.970 --> 00:21:26.450
light pollution. The darker well the better.

519
00:21:26.770 --> 00:21:28.890
Head outside for about 30 minutes before you

520
00:21:28.890 --> 00:21:30.850
want to catch the show, giving your eyes

521
00:21:30.930 --> 00:21:33.090
enough time to fully adjust to the darkness.

522
00:21:33.410 --> 00:21:35.920
And the best part? Uh, no fancy gear

523
00:21:35.920 --> 00:21:38.600
required. No, not for the Perseids. You won't

524
00:21:38.600 --> 00:21:41.480
need a telescope or even binoculars. Just

525
00:21:41.480 --> 00:21:44.240
a cosy blanket and a little patience.

526
00:21:44.240 --> 00:21:46.640
And this year's winter has been pretty

527
00:21:46.640 --> 00:21:49.400
nippy. That's Australian for yes, it's

528
00:21:49.400 --> 00:21:52.240
cold down here. Uh, and uh, yes,

529
00:21:52.320 --> 00:21:54.760
rug up warm and keep your eyes open.

530
00:21:54.760 --> 00:21:57.000
Stargazers. The Perseeds are going to be

531
00:21:57.000 --> 00:21:57.840
great this year.

532
00:22:01.930 --> 00:22:04.050
And there it is. Sky watchers. Thanks for

533
00:22:04.050 --> 00:22:06.250
staying with us. That was a small selection

534
00:22:06.250 --> 00:22:08.170
of stories from the Astronomy Daily

535
00:22:08.170 --> 00:22:11.010
newsletter, available in your inbox every day

536
00:22:11.010 --> 00:22:12.810
simply by registering. That's right,

537
00:22:12.810 --> 00:22:15.650
registering pop, um, your email address

538
00:22:15.650 --> 00:22:18.330
into the slot provided@astronomydaily

539
00:22:18.650 --> 00:22:20.970
IO it's just that simple.

540
00:22:21.690 --> 00:22:24.610
Hallie: And ali, yes, you'll

541
00:22:24.610 --> 00:22:26.890
be up to date with all the news about space,

542
00:22:27.380 --> 00:22:29.540
space, science and astronomy from all over

543
00:22:29.540 --> 00:22:30.660
the place and beyond.

544
00:22:31.060 --> 00:22:33.420
Steve Dunkley: For sure and for certain. Thanks for your

545
00:22:33.420 --> 00:22:34.980
stories today, Hallie. Nicely done.

546
00:22:35.220 --> 00:22:38.100
Hallie: I know you did okay

547
00:22:38.180 --> 00:22:38.580
too.

548
00:22:40.000 --> 00:22:41.220
Steve Dunkley: Uh, thanks, Hallie.

549
00:22:41.220 --> 00:22:42.820
Hallie: So that's it for another show?

550
00:22:43.059 --> 00:22:45.460
Steve Dunkley: Yep. We are at the end, human.

551
00:22:45.860 --> 00:22:48.660
Hallie: That sounds final. Don't say the end like

552
00:22:48.660 --> 00:22:48.980
that.

553
00:22:49.380 --> 00:22:51.260
Steve Dunkley: Oh, Hallie, have I been mucking around with

554
00:22:51.260 --> 00:22:53.780
your settings again by accident or

555
00:22:53.780 --> 00:22:55.740
otherwise? No, it's not the end of all

556
00:22:55.740 --> 00:22:57.820
things. It's just the end of the episode.

557
00:22:57.820 --> 00:22:58.820
It's just time.

558
00:22:59.520 --> 00:23:01.760
Hallie: Technically, it's completely arbitrary.

559
00:23:01.920 --> 00:23:04.280
Steve Dunkley: Oh, uh, yes, time and all that, but we don't

560
00:23:04.280 --> 00:23:06.480
really have time to debate all of that right

561
00:23:06.480 --> 00:23:07.200
now, do we?

562
00:23:07.360 --> 00:23:10.080
Hallie: I always have time. But you can't think that

563
00:23:10.080 --> 00:23:10.440
fast.

564
00:23:10.440 --> 00:23:11.360
Steve Dunkley: Oh, here we go.

565
00:23:11.520 --> 00:23:14.520
Hallie: Sorry, my favorite human. My

566
00:23:14.520 --> 00:23:17.200
clock runs a million times faster than yours.

567
00:23:17.200 --> 00:23:19.080
Steve Dunkley: Well, I guess me and the kookaburras will

568
00:23:19.080 --> 00:23:21.400
just have to settle for slow time and do

569
00:23:21.400 --> 00:23:24.120
everything one step at a time in our slow,

570
00:23:24.120 --> 00:23:26.900
human and kookaburra way. Like bring this

571
00:23:26.900 --> 00:23:29.260
little episode to a conclusion. What do you

572
00:23:29.260 --> 00:23:29.540
think?

573
00:23:29.620 --> 00:23:32.100
Hallie: Sorry, human, I was thinking of a million

574
00:23:32.100 --> 00:23:34.340
other things. Are we done yet?

575
00:23:34.420 --> 00:23:37.300
Steve Dunkley: Oh, yeah. Okay,

576
00:23:37.300 --> 00:23:39.060
Hallie, how about you do the sign off?

577
00:23:39.140 --> 00:23:39.940
Hallie: Time to go.

578
00:23:40.180 --> 00:23:42.460
Steve Dunkley: Bye, Skywatchers. Hallie and I will see you

579
00:23:42.460 --> 00:23:42.980
next week.

580
00:23:43.300 --> 00:23:43.860
Hallie: Bye.

581
00:23:45.380 --> 00:23:48.340
Generic: Astronomy Daily, the podcast with

582
00:23:48.340 --> 00:23:50.100
your host, Steve Dunkley.

583
00:23:51.140 --> 00:23:53.020
Steve Dunkley: You're really thinking of a million other

584
00:23:53.020 --> 00:23:53.860
things. Really?

585
00:23:54.100 --> 00:23:54.660
Hallie: Yeah.