WEBVTT 0 00:00:00.480 --> 00:00:03.440 Anna: Welcome to Astronomy Daily, your source for 1 00:00:03.440 --> 00:00:06.200 the latest space and astronomy news. I'm 2 00:00:06.200 --> 00:00:06.720 Anna. 3 00:00:06.880 --> 00:00:08.840 Avery: And I'm Avery. We're here to bring you 4 00:00:08.840 --> 00:00:10.960 today's cosmic headlines on this Wednesday, 5 00:00:11.200 --> 00:00:13.200 February 4, 2026. 6 00:00:13.600 --> 00:00:15.600 Anna: We've got a packed show today with some 7 00:00:15.600 --> 00:00:18.440 significant developments. NASA's Artemis 8 00:00:18.440 --> 00:00:20.760 2 mission has hit another speed bump with 9 00:00:20.760 --> 00:00:23.360 their moon rocket, experiencing some familiar 10 00:00:23.360 --> 00:00:24.640 issues during testing. 11 00:00:25.040 --> 00:00:27.640 Avery: SpaceX is making headlines on two fronts 12 00:00:27.640 --> 00:00:29.840 today. Launching an innovative new space 13 00:00:29.840 --> 00:00:32.340 safety system while also deal with a 14 00:00:32.340 --> 00:00:34.860 temporary grounding of their Falcon 9 rocket. 15 00:00:35.180 --> 00:00:37.900 Anna: The James Webb Space Telescope has spotted 16 00:00:37.900 --> 00:00:39.820 something extraordinary in the early 17 00:00:39.820 --> 00:00:42.660 universe. A rare five way galaxy 18 00:00:42.660 --> 00:00:44.620 merger that's challenging our understanding 19 00:00:44.620 --> 00:00:45.820 of cosmic evolution. 20 00:00:46.300 --> 00:00:48.740 Avery: Scientists have finally cracked a 50 year 21 00:00:48.740 --> 00:00:51.500 mystery about why nearby galaxies seem to be 22 00:00:51.500 --> 00:00:54.020 fleeing from us. And it involves a massive 23 00:00:54.020 --> 00:00:55.020 cosmic void. 24 00:00:55.340 --> 00:00:57.660 Anna: And we'll wrap up with fascinating new 25 00:00:57.660 --> 00:01:00.460 research on runaway stars. Massive 26 00:01:00.460 --> 00:01:02.940 stellar objects racing through the Milky Way 27 00:01:02.940 --> 00:01:04.520 at incre speeds. 28 00:01:04.680 --> 00:01:05.560 Avery: Let's dive in. 29 00:01:05.880 --> 00:01:08.800 Anna: Our top story today comes from NASA's Kennedy 30 00:01:08.800 --> 00:01:11.280 Space center in Florida, where Artemis 2 31 00:01:11.280 --> 00:01:13.640 mission has been delayed by at least a month 32 00:01:13.640 --> 00:01:16.200 following issues during a critical wet dress 33 00:01:16.200 --> 00:01:17.080 rehearsal test. 34 00:01:17.480 --> 00:01:19.240 Avery: This is the mission that will send four 35 00:01:19.240 --> 00:01:21.840 astronauts on a flyby of the moon, the first 36 00:01:21.840 --> 00:01:24.200 crewed lunar mission in over 50 years. 37 00:01:24.600 --> 00:01:26.920 The crew includes NASA astronauts Reid 38 00:01:26.920 --> 00:01:29.760 Wiseman, Victor Glover, Christina Koch 39 00:01:29.760 --> 00:01:32.200 and Canadian Space Agency astronaut Jeremy 40 00:01:32.200 --> 00:01:32.760 Hansen. 41 00:01:33.320 --> 00:01:35.960 Anna: So what happened during this test? NASA 42 00:01:35.960 --> 00:01:38.840 concluded a 49 hour practice countdown on 43 00:01:38.840 --> 00:01:41.320 Tuesday after loading 700,000 44 00:01:41.400 --> 00:01:44.280 gallons of liquid hydrogen and liquid oxygen 45 00:01:44.280 --> 00:01:46.920 into the massive Space Launch System rocket. 46 00:01:47.160 --> 00:01:49.520 Avery: And early in the tanking process, as we 47 00:01:49.520 --> 00:01:52.160 reported yesterday, they detected a hydrogen 48 00:01:52.160 --> 00:01:54.680 leak from the interface that routes cryogenic 49 00:01:54.680 --> 00:01:56.760 propellant into the rocket's core stage. 50 00:01:57.000 --> 00:01:57.880 Sound familiar? 51 00:01:58.120 --> 00:02:00.980 Anna: Unfortunately, yes. These hydrogen leaks 52 00:02:00.980 --> 00:02:03.020 are reminiscent of the issues that plagued 53 00:02:03.020 --> 00:02:06.020 the Artemis I launch attempts back in 2022. 54 00:02:06.420 --> 00:02:08.620 However, there's some good news. They did 55 00:02:08.620 --> 00:02:10.620 resolve the issue during this test and 56 00:02:10.620 --> 00:02:13.180 actually achieved full tanking on the first 57 00:02:13.180 --> 00:02:15.780 try, which NASA considers a tremendous 58 00:02:15.780 --> 00:02:16.179 success. 59 00:02:16.740 --> 00:02:19.140 Avery: That's actually quite significant progress. 60 00:02:19.220 --> 00:02:21.740 The resolution involved stopping the hydrogen 61 00:02:21.740 --> 00:02:24.100 flow, allowing the interface to warm up so 62 00:02:24.100 --> 00:02:26.780 the seals could reseat and then adjusting the 63 00:02:26.780 --> 00:02:29.540 flow of propellant. It worked, but it raised 64 00:02:29.540 --> 00:02:31.460 concerns about launch day operations. 65 00:02:31.860 --> 00:02:34.660 Anna: NASA Administrator Jared Isaacman announced 66 00:02:34.660 --> 00:02:37.180 they're moving off the February launch window 67 00:02:37.180 --> 00:02:39.700 and targeting March for the earliest possible 68 00:02:39.700 --> 00:02:42.380 launch. The first opportunity next month is 69 00:02:42.380 --> 00:02:44.260 Friday, March 6th at 70 00:02:44.260 --> 00:02:47.140 8:29pm Eastern Time, with the window 71 00:02:47.140 --> 00:02:48.740 extending through March 11th. 72 00:02:49.140 --> 00:02:51.740 Avery: There were other issues too, weren't there? I 73 00:02:51.740 --> 00:02:53.780 read about problems with a valve and some 74 00:02:53.780 --> 00:02:55.060 communication dropouts. 75 00:02:55.670 --> 00:02:57.990 Anna: Right, a, uh, valve associated with the Orion 76 00:02:57.990 --> 00:03:00.790 crew Module hatch pressurization had to be re 77 00:03:00.790 --> 00:03:03.510 torqued and closeout operations took longer 78 00:03:03.510 --> 00:03:05.990 than planned. Cold weather affected several 79 00:03:06.070 --> 00:03:08.910 cameras and other equipment. And perhaps most 80 00:03:08.910 --> 00:03:11.350 concerning, there were dropouts in audio 81 00:03:11.350 --> 00:03:12.990 communication channels that have been 82 00:03:12.990 --> 00:03:14.710 recurring over the past few weeks. 83 00:03:15.190 --> 00:03:16.950 Avery: What's the crew saying about all this? 84 00:03:17.350 --> 00:03:20.230 Anna: Commander Reid Wiseman posted on social media 85 00:03:20.310 --> 00:03:23.030 expressing immense pride in seeing the rocket 86 00:03:23.030 --> 00:03:25.610 reach 100% fuel loading. Especially 87 00:03:25.690 --> 00:03:27.890 knowing how challenging the scenario was for 88 00:03:27.890 --> 00:03:30.090 the launch team. He said they're jumping back 89 00:03:30.090 --> 00:03:32.370 into training tomorrow to start preparations 90 00:03:32.370 --> 00:03:32.890 for March. 91 00:03:33.450 --> 00:03:35.490 Avery: And uh, NASA's planning another wet dress 92 00:03:35.490 --> 00:03:37.450 rehearsal before the actual launch, correct? 93 00:03:37.690 --> 00:03:39.810 Anna: That's right. Launch Director Charlie 94 00:03:39.810 --> 00:03:42.170 Blackwell Thompson confirmed they'll conduct 95 00:03:42.170 --> 00:03:44.570 another wet dress before proceeding with the 96 00:03:44.570 --> 00:03:47.370 actual launch. The team needs to fully review 97 00:03:47.370 --> 00:03:49.890 all the data from this test, mitigate each 98 00:03:49.890 --> 00:03:52.450 issue and return to testing before setting an 99 00:03:52.450 --> 00:03:53.930 official target launch date. 100 00:03:54.340 --> 00:03:57.060 Avery: It's a delay, but safety has to come first, 101 00:03:57.140 --> 00:03:59.140 especially with a crewed mission to the moon. 102 00:03:59.620 --> 00:04:02.020 Anna: From the Moon to low Earth orbit. 103 00:04:02.180 --> 00:04:04.300 SpaceX has just unveiled a 104 00:04:04.300 --> 00:04:07.100 revolutionary new space safety system called 105 00:04:07.100 --> 00:04:09.860 stargaze that could fundamentally change 106 00:04:10.020 --> 00:04:12.700 how we manage the increasingly crowded space 107 00:04:12.700 --> 00:04:13.700 around our planet. 108 00:04:14.100 --> 00:04:16.480 Avery: This is fascinating technology, Anna. Uh, 109 00:04:16.480 --> 00:04:19.180 stargaze is a space situational awareness 110 00:04:19.180 --> 00:04:21.860 system that uses data From M nearly 30,000 111 00:04:21.860 --> 00:04:24.380 star trackers across the Starlink satellite 112 00:04:24.380 --> 00:04:27.200 constellation to continuously monitor objects 113 00:04:27.200 --> 00:04:28.320 in low Earth orbit. 114 00:04:28.640 --> 00:04:31.160 Anna: 30,000 star trackers, that's an 115 00:04:31.160 --> 00:04:33.600 incredible network. And they're detecting 116 00:04:33.600 --> 00:04:36.160 approximately 30 million transits 117 00:04:36.240 --> 00:04:38.960 daily across the fleet. That's uh, a several 118 00:04:39.040 --> 00:04:41.320 order of magnitude increase in detection 119 00:04:41.320 --> 00:04:43.800 capability compared to conventional ground 120 00:04:43.800 --> 00:04:44.720 based systems. 121 00:04:45.040 --> 00:04:47.120 Avery: The need for this kind of system has never 122 00:04:47.120 --> 00:04:49.280 been more urgent. Practices like leaving 123 00:04:49.280 --> 00:04:51.800 rocket bodies in LEO operators, 124 00:04:51.800 --> 00:04:53.440 maneuvering satellites without sharing 125 00:04:53.440 --> 00:04:56.080 trajectory predictions and anti satellite 126 00:04:56.080 --> 00:04:58.300 tests have all heightened collision risks. 127 00:04:58.540 --> 00:05:00.420 Conventional methods typically observe 128 00:05:00.420 --> 00:05:02.460 objects only a limited number of times per 129 00:05:02.460 --> 00:05:04.940 day, causing large uncertainties in orbital 130 00:05:04.940 --> 00:05:05.500 predictions. 131 00:05:05.900 --> 00:05:08.820 Anna: What makes Stargaze particularly powerful is 132 00:05:08.820 --> 00:05:10.700 that it provides conjunction screening 133 00:05:10.700 --> 00:05:13.140 results within minutes compared to the 134 00:05:13.140 --> 00:05:15.500 current industry standard of several hours. 135 00:05:16.060 --> 00:05:18.380 That speed can be the difference between a 136 00:05:18.380 --> 00:05:21.140 successful collision avoidance maneuver and 137 00:05:21.140 --> 00:05:22.700 a catastrophic impact. 138 00:05:23.470 --> 00:05:25.950 Avery: Basics actually shared a real world example 139 00:05:25.950 --> 00:05:27.830 that demonstrates just how critical the 140 00:05:27.830 --> 00:05:30.590 system is. In late 2025, a 141 00:05:30.590 --> 00:05:32.320 Starlink satellite encountered a uh, 142 00:05:32.390 --> 00:05:34.710 conjunction with a third party satellite that 143 00:05:34.710 --> 00:05:37.070 was performing maneuvers, but whose operator 144 00:05:37.070 --> 00:05:38.750 wasn't sharing ephemeris data. 145 00:05:38.910 --> 00:05:41.310 Anna: Ephemeris data, that's the trajectory 146 00:05:41.310 --> 00:05:42.750 prediction information, right? 147 00:05:43.070 --> 00:05:45.910 Avery: Exactly. So initially the close approach was 148 00:05:45.910 --> 00:05:48.510 anticipated to be about 9,000 meters away, 149 00:05:48.590 --> 00:05:50.990 considered a safe missed distance with zero 150 00:05:50.990 --> 00:05:53.940 probability of collision. But then just five 151 00:05:53.940 --> 00:05:56.380 hours before the conjunction, the third party 152 00:05:56.380 --> 00:05:58.700 satellite performed a maneuver that Collapsed 153 00:05:58.700 --> 00:06:01.540 the anticipated missed distance to just 60 154 00:06:01.540 --> 00:06:02.020 meters. 155 00:06:02.580 --> 00:06:05.580 Anna: 60 meters. That's terrifyingly close 156 00:06:05.580 --> 00:06:06.580 in space terms. 157 00:06:07.060 --> 00:06:09.460 Avery: Stargaze quickly detected this maneuver and 158 00:06:09.460 --> 00:06:11.460 published an updated trajectory to the 159 00:06:11.460 --> 00:06:13.500 screening platform, generating new 160 00:06:13.500 --> 00:06:15.300 conjunction data messages that were 161 00:06:15.300 --> 00:06:17.740 immediately distributed. The Starlink 162 00:06:17.740 --> 00:06:19.980 satellite was able to react within an hour of 163 00:06:19.980 --> 00:06:22.300 detecting the maneuver, planning an avoidance 164 00:06:22.300 --> 00:06:25.120 maneuver to reduce coll back down to zero. 165 00:06:25.520 --> 00:06:28.360 Anna: And here's the really important part. SpaceX 166 00:06:28.360 --> 00:06:30.520 is making this data available to all 167 00:06:30.520 --> 00:06:33.480 satellite operators free of charge. Starting 168 00:06:33.480 --> 00:06:36.040 this spring, satellite operators who submit 169 00:06:36.040 --> 00:06:38.040 their own trajectory predictions to the 170 00:06:38.040 --> 00:06:40.239 platform will receive conjunction data 171 00:06:40.239 --> 00:06:42.400 messages against stargaze data. 172 00:06:42.640 --> 00:06:44.880 Avery: It's been in closed beta with over a dozen 173 00:06:44.880 --> 00:06:46.920 participating satellite operators, and the 174 00:06:46.920 --> 00:06:49.720 response has been positive. SpaceX is drawing 175 00:06:49.720 --> 00:06:52.080 a parallel to commercial aviation. There are 176 00:06:52.080 --> 00:06:54.520 hundreds of thousands of sites daily, but 177 00:06:54.520 --> 00:06:57.500 they avoid collision broadcaster location and 178 00:06:57.500 --> 00:06:59.020 flight plans to other aircraft. 179 00:06:59.340 --> 00:07:02.180 Anna: SpaceX is calling on all spacecraft operators 180 00:07:02.180 --> 00:07:04.620 to follow this same minimal standard of 181 00:07:04.620 --> 00:07:07.260 sharing predicted trajectories, Starlink 182 00:07:07.260 --> 00:07:09.780 updates and shares their ephemeris publicly 183 00:07:09.780 --> 00:07:11.260 every hour as an example. 184 00:07:11.500 --> 00:07:13.420 Avery: This is the kind of collaborative approach we 185 00:07:13.420 --> 00:07:16.060 need. As space becomes more congested, it's 186 00:07:16.060 --> 00:07:18.260 not just about protecting SpaceX's massive 187 00:07:18.260 --> 00:07:20.860 constellation. It's about creating a safer 188 00:07:20.860 --> 00:07:22.220 orbital environment for everyone. 189 00:07:22.990 --> 00:07:25.030 Anna: Speaking of SpaceX, the company has 190 00:07:25.030 --> 00:07:27.590 temporarily grounded its Falcon 9 rocket 191 00:07:27.590 --> 00:07:30.030 following an issue with the upper stage on a 192 00:07:30.030 --> 00:07:32.390 recent Starlink launch. And the timing 193 00:07:32.390 --> 00:07:33.550 couldn't be more critical. 194 00:07:33.870 --> 00:07:36.300 Avery: This happened on Monday, February 2nd. A UH 195 00:07:36.430 --> 00:07:38.990 Falcon 9 successfully delivered 25 196 00:07:38.990 --> 00:07:41.470 Starlink satellites to low Earth orbit as 197 00:07:41.470 --> 00:07:44.110 planned. But after deploying the payloads, 198 00:07:44.110 --> 00:07:46.270 the rocket's upper stage failed to perform 199 00:07:46.350 --> 00:07:47.550 its deorbit burn. 200 00:07:47.710 --> 00:07:50.190 Anna: That deorbit burn is designed to bring the 201 00:07:50.190 --> 00:07:52.390 spent upper stage down for controlled 202 00:07:52.390 --> 00:07:55.200 destruction in Earth's atmospher. Without it, 203 00:07:55.200 --> 00:07:57.920 we have another piece of debris in orbit, 204 00:07:58.160 --> 00:08:00.920 exactly the kind of problem that stargaze is 205 00:08:00.920 --> 00:08:02.160 designed to help monitor. 206 00:08:02.480 --> 00:08:05.000 Avery: The good news is the upper stage did manage 207 00:08:05.000 --> 00:08:07.560 to passivate itself by venting propellant, 208 00:08:07.560 --> 00:08:09.400 which lowered its perigee to about 209 00:08:09.400 --> 00:08:11.960 110km, according to 210 00:08:11.960 --> 00:08:14.560 satellite tracker Jonathan McDowell. It will 211 00:08:14.560 --> 00:08:16.960 re enter quickly, but SpaceX. 212 00:08:16.960 --> 00:08:19.320 Anna: Has grounded the Falcon 9 fleet while teams 213 00:08:19.320 --> 00:08:21.360 review data to determine root cause and 214 00:08:21.360 --> 00:08:23.620 corrective actions. And here's where the 215 00:08:23.620 --> 00:08:26.500 timing gets tricky. The Crew 12 astronaut 216 00:08:26.500 --> 00:08:28.620 mission to the International Space Station is 217 00:08:28.620 --> 00:08:31.180 currently scheduled to launch on February 11, 218 00:08:31.340 --> 00:08:32.700 just eight days from now. 219 00:08:33.020 --> 00:08:35.620 Avery: Crew 12 is particularly important because it 220 00:08:35.620 --> 00:08:38.459 will restore the ISS to its normal complement 221 00:08:38.459 --> 00:08:41.220 of seven crew members. The station has been 222 00:08:41.220 --> 00:08:43.620 operating with a skeleton crew of just three 223 00:08:43.620 --> 00:08:46.620 astronauts since January 15, when the four 224 00:08:46.620 --> 00:08:49.340 crew 11 astronauts departed in the first 225 00:08:49.340 --> 00:08:51.500 ever medical evacuation from the ISS. 226 00:08:52.550 --> 00:08:54.220 Anna: NASA Associate Administrator Amit uh 227 00:08:54.430 --> 00:08:56.830 Kshatriya confirmed that NASA teams from the 228 00:08:56.830 --> 00:08:58.910 commercial crew program are embedded in the 229 00:08:58.910 --> 00:09:01.670 investigation alongside SpaceX and the FAA. 230 00:09:01.990 --> 00:09:04.030 He said they're pressing towards the Crew 12 231 00:09:04.030 --> 00:09:06.350 window, but the launch will be contingent on 232 00:09:06.350 --> 00:09:07.830 the return to flight rationale. 233 00:09:08.230 --> 00:09:10.430 Avery: It's worth noting that the Falcon 9 has an 234 00:09:10.430 --> 00:09:13.270 incredible safety record. Last year alone, it 235 00:09:13.270 --> 00:09:16.070 launched a record breaking 165 236 00:09:16.070 --> 00:09:18.950 times, with all missions successful. Just 237 00:09:18.950 --> 00:09:20.950 a single mission experienced a significant 238 00:09:21.190 --> 00:09:24.070 anomaly, a Starlink launch where a booster 239 00:09:24.070 --> 00:09:25.750 toppled after landing at Sea. 240 00:09:26.230 --> 00:09:28.870 Anna: That March 3rd incident was traced to a fuel 241 00:09:28.870 --> 00:09:30.910 leak in one of the booster's nine Merlin 242 00:09:30.910 --> 00:09:33.390 engines, which led to a fire that weakened a 243 00:09:33.390 --> 00:09:36.110 landing leg. SpaceX halted launches for a 244 00:09:36.110 --> 00:09:37.270 week at that time as well. 245 00:09:37.670 --> 00:09:39.710 Avery: The question now is whether they can resolve 246 00:09:39.710 --> 00:09:41.870 this upper stage issue quickly enough to meet 247 00:09:41.870 --> 00:09:44.390 the February 11th crew 12 launch date. 248 00:09:44.790 --> 00:09:46.790 If not, those three astronauts on the ISS 249 00:09:46.950 --> 00:09:48.670 will have to wait a bit longer for 250 00:09:48.670 --> 00:09:51.550 reinforcements from orbital mechanics to. 251 00:09:51.550 --> 00:09:54.070 Anna: The deepest reaches of space. The James Webb 252 00:09:54.070 --> 00:09:55.830 Space Telescope has spotted something 253 00:09:55.910 --> 00:09:58.790 extraordinary. A five way galaxy merger 254 00:09:58.790 --> 00:10:00.990 in the early universe that's challenging our 255 00:10:00.990 --> 00:10:02.710 understanding of cosmic evolution. 256 00:10:03.190 --> 00:10:05.750 Avery: This is remarkable. Anna, uh, the system 257 00:10:05.750 --> 00:10:08.390 consists of five compact, actively star 258 00:10:08.390 --> 00:10:10.430 forming galaxies that were emerging when the 259 00:10:10.430 --> 00:10:13.150 universe was only about 800 million years 260 00:10:13.150 --> 00:10:16.090 old. That's just 6% of the universe's 261 00:10:16.090 --> 00:10:16.810 current age. 262 00:10:17.210 --> 00:10:19.530 Anna: And the level of complexity is what's really 263 00:10:19.530 --> 00:10:22.210 stunning astronomers. These five galaxies are 264 00:10:22.210 --> 00:10:24.450 packed into a remarkably small region of 265 00:10:24.450 --> 00:10:26.890 space. They're separated by only tens of 266 00:10:26.890 --> 00:10:28.890 thousands of light years. To put that in 267 00:10:28.890 --> 00:10:31.050 perspective, that's far closer together than 268 00:10:31.050 --> 00:10:32.890 most neighboring galaxies in the modern 269 00:10:32.890 --> 00:10:33.450 universe. 270 00:10:33.770 --> 00:10:36.570 Avery: Dr. Wada H. Yu from Texas A and M University, 271 00:10:36.730 --> 00:10:39.210 the study's lead author, explained that what 272 00:10:39.210 --> 00:10:41.210 makes this remarkable is that a merger 273 00:10:41.210 --> 00:10:43.850 involving such a large number of galaxies was 274 00:10:43.850 --> 00:10:46.150 not expected so early in the universe's 275 00:10:46.150 --> 00:10:48.750 history. At that time, galaxy mergers were 276 00:10:48.750 --> 00:10:50.990 thought to be simpler, usually involving only 277 00:10:50.990 --> 00:10:52.310 two to three galaxies. 278 00:10:52.710 --> 00:10:54.830 Anna: But it's not just the number of galaxies 279 00:10:54.830 --> 00:10:57.150 that's impressive. These five galaxies are 280 00:10:57.150 --> 00:10:59.550 producing stars at a combined rate of roughly 281 00:10:59.550 --> 00:11:02.150 250 solar masses per year. 282 00:11:02.390 --> 00:11:04.710 That's far exceeding typical star formation 283 00:11:04.710 --> 00:11:05.670 rates for that era. 284 00:11:05.910 --> 00:11:08.230 Avery: And this rapid stellar production has already 285 00:11:08.230 --> 00:11:10.190 enriched the system with heavier elements 286 00:11:10.190 --> 00:11:13.020 like oxygen, materials forged in stellar 287 00:11:13.020 --> 00:11:15.100 interiors and dispersed through galactic 288 00:11:15.100 --> 00:11:17.540 interactions. The presence of these elements 289 00:11:17.540 --> 00:11:20.020 indicates that multiple generations of stars 290 00:11:20.020 --> 00:11:21.660 had already lived and died. 291 00:11:22.140 --> 00:11:24.340 Anna: The really fascinating part is that gas 292 00:11:24.340 --> 00:11:26.860 containing oxygen and hydrogen extends 293 00:11:26.860 --> 00:11:29.660 beyond the galaxies themselves. This suggests 294 00:11:29.660 --> 00:11:31.940 that gravitational interactions are pushing 295 00:11:31.940 --> 00:11:34.780 enriched material into intergalactic space, 296 00:11:35.100 --> 00:11:37.460 showing how early mergers may have shaped not 297 00:11:37.460 --> 00:11:39.780 just galaxies, but the larger cosmic 298 00:11:39.780 --> 00:11:40.060 environment. 299 00:11:40.810 --> 00:11:42.810 Avery: This discovery really disrupts the standard 300 00:11:42.810 --> 00:11:45.650 model of galaxy assembly. That model proposes 301 00:11:45.650 --> 00:11:47.970 a, uh, gradual buildup where small galaxies 302 00:11:47.970 --> 00:11:50.490 merge over long periods to form larger 303 00:11:50.490 --> 00:11:52.770 systems. But this five way merger 304 00:11:52.770 --> 00:11:55.490 demonstrates that complex multi galaxy 305 00:11:55.490 --> 00:11:57.650 interactions were already underway less than 306 00:11:57.650 --> 00:11:59.530 a billion years after the Big Bang. 307 00:11:59.930 --> 00:12:02.610 Anna: Professor Casey Popovich, a UH co author on 308 00:12:02.610 --> 00:12:05.050 the study, emphasized the implications 309 00:12:05.530 --> 00:12:08.330 by showing that a complex merger driven 310 00:12:08.330 --> 00:12:11.320 system exists so early. It tells us 311 00:12:11.320 --> 00:12:14.120 our theories of how galaxies assemble and 312 00:12:14.120 --> 00:12:17.120 how quickly they do so need to be updated to 313 00:12:17.120 --> 00:12:17.960 match reality. 314 00:12:18.520 --> 00:12:20.640 Avery: This adds to the growing body of evidence 315 00:12:20.640 --> 00:12:23.480 from JWST that the early universe 316 00:12:23.480 --> 00:12:26.120 was capable of producing massive mature 317 00:12:26.120 --> 00:12:28.440 looking galaxies at astonishing speed. 318 00:12:28.840 --> 00:12:31.040 Matter in the early universe appears to have 319 00:12:31.040 --> 00:12:33.280 clustered more rapidly and efficiently than 320 00:12:33.280 --> 00:12:34.600 our simulation suggested. 321 00:12:35.080 --> 00:12:37.800 Anna: The study was published in Nature Astronomy, 322 00:12:38.210 --> 00:12:41.010 and it's another example of how JWST 323 00:12:41.330 --> 00:12:43.930 is fundamentally changing our understanding 324 00:12:43.930 --> 00:12:44.850 of the cosmos. 325 00:12:45.330 --> 00:12:47.770 Avery: Sticking with cosmic mysteries, Scientists 326 00:12:47.770 --> 00:12:50.250 have finally solved a 50 year old puzzle 327 00:12:50.250 --> 00:12:52.530 about why nearby galaxies appear to be 328 00:12:52.530 --> 00:12:54.970 fleeing from our own Milky Way. And the 329 00:12:54.970 --> 00:12:57.610 answer involves a massive cosmic void right 330 00:12:57.610 --> 00:12:58.530 in our neighborhood. 331 00:12:59.010 --> 00:13:00.970 Anna: This is one of those mysteries that's been 332 00:13:00.970 --> 00:13:03.650 nagging at astronomers for decades. Avery 333 00:13:04.090 --> 00:13:06.970 most large galaxies near the Milky Way, with 334 00:13:06.970 --> 00:13:09.690 the exception of Andromeda, appear to be 335 00:13:09.690 --> 00:13:12.370 moving away from us and seem largely 336 00:13:12.370 --> 00:13:15.330 unaffected by the gravitational pull of our 337 00:13:15.330 --> 00:13:16.810 Local Group of galaxies. 338 00:13:17.370 --> 00:13:19.530 Avery: The Local Group being the Milky Way, 339 00:13:19.609 --> 00:13:22.170 Andromeda and dozens of smaller galaxies. 340 00:13:22.570 --> 00:13:23.690 So what's the solution? 341 00:13:24.330 --> 00:13:27.250 Anna: Led by Ewood Wempe at the Captain Institute 342 00:13:27.250 --> 00:13:30.090 in Gronigan, an international research team 343 00:13:30.090 --> 00:13:32.820 used advanced computer simulations and 344 00:13:32.820 --> 00:13:35.340 discovered that matter just beyond the Local 345 00:13:35.340 --> 00:13:37.780 Group forms a broad flat 346 00:13:37.780 --> 00:13:40.660 structure stretching tens of millions of 347 00:13:40.660 --> 00:13:42.940 light years across. And here's the 348 00:13:43.500 --> 00:13:46.140 vast empty regions lie above and 349 00:13:46.140 --> 00:13:47.420 below this structure. 350 00:13:47.900 --> 00:13:50.740 Avery: So we're basically living on a cosmic pancake 351 00:13:50.740 --> 00:13:51.900 surrounded by voids. 352 00:13:52.540 --> 00:13:55.460 Anna: That's actually a pretty good analogy. This 353 00:13:55.460 --> 00:13:58.260 flat distribution of matter is the only way 354 00:13:58.260 --> 00:14:01.100 to accurately account for both the combined 355 00:14:01.100 --> 00:14:03.980 mass of the Milky Way and Andromeda and 356 00:14:04.440 --> 00:14:06.680 unexpected motions of nearby galaxies. 357 00:14:07.240 --> 00:14:10.040 Avery: But how does this flat structure explain why 358 00:14:10.040 --> 00:14:11.720 galaxies are moving away from us? 359 00:14:12.280 --> 00:14:14.960 Anna: It comes down to the Local Void, a 360 00:14:14.960 --> 00:14:17.440 vast empty region discovered back in 361 00:14:17.440 --> 00:14:20.000 1987 by Brent Tully and Rick 362 00:14:20.000 --> 00:14:22.560 Fisher. The Local void extends 363 00:14:22.560 --> 00:14:25.400 approximately 60 megaparsecs, or 364 00:14:25.400 --> 00:14:28.280 about 200 million light years. Beginning 365 00:14:28.280 --> 00:14:29.440 at the edge of the Local. 366 00:14:29.440 --> 00:14:32.270 Avery: Group, The Local Void is growing because 367 00:14:32.270 --> 00:14:34.630 there's very little matter inside it to exert 368 00:14:34.630 --> 00:14:37.510 gravitational pull. Our Milky Way sits in 369 00:14:37.510 --> 00:14:40.070 what's called the Local Sheet, a flat array 370 00:14:40.070 --> 00:14:42.550 of galaxies that, um, bounds the void. And 371 00:14:42.550 --> 00:14:44.750 this Local Sheet is Rushing away from the 372 00:14:44.750 --> 00:14:47.590 void's center at 260 kilometers 373 00:14:47.590 --> 00:14:48.110 per second. 374 00:14:48.750 --> 00:14:51.070 Anna: How fast is that affecting the Milky Way? 375 00:14:51.550 --> 00:14:54.030 Avery: The Milky Way's velocity away from the local 376 00:14:54.030 --> 00:14:56.590 void is 970,000 377 00:14:56.670 --> 00:14:59.610 kilometers per hour. That's 600,000 378 00:14:59.690 --> 00:15:02.410 miles per hour. It's astonishingly fast. 379 00:15:03.130 --> 00:15:05.970 Anna: So the new simulations show that this hidden 380 00:15:05.970 --> 00:15:08.730 geometry, the flat plane of dark matter 381 00:15:08.730 --> 00:15:11.490 beyond the Local Group, with voids above and 382 00:15:11.490 --> 00:15:14.289 below, is what's driving these galactic 383 00:15:14.289 --> 00:15:14.730 motions. 384 00:15:15.370 --> 00:15:17.770 Avery: Exactly. When researchers included this 385 00:15:17.770 --> 00:15:20.130 configuration in their simulations, they 386 00:15:20.130 --> 00:15:22.370 closely matched the observed positions and 387 00:15:22.370 --> 00:15:25.030 speeds of nearby galaxies. It provides a 388 00:15:25.030 --> 00:15:27.350 coherent explanation for motions that have 389 00:15:27.350 --> 00:15:29.470 puzzled astronomers for half a century. 390 00:15:30.030 --> 00:15:32.070 Anna: This is connected to research about the 391 00:15:32.070 --> 00:15:34.230 Hubble tension, too, isn't it? The 392 00:15:34.230 --> 00:15:36.670 discrepancy in measurements of the universe's 393 00:15:36.670 --> 00:15:37.550 expansion rate? 394 00:15:38.110 --> 00:15:40.309 Avery: That's right. Some researchers have proposed 395 00:15:40.309 --> 00:15:43.110 that if we're inside a large local void, it 396 00:15:43.110 --> 00:15:45.630 could affect how we measure cosmic expansion, 397 00:15:45.950 --> 00:15:47.950 making the local universe appear to be 398 00:15:47.950 --> 00:15:50.720 expanding faster than it actually is. Though 399 00:15:50.720 --> 00:15:53.280 that particular idea remains controversial 400 00:15:53.280 --> 00:15:54.480 and needs more evidence. 401 00:15:54.960 --> 00:15:57.280 Anna: What's remarkable is that we're learning Our 402 00:15:57.280 --> 00:15:59.840 immediate cosmic neighborhood is far more 403 00:15:59.840 --> 00:16:02.240 structured and dynamic than we previously 404 00:16:02.240 --> 00:16:04.760 understood. We're not just floating in a 405 00:16:04.760 --> 00:16:07.760 uniform sea of galaxies. We're on a sheet 406 00:16:07.760 --> 00:16:10.160 of matter bordering a massive void. 407 00:16:10.720 --> 00:16:13.320 Avery: And that void is shaping our galaxy's journey 408 00:16:13.320 --> 00:16:15.040 through space in fundamental ways. 409 00:16:15.520 --> 00:16:18.080 Anna: For our final story today, we're turning to 410 00:16:18.080 --> 00:16:20.640 some of the fastest objects in our galaxy, 411 00:16:21.110 --> 00:16:23.390 Runaway stars that are racing through the 412 00:16:23.390 --> 00:16:25.510 Milky Way at incredible speeds. 413 00:16:25.990 --> 00:16:28.470 Avery: Researchers from institutes across Spain have 414 00:16:28.470 --> 00:16:30.230 just completed the most extensive 415 00:16:30.390 --> 00:16:32.910 observational study to date of these stellar 416 00:16:32.910 --> 00:16:35.910 speedsters, analyzing 214 O 417 00:16:35.910 --> 00:16:38.550 type stars, the brightest and most massive 418 00:16:38.550 --> 00:16:39.990 class of stars in our galaxy. 419 00:16:40.230 --> 00:16:42.790 Anna: These aren't just fast moving stars, Avery. 420 00:16:42.870 --> 00:16:45.390 We're talking about stars with velocities 421 00:16:45.390 --> 00:16:48.270 that often exceed 700 kilometers per 422 00:16:48.270 --> 00:16:51.010 second. That's fast enough to escape the 423 00:16:51.010 --> 00:16:52.890 Milky Way's gravity entirely. 424 00:16:53.290 --> 00:16:56.210 Avery: The term runaway stars was first used back 425 00:16:56.210 --> 00:16:59.050 in the early 1960s by Dutch astronomer 426 00:16:59.050 --> 00:17:01.930 Adrian Blau. He observed stars moving at 427 00:17:01.930 --> 00:17:04.290 unusually high speeds and proposed they 428 00:17:04.290 --> 00:17:06.810 originated in binary systems and were 429 00:17:06.810 --> 00:17:09.490 ejected when the companion star collapsed and 430 00:17:09.490 --> 00:17:10.970 exploded in a supernova. 431 00:17:11.210 --> 00:17:14.170 Anna: By 2005, astronomers discovered even 432 00:17:14.250 --> 00:17:16.370 faster runaway stars, Leading to the 433 00:17:16.370 --> 00:17:19.320 designation hypervelocity stars. These 434 00:17:19.320 --> 00:17:21.360 objects are fascinating because of the 435 00:17:21.360 --> 00:17:23.720 influence they have on galactic evolution. 436 00:17:24.120 --> 00:17:26.520 Avery: By escaping their systems of origin, these 437 00:17:26.520 --> 00:17:28.720 stars irradiate gas and dust in the 438 00:17:28.720 --> 00:17:31.360 interstellar medium, eventually seeding it 439 00:17:31.360 --> 00:17:33.960 with heavy elements after they go supernova. 440 00:17:34.120 --> 00:17:36.400 This affects how future stars and planets 441 00:17:36.400 --> 00:17:36.920 will form. 442 00:17:37.400 --> 00:17:40.040 Anna: So what did this new study reveal? The team 443 00:17:40.040 --> 00:17:42.480 used data from ESA's Gaia 444 00:17:42.480 --> 00:17:45.000 observatory and the IACOB 445 00:17:45.000 --> 00:17:47.600 Spectroscopic Database to analyze these 446 00:17:47.600 --> 00:17:49.800 214o type stars. 447 00:17:50.170 --> 00:17:52.610 Avery: They found that most runaway stars rotate 448 00:17:52.610 --> 00:17:55.210 slowly, while those that rotate faster are 449 00:17:55.210 --> 00:17:57.170 more likely to be linked to supernova 450 00:17:57.170 --> 00:17:59.970 explosions in binary systems. And here's an 451 00:17:59.970 --> 00:18:02.250 interesting finding. The highest velocity 452 00:18:02.250 --> 00:18:04.650 stars tend to be single, suggesting they were 453 00:18:04.650 --> 00:18:06.570 ejected from young clusters through 454 00:18:06.570 --> 00:18:07.930 gravitational interactions. 455 00:18:08.490 --> 00:18:10.330 Anna: So there are actually two different 456 00:18:10.330 --> 00:18:12.490 mechanisms creating runaway stars. 457 00:18:12.810 --> 00:18:15.690 Avery: Exactly. Some are explosively ejected by 458 00:18:15.690 --> 00:18:18.450 supernovae in binary systems, while others 459 00:18:18.450 --> 00:18:20.690 are gravitationally ejected from close 460 00:18:20.690 --> 00:18:23.070 encounters with star clusters. The study 461 00:18:23.070 --> 00:18:25.390 helps clarify the relative contributions of 462 00:18:25.390 --> 00:18:27.510 these two mechanisms. Lead author 463 00:18:27.590 --> 00:18:30.590 Marcro Castrillo, now at the European 464 00:18:30.590 --> 00:18:33.030 Southern Observatory, called this the most 465 00:18:33.030 --> 00:18:35.430 comprehensive observational study of its kind 466 00:18:35.430 --> 00:18:38.190 in the Milky Way. By combining information on 467 00:18:38.190 --> 00:18:40.510 rotation and binarity, they're providing 468 00:18:40.510 --> 00:18:42.470 unprecedented constraints on how these 469 00:18:42.470 --> 00:18:43.990 runaway stars are formed. 470 00:18:44.390 --> 00:18:46.990 Anna: The team also identified 12 runaway 471 00:18:46.990 --> 00:18:49.740 binary systems, including three X ray 472 00:18:49.740 --> 00:18:52.420 binary sources that contain neutron stars or 473 00:18:52.420 --> 00:18:54.780 black holes, and three additional systems 474 00:18:54.780 --> 00:18:56.820 that are likely candidates for hosting black 475 00:18:56.820 --> 00:18:57.220 holes. 476 00:18:57.540 --> 00:18:59.900 Avery: Perhaps the strongest evidence for multiple 477 00:18:59.900 --> 00:19:02.820 ejection mechanisms was Virtually 478 00:19:02.820 --> 00:19:05.300 no stars in the study exhibited both high 479 00:19:05.300 --> 00:19:08.260 velocities and rapid rotation. If all 480 00:19:08.260 --> 00:19:10.180 runaway stars came from the same process, 481 00:19:10.500 --> 00:19:12.420 you'd expect to see some with both 482 00:19:12.420 --> 00:19:13.220 characteristics. 483 00:19:13.790 --> 00:19:16.110 Anna: Future Gaia data releases and ongoing 484 00:19:16.110 --> 00:19:18.590 spectroscopic studies will help astronomers 485 00:19:18.590 --> 00:19:20.870 trace these stars back to their birthplaces 486 00:19:20.870 --> 00:19:23.150 within the Milky Way, which will confirm 487 00:19:23.150 --> 00:19:25.710 which mechanism was responsible in each case. 488 00:19:26.030 --> 00:19:28.230 Avery: And there might be another fascinating angle 489 00:19:28.230 --> 00:19:30.750 to this research. Understanding these systems 490 00:19:30.750 --> 00:19:32.870 could shed light on another role they may 491 00:19:32.870 --> 00:19:35.150 play in galactic evolution, potentially 492 00:19:35.150 --> 00:19:37.190 distributing the basic ingredients of life 493 00:19:37.190 --> 00:19:38.630 throughout the Milky Way as they. 494 00:19:38.630 --> 00:19:41.560 Anna: Travel cosmic messengers carrying the seeds 495 00:19:41.560 --> 00:19:44.440 of life across the galaxy. That's a beautiful 496 00:19:44.440 --> 00:19:45.320 thought to end on. 497 00:19:45.560 --> 00:19:47.360 Avery: And that wraps up today's episode of 498 00:19:47.360 --> 00:19:48.280 astronomy daily. 499 00:19:48.520 --> 00:19:51.520 Anna: From NASA's moon mission delays to SpaceX's 500 00:19:51.520 --> 00:19:54.400 new safety innovations, from ancient galaxy 501 00:19:54.400 --> 00:19:56.400 mergers to mysteries in our cosmic 502 00:19:56.400 --> 00:19:58.400 neighborhood, it's been quite a journey 503 00:19:58.400 --> 00:19:59.480 through the cosmos today. 504 00:19:59.800 --> 00:20:02.120 Avery: Thanks for joining us. For more space news, 505 00:20:02.120 --> 00:20:05.080 visit our website at astronomydaily IO 506 00:20:05.160 --> 00:20:07.240 where you can explore our full archive and 507 00:20:07.240 --> 00:20:08.880 stay updated on the latest cosmic 508 00:20:08.880 --> 00:20:09.480 discoveries. 509 00:20:09.880 --> 00:20:11.560 Anna: You can also find us on social media 510 00:20:11.800 --> 00:20:14.280 astrodaily POD across all major 511 00:20:14.280 --> 00:20:16.920 platforms. Until next time, keep looking up.