Episode 77 of Astronomy Daily, Season 5. Recorded 31 March 2026. Today's episode is our Artemis II launch-eve special — humanity prepares to return to the Moon for the first time in over 53 years. We also cover a record-breaking 'space laser' 8 billion light-years away, the ancient age of interstellar comet 3I/ATLAS, a star bearing the fingerprint of the universe's first stars, and new simulations supporting the shattered moon origin of Saturn's rings. STORY SOURCES • Artemis II Countdown — NASA.gov: https://www.nasa.gov/blogs/missions/2026/03/30/nasas-artemis-ii-launch-mission-countdown-begins/ • Artemis II Mission Guide — NBC News: https://www.nbcnews.com/science/space/artemis-ii-nasa-moon-launch-time-astronauts-how-watch-what-know-rcna255627 • Artemis II Launch Coverage — CBS News: https://www.cbsnews.com/news/nasa-artemis-ii-moon-launch-astronauts-flight-plan/ • X1.4 Solar Flare — Space.com: https://www.space.com/astronomy/sun/powerful-x-class-solar-flare-triggers-radio-blackout-ahead-of-artemis-2-launch • Solar Flare NASA Statement — NASA Science: https://science.nasa.gov/blogs/solar-cycle-25/2026/03/30/strong-solar-flare-erupts-from-sun-30/ • Gigamaser Discovery — Space.com: https://www.space.com/astronomy/galaxies/record-breaking-space-laser-erupts-from-merging-galaxies-8-billion-light-years-away • Gigamaser — ScienceAlert: https://www.sciencealert.com/astronomers-spot-a-record-breaking-space-laser-8-billion-light-years-away • 3I/ATLAS Age — Space.com: https://www.space.com/astronomy/comets/interstellar-comet-3i-atlas-may-be-nearly-12-billion-years-old-so-ancient-its-star-system-may-no-longer-exist • 3I/ATLAS — Live Science: https://www.livescience.com/space/comets/interstellar-messenger-3i-atlas-could-be-nearly-as-old-as-the-universe-itself-james-webb-telescope-observations-reveal • PicII-503 Star — Smithsonian Magazine: https://www.smithsonianmag.com/smart-news/astronomers-discovere-a-rare-primitive-star-that-provides-a-chemical-snapshot-of-the-early-universe-180988454/ • PicII-503 — NOIRLab: https://noirlab.edu/public/news/noirlab2607/ • Saturn Rings / Chrysalis — Space.com: https://www.space.com/astronomy/saturn/are-saturns-rings-made-of-a-lost-shattered-moon-new-evidence-arises-for-the-case
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00:00:00 --> 00:00:03 Hello and welcome to Astronomy Daily.
00:00:03 --> 00:00:04 I'm Anna.
00:00:04 --> 00:00:06 >> And I'm Avery. And if you're listening
00:00:06 --> 00:00:08 to this on the morning of Wednesday, the
00:00:08 --> 00:00:10 1st of April here in Australia, there is
00:00:10 --> 00:00:13 a rocket on a launchpad in Florida right
00:00:13 --> 00:00:16 now, fully fueled, fully crewed, and
00:00:16 --> 00:00:18 pointed at the moon.
00:00:18 --> 00:00:21 >> This is not an April Fool's joke.
00:00:21 --> 00:00:24 >> Absolutely not. For the first time in
00:00:24 --> 00:00:26 over 50 years, human beings are
00:00:26 --> 00:00:29 preparing to leave Earth and head toward
00:00:29 --> 00:00:31 the moon. And today on this very special
00:00:31 --> 00:00:35 episode 77 of season 5, we are your
00:00:35 --> 00:00:38 countdown companion. We have six stories
00:00:38 --> 00:00:41 for you today. And yes, Artemis 2 is
00:00:41 --> 00:00:43 front and center. But we've also got a
00:00:43 --> 00:00:46 record-breaking space laser, a 12
00:00:46 --> 00:00:49 billionyear-old comet, a star born from
00:00:49 --> 00:00:51 the ashes of the very first stars in the
00:00:51 --> 00:00:54 universe, and a new chapter in the
00:00:54 --> 00:00:56 mystery of Saturn's rings.
00:00:56 --> 00:00:58 >> It is without question one of the most
00:00:58 --> 00:01:00 extraordinary days in the history of
00:01:00 --> 00:01:02 human space flight. Let's go.
00:01:02 --> 00:01:05 >> We begin where the world's attention is
00:01:05 --> 00:01:07 today. Kennedy Space Center, Cape
00:01:07 --> 00:01:09 Canaveral, Florida, where the countdown
00:01:09 --> 00:01:12 clock for NASA's Aremis 2 mission is
00:01:12 --> 00:01:13 ticking.
00:01:13 --> 00:01:16 >> At 4:44 p.m. Eastern time yesterday,
00:01:16 --> 00:01:17 that's early this morning for our
00:01:17 --> 00:01:19 Australian listeners. NASA flight
00:01:20 --> 00:01:21 controllers started the official
00:01:21 --> 00:01:25 countdown. Liftoff is targeted at 6:24
00:01:25 --> 00:01:27 p.m. Eastern, which is 8:24 tomorrow
00:01:27 --> 00:01:30 morning, AEDT. The crew has been in
00:01:30 --> 00:01:32 quarantine at the Neil Armstrong
00:01:32 --> 00:01:34 operations and checkout building
00:01:34 --> 00:01:37 following a strict schedule of sleep,
00:01:37 --> 00:01:39 nutrition, and technical briefings.
00:01:39 --> 00:01:41 Commander Reed Wiseman told reporters on
00:01:42 --> 00:01:44 the weekend, and I love this quote,
00:01:44 --> 00:01:46 "Hey, let's go to the moon."
00:01:46 --> 00:01:49 >> That is the energy we need. Wisemen
00:01:49 --> 00:01:51 leads a crew of four. Commander Reed
00:01:51 --> 00:01:54 Wisman, pilot Victor Glover, mission
00:01:54 --> 00:01:56 specialist Christina Coch, and Canadian
00:01:56 --> 00:01:59 astronaut Jeremy Hansen. Together, they
00:01:59 --> 00:02:01 will become the first humans to travel
00:02:01 --> 00:02:03 to the vicinity of the moon since Apollo
00:02:03 --> 00:02:06 17 in December 1972.
00:02:06 --> 00:02:10 >> More than 53 years. And this mission,
00:02:10 --> 00:02:13 Artemis 2, won't land on the moon. It's
00:02:13 --> 00:02:16 a 10-day test flight. The Orion capsule
00:02:16 --> 00:02:18 launched aboard the massive space launch
00:02:18 --> 00:02:21 system rocket will perform a figure 8
00:02:21 --> 00:02:23 trajectory out around the moon coming
00:02:23 --> 00:02:26 within about 6 m of the lunar
00:02:26 --> 00:02:29 surface on April 6th, then back to Earth
00:02:29 --> 00:02:31 for splashdown in the Pacific on
00:02:31 --> 00:02:33 approximately April 11th.
00:02:33 --> 00:02:35 >> The purpose is to stress test the Orion
00:02:36 --> 00:02:37 capsule's life support systems with
00:02:37 --> 00:02:40 humans on board for the first time.
00:02:40 --> 00:02:42 Everything they learn paves the way for
00:02:42 --> 00:02:45 Artemis 3, now planned as a low Earth
00:02:45 --> 00:02:48 orbit docking test in 2027 and
00:02:48 --> 00:02:50 ultimately the first lunar landing since
00:02:50 --> 00:02:53 Apollo in 2028.
00:02:53 --> 00:02:55 >> NASA launch director Charlie Blackwell
00:02:55 --> 00:02:57 Thompson reported yesterday that the
00:02:57 --> 00:03:00 countdown runup has been quote extremely
00:03:00 --> 00:03:03 smooth with only very minor ground
00:03:03 --> 00:03:05 equipment issues. Weather is currently
00:03:05 --> 00:03:08 forecast at 80% favorable. Some cloud
00:03:08 --> 00:03:10 cover and potential high winds on the
00:03:10 --> 00:03:12 ground are the primary concerns.
00:03:12 --> 00:03:15 >> And NASA has confirmed there's a 6-day
00:03:15 --> 00:03:17 launch window from April 1st through
00:03:17 --> 00:03:19 April 6th before the next opportunity
00:03:19 --> 00:03:21 opens at the end of the month. So,
00:03:21 --> 00:03:22 there's some flexibility if they need
00:03:22 --> 00:03:23 it.
00:03:23 --> 00:03:25 >> For our Southern Hemisphere listeners,
00:03:25 --> 00:03:28 and this is genuinely moving, this is
00:03:28 --> 00:03:30 the moment our generation has been
00:03:30 --> 00:03:33 waiting for. The next chapter of human
00:03:33 --> 00:03:35 exploration of the cosmos begins
00:03:35 --> 00:03:39 Thursday morning, April 2nd at 9:24 a.m.
00:03:39 --> 00:03:42 Australian Eastern time. And if in the
00:03:42 --> 00:03:46 US, 6:24 p.m. Eastern Daylight Time on
00:03:46 --> 00:03:51 April 1st, which all translates to 22:24
00:03:51 --> 00:03:55 UTC on April 2nd. I hope I got all those
00:03:55 --> 00:03:56 conversions right.
00:03:56 --> 00:03:59 >> We will be watching every second. Now,
00:03:59 --> 00:04:01 there was a dramatic subplot to
00:04:01 --> 00:04:03 yesterday's launch preparations. The sun
00:04:04 --> 00:04:06 decided to get involved. On Sunday
00:04:06 --> 00:04:10 night, a massive X1.4 class solar flare
00:04:10 --> 00:04:13 erupted from an active sunspot region
00:04:13 --> 00:04:16 designated AR4405.
00:04:16 --> 00:04:19 It peaked at just after 11:00 p.m.
00:04:19 --> 00:04:21 Eastern time and triggered a significant
00:04:21 --> 00:04:24 highfrequency radio blackout across the
00:04:24 --> 00:04:26 sunlit side of Earth, including, as it
00:04:26 --> 00:04:29 happens, parts of Southeast Asia and
00:04:29 --> 00:04:31 Northern Australia.
00:04:31 --> 00:04:33 >> Class flares are the most powerful
00:04:33 --> 00:04:36 category the sun produces. An X1.4 is
00:04:36 --> 00:04:39 serious business. The flare also
00:04:39 --> 00:04:41 launched a coronal mass ejection, a
00:04:41 --> 00:04:44 massive cloud of solar plasma with a
00:04:44 --> 00:04:46 possible earthdirected component.
00:04:46 --> 00:04:49 >> So NASA had something of an anxious
00:04:49 --> 00:04:51 Monday morning, but at the Lminus2 press
00:04:51 --> 00:04:54 conference, associate administrator Amit
00:04:54 --> 00:04:56 Cashatria gave everyone the all clear.
00:04:56 --> 00:04:59 Quote, we're not expecting the CME to
00:04:59 --> 00:05:01 cause any effects. We're not tracking
00:05:01 --> 00:05:03 concerns for the mission in general.
00:05:04 --> 00:05:07 Artemis 2 is go for April 1st. DOA's
00:05:07 --> 00:05:09 space weather prediction center has
00:05:09 --> 00:05:12 issued a G2, that's moderate,
00:05:12 --> 00:05:14 geomagnetic storm watch for today,
00:05:14 --> 00:05:18 Tuesday, March 31st, with G1, minor
00:05:18 --> 00:05:20 storm conditions possible through launch
00:05:20 --> 00:05:21 day tomorrow.
00:05:21 --> 00:05:23 >> And here's the silver lining for our
00:05:23 --> 00:05:26 listeners. That geomagnetic activity
00:05:26 --> 00:05:28 means auroras could be visible at lower
00:05:28 --> 00:05:31 latitudes than usual tonight. Under G2
00:05:31 --> 00:05:33 conditions, the Southern Aurora, the
00:05:33 --> 00:05:36 Aurora Arralis, may be visible further
00:05:36 --> 00:05:38 north than normal. Southern Hemisphere
00:05:38 --> 00:05:41 aurora watchers get outside tonight.
00:05:41 --> 00:05:43 >> We'll be watching the skies and the
00:05:43 --> 00:05:45 launchpad at the same time.
00:05:45 --> 00:05:47 >> All right, now let's travel to the other
00:05:47 --> 00:05:49 end of the universe. Because while
00:05:49 --> 00:05:51 everyone's been watching the launchpad,
00:05:51 --> 00:05:53 astronomers have spotted something
00:05:53 --> 00:05:55 extraordinary in the deep cosmos.
00:05:55 --> 00:05:57 Scientists have discovered the most
00:05:57 --> 00:06:00 distant and most powerful natural space
00:06:00 --> 00:06:03 laser ever detected. And I know that
00:06:03 --> 00:06:05 sounds like science fiction, but these
00:06:05 --> 00:06:07 things are very much real. They're
00:06:07 --> 00:06:10 called, the microwave equivalent of a
00:06:10 --> 00:06:13 laser. Where a laser amplifies visible
00:06:13 --> 00:06:15 light, a mermpic
00:06:15 --> 00:06:18 radiation. When a mer is powerful enough
00:06:18 --> 00:06:20 to be seen in other galaxies, it gets
00:06:20 --> 00:06:23 the name megaer. And now astronomers
00:06:23 --> 00:06:25 have found something so powerful they're
00:06:25 --> 00:06:28 proposing an entirely new category.
00:06:28 --> 00:06:31 >> A gigamaser. The signal comes from a
00:06:31 --> 00:06:35 galaxy system designated deep breath h a
00:06:35 --> 00:06:41 t lsj42.3us
00:06:41 --> 00:06:44 2.
00:06:44 --> 00:06:46 Located approximately 8 billion
00:06:46 --> 00:06:49 lightyear from Earth. The light we're
00:06:49 --> 00:06:51 detecting began its journey when the
00:06:51 --> 00:06:53 universe was barely half its current
00:06:53 --> 00:06:54 age.
00:06:54 --> 00:06:56 >> It was discovered by the Mircat radio
00:06:56 --> 00:06:59 telescope array in South Africa. 64
00:06:59 --> 00:07:01 linked radio dishes working as one
00:07:01 --> 00:07:04 instrument. The detection was completely
00:07:04 --> 00:07:07 serendipitous. Team leader Tat Manamela
00:07:07 --> 00:07:09 from the University of Ptoria described
00:07:09 --> 00:07:12 it as quote, "We are seeing the radio
00:07:12 --> 00:07:14 equivalent of a laser halfway across the
00:07:14 --> 00:07:17 universe." And the mechanism is
00:07:17 --> 00:07:20 spectacular. Two galaxies are colliding.
00:07:20 --> 00:07:22 The gravitational violence of the merger
00:07:22 --> 00:07:25 compresses enormous clouds of gas,
00:07:25 --> 00:07:27 triggering a burst of new star
00:07:27 --> 00:07:29 formation. The intense radiation from
00:07:29 --> 00:07:31 those newborn stars then excites
00:07:31 --> 00:07:34 hydroxal molecules. That's one oxygen
00:07:34 --> 00:07:36 atom bonded to one hydrogen atom,
00:07:36 --> 00:07:39 causing them to emit microwaves in a
00:07:39 --> 00:07:41 focused amplified beam.
00:07:41 --> 00:07:43 >> The signal is so intense, roughly a
00:07:43 --> 00:07:47 100 times the luminosity of a star
00:07:47 --> 00:07:49 concentrated into a very narrow slice of
00:07:50 --> 00:07:52 the electromagnetic spectrum that it
00:07:52 --> 00:07:55 warrants its own classification beyond
00:07:55 --> 00:07:57 Mega Mazer. And it wouldn't even be
00:07:57 --> 00:08:01 visible without a stroke of cosmic luck.
00:08:01 --> 00:08:04 A completely unrelated foreground galaxy
00:08:04 --> 00:08:06 is perfectly aligned between the source
00:08:06 --> 00:08:10 and earth acting as a gravitational lens
00:08:10 --> 00:08:12 and amplifying the signal further.
00:08:12 --> 00:08:15 >> Bead researcher Mona said this is just
00:08:15 --> 00:08:16 the beginning. We don't want to find
00:08:16 --> 00:08:18 just one system. We want to find
00:08:18 --> 00:08:21 hundreds to thousands. The expectation
00:08:21 --> 00:08:23 is that when the square kilometer array
00:08:23 --> 00:08:25 comes fully online in South Africa,
00:08:26 --> 00:08:28 we'll start finding these gigamasers
00:08:28 --> 00:08:29 across cosmic history.
00:08:29 --> 00:08:32 >> The universe is remarkable.
00:08:32 --> 00:08:35 >> From one ancient signal to another, our
00:08:35 --> 00:08:37 old friend, the interstellar comet
00:08:37 --> 00:08:40 Threeey Atlas has just revealed a
00:08:40 --> 00:08:42 staggering secret about its age.
00:08:42 --> 00:08:44 >> We've been following Threeey Atlas since
00:08:44 --> 00:08:47 it was discovered back in July 2025. the
00:08:47 --> 00:08:49 third known interstellar object to pass
00:08:50 --> 00:08:51 through our solar system. It swung
00:08:52 --> 00:08:53 around the sun, caused enormous
00:08:53 --> 00:08:56 excitement, and now it's heading back
00:08:56 --> 00:08:58 out toward Jupiter and beyond. But new
00:08:58 --> 00:09:00 analysis using data from the James Web
00:09:00 --> 00:09:03 Space Telescope has given scientists a
00:09:03 --> 00:09:05 remarkable new insight by examining the
00:09:06 --> 00:09:08 isotopic composition of gases outgassing
00:09:08 --> 00:09:11 from the comet, specifically the ratio
00:09:11 --> 00:09:13 of carbon 12 to carbon 13 and the
00:09:13 --> 00:09:15 dutyium content of its water.
00:09:16 --> 00:09:18 Researchers now believe threeey atlas
00:09:18 --> 00:09:21 may be between 10 and 12 billion years
00:09:21 --> 00:09:22 old.
00:09:22 --> 00:09:27 >> Let that sink in. Our sun is 4.6 billion
00:09:27 --> 00:09:30 years old. Earth is 4.5 billion years
00:09:30 --> 00:09:33 old. This comet may have formed nearly
00:09:33 --> 00:09:35 three times earlier than that in the
00:09:35 --> 00:09:38 very earliest epoch of the Milky Way's
00:09:38 --> 00:09:40 history when the galaxy was first
00:09:40 --> 00:09:42 igniting with star formation.
00:09:42 --> 00:09:45 >> The chemical signature tells the story.
00:09:45 --> 00:09:47 3i-TLS's
00:09:47 --> 00:09:49 water contains more dutyium, a heavier
00:09:49 --> 00:09:52 form of hydrogen, than any comet
00:09:52 --> 00:09:54 previously studied. Its carbon isotope
00:09:54 --> 00:09:57 ratios are also markedly different from
00:09:57 --> 00:09:59 anything in our solar system. These
00:09:59 --> 00:10:01 signatures point to formation in an
00:10:01 --> 00:10:04 extremely cold environment around 30
00:10:04 --> 00:10:08 Kelvin. That's minus243
00:10:08 --> 00:10:11 degrees C in the early metal pore
00:10:11 --> 00:10:14 protolanetary disc of some ancient long
00:10:14 --> 00:10:16 vanished star.
00:10:16 --> 00:10:18 >> And here's the haunting part. The star
00:10:18 --> 00:10:21 that gave birth to this comet, the star
00:10:21 --> 00:10:23 it originally orbited, almost certainly
00:10:24 --> 00:10:26 no longer exists. It would have burned
00:10:26 --> 00:10:28 through its nuclear fuel and died
00:10:28 --> 00:10:32 billions of years ago. 3II/ATLS
00:10:32 --> 00:10:34 has been drifting through interstellar
00:10:34 --> 00:10:37 space alone for longer than our planet
00:10:37 --> 00:10:41 has existed. Researcher Roma Miola of
00:10:41 --> 00:10:43 the Royal Belgian Institute for Space
00:10:43 --> 00:10:45 Aeronomi put it beautifully. He said,
00:10:46 --> 00:10:48 "If 3II-ATLS
00:10:48 --> 00:10:51 is indeed as old as this study suggests,
00:10:51 --> 00:10:53 the large amounts of volatile molecules
00:10:53 --> 00:10:56 it contains indicate that rich prebiotic
00:10:56 --> 00:10:58 chemistry may have already been
00:10:58 --> 00:11:01 occurring in star forming regions very
00:11:01 --> 00:11:03 early in the history of our galaxy."
00:11:03 --> 00:11:06 >> A comet as a time capsule from the dawn
00:11:06 --> 00:11:08 of the Milky Way. We may never get
00:11:08 --> 00:11:10 another chance to study one like this.
00:11:10 --> 00:11:12 And staying with the theme of ancient
00:11:12 --> 00:11:14 messengers, astronomers have found a
00:11:14 --> 00:11:17 star in our own cosmic backyard that
00:11:17 --> 00:11:19 preserves the chemical fingerprint of
00:11:19 --> 00:11:22 the very first stars that ever existed.
00:11:22 --> 00:11:26 The star is called Pictor II503 and it
00:11:26 --> 00:11:28 lives in an ultra faint dwarf galaxy
00:11:28 --> 00:11:31 called Pictor 2 about 150
00:11:31 --> 00:11:33 light-years from Earth, which in cosmic
00:11:34 --> 00:11:36 terms is practically next door. The
00:11:36 --> 00:11:38 galaxy itself is more than 10 billion
00:11:38 --> 00:11:42 years old. Ptor II503
00:11:42 --> 00:11:44 is what astronomers call a second
00:11:44 --> 00:11:47 generation star. Meaning it formed from
00:11:47 --> 00:11:49 the debris of the very first stars in
00:11:49 --> 00:11:52 the universe. Those first stars made
00:11:52 --> 00:11:55 almost entirely of hydrogen and helium
00:11:55 --> 00:11:57 burned hot and fast and exploded in
00:11:57 --> 00:12:00 supernova, scattering the first heavier
00:12:00 --> 00:12:04 elements into the cosmos. Pctor II503
00:12:04 --> 00:12:06 formed from that debris.
00:12:06 --> 00:12:09 >> The evidence is unmistakable. The star
00:12:09 --> 00:12:11 contains less iron than any other star
00:12:11 --> 00:12:14 ever measured outside the Milky Way,
00:12:14 --> 00:12:16 less than a 40th the iron content of
00:12:16 --> 00:12:19 our sun, and it's enormously rich in
00:12:19 --> 00:12:21 carbon. That specific chemical signature
00:12:21 --> 00:12:24 is the hallmark of material enriched by
00:12:24 --> 00:12:26 the first generation of stellar
00:12:26 --> 00:12:29 explosions. The discovery published in
00:12:29 --> 00:12:31 Nature Astronomy in March was led by Ani
00:12:32 --> 00:12:34 Ruth Cheety, a Brinsen Prize Fellow at
00:12:34 --> 00:12:37 Stanford University. It used the dark
00:12:37 --> 00:12:39 energy camera at the Victor M. Blanco
00:12:39 --> 00:12:42 4meter telescope at Sero Interamerican
00:12:42 --> 00:12:45 Observatory in Chile. So this is
00:12:45 --> 00:12:47 beautifully a southern hemisphere
00:12:47 --> 00:12:48 discovery.
00:12:48 --> 00:12:50 >> MIT astrophysicist Anna Frabel who was
00:12:50 --> 00:12:53 not involved in study told science news,
00:12:53 --> 00:12:56 "It's a fantastic discovery. I know how
00:12:56 --> 00:12:58 hard it is to find these stars. They are
00:12:58 --> 00:13:01 so so rare." What's making this
00:13:01 --> 00:13:04 particularly significant is that Ptor
00:13:04 --> 00:13:07 II503 is the first unambiguous example
00:13:07 --> 00:13:10 of a second generation star found inside
00:13:10 --> 00:13:13 an ultra faint dwarf galaxy like Pctor
00:13:14 --> 00:13:16 2, which matters because it validates
00:13:16 --> 00:13:18 the theory that many of the most
00:13:18 --> 00:13:20 primitive stars we see in the Milky Ways
00:13:20 --> 00:13:23 halo were originally formed in tiny
00:13:23 --> 00:13:26 ancient dwarf galaxies like Pctor 2,
00:13:26 --> 00:13:28 which eventually merged with our own
00:13:28 --> 00:13:31 galaxy over cosmic time. As NSF program
00:13:31 --> 00:13:32 director Chris Davis put it,
00:13:32 --> 00:13:34 "Discoveries like this are cosmic
00:13:34 --> 00:13:37 archaeology, uncovering rare stellar
00:13:37 --> 00:13:39 fossils that preserve the fingerprints
00:13:39 --> 00:13:42 of the universe's first stars." I love
00:13:42 --> 00:13:44 that phrase, cosmic archaeology.
00:13:44 --> 00:13:47 >> And we close today with Saturn, because
00:13:47 --> 00:13:49 who doesn't love Saturn? And a fresh new
00:13:50 --> 00:13:52 chapter in one of planetary science's
00:13:52 --> 00:13:54 best mysteries. Where did those
00:13:54 --> 00:13:56 magnificent rings come from? Saturn's
00:13:56 --> 00:13:58 rings are one of the most iconic sites
00:13:58 --> 00:14:00 in the solar system. But here's the
00:14:00 --> 00:14:03 thing, they're surprisingly young.
00:14:03 --> 00:14:06 Saturn itself is over 4 12 billion years
00:14:06 --> 00:14:08 old, but its rings appear to be only
00:14:08 --> 00:14:10 somewhere between a 100 million and a
00:14:10 --> 00:14:12 few hundred million years old. The
00:14:12 --> 00:14:14 question has always been, why are they
00:14:14 --> 00:14:17 so young? New research presented at the
00:14:17 --> 00:14:19 Lunar and Planetary Science Conference
00:14:19 --> 00:14:21 in Texas this month adds compelling new
00:14:21 --> 00:14:23 weight to what's become the leading
00:14:23 --> 00:14:25 hypothesis that the rings were created
00:14:25 --> 00:14:27 when Saturn destroyed one of its own
00:14:28 --> 00:14:30 moons. The hypothetical moon has been
00:14:30 --> 00:14:32 named Chrysalis, a beautiful name
00:14:32 --> 00:14:34 because it transformed into something
00:14:34 --> 00:14:38 else entirely. The scenario led by Ye Fe
00:14:38 --> 00:14:39 Xiao of the University of California,
00:14:39 --> 00:14:42 Santa Cruz goes like this. Sometime
00:14:42 --> 00:14:45 between a 100 and 200 million years ago,
00:14:45 --> 00:14:47 the orbit of Chrysalis became
00:14:47 --> 00:14:49 gravitationally destabilized, sending it
00:14:49 --> 00:14:52 on a fatal trajectory towards Saturn.
00:14:52 --> 00:14:55 >> Saturn's tidal forces then went to work.
00:14:55 --> 00:14:57 The simulations show that the planet
00:14:57 --> 00:15:00 would have preferentially stripped away
00:15:00 --> 00:15:02 the moon's icy outer mantle while
00:15:02 --> 00:15:05 leaving much of its denser, rocky core
00:15:05 --> 00:15:09 intact. That distinction is crucial
00:15:09 --> 00:15:11 because it explains a long-standing
00:15:11 --> 00:15:14 puzzle. Why are Saturn's rings composed
00:15:14 --> 00:15:18 almost entirely of water ice with almost
00:15:18 --> 00:15:19 no rock?
00:15:19 --> 00:15:21 >> Because the rock sank into Saturn and
00:15:21 --> 00:15:24 the ice became the rings. The stripped
00:15:24 --> 00:15:26 icy material remained in orbit, was
00:15:26 --> 00:15:28 gradually shaped and sculpted by the
00:15:28 --> 00:15:30 gravitational influence of Saturn's
00:15:30 --> 00:15:33 larger moons, particularly Titan, and
00:15:33 --> 00:15:35 spread into the magnificent ring system
00:15:35 --> 00:15:36 we see today.
00:15:36 --> 00:15:39 >> And there's a bonus explanation. Saturn
00:15:39 --> 00:15:42 has a surprisingly steep axial tilt.
00:15:42 --> 00:15:45 It's tilted about 26.7°.
00:15:45 --> 00:15:47 The loss of Chrysalis is thought to have
00:15:47 --> 00:15:49 been the gravitational trigger that
00:15:49 --> 00:15:51 knocked Saturn out of a resonance with
00:15:51 --> 00:15:53 Neptune, which had been controlling its
00:15:53 --> 00:15:56 tilt for billions of years. Lose the
00:15:56 --> 00:15:58 moon, lose the resonance, and the tilt
00:15:58 --> 00:16:01 changes. As lead researcher Jiao told
00:16:01 --> 00:16:03 space.com, "This scenario can clearly
00:16:03 --> 00:16:06 explain why Saturn's rings are young.
00:16:06 --> 00:16:08 It's one of those moments where a single
00:16:08 --> 00:16:10 event, a moon falling to its doom,
00:16:10 --> 00:16:13 explains multiple mysteries at once."
00:16:13 --> 00:16:15 Chrysalis, the moon that became a
00:16:15 --> 00:16:18 butterfly, or in this case, one of the
00:16:18 --> 00:16:20 most breathtaking sites in the solar
00:16:20 --> 00:16:20 system.
00:16:20 --> 00:16:22 >> And that is your astronomy daily for
00:16:22 --> 00:16:26 today, episode 77 of season 5. What a
00:16:26 --> 00:16:28 day to be a space fan.
00:16:28 --> 00:16:30 >> Tomorrow, if all goes to plan, four
00:16:30 --> 00:16:33 human beings will ride fire into the sky
00:16:33 --> 00:16:35 and begin the journey to the moon for
00:16:35 --> 00:16:38 the first time since 1972.
00:16:38 --> 00:16:40 It's hard to fully comprehend what that
00:16:40 --> 00:16:43 means. We'll be back as soon as we can
00:16:43 --> 00:16:45 with launch coverage. In the meantime,
00:16:45 --> 00:16:47 if you're in Australia or New Zealand
00:16:47 --> 00:16:49 tonight, look south. There may be
00:16:49 --> 00:16:49 auroras.
00:16:50 --> 00:16:51 >> And if you're watching the launch and
00:16:51 --> 00:16:53 you feel a lump in your throat when that
00:16:53 --> 00:16:56 rocket clears the tower, that's exactly
00:16:56 --> 00:16:57 the right reaction.
00:16:57 --> 00:16:59 >> From Anna and me, this is Astronomy
00:16:59 --> 00:17:12 Daily. Clear skies, everyone.
00:17:12 --> 00:17:20 The stories told
00:17:20 --> 00:17:23 stories