- Biggest Supermoon of 2025: Mark your calendars for October 6th at 11:48 PM Eastern Time, as we prepare for the largest supermoon of 2025. This full moon, known as the Harvest Moon, will appear up to 14% larger and 30% brighter than a typical micro moon, offering a stunning celestial display just after sunset.
- Interstellar Comet 3i Atlas: Excitement is building around the interstellar comet 3i Atlas, the third such object detected in our solar system. The European Space Agency is mobilizing three spacecraft to study its unique trajectory as it approaches the sun, providing a rare opportunity to analyze its composition and understand the building blocks of distant star systems.
- Mysterious Ozone Surge on Mars: Scientists are investigating a puzzling increase in ozone levels over Mars' north pole during winter months. The ExoMars Trace Gas Orbiter has revealed that extreme cold conditions lead to the freezing of water vapor, halting ozone-depleting reactions and allowing ozone concentrations to rise, offering insights into Mars' atmospheric dynamics and water history.
- Challenging Dark Matter: A new theory proposed by physicist Rajendra Gupta from the University of Ottawa questions the existence of dark matter and dark energy. By suggesting that fundamental constants of nature may change over time, this model could explain cosmic phenomena traditionally attributed to dark matter, prompting a reevaluation of our understanding of the universe.
- For more cosmic updates, visit our website at astronomydaily.io. Join our community on social media by searching for #AstroDailyPod on Facebook, X, YouTubeMusic, TikTok, and our new Instagram account! Donât forget to subscribe to the podcast on Apple Podcasts, Spotify, iHeartRadio, or wherever you get your podcasts.
- Thank you for tuning in. This is Anna and Avery signing off. Until next time, keep looking up and exploring the wonders of our universe.
Supermoon Details
[NASA](https://www.nasa.gov/)
Comet 3i Atlas Updates
[ESA](https://www.esa.int/)
Mars Ozone Research
[ExoMars](https://exploration.esa.int/)
Dark Matter Theory
[University of Ottawa](https://www.uottawa.ca/)
Astronomy Daily
[Astronomy Daily](http://www.astronomydaily.io/)
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00:00:00 --> 00:00:02 Avery: Welcome, listeners, to Astronomy Daily, the
00:00:02 --> 00:00:05 podcast that brings the cosmos down to Earth.
00:00:05 --> 00:00:06 I'm Avery.
00:00:06 --> 00:00:09 Anna: And I'm Anna. We have a fantastic
00:00:09 --> 00:00:12 show for you today, packed with news from our
00:00:12 --> 00:00:14 celestial neighborhood and the farthest
00:00:14 --> 00:00:15 reaches of the universe.
00:00:15 --> 00:00:17 Avery: That's right, we'll be looking up at the
00:00:17 --> 00:00:20 biggest supermoon of 2025,
00:00:20 --> 00:00:22 tracking an interstellar visitor as it zips
00:00:22 --> 00:00:25 past the sun and uncovering a strange
00:00:25 --> 00:00:27 atmospheric mystery on Mars.
00:00:27 --> 00:00:30 Anna: And to cap it all off, we'll be exploring a
00:00:30 --> 00:00:33 mind bending new the that asks, what if
00:00:33 --> 00:00:35 dark matter doesn't exist at all?
00:00:35 --> 00:00:37 Avery: It's going to be a, um, big one.
00:00:37 --> 00:00:40 Let's get started with a sight we can all
00:00:40 --> 00:00:42 look forward to in our own night sky.
00:00:42 --> 00:00:45 Anna: Indeed, after a year of seeing the Moon
00:00:45 --> 00:00:47 looking a bit smaller than usual, we're in
00:00:47 --> 00:00:49 for a treat next week.
00:00:49 --> 00:00:52 11:48pm Eastern Time on
00:00:52 --> 00:00:55 October 6, to be precise, which,
00:00:55 --> 00:00:57 if I've done my math correctly,
00:00:57 --> 00:00:59 corresponds to 3:48
00:01:00 --> 00:01:02 UTC on October 7th
00:01:03 --> 00:01:05 will see the biggest and brightest supermoon
00:01:05 --> 00:01:07 of 2025.
00:01:07 --> 00:01:10 Avery: I'm already marking my calendar. So for
00:01:10 --> 00:01:13 our listeners who might be new to this, what
00:01:13 --> 00:01:15 exactly makes a full moon a, uh,
00:01:15 --> 00:01:16 supermoon?
00:01:16 --> 00:01:19 Anna: It's all about the moon's orbit. It's not a
00:01:19 --> 00:01:21 perfect circle, it's an ellipse. So
00:01:21 --> 00:01:24 sometimes the Moon is at its farthest point
00:01:24 --> 00:01:26 from Earth, which we call apogee. And
00:01:26 --> 00:01:28 sometimes it's at its closest point, or
00:01:28 --> 00:01:31 perigee. A supermoon happens when a full
00:01:31 --> 00:01:33 moon coincides with its perigee.
00:01:33 --> 00:01:35 Avery: And that makes it look bigger and brighter in
00:01:35 --> 00:01:38 the sky. Right. I read it can appear up to
00:01:38 --> 00:01:41 14% larger and 30% brighter than a
00:01:41 --> 00:01:43 micro moon, which is when the full moon
00:01:43 --> 00:01:44 happens at apogee.
00:01:44 --> 00:01:47 Anna: Exactly. And we've just come through a period
00:01:47 --> 00:01:49 of micro moons, so the difference will be
00:01:49 --> 00:01:52 quite noticeable. This particular supermoon
00:01:52 --> 00:01:54 is also the Harvest Moon, which is the full
00:01:54 --> 00:01:57 moon closest to the autumnal equinox.
00:01:57 --> 00:01:59 Avery: The harvest Moon. That's the one that
00:01:59 --> 00:02:01 historically helped farmers bring in their
00:02:01 --> 00:02:04 crops. Because it rises so close to sunset,
00:02:04 --> 00:02:07 giving them extra light to work by, it often
00:02:07 --> 00:02:09 looks huge and orange on the horizon.
00:02:09 --> 00:02:12 Anna: That's the one. The orange color is due to
00:02:12 --> 00:02:14 the same effect that makes sunsets red. The
00:02:14 --> 00:02:16 light is passing through more of Earth's
00:02:16 --> 00:02:19 atmosphere. So next week we get a combination
00:02:19 --> 00:02:22 of things. The closest full moon of the year
00:02:22 --> 00:02:24 and the beautiful effect of the harvest moon,
00:02:25 --> 00:02:27 all making for a spectacular celestial event.
00:02:28 --> 00:02:30 Avery: From something we can see with our own eyes
00:02:30 --> 00:02:32 to something that requires a fleet of
00:02:32 --> 00:02:34 interplanetary spacecraft.
00:02:34 --> 00:02:37 Let's get an update on the interstellar comet
00:02:37 --> 00:02:38 3i Atlas.
00:02:38 --> 00:02:41 Anna: This is incredibly exciting.
00:02:41 --> 00:02:43 3i Atlas is only the third
00:02:43 --> 00:02:46 interstellar object we've ever detected
00:02:46 --> 00:02:48 passing through our solar system. The first
00:02:48 --> 00:02:51 was Oumuamua and The second was
00:02:51 --> 00:02:54 2i Borisov. These objects are
00:02:54 --> 00:02:56 cosmic messengers from other star systems.
00:02:57 --> 00:02:59 Avery: And the European Space Agency is pulling out
00:02:59 --> 00:03:02 all the stops to study this one. From now
00:03:02 --> 00:03:04 until early November, they're planning to use
00:03:04 --> 00:03:07 a trio of their spacecraft, the Mars
00:03:07 --> 00:03:10 Express and ExoMars Trace Gas Orbiter,
00:03:10 --> 00:03:13 which are both orbiting Mars, and the JUICE
00:03:13 --> 00:03:15 spacecraft, which is on its way to Jupiter.
00:03:16 --> 00:03:18 Anna: The reason this is such a unique opportunity
00:03:18 --> 00:03:21 is because of the comet's trajectory. As it
00:03:21 --> 00:03:24 makes its closest approach to the sun, it's
00:03:24 --> 00:03:26 going to heat up dramatically. This heating
00:03:26 --> 00:03:29 causes ices on its surface to sublimate,
00:03:29 --> 00:03:32 turn directly into gas, releasing dust
00:03:32 --> 00:03:34 and revealing the chemical composition of the
00:03:34 --> 00:03:35 comet's nucleus.
00:03:36 --> 00:03:38 Avery: So it's like unwrapping a gift from another
00:03:38 --> 00:03:41 star. And using three different spacecraft
00:03:41 --> 00:03:43 gives them a huge advantage, doesn't it?
00:03:43 --> 00:03:46 Anna: It certainly does. Each spacecraft has
00:03:46 --> 00:03:48 different instruments and will see the comet
00:03:48 --> 00:03:50 from a different vantage point. This
00:03:50 --> 00:03:53 triangulation allows scientists to build a
00:03:53 --> 00:03:56 much more complete 3D picture of the comet's
00:03:56 --> 00:03:59 activity and the mater its shedding. By
00:03:59 --> 00:04:01 studying the composition of this gas and
00:04:01 --> 00:04:03 dust, we can learn about the building blocks
00:04:03 --> 00:04:06 of planets in whatever distant star system
00:04:06 --> 00:04:07 this comet came from.
00:04:07 --> 00:04:09 Avery: It's a reminder of how interconnected the
00:04:09 --> 00:04:12 galaxy is. A piece of another solar system
00:04:13 --> 00:04:15 just passing through for a quick visit.
00:04:15 --> 00:04:16 Incredible.
00:04:17 --> 00:04:18 Anna: Absolutely.
00:04:19 --> 00:04:21 Now let's bring our focus a little closer to
00:04:21 --> 00:04:24 home, to our planetary neighborhood,
00:04:24 --> 00:04:27 Mars. Scientists have been puzzled
00:04:27 --> 00:04:30 by a mysterious surge in ozone
00:04:30 --> 00:04:33 that appears over its north pole during the
00:04:33 --> 00:04:33 winter.
00:04:33 --> 00:04:36 Avery: M ozone on Mars. I, uh, usually
00:04:36 --> 00:04:39 associate ozone with Earth's protective
00:04:39 --> 00:04:41 layer. Is it the same thing?
00:04:41 --> 00:04:43 Anna: It's the same molecule. Three
00:04:43 --> 00:04:46 oxygen atoms bonded together. But
00:04:46 --> 00:04:49 on Mars, its behavior is very different.
00:04:50 --> 00:04:53 Using the ExoMars Trace Gas Orbiter.
00:04:53 --> 00:04:55 The same one. Watching the comet,
00:04:56 --> 00:04:58 scientists noticed that ozone
00:04:58 --> 00:05:00 concentrations in the middle atmosphere
00:05:01 --> 00:05:03 spike during the winter inside the
00:05:03 --> 00:05:04 polar vortex.
00:05:05 --> 00:05:08 Avery: A, uh, polar vortex. We have those on
00:05:08 --> 00:05:11 Earth too. Basically a giant spinning cyclone
00:05:11 --> 00:05:12 of frigid air, right?
00:05:12 --> 00:05:15 Anna: Precisely. And on Mars, it
00:05:15 --> 00:05:17 gets incredibly cold inside this
00:05:17 --> 00:05:20 vortex, dropping below minus
00:05:20 --> 00:05:22 1, 130 degrees Celsius.
00:05:23 --> 00:05:25 This cold is the key to the mystery.
00:05:26 --> 00:05:29 Normally, water vapor in the atmosphere
00:05:29 --> 00:05:31 reacts with other chemicals to destroy
00:05:31 --> 00:05:32 ozone.
00:05:33 --> 00:05:35 Avery: But when it gets that cold, the water vapor
00:05:35 --> 00:05:38 freezes out, forming ice clouds.
00:05:38 --> 00:05:41 So with the water vapor gone, the.
00:05:41 --> 00:05:43 Anna: Ozone destroying chemical reactions Stop.
00:05:44 --> 00:05:46 And the ozone is allowed to build up to
00:05:46 --> 00:05:49 much higher concentrations than seen
00:05:49 --> 00:05:51 anywhere else on the planet.
00:05:52 --> 00:05:53 Avery: That's a clever piece of atmospheric
00:05:53 --> 00:05:56 detective work. What does this tell us about
00:05:56 --> 00:05:56 Mars?
00:05:57 --> 00:05:59 Anna: It gives us a new way to trace the
00:05:59 --> 00:06:02 circulation of gases in the Martian
00:06:02 --> 00:06:04 atmosphere. And more importantly,
00:06:05 --> 00:06:07 it helps us understand the history of water
00:06:07 --> 00:06:10 on Mars. By tracking where and
00:06:10 --> 00:06:13 when water vapor is present, we can build
00:06:13 --> 00:06:16 better models of Mars past climate and
00:06:16 --> 00:06:19 figure out where all its ancient water went.
00:06:20 --> 00:06:22 Avery: From a mystery on Mars to the biggest
00:06:22 --> 00:06:25 mystery in the entire cosmos. Ana, uh, we
00:06:25 --> 00:06:27 have to talk about this new theory that
00:06:27 --> 00:06:30 challenges the very existence of dark matter
00:06:30 --> 00:06:31 and dark energy.
00:06:31 --> 00:06:34 Anna: This is one of those ideas that could either
00:06:34 --> 00:06:36 be a dead end or completely
00:06:36 --> 00:06:39 revolutionized cosmology. The standard
00:06:39 --> 00:06:42 model of the universe called Lambda
00:06:42 --> 00:06:44 CDM tells us that about
00:06:44 --> 00:06:47 95% of the universe is made of
00:06:47 --> 00:06:50 two invisible components, dark
00:06:50 --> 00:06:51 matter and dark energy.
00:06:52 --> 00:06:54 Avery: Right. Dark matter provides the extra gravity
00:06:54 --> 00:06:57 needed to hold galaxies together. And dark
00:06:57 --> 00:06:59 energy is, ah, a force that's causing the
00:06:59 --> 00:07:02 universe's expansion to accelerate. We can't
00:07:02 --> 00:07:04 see them, but we infer their existence from
00:07:04 --> 00:07:04 their effects.
00:07:05 --> 00:07:08 Anna: Exactly. But physicist Rajendra
00:07:08 --> 00:07:11 Gupta, uh, from the University of Ottawa, has
00:07:11 --> 00:07:13 proposed a new model that gets rid of both.
00:07:14 --> 00:07:17 His idea is based on a combination of
00:07:17 --> 00:07:20 other theories, including one about tired
00:07:20 --> 00:07:23 light and another covariing
00:07:23 --> 00:07:24 coupling constants.
00:07:25 --> 00:07:27 Avery: Whoa, those are some heavy terms. Let's break
00:07:27 --> 00:07:30 that down. Covariing coupling
00:07:30 --> 00:07:32 constants. What does that mean?
00:07:32 --> 00:07:34 Anna: In simple terms? It means that the
00:07:34 --> 00:07:37 fundamental constants of nature, things like
00:07:37 --> 00:07:39 the strength of gravity or the
00:07:39 --> 00:07:42 electromagnetic force, might not actually
00:07:42 --> 00:07:45 be constant. They could be changing very,
00:07:45 --> 00:07:48 very slowly as the universe ages and
00:07:48 --> 00:07:49 expands.
00:07:49 --> 00:07:52 Avery: So if the strength of these forces changed
00:07:52 --> 00:07:54 over billions of years, how would that
00:07:54 --> 00:07:55 replace dark matter?
00:07:56 --> 00:07:58 Anna: Gupta's model suggests that these
00:07:58 --> 00:08:01 changing constants could create effects that
00:08:01 --> 00:08:04 we currently misinterpret as dark matter.
00:08:04 --> 00:08:07 For example, the way galaxies rotate
00:08:07 --> 00:08:10 much faster than they should, which is, uh, a
00:08:10 --> 00:08:12 key piece of evidence for Dark matter could
00:08:12 --> 00:08:15 be explained by these evolving physical
00:08:15 --> 00:08:17 laws instead of an unseen particle.
00:08:18 --> 00:08:21 The model also accounts for the accelerated
00:08:21 --> 00:08:24 expansion of the universe without needing
00:08:24 --> 00:08:24 dark energy.
00:08:25 --> 00:08:28 Avery: So we might not be living in a universe
00:08:28 --> 00:08:31 filled with mysterious dark stuff, but in a
00:08:31 --> 00:08:33 universe where the fundamental rules are
00:08:33 --> 00:08:36 slowly changing. That's a profound thought.
00:08:37 --> 00:08:39 Anna: It is. It's important to stress that
00:08:39 --> 00:08:42 this is still a very new and
00:08:42 --> 00:08:45 untested hypothesis. The vast
00:08:45 --> 00:08:47 majority of evidence still points towards the
00:08:47 --> 00:08:50 standard lambda CDM model. But
00:08:50 --> 00:08:53 it's a fascinating alternative that reminds
00:08:53 --> 00:08:55 us to keep questioning our assumptions.
00:08:56 --> 00:08:58 It shows that there are still huge
00:08:58 --> 00:09:01 fundamental questions about our universe left
00:09:01 --> 00:09:02 to answer.
00:09:02 --> 00:09:04 Avery: And that is a perfect place to wrap up for
00:09:04 --> 00:09:05 today.
00:09:05 --> 00:09:07 From a supermoon in our backyard to an
00:09:07 --> 00:09:09 interstellar comet, a Martian weather
00:09:09 --> 00:09:11 mystery, and a whole new way to think about
00:09:11 --> 00:09:14 the universe itself, it's been a.
00:09:14 --> 00:09:17 Anna: Whirlwind tour of the cosmos. Thank you so
00:09:17 --> 00:09:19 much for joining us on Astronomy Daily. If
00:09:19 --> 00:09:21 you'd like to see more details on these
00:09:21 --> 00:09:23 stories and more, please visit our
00:09:23 --> 00:09:26 website@astronomydaily.IO
00:09:26 --> 00:09:28 and check out our continually updated
00:09:28 --> 00:09:31 newsfeed. And while there, you may like to
00:09:31 --> 00:09:34 sign up for our free daily newsletter as
00:09:34 --> 00:09:34 well.
00:09:34 --> 00:09:37 Avery: Join us again tomorrow as we continue to
00:09:37 --> 00:09:39 explore the wonders of the universe. Clear
00:09:39 --> 00:09:41 skies, everyone. And remember to keep looking
00:09:41 --> 00:09:43 up, especially this week.