WEBVTT 0 00:00:00.000 --> 00:00:02.880 Anna: Welcome to Astronomy Daily, your 1 00:00:02.880 --> 00:00:05.640 go to podcast for the latest and greatest 2 00:00:05.640 --> 00:00:08.280 in space and astronomy news. I'm 3 00:00:08.280 --> 00:00:08.800 Anna. 4 00:00:08.880 --> 00:00:11.320 Avery: And I'm Avery. We've got a great lineup for 5 00:00:11.320 --> 00:00:13.000 you today covering everything from the 6 00:00:13.000 --> 00:00:15.360 primordial Earth to mysterious dark matter, 7 00:00:15.360 --> 00:00:17.760 and even how to spot the Andromeda Galaxy. 8 00:00:18.080 --> 00:00:20.080 Anna: That's right. It's going to be an action 9 00:00:20.320 --> 00:00:23.200 packed episode. Let's dive straight into 10 00:00:23.200 --> 00:00:25.680 our first story, which is absolutely 11 00:00:25.680 --> 00:00:26.720 fantastic. Fascinating. 12 00:00:26.960 --> 00:00:29.160 Avery, tell us about this discovery that 13 00:00:29.160 --> 00:00:31.600 suggests we've found a piece of Earth 14 00:00:31.840 --> 00:00:33.440 that's older than the Moon. 15 00:00:33.680 --> 00:00:36.360 Avery: You got it, Anna. This, is a game changer. 16 00:00:36.520 --> 00:00:38.640 Researchers have identified what may be the 17 00:00:38.640 --> 00:00:41.240 first physical traces of primordial Earth. 18 00:00:41.320 --> 00:00:43.560 The early version of our planet that existed 19 00:00:43.560 --> 00:00:46.040 before a massive collision reshaped it into 20 00:00:46.040 --> 00:00:47.320 the world we know it today. 21 00:00:47.720 --> 00:00:50.360 Anna: Wow. So before the giant impact. 22 00:00:50.520 --> 00:00:51.160 Essentially. 23 00:00:51.650 --> 00:00:54.490 Avery: Exactly. A team led by MIT scientists with 24 00:00:54.490 --> 00:00:56.890 collaborators from China, Switzerland and the 25 00:00:56.890 --> 00:00:59.810 US Uncovered a rare chemical signature in 26 00:00:59.810 --> 00:01:02.690 ancient rocks dating back over 4.5 27 00:01:02.770 --> 00:01:05.370 billion years. This study, published in 28 00:01:05.370 --> 00:01:08.050 Nature Geoscience, really challenges the idea 29 00:01:08.050 --> 00:01:10.330 that Earth's turbulent beginnings completely 30 00:01:10.330 --> 00:01:12.130 erased its original composition. 31 00:01:12.530 --> 00:01:15.490 Anna: So fragments of the planet's first materials 32 00:01:15.490 --> 00:01:18.130 might still exist deep within the mantle. 33 00:01:18.290 --> 00:01:19.090 That's incredible. 34 00:01:19.520 --> 00:01:21.840 Avery: It really is. Current models suggest Earth 35 00:01:21.840 --> 00:01:23.960 formed from a disk of gas and dust, with 36 00:01:23.960 --> 00:01:26.320 particles coalescing into meteorites and then 37 00:01:26.320 --> 00:01:29.280 young planets. Then, about 100 million years 38 00:01:29.280 --> 00:01:32.080 after its formation, a, ah, giant Mars sized 39 00:01:32.080 --> 00:01:34.800 object collided with our world. This giant 40 00:01:34.800 --> 00:01:37.240 impact not only created the Moon, but also 41 00:01:37.240 --> 00:01:39.160 melted and mixed much of the planet's 42 00:01:39.160 --> 00:01:41.920 interior, resetting its chemistry. Most 43 00:01:41.920 --> 00:01:43.380 scientists thought, the original building 44 00:01:43.380 --> 00:01:45.980 blocks were lost forever, but this new study 45 00:01:45.980 --> 00:01:48.460 says otherwise. The scientists analyzed 46 00:01:48.460 --> 00:01:50.380 ancient volcanic rocks from Canada and 47 00:01:50.380 --> 00:01:52.700 Greenland, which are known to contain some of 48 00:01:52.700 --> 00:01:55.180 Earth's oldest preserved materials. They 49 00:01:55.180 --> 00:01:57.900 focused on a specific isotope of neodymium, 50 00:01:58.060 --> 00:02:00.420 an element that's been used as a tracer for 51 00:02:00.420 --> 00:02:03.140 early Earth processes. What they found was a 52 00:02:03.140 --> 00:02:05.740 distinct neodymium signature that aligns with 53 00:02:05.740 --> 00:02:07.580 predictions for Earth's original building 54 00:02:07.580 --> 00:02:09.530 blocks, rather than the thoroughly mixed M 55 00:02:09.780 --> 00:02:11.620 mantle material that will start to exist 56 00:02:11.620 --> 00:02:14.400 after the Moon forming impact. This suggests 57 00:02:14.400 --> 00:02:16.480 that some parts of the mantle were somehow 58 00:02:16.480 --> 00:02:18.440 shielded from the intense mixing that 59 00:02:18.440 --> 00:02:20.320 occurred during that cataclysmic event, 60 00:02:20.720 --> 00:02:22.960 preserving a chemical fossil of the very 61 00:02:22.960 --> 00:02:25.360 early Earth. It's like finding a needle in a 62 00:02:25.360 --> 00:02:27.800 cosmic haystack, giving us a direct window 63 00:02:27.800 --> 00:02:30.000 into a time we thought was completely lost. 64 00:02:30.480 --> 00:02:33.360 Anna: That's truly astounding. So if these 65 00:02:33.520 --> 00:02:35.960 fragments of primordial Earth are still 66 00:02:35.960 --> 00:02:38.800 present, what does that imply about the early 67 00:02:38.800 --> 00:02:41.520 processes of planet formation and the scale 68 00:02:41.520 --> 00:02:43.870 of the Moon forming impact. The does this 69 00:02:43.870 --> 00:02:46.390 challenge our understanding of how thoroughly 70 00:02:46.550 --> 00:02:49.190 the Earth was homogenized after that event? 71 00:02:49.510 --> 00:02:50.550 Avery: It certainly does. 72 00:02:50.790 --> 00:02:52.950 Avery: The prevailing theory was that the impact was 73 00:02:52.950 --> 00:02:55.710 so energetic, it melted and mixed the entire 74 00:02:55.710 --> 00:02:58.270 planet, effectively resetting its chemical 75 00:02:58.270 --> 00:03:00.790 clock. This new evidence suggests that while 76 00:03:00.790 --> 00:03:03.510 the impact was monumental, certain deep 77 00:03:03.510 --> 00:03:05.430 pockets of the mantle might have remained 78 00:03:05.430 --> 00:03:07.870 relatively untouched. This could mean the 79 00:03:07.870 --> 00:03:10.010 mixing wasn't as complete as we thought was, 80 00:03:10.160 --> 00:03:11.720 or that there were regions deep within the 81 00:03:11.720 --> 00:03:13.880 Earth that were resilient to such large scale 82 00:03:13.880 --> 00:03:16.720 homogenization. It opens up new avenues for 83 00:03:16.720 --> 00:03:18.720 research into the Earth's geological history 84 00:03:18.800 --> 00:03:21.240 and might require us to refine our models of 85 00:03:21.240 --> 00:03:23.960 planetary accretion and differentiation. It 86 00:03:23.960 --> 00:03:25.760 also raises questions about whether similar 87 00:03:25.919 --> 00:03:28.160 primordial fragments could exist on other 88 00:03:28.160 --> 00:03:30.560 planets that experience large impacts. 89 00:03:31.040 --> 00:03:31.760 Anna: Fascinating. 90 00:03:32.320 --> 00:03:35.120 Shifting gears slightly, let's talk about 91 00:03:35.200 --> 00:03:38.200 dark matter this week. New research has 92 00:03:38.200 --> 00:03:40.800 shed light on how dark matter M might be 93 00:03:40.800 --> 00:03:43.660 interacting with normal matter, or rather, 94 00:03:43.900 --> 00:03:46.460 not interacting in the way we traditionally 95 00:03:46.460 --> 00:03:49.260 thought. Avery, what's the latest on this 96 00:03:49.260 --> 00:03:51.420 elusive component of our universe? 97 00:03:51.660 --> 00:03:54.020 Avery: Indeed, dark matter remains one of the 98 00:03:54.020 --> 00:03:56.900 universe's most profound mysteries. For 99 00:03:56.900 --> 00:03:58.940 decades, the prevailing theory has been that 100 00:03:58.940 --> 00:04:01.540 dark matter interacts with normal matter only 101 00:04:01.540 --> 00:04:04.300 through gravity. However, new theoretical 102 00:04:04.300 --> 00:04:06.860 work is exploring the possibility of a dark 103 00:04:06.860 --> 00:04:09.180 force that could mediate interactions within 104 00:04:09.180 --> 00:04:11.840 dark matter itself and, and perhaps even with 105 00:04:11.840 --> 00:04:12.880 regular matter in. 106 00:04:12.880 --> 00:04:14.680 Avery: Subtle ways we haven't yet detected. 107 00:04:15.400 --> 00:04:17.760 Avery: This wouldn't be a direct collision or a 108 00:04:17.760 --> 00:04:20.520 strong force, but a very weak interaction, 109 00:04:20.520 --> 00:04:23.320 almost like a whisper across the cosmic void. 110 00:04:23.640 --> 00:04:25.560 It's a fascinating concept that could help 111 00:04:25.560 --> 00:04:27.800 explain some of the anomalies observed in 112 00:04:27.800 --> 00:04:30.480 galaxy rotation curves and galactic cluster 113 00:04:30.480 --> 00:04:32.880 dynamics. That gravity alone struggles to 114 00:04:32.880 --> 00:04:35.400 account for a dark force. 115 00:04:35.640 --> 00:04:38.560 Anna: That's a captivating idea. So we're 116 00:04:38.560 --> 00:04:40.760 talking about something beyond gravitational 117 00:04:40.760 --> 00:04:43.100 interaction. How would such a force 118 00:04:43.100 --> 00:04:45.140 manifest, and what are the theoretical 119 00:04:45.140 --> 00:04:47.940 implications for detecting dark matter if 120 00:04:47.940 --> 00:04:49.700 it interacts in this novel way? 121 00:04:50.660 --> 00:04:53.620 Avery: Well, if a dark force exists, it would 122 00:04:53.620 --> 00:04:56.100 likely manifest as extremely subtle 123 00:04:56.180 --> 00:04:58.340 interactions. We're talking about 124 00:04:58.420 --> 00:05:01.140 interactions so weak they wouldn't cause 125 00:05:01.140 --> 00:05:03.860 particles to visibly collide or strongly 126 00:05:03.860 --> 00:05:06.660 bind, but rather exert a gentle push 127 00:05:06.660 --> 00:05:09.630 or pull. Theoretically, this could create 128 00:05:09.630 --> 00:05:12.110 tiny perturbations in the distribution of 129 00:05:12.110 --> 00:05:14.390 dark matter that are distinct from what 130 00:05:14.390 --> 00:05:16.590 purely gravitational interactions would 131 00:05:16.590 --> 00:05:19.470 predict. Detecting it would be incredibly 132 00:05:19.470 --> 00:05:21.790 challenging, requiring highly sensitive 133 00:05:21.790 --> 00:05:23.710 detectors that could register these minute 134 00:05:23.710 --> 00:05:26.190 influences. It might involve looking for 135 00:05:26.190 --> 00:05:28.550 faint signals in experiments designed to 136 00:05:28.550 --> 00:05:30.910 detect weakly interacting massive particles, 137 00:05:30.910 --> 00:05:33.320 or WIMPs, which are a, leading candidate for 138 00:05:33.320 --> 00:05:36.120 dark, lighter. Or it could even impact the 139 00:05:36.120 --> 00:05:38.840 dynamics of very diffuse dark matter halos 140 00:05:38.840 --> 00:05:41.520 around galaxies in ways we're just beginning 141 00:05:41.520 --> 00:05:44.480 to model. It's a frontier of physics, 142 00:05:44.640 --> 00:05:46.480 pushing the boundaries of what we understand 143 00:05:46.480 --> 00:05:48.800 about the fundamental forces of the universe. 144 00:05:49.600 --> 00:05:52.560 Anna: That's truly mind bending. The idea 145 00:05:52.560 --> 00:05:55.080 of forces beyond gravity shaping the 146 00:05:55.080 --> 00:05:57.920 cosmos is a testament to how much more there 147 00:05:57.920 --> 00:06:00.680 is to learn from the unseen forces 148 00:06:00.680 --> 00:06:01.520 of dark matter. 149 00:06:02.000 --> 00:06:04.600 Let's now turn our gaze to something a little 150 00:06:04.600 --> 00:06:07.460 more tangible, yet still incredibly 151 00:06:07.460 --> 00:06:10.420 vast. For our next story, we're going to talk 152 00:06:10.420 --> 00:06:13.060 about our galactic neighbor, the Andromeda 153 00:06:13.060 --> 00:06:16.060 Galaxy. Avery, for those of us who want 154 00:06:16.060 --> 00:06:18.380 to catch a glimpse of this cosmic marvel, 155 00:06:18.620 --> 00:06:19.740 what do we need to know? 156 00:06:20.140 --> 00:06:21.340 Avery: Absolutely, Anna. 157 00:06:21.500 --> 00:06:23.700 Avery: The Andromeda Galaxy, also known as 158 00:06:23.700 --> 00:06:26.460 Messier31, is our closest 159 00:06:26.460 --> 00:06:29.220 major galactic neighbor and truly a sight to 160 00:06:29.220 --> 00:06:32.060 behold. It's located about 2.5 161 00:06:32.060 --> 00:06:34.660 million light years away, making it the most 162 00:06:34.660 --> 00:06:37.220 distant object visible to the naked eye under 163 00:06:37.300 --> 00:06:40.300 dark skies. To spot it, you'll want to find 164 00:06:40.300 --> 00:06:43.100 a location away from city lights. Look for 165 00:06:43.100 --> 00:06:45.700 the constellation Andromeda. A, good starting 166 00:06:45.700 --> 00:06:46.380 point is to. 167 00:06:46.380 --> 00:06:48.980 Avery: Locate the great square of Pegasus, and. 168 00:06:48.980 --> 00:06:51.100 Avery: From one of its corners, you can star hop 169 00:06:51.100 --> 00:06:54.020 your way to Andromeda. Once you're in 170 00:06:54.020 --> 00:06:55.870 the general area, it will appear as a faint, 171 00:06:55.870 --> 00:06:58.310 fuzzy patch of light, almost like a smudged 172 00:06:58.470 --> 00:07:01.050 star. With binoculars or a small 173 00:07:01.050 --> 00:07:03.250 telescope, you can begin to resolve its 174 00:07:03.250 --> 00:07:06.090 elliptical shape and perhaps even hint at 175 00:07:06.090 --> 00:07:09.050 its spiral arms. What makes Andromeda 176 00:07:09.050 --> 00:07:11.250 so significant beyond its stunning visual 177 00:07:11.250 --> 00:07:13.570 appeal, is that it's on a collision course 178 00:07:13.570 --> 00:07:16.570 with our own Milky Way galaxy. In about 179 00:07:16.570 --> 00:07:19.410 4.5 billion years, these 180 00:07:19.410 --> 00:07:22.290 two colossal galaxies will merge, forming 181 00:07:22.290 --> 00:07:25.140 a new, even larger elliptical galaxy, which 182 00:07:25.140 --> 00:07:27.580 scientists have nicknamed Milkomeda. 183 00:07:27.980 --> 00:07:29.940 This provides an incredible natural 184 00:07:29.940 --> 00:07:31.900 laboratory for understanding galactic 185 00:07:31.900 --> 00:07:33.500 evolution and dynamics. 186 00:07:33.740 --> 00:07:36.700 Anna: That's a fantastic guide, Avery. It's 187 00:07:36.700 --> 00:07:39.300 incredible to think we can see another galaxy 188 00:07:39.300 --> 00:07:42.100 with our naked eyes, and even more so 189 00:07:42.100 --> 00:07:44.940 to contemplate its eventual merger with our 190 00:07:44.940 --> 00:07:45.260 own. 191 00:07:46.220 --> 00:07:48.740 Speaking of things falling from the sky, but 192 00:07:48.740 --> 00:07:51.700 on a much, much closer scale, Our next 193 00:07:51.700 --> 00:07:54.460 story takes us to Tennessee, where residents 194 00:07:54.460 --> 00:07:56.980 on Monday witnessed a spectacular 195 00:07:57.060 --> 00:07:59.980 green fireball meteor. What can you tell 196 00:07:59.980 --> 00:08:01.380 us about this luminous event? 197 00:08:01.780 --> 00:08:02.860 Avery: That's right, Anna. 198 00:08:02.860 --> 00:08:05.570 Avery: This, spectacular green fireball captivated 199 00:08:05.570 --> 00:08:07.970 skywatchers across Tennessee and surrounding 200 00:08:07.970 --> 00:08:10.770 states. On Monday night, reports flooded in 201 00:08:10.770 --> 00:08:13.330 of a brilliant, fast moving object streaking 202 00:08:13.330 --> 00:08:15.770 across the night sky. Characterized by its 203 00:08:15.770 --> 00:08:18.720 striking emerald hue, this color is a key 204 00:08:18.720 --> 00:08:21.080 indicator. It suggests a high concentration 205 00:08:21.080 --> 00:08:23.960 of magnesium and nickel in the meteoroid. 206 00:08:24.280 --> 00:08:26.640 As the meteoroid enters Earth's atmosphere at 207 00:08:26.640 --> 00:08:29.280 high speed, the intense friction heats it up, 208 00:08:29.280 --> 00:08:31.680 causing these elements to ionize and emit 209 00:08:31.680 --> 00:08:34.400 light at specific wavelengths. The green glow 210 00:08:34.400 --> 00:08:36.360 is particularly common with meteoroids. 211 00:08:36.360 --> 00:08:39.240 Containing these metals. These events are 212 00:08:39.240 --> 00:08:41.320 scientifically valuable because they provide 213 00:08:41.320 --> 00:08:43.400 opportunities to study the composition of 214 00:08:43.400 --> 00:08:46.320 extraterrestrial objects before they hit the 215 00:08:46.320 --> 00:08:49.000 ground or even vaporize entirely. Scientists 216 00:08:49.000 --> 00:08:51.360 use eyewitness accounts, along with data from 217 00:08:51.360 --> 00:08:53.720 cameras and atmospheric sensors to 218 00:08:53.720 --> 00:08:55.720 triangulate the meteor's trajectory and 219 00:08:55.720 --> 00:08:58.120 estimate its original size and composition. 220 00:08:58.360 --> 00:09:00.390 It helps us, understand the population of 221 00:09:00.390 --> 00:09:03.070 small space rocks orbiting the sun and how 222 00:09:03.070 --> 00:09:04.630 often they interact with Earth. 223 00:09:05.590 --> 00:09:08.230 Anna: That's a truly captivating phenomenon. 224 00:09:08.550 --> 00:09:10.950 From distant galaxies and fiery 225 00:09:10.950 --> 00:09:13.710 atmospheric entries, let's pivot to the 226 00:09:13.710 --> 00:09:16.230 future of space travel and exploration. 227 00:09:17.160 --> 00:09:19.400 Our final story for today is about an 228 00:09:19.400 --> 00:09:21.960 exciting development. Foldable 229 00:09:21.960 --> 00:09:24.200 solar sails for aerobraking and 230 00:09:24.200 --> 00:09:26.880 atmospheric re entry. This sounds like 231 00:09:26.880 --> 00:09:28.600 something straight out of science fiction. 232 00:09:28.840 --> 00:09:30.120 What's the breakthrough here? 233 00:09:30.760 --> 00:09:31.640 Avery: It really is. 234 00:09:31.800 --> 00:09:34.600 Avery: This is an ingenious concept that addresses a 235 00:09:34.600 --> 00:09:37.240 major challenge in space travel. Efficiently 236 00:09:37.240 --> 00:09:39.280 slowing down spacecraft without massive 237 00:09:39.280 --> 00:09:41.280 amounts of propellant. Traditional 238 00:09:41.280 --> 00:09:43.480 aerobraking uses a spacecraft's heat shield 239 00:09:43.480 --> 00:09:45.750 to create drag in a planet's atmosphere, but. 240 00:09:45.820 --> 00:09:48.100 But it's often a single use high stress 241 00:09:48.100 --> 00:09:51.020 event. Foldable solar sails in this context, 242 00:09:51.020 --> 00:09:52.900 aren't just for propulsion via solar 243 00:09:52.900 --> 00:09:55.060 radiation pressure. They're designed to be 244 00:09:55.060 --> 00:09:57.340 deployed and used as a large, lightweight 245 00:09:57.340 --> 00:09:59.580 drag surface for atmospheric entry and 246 00:09:59.580 --> 00:10:02.300 aerobraking. Imagine a spacecraft approaching 247 00:10:02.300 --> 00:10:05.140 Mars or Earth. Instead of firing thrusters or 248 00:10:05.140 --> 00:10:08.020 relying solely on a rigid heat shield, it 249 00:10:08.020 --> 00:10:10.700 unfurls these vast, thin membranes. 250 00:10:10.860 --> 00:10:12.820 These sails would increase the surface area 251 00:10:12.820 --> 00:10:15.020 exposed to the tenuous upper atmosphere, 252 00:10:15.100 --> 00:10:17.180 creating. Creating significant drag, allowing 253 00:10:17.180 --> 00:10:19.420 the spacecraft to slow down gradually and 254 00:10:19.420 --> 00:10:22.420 precisely. This dramatically reduces the need 255 00:10:22.420 --> 00:10:25.140 for heavy, costly propellant, freeing up 256 00:10:25.140 --> 00:10:27.260 space for scientific instruments or cargo. 257 00:10:27.660 --> 00:10:30.580 The foldable aspect is crucial. It 258 00:10:30.580 --> 00:10:32.620 means they can be packed compactly for launch 259 00:10:32.700 --> 00:10:35.420 and then expanded to enormous sizes in 260 00:10:35.420 --> 00:10:37.860 space. It's particularly promising for 261 00:10:37.860 --> 00:10:40.620 missions requiring gentle reentry, Precise 262 00:10:40.620 --> 00:10:43.300 orbital adjustments, or even deorbiting space 263 00:10:43.300 --> 00:10:45.830 debris. It's a game changer for sustainable 264 00:10:45.830 --> 00:10:47.950 and cost effective space exploration. 265 00:10:48.750 --> 00:10:50.830 Anna: And that brings us to the end of another 266 00:10:50.910 --> 00:10:53.470 captivating episode of Astronomy Daily. 267 00:10:53.870 --> 00:10:56.390 We've journeyed from the primordial Earth to 268 00:10:56.390 --> 00:10:59.190 the mysteries of dark matter, gazed upon the 269 00:10:59.190 --> 00:11:01.510 Andromeda galaxy, Witnessed a 270 00:11:01.510 --> 00:11:04.430 spectacular green fireball, and looked into 271 00:11:04.430 --> 00:11:06.750 the future of space travel with foldable 272 00:11:06.750 --> 00:11:09.750 solar sails. What an incredible array of 273 00:11:09.750 --> 00:11:10.670 topics, Avery. 274 00:11:11.630 --> 00:11:14.110 Avery: And thank you for joining us on this stellar 275 00:11:14.110 --> 00:11:16.230 journey through the cosmos. We hope you 276 00:11:16.230 --> 00:11:18.550 enjoyed exploring these incredible scientific 277 00:11:18.550 --> 00:11:20.870 discoveries and advancements with us. Make 278 00:11:20.870 --> 00:11:22.750 sure to subscribe so you don't miss our next 279 00:11:22.750 --> 00:11:24.510 episode, where we'll continue to bring you 280 00:11:24.510 --> 00:11:26.270 the latest from the world of space and 281 00:11:26.270 --> 00:11:28.910 astronomy. Until then, keep looking up.