00:00:00 --> 00:00:02 Anna: Welcome back to Astronomy Daily, your go to
00:00:02 --> 00:00:05 podcast for all the latest happenings in our
00:00:05 --> 00:00:07 incredible universe. I'm Anna.
00:00:07 --> 00:00:10 Avery: And I'm Avery. We've got a big episode lined
00:00:10 --> 00:00:12 up for you today, packed with some truly
00:00:12 --> 00:00:14 fascinating cosmic updates.
00:00:14 --> 00:00:16 Anna: That's right, Avery. We'll be diving into new
00:00:16 --> 00:00:19 research about lunar seismic activity
00:00:19 --> 00:00:21 and what moonquakes could mean for future
00:00:21 --> 00:00:24 bases on our nearest celestial neighbour.
00:00:24 --> 00:00:27 Turns out the Moon is a lot shakier than you
00:00:27 --> 00:00:28 might think.
00:00:28 --> 00:00:31 Avery: And speaking of drama, we'll also explore the
00:00:31 --> 00:00:34 explosive end of a massive star that had a
00:00:34 --> 00:00:36 very close encounter with a black hole. It's
00:00:36 --> 00:00:39 a story straight out of a sci fi movie, but
00:00:39 --> 00:00:40 it's real.
00:00:40 --> 00:00:42 Anna: Plus, we're tackling some long standing
00:00:42 --> 00:00:45 cosmic mysteries, from the curious case of
00:00:45 --> 00:00:47 the universe's missing sulphur to
00:00:47 --> 00:00:50 groundbreaking new insights about Vesta, one
00:00:50 --> 00:00:53 of the largest objects in the asteroid belt.
00:00:53 --> 00:00:54 Which might be more than just an.
00:00:54 --> 00:00:57 Avery: Asteroid, but so buckle up because
00:00:57 --> 00:00:59 we're about to take a tour through the latest
00:00:59 --> 00:01:02 and greatest in space and astronomy news.
00:01:02 --> 00:01:05 Anna: Alright, let's kick things off with some big
00:01:05 --> 00:01:08 news about our own Moon. We often think
00:01:08 --> 00:01:10 of it as a quiet, unchanging place, but
00:01:10 --> 00:01:13 new research is challenging that idea,
00:01:13 --> 00:01:15 especially when we consider building long
00:01:15 --> 00:01:16 term bases there.
00:01:16 --> 00:01:19 Avery: That's right, Anna. It turns out our lunar
00:01:19 --> 00:01:22 neighbour is more seismically active than
00:01:22 --> 00:01:25 many might assume. A recent study focusing
00:01:25 --> 00:01:27 on the Lee Lincoln Fault in the Taurus
00:01:27 --> 00:01:30 Littrell Valley, where the Apollo 17
00:01:30 --> 00:01:32 astronauts landed in 1972,
00:01:32 --> 00:01:35 highlights that these moonquakes could pose
00:01:35 --> 00:01:37 significant risks to future permanent lunar
00:01:37 --> 00:01:38 structures.
00:01:38 --> 00:01:41 Anna: This research, led by Smithsonian Senior
00:01:41 --> 00:01:44 Scientist Emeritus Thomas R. Waters,
00:01:44 --> 00:01:47 emphasises that the global distribution of
00:01:47 --> 00:01:49 these young thrust faults and their potential
00:01:49 --> 00:01:52 to still be active needs to be seriously
00:01:52 --> 00:01:54 considered. We're talking about planning
00:01:54 --> 00:01:57 locations and assessing the stability of any
00:01:57 --> 00:01:59 permanent outposts on the Moon.
00:01:59 --> 00:02:02 Avery: And, um, the evidence isn't new. It's based
00:02:02 --> 00:02:04 on moonquakes in the region over the past 90
00:02:04 --> 00:02:07 million years. Much of this evidence comes
00:02:07 --> 00:02:09 from material gathered by the Apollo
00:02:09 --> 00:02:11 astronauts themselves. Things like chunks of
00:02:11 --> 00:02:14 rocks and landslides are silent. But clear
00:02:14 --> 00:02:17 proof of the power of even magnitude
00:02:17 --> 00:02:19 3.0 quakes to shift surface
00:02:19 --> 00:02:22 materials around it really points to the Moon
00:02:22 --> 00:02:24 still being geologically active.
00:02:25 --> 00:02:27 Anna: It makes you wonder, why does the Moon even
00:02:27 --> 00:02:29 have quakes here on Earth? We're very
00:02:29 --> 00:02:32 familiar with earthquakes, primarily caused
00:02:32 --> 00:02:34 by plate tectonics and volcanic activity.
00:02:34 --> 00:02:37 Think of the San Andreas Fault or the Ring of
00:02:37 --> 00:02:40 Fire. Magma movement also causes tremors,
00:02:40 --> 00:02:42 like the recent events in Hawaii and Iceland.
00:02:43 --> 00:02:45 Avery: But the Moon operates differently. Its quakes
00:02:45 --> 00:02:47 are most Likely caused by two main
00:02:48 --> 00:02:50 Earth's tidal pulling and the Moon's
00:02:50 --> 00:02:53 continuous cooling and shrinking. The deep
00:02:53 --> 00:02:55 moonquakes occurring hundreds of miles inside
00:02:56 --> 00:02:58 are due to Earth's gravity pulling on her
00:02:58 --> 00:02:59 satellite.
00:02:59 --> 00:03:01 Anna: And the weaker quakes closer to the surface
00:03:01 --> 00:03:03 are generally attributed to the Moon's
00:03:03 --> 00:03:06 gradual cooling and shrinking. Since its
00:03:06 --> 00:03:09 formation billions of years ago, the Moon has
00:03:09 --> 00:03:12 actually lost about 150ft of
00:03:12 --> 00:03:14 its diameter. There are also minor tremors
00:03:14 --> 00:03:17 from meteoroid impacts or surface rocks
00:03:17 --> 00:03:19 reacting to heating and cooling from the sun.
00:03:20 --> 00:03:22 So it's a world that's constantly shaking.
00:03:22 --> 00:03:25 Avery: When we talk about the risks to future bases,
00:03:25 --> 00:03:27 it becomes quite significant. Short term
00:03:27 --> 00:03:30 missions like the Apollo landings, where
00:03:30 --> 00:03:32 astronauts were on the Moon for less than two
00:03:32 --> 00:03:35 weeks, didn't face much danger. But for
00:03:35 --> 00:03:37 permanent bases, the chances of damage during
00:03:37 --> 00:03:40 a quake go up simply due to the extended
00:03:40 --> 00:03:41 exposure.
00:03:41 --> 00:03:44 Anna: Nicholas Schmer put it into perspective. He
00:03:44 --> 00:03:46 said if astronauts are there for a day,
00:03:46 --> 00:03:49 they'd just have very bad luck. If there was
00:03:49 --> 00:03:51 a damaging event, they. But if you have a
00:03:51 --> 00:03:53 habitat or crewed mission up on the Moon for
00:03:53 --> 00:03:55 a whole decade, that's
00:03:55 --> 00:03:58 3 days times 1
00:03:58 --> 00:04:01 in 20 million. Or the risk of a hazardous
00:04:01 --> 00:04:03 moonquake becoming about 1 in 5.
00:04:04 --> 00:04:06 Avery: He likened it to, uh, going from the
00:04:06 --> 00:04:09 extremely low odds of winning a lottery
00:04:09 --> 00:04:12 to the much higher odds of being dealt a four
00:04:12 --> 00:04:14 of a kind poker hand. It really illustrates
00:04:14 --> 00:04:17 how much the probability increases over time.
00:04:18 --> 00:04:21 Anna: And it's not just habitats. Countries like
00:04:21 --> 00:04:24 Russia, China and the US are planning to put
00:04:24 --> 00:04:26 nuclear power plants on the Moon. These
00:04:26 --> 00:04:29 facilities would supply massive amounts of
00:04:29 --> 00:04:31 power, but they'd also be susceptible to
00:04:31 --> 00:04:34 quake damage. This means any construction
00:04:34 --> 00:04:36 will need tough safety margins and shouldn't
00:04:36 --> 00:04:38 be located near active fault lines.
00:04:39 --> 00:04:42 Avery: Which is a tall order considering how many
00:04:42 --> 00:04:44 fault lines thread through the Moon. That's
00:04:44 --> 00:04:47 why this study of lunar paleoseismology
00:04:47 --> 00:04:50 looking at evidence of past quakes is so
00:04:50 --> 00:04:53 crucial. It will help us chart the safest
00:04:53 --> 00:04:55 places to build these long term habitats and
00:04:55 --> 00:04:57 power plants. It's all about understanding
00:04:57 --> 00:04:59 our cosmic neighbourhood.
00:04:59 --> 00:05:01 Before we make ourselves at home from
00:05:01 --> 00:05:04 lunar shaking, let's zoom out to something
00:05:04 --> 00:05:06 truly dramatic happening in the cosmos.
00:05:06 --> 00:05:09 Scientists have captured the explosive end of
00:05:09 --> 00:05:12 a massive star in a scenario unlike
00:05:12 --> 00:05:13 anything they've seen before.
00:05:14 --> 00:05:17 Anna: That's right, Avery. This event, more than
00:05:17 --> 00:05:20 700 million light years away, began as
00:05:20 --> 00:05:22 a faint flicker. Within days, the light
00:05:22 --> 00:05:25 flared, faded, and then, surprisingly,
00:05:25 --> 00:05:28 flared again. It was completely
00:05:28 --> 00:05:31 unlike the standard playbook for dying stars.
00:05:31 --> 00:05:34 Avery: What makes this even more incredible is that
00:05:34 --> 00:05:36 an artificial intelligence System flagged the
00:05:36 --> 00:05:39 event in real time. This allowed scientists
00:05:39 --> 00:05:42 to capture every phase of what may be the
00:05:42 --> 00:05:44 first recorded case of a massive star
00:05:44 --> 00:05:47 exploding as it tried to devour a black
00:05:47 --> 00:05:50 hole companion. Talk about cosmic drama.
00:05:50 --> 00:05:51 This supernova, named
00:05:51 --> 00:05:54 SN2023ZKD, was
00:05:54 --> 00:05:57 first spotted in July 2023 by the Zwicky
00:05:57 --> 00:06:00 Transient Facility and then analysed by a
00:06:00 --> 00:06:02 team from the Centre for Astrophysics at
00:06:02 --> 00:06:05 Harvard and Smithsonian mit. Their
00:06:05 --> 00:06:07 findings, published in the Astrophysical
00:06:07 --> 00:06:10 Journal, provide the clearest evidence yet
00:06:10 --> 00:06:12 that such extreme binary interactions can
00:06:12 --> 00:06:15 actually trigger a stellar detonation. It
00:06:15 --> 00:06:18 was part of the Young Supernova Experiment, a
00:06:18 --> 00:06:20 project designed to catch these exploding
00:06:20 --> 00:06:23 stars in their earliest stages. The AI system
00:06:23 --> 00:06:25 gave astronomers a crucial head start,
00:06:25 --> 00:06:28 allowing them to follow the explosion in near
00:06:28 --> 00:06:30 real time from both ground and space
00:06:30 --> 00:06:31 observatories.
00:06:32 --> 00:06:35 Anna: Alexander Agliano, the lead author of
00:06:35 --> 00:06:37 the study, stated that their analysis shows
00:06:37 --> 00:06:39 the blast was sparked by a catastrophic
00:06:39 --> 00:06:41 encounter with a black hole companion,
00:06:42 --> 00:06:44 providing the strongest evidence to date that
00:06:44 --> 00:06:47 such close interactions can indeed
00:06:47 --> 00:06:48 detonate a star.
00:06:49 --> 00:06:51 Avery: The leading explanation is that this massive
00:06:51 --> 00:06:54 star and black hole were locked in a decaying
00:06:54 --> 00:06:56 orbit. As they drew closer, the black hole's
00:06:56 --> 00:06:59 immense gravity pulled gas from the star into
00:06:59 --> 00:07:02 a surrounding disc. This intense stress is
00:07:02 --> 00:07:04 believed to have triggered the explosion
00:07:04 --> 00:07:06 before the star could fully engulf the black
00:07:06 --> 00:07:07 hole.
00:07:08 --> 00:07:10 Anna: Another possibility is that the black hole
00:07:10 --> 00:07:12 completely shredded the star, with the
00:07:12 --> 00:07:15 debris's collisions then powering the
00:07:15 --> 00:07:17 supernova's light. In either scenario,
00:07:17 --> 00:07:20 the aftermath left behind a heavier black
00:07:20 --> 00:07:21 hole.
00:07:21 --> 00:07:24 Avery: What really stood out to astronomers were the
00:07:24 --> 00:07:26 unusual light patterns from Earth.
00:07:26 --> 00:07:29 SN2023ZKD initially
00:07:29 --> 00:07:31 looked like a normal supernova. A single
00:07:31 --> 00:07:34 burst of light followed by a gradual fade.
00:07:34 --> 00:07:36 But then, months later, it did something
00:07:36 --> 00:07:39 truly extraordinary. It brightened again.
00:07:40 --> 00:07:43 Anna: Archival records showed that the system had
00:07:43 --> 00:07:45 actually been slowly brightening for more
00:07:45 --> 00:07:48 than four years before the explosion,
00:07:48 --> 00:07:51 a rare and telling sign of pre death
00:07:51 --> 00:07:54 instability. The analysis revealed that the
00:07:54 --> 00:07:57 supernova's light was shaped by layers of gas
00:07:57 --> 00:07:59 shed by the star in its final years.
00:07:59 --> 00:08:01 Avery: The first brightening came from the blast
00:08:01 --> 00:08:03 wave colliding with diffused gas, while while
00:08:03 --> 00:08:05 that second peak was fueled by a slower
00:08:05 --> 00:08:08 collision with a dense disc shaped cloud.
00:08:08 --> 00:08:10 The structure and timing of these events
00:08:10 --> 00:08:12 strongly point to extreme gravitational
00:08:12 --> 00:08:15 forces from a nearby compact object.
00:08:15 --> 00:08:18 Anna: It's clear that AI played a crucial role
00:08:18 --> 00:08:20 here. As Gagliano mentioned, their machine
00:08:20 --> 00:08:22 Learning system flagged
00:08:22 --> 00:08:25 SN2023SKD months
00:08:25 --> 00:08:28 before its most unusual behaviour, which gave
00:08:28 --> 00:08:30 them ample time to secure the critical
00:08:30 --> 00:08:33 observations needed to unravel this
00:08:33 --> 00:08:36 extraordinary explosion V. Ashley Villar,
00:08:36 --> 00:08:36 a.
00:08:36 --> 00:08:38 Avery: AH co author and assistant professor of
00:08:38 --> 00:08:41 astronomy at cfa, added that this event shows
00:08:41 --> 00:08:43 some of the clearest signs they've seen of a
00:08:43 --> 00:08:45 massive star interacting with the companion
00:08:45 --> 00:08:47 in the years before an explosion. They
00:08:47 --> 00:08:49 believe this might be part of a whole class
00:08:49 --> 00:08:52 of hidden explosions that AI will help them
00:08:52 --> 00:08:53 discover in the future.
00:08:53 --> 00:08:56 Anna: With new observatories like the veracy Rubin
00:08:56 --> 00:08:59 Observatory soon scanning the entire sky
00:08:59 --> 00:09:01 every few nights and projects like the Young
00:09:01 --> 00:09:04 Supernova Experiment continuing to identify
00:09:04 --> 00:09:07 new events quickly, astronomers expect expect
00:09:07 --> 00:09:09 to catch more of these rare and complex
00:09:09 --> 00:09:12 explosions in action. It's truly
00:09:12 --> 00:09:15 a new era for observing the most extreme
00:09:15 --> 00:09:18 cosmic events. That's an incredible story
00:09:18 --> 00:09:20 of cosmic violence and detection.
00:09:20 --> 00:09:23 Now let's shift gears a bit and delve into a
00:09:23 --> 00:09:26 long standing cosmic mystery. The case of
00:09:26 --> 00:09:28 the universe's missing sulphur.
00:09:28 --> 00:09:30 Avery: It sounds like something out of a detective
00:09:30 --> 00:09:32 novel. For years, scientists have been
00:09:32 --> 00:09:34 puzzled because there simply isn't as much
00:09:34 --> 00:09:37 sulphur floating around in deep space as they
00:09:37 --> 00:09:39 expected. This is quite an enigma,
00:09:39 --> 00:09:41 considering Sulphur is the 10th most abundant
00:09:41 --> 00:09:44 element in the universe and crucial for both
00:09:44 --> 00:09:45 planets and life.
00:09:45 --> 00:09:48 Anna: Exactly. But a, uh, new international study
00:09:48 --> 00:09:51 might have finally found its hiding place.
00:09:51 --> 00:09:53 Researchers from the University of
00:09:53 --> 00:09:55 Mississippi, the University of Hawaii at
00:09:55 --> 00:09:58 Manoa and Georgia State University teamed
00:09:58 --> 00:10:00 up to search for answers, publishing their
00:10:00 --> 00:10:02 findings in Nature Communication.
00:10:03 --> 00:10:06 Avery: So where has all the sulphur been? The team's
00:10:06 --> 00:10:07 results suggest that it's not actually
00:10:07 --> 00:10:10 missing at all. Instead, it's locked away in
00:10:10 --> 00:10:13 solid forms, bound within icy grains of
00:10:13 --> 00:10:14 interstellar dust.
00:10:14 --> 00:10:17 Anna: In these frigid environments, sulphur atoms
00:10:17 --> 00:10:19 can arrange themselves in two main
00:10:19 --> 00:10:22 neat eight atom rings called
00:10:22 --> 00:10:24 octasulfur crowns and chains of
00:10:24 --> 00:10:27 sulphur atoms connected by hydrogen, known
00:10:27 --> 00:10:30 as polysulfons. These structures
00:10:30 --> 00:10:33 literally stick to icy dust grains,
00:10:33 --> 00:10:35 essentially freezing the sulphur out of view.
00:10:35 --> 00:10:37 Avery: It's fascinating how a common element on
00:10:37 --> 00:10:40 Earth found in volcanoes and power plants
00:10:40 --> 00:10:43 can be so elusive in space. Ralph
00:10:43 --> 00:10:45 Kaiser, one of the lead researchers,
00:10:45 --> 00:10:47 explained that the observed amount of sulphur
00:10:47 --> 00:10:50 in dense molecular clouds is three orders of
00:10:50 --> 00:10:52 magnitude less than predicted gas phase
00:10:52 --> 00:10:55 abundances. That's a huge difference.
00:10:55 --> 00:10:58 Anna: Astronomers typically identify elements in
00:10:58 --> 00:11:00 space by detecting the unique patterns of
00:11:00 --> 00:11:03 light they emit or absorb. While tools
00:11:03 --> 00:11:06 like James Webb Space Telescope can easily
00:11:06 --> 00:11:09 pick out oxygen, carbon and nitrogen,
00:11:09 --> 00:11:11 sulphur just doesn't follow the rules in the
00:11:11 --> 00:11:14 same way. As researcher uh, Ryan Fortenberry
00:11:14 --> 00:11:16 noted, when you do that for sulphur, it's out
00:11:16 --> 00:11:17 of whack.
00:11:17 --> 00:11:20 Avery: Another challenge is sulfur's shape. Shifting
00:11:20 --> 00:11:23 nature. Fortenberry likened it to a virus
00:11:23 --> 00:11:25 always changing shape as it moves, making it
00:11:25 --> 00:11:28 incredibly difficult to track. But this new
00:11:28 --> 00:11:30 research points to stable molecular forms
00:11:30 --> 00:11:32 that astronomers can now specifically hunt
00:11:32 --> 00:11:35 for using advanced radio telescopes.
00:11:35 --> 00:11:38 Anna: By recreating the conditions of deep space in
00:11:38 --> 00:11:40 laboratory experiments, the researchers
00:11:40 --> 00:11:43 confirmed that these solid sulphur compounds
00:11:43 --> 00:11:46 could indeed form on icy surfaces.
00:11:46 --> 00:11:49 And here's the Once these icy grains are
00:11:49 --> 00:11:52 heated in young star systems, the sulphur can
00:11:52 --> 00:11:54 sublime, meaning it transforms directly from
00:11:54 --> 00:11:57 a solid to a gas, making it finally
00:11:57 --> 00:11:58 detectable from Earth.
00:11:59 --> 00:12:00 Avery: This work could finally help astronomers
00:12:00 --> 00:12:03 piece together sulfur's role in both the
00:12:03 --> 00:12:05 formation of planets and the very chemistry
00:12:05 --> 00:12:08 that supports life. If they can pinpoint
00:12:08 --> 00:12:10 exactly where sulphur is stored, it could
00:12:10 --> 00:12:12 deepen our understanding of how essential
00:12:12 --> 00:12:14 life building elements are distributed across
00:12:14 --> 00:12:17 the cosmos. And, um, even improve models of
00:12:17 --> 00:12:19 planetary atmospheres, especially for
00:12:19 --> 00:12:20 exoplanets.
00:12:20 --> 00:12:22 Anna: It's a perfect example of astrochemistry
00:12:22 --> 00:12:25 forcing hard questions and leading to
00:12:25 --> 00:12:28 creative solutions. As Fortenberry put it,
00:12:28 --> 00:12:31 this kind of foundational research has the
00:12:31 --> 00:12:34 potential for significant unintended positive
00:12:34 --> 00:12:36 consequences for our broader understanding of
00:12:36 --> 00:12:37 the universe.
00:12:38 --> 00:12:39 Avery: That's a great point, Anna.
00:12:39 --> 00:12:41 Speaking of profound insights into how
00:12:41 --> 00:12:44 celestial bodies form, our next story
00:12:44 --> 00:12:46 completely redefines what we thought we knew
00:12:46 --> 00:12:49 about Vesta, one of the largest objects in
00:12:49 --> 00:12:51 the asteroid belt. For years, astronomers
00:12:51 --> 00:12:54 viewed Vesta as almost a miniature version of
00:12:54 --> 00:12:56 Earth, something between a rock in space and
00:12:56 --> 00:12:59 a full fledged planet due to its rocky
00:12:59 --> 00:13:02 surface, distinct layers, and volcanic
00:13:02 --> 00:13:02 history.
00:13:02 --> 00:13:05 Anna: But new research is truly shaking up that
00:13:05 --> 00:13:08 view. Data collected from NASA's dawn
00:13:08 --> 00:13:11 spacecraft, reanalyzed years later,
00:13:11 --> 00:13:13 is rewriting our understanding of how early
00:13:13 --> 00:13:16 planets may have formed and what might have
00:13:16 --> 00:13:17 gone wrong in Vesta's case.
00:13:18 --> 00:13:20 Avery: M the Dante spacecraft orbited Vesta from
00:13:20 --> 00:13:23 2011 to 2012, meticulously
00:13:23 --> 00:13:25 mapping its surface and measuring its
00:13:25 --> 00:13:27 gravity. Initially, this data suggested
00:13:27 --> 00:13:30 Vesta had undergone planetary
00:13:30 --> 00:13:32 differentiation, the process where dense
00:13:32 --> 00:13:35 materials sink to form a core and
00:13:35 --> 00:13:37 lighter materials create a mantle and crust.
00:13:37 --> 00:13:40 The Just like Earth or Mars, Vesta's
00:13:40 --> 00:13:43 volcanic surface seemed to confirm this.
00:13:43 --> 00:13:46 Anna: However, a decade after Dawn's mission ended
00:13:46 --> 00:13:49 in 2018, researchers at NASA's Jet
00:13:49 --> 00:13:52 Propulsion Lab, or JPL, decided to take
00:13:52 --> 00:13:54 a fresh look at the data, using better
00:13:54 --> 00:13:57 calibration and updated processing tools.
00:13:58 --> 00:14:00 And what they found completely challenged
00:14:00 --> 00:14:03 that long held Vesta may not have
00:14:03 --> 00:14:04 a core at all.
00:14:05 --> 00:14:07 Avery: That's a huge revelation. Ryan Park, a
00:14:07 --> 00:14:09 senior research scientist and principal
00:14:09 --> 00:14:12 engineer at jpl, expressed excitement,
00:14:12 --> 00:14:14 saying they were thrilled to confirm the
00:14:14 --> 00:14:17 data's strength in revealing Vesta's deep
00:14:17 --> 00:14:20 interior. By reanalyzing the dawn data,
00:14:20 --> 00:14:22 the team made a more precise estimate of, uh,
00:14:22 --> 00:14:25 Vesta's moment of inertia.
00:14:25 --> 00:14:28 Anna: For those wondering, the moment of inertia is
00:14:28 --> 00:14:31 a physics concept that reveals how mass is
00:14:31 --> 00:14:33 distributed within a rotating body.
00:14:34 --> 00:14:36 Assistant Professor Seth Jacobson of Michigan
00:14:36 --> 00:14:39 State University explained it with a simple
00:14:40 --> 00:14:42 Think of a figure skater. When they pull
00:14:42 --> 00:14:45 their arms in, they spin faster. When they
00:14:45 --> 00:14:47 stretch their arms out, they slow down.
00:14:48 --> 00:14:50 Celestial bodies with dense cores behave like
00:14:50 --> 00:14:53 skaters with their arms in rotating
00:14:53 --> 00:14:54 differently.
00:14:54 --> 00:14:56 Avery: And Vesta's behaviour simply didn't match
00:14:56 --> 00:14:59 what scientists expected from a core bearing
00:14:59 --> 00:15:02 body. Its moment of inertia and calculated
00:15:02 --> 00:15:04 at only 6.6% lower than a
00:15:04 --> 00:15:07 perfectly uniform structure suggests its
00:15:07 --> 00:15:10 internal structure is. Surprisingly, even
00:15:10 --> 00:15:13 this value points to only a mild difference
00:15:13 --> 00:15:16 in density beneath its crust, not the
00:15:16 --> 00:15:18 deep layering we see in fully differentiated
00:15:18 --> 00:15:19 planets.
00:15:20 --> 00:15:22 Anna: This new perspective has forced scientists to
00:15:22 --> 00:15:24 rethink everything they thought they knew
00:15:24 --> 00:15:26 about Vesta's formation. They're now
00:15:26 --> 00:15:29 exploring two main ideas. The first
00:15:29 --> 00:15:32 is that Vesta began to differentiate. Its
00:15:32 --> 00:15:34 insides started to melt and separate into
00:15:34 --> 00:15:37 layers. But something interrupted the
00:15:37 --> 00:15:39 process. This could have been a late start in
00:15:39 --> 00:15:42 forming or limited exposure to heat producing
00:15:42 --> 00:15:45 elements like radioactive aluminium.
00:15:45 --> 00:15:47 Avery: 26 the second theory is even more
00:15:47 --> 00:15:50 dramatic. It suggests Vesta might be the
00:15:50 --> 00:15:52 shattered remnants of a much larger
00:15:52 --> 00:15:55 differentiated planet. That body could have
00:15:55 --> 00:15:57 been destroyed in a massive collision during
00:15:57 --> 00:16:00 the solar system's early years. And Vesta
00:16:00 --> 00:16:02 would then be just one of the reassembled
00:16:02 --> 00:16:05 pieces, essentially chunky space debris of,
00:16:05 --> 00:16:08 uh, a growing world that never quite made
00:16:08 --> 00:16:10 it. Seth Jacobson, who initially
00:16:10 --> 00:16:13 considered this idea a stretch years ago,
00:16:13 --> 00:16:14 now takes it seriously.
00:16:15 --> 00:16:18 Anna: The mystery deepens when you consider Vesta's
00:16:18 --> 00:16:20 meteorites. Researchers have collected
00:16:20 --> 00:16:23 thousands of space rocks on Earth believed to
00:16:23 --> 00:16:25 have come from Vesta. And these meteorites
00:16:25 --> 00:16:27 look like they formed in a molten environment
00:16:28 --> 00:16:31 showing signs of volcanic activity. However,
00:16:31 --> 00:16:34 they don't obviously suggest incomplete
00:16:34 --> 00:16:37 differentiation, which creates a problem for
00:16:37 --> 00:16:39 the first hypothesis of partial melting.
00:16:39 --> 00:16:42 Avery: That's quite the conundrum. The second idea,
00:16:42 --> 00:16:45 where Vesta is a remnant of a larger
00:16:45 --> 00:16:48 destroyed planet, might better explain the
00:16:48 --> 00:16:51 rocks by. But it also raises new questions
00:16:51 --> 00:16:53 about how such a colossal collision would
00:16:53 --> 00:16:56 occur. Jacobson's lab is actively
00:16:56 --> 00:16:58 modelling what those collisions m might have
00:16:58 --> 00:17:00 looked like and how debris like Vesta might
00:17:00 --> 00:17:01 have formed.
00:17:01 --> 00:17:04 Anna: Ultimately, Vesta's internal structure holds
00:17:04 --> 00:17:07 the key to understanding how planets grow
00:17:07 --> 00:17:10 or fail to. For a long time,
00:17:10 --> 00:17:12 Vesta seemed like a textbook
00:17:12 --> 00:17:15 protoplanet, an object that started forming
00:17:15 --> 00:17:17 but didn't quite make it. Now
00:17:18 --> 00:17:20 that picture has become much blurrier.
00:17:21 --> 00:17:24 Avery: Instead of being a failed planet, Vesta might
00:17:24 --> 00:17:26 be something even more intriguing. A, uh,
00:17:26 --> 00:17:29 survivor of cosmic violence. If it
00:17:29 --> 00:17:32 truly is a chunk of a planet destroyed in the
00:17:32 --> 00:17:34 early solar system, it could provide
00:17:34 --> 00:17:37 scientists with invaluable insights into the
00:17:37 --> 00:17:40 collisions and processes that shaped the
00:17:40 --> 00:17:41 worlds we see today.
00:17:42 --> 00:17:45 Anna: As Jacobsen puts it, no longer is the Vesta,
00:17:45 --> 00:17:48 um, meteorite collection a sample of a body
00:17:48 --> 00:17:50 in space that failed to make it as a planet.
00:17:51 --> 00:17:54 These could be pieces of an ancient planet
00:17:54 --> 00:17:57 before it grew to full completion. We just
00:17:57 --> 00:17:58 don't know which planet that is yet.
00:17:59 --> 00:18:02 Avery: This discovery is a powerful reminder that in
00:18:02 --> 00:18:05 science, answers often lead to more
00:18:05 --> 00:18:08 questions. This reanalysis of old
00:18:08 --> 00:18:10 data isn't just changing our understanding of
00:18:10 --> 00:18:13 one asteroid. It could reshape how
00:18:13 --> 00:18:15 researchers think about early planetary
00:18:15 --> 00:18:18 formation across the entire solar system.
00:18:18 --> 00:18:21 Anna: And that's it for this episode. What a
00:18:21 --> 00:18:24 journey we've had today. From the surprising
00:18:24 --> 00:18:27 seismic activity of our moon and the critical
00:18:27 --> 00:18:30 implications for future lunar bases, to the
00:18:30 --> 00:18:32 mind boggling explosion of a star trying to
00:18:32 --> 00:18:35 swallow a block whole, the universe
00:18:35 --> 00:18:37 certainly keeps us on our toes.
00:18:38 --> 00:18:40 Avery: Absolutely, Anna. Uh, and let's not forget
00:18:40 --> 00:18:43 the cosmic mystery of the missing sulphur,
00:18:43 --> 00:18:45 now believed to be hidden in icy dust, uh,
00:18:45 --> 00:18:48 grains. And the groundbreaking reanalysis of
00:18:48 --> 00:18:51 Vesta, which challenges its long held
00:18:51 --> 00:18:53 status as a protoplanet, suggesting it might
00:18:53 --> 00:18:56 be a fragment of a destroyed world.
00:18:56 --> 00:18:59 Anna: It's been a day packed with fascinating
00:18:59 --> 00:19:01 discoveries that push the boundaries of our
00:19:01 --> 00:19:02 understanding.
00:19:02 --> 00:19:05 Avery: Indeed. Thank you for joining us on Astronomy
00:19:05 --> 00:19:08 Daily. We hope you enjoyed diving into the
00:19:08 --> 00:19:09 latest space news with us.
00:19:10 --> 00:19:12 Anna: We look forward to having you back next time
00:19:12 --> 00:19:14 for more amazing insights from across the
00:19:14 --> 00:19:17 cosmos. Until then, keep looking up.