Vanishing Stars and Invisible Galaxies

Summary

Awesome Astronomy Podcast

Episode 169: Vanishing Stars and Invisible Galaxies

Date: March 1, 2026
Hosts: Paul & Dr. Jeni

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Episode Overview

This episode of Awesome Astronomy takes a deep dive into groundbreaking discoveries about disappearing stars and nearly invisible galaxies composed almost entirely of dark matter. Paul and Dr. Jeni blend cutting-edge astronomical research with their signature humor, bringing listeners up to speed on everything from rare stellar dimming events and elusive dark galaxies to observational highlights for amateur astronomers.

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Major Discussion Points & Insights

Catching Up, Housekeeping, and Upcoming Events

0:00–9:52

• Personal Anecdotes: Jeni recounts her chaotic week featuring an accidental adventure into new forms of ‘bioscience’ while fixing a blocked drain—“There must be organisms living in this thing that no one has discovered, no one's seen before.” (A, 02:42)
• AstroCamp Announcement: Tickets officially on sale! Open invitation for listeners worldwide. “We'd love to break the record for the, like, most distant traveler.” (A, 06:26)
• Email Troubles: The team addresses ongoing technical issues with their email inbox and encourages continued listener contact as they work to resolve it, quipping, “Unless it's a dick dick.” (A, 08:20)
• Upcoming Stargazing Trips: Jeni prepares for another cruise to Norway, hopeful for multiple nights under the northern lights. “If I can have three good nights out... I'd be happy.” (A, 09:15)

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NEWS: Stellar Mysteries & Discoveries

9:52–33:12

The Vanishing Star in Monoceros

10:29–19:48

• Headline: Sun-like star ASAS-SN 24fw exhibited a dramatic dimming—40x fainter for ~9 months (Sep 2024).
• Irregularity: Such behavior is unheard of for stable main sequence stars. “Regular main sequence stars don't do that sort of thing. No, they just don't.” (A & B, 11:30–11:44)
• History Repeats: Past records revealed similar events in 1937 and 1981, implying a 44-year periodicity. “If they'd thrown those plates away... wouldn't have known about this. You got to keep it all.” (B, 12:56)
• Spectroscopic Findings: Using multiple observatories, researchers found not a typical dusty thin disk but a thick, gas- and metal-rich circumstellar disk. “Rather than a dusky, dusty, thin disc... this is surprising in a couple of ways...” (B, 14:04)
• Possible Cause: Debris from a major planetary collision long after the star’s formation—“Do you know what, that was in my brain! I wonder if it's gonna be some kind of event.” (A, 15:58)
• Further Theories: A massive planet (several Jupiter masses) may shepherd disk material, leading to periodic obscurations—likened to a “diamond ring” with a clump.
• Memorable Quote: “Shows the universe is very far from static... billions of years later, massive collisions... create these kind of debris fields.” (B, 19:25)

Discovery: (Almost) Invisible "Dark" Galaxies

19:49–33:12

• Context: Discussion on ultra-diffuse galaxies—difficult to detect due to low starlight but identified by clusters of globular clusters (“globs”).
• Perseus Cluster Discovery: Using Hubble, astronomers find a candidate galaxy almost entirely composed of dark matter; only the faintest starlight is visible, with ≥16% of its stellar mass in globs.
• “You can see the four dots for the glob... and then you kind of squint and you're like, maybe there's some starlight.” (A, 26:12)
• Key Technique: Looking for globular cluster overdensities to find galaxies that are otherwise optically invisible.
• Galaxy Evolution: Such “dark galaxies” likely lost their normal matter through tidal stripping in cluster interactions, leaving globs behind; opens the possibility of even fainter (truly starless) galaxies.
• Implications for Dark Matter: These discoveries provide indirect support for dark matter’s existence. “These globs are being tied together by something and you can't see that something. So it has to be dark matter.” (A, 29:24)
• Scientific Context: Ongoing debate—dark matter remains a leading hypothesis, but without direct particle detection, the field remains open. “It's not strong enough to be a theory even, because there's so many competing ideas.” (B, 30:21)
• Resource Recommendation: Astronomy Now magazine’s latest issue features an in-depth dark matter article—praised for new editorial quality and QR code enhancements for sourcing papers.

Artemis 2 and Spaceflight Updates

33:12–36:52

• Quick Mention: NASA’s Artemis II mission rolled back due to a helium pressurization issue; launch likely delayed beyond the targeted April window.
• Predictions: Paul bets autumn 2026 for liftoff; Jeni hopes for June to match upcoming travel.
• Memorable Banter: “I'm gonna make a prediction… end of summer into autumn...” (B, 34:38)

ALMA’s Largest Ever Image and Multispectral Galactic Core Research

36:42–37:34

• Science News: ALMA captures its largest image ever, spanning three full moons and revealing the star-forming heart of the Milky Way’s central molecular zone; more findings expected as the data is analyzed.

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Observing Guide: What’s Up in the March Sky?

37:34–59:01

Planets & Occultations

• Venus returns to the evening sky, low on the western horizon after sunset, bright and unmistakable. “...the brightest thing in the sky bar the moon and sun is going to be starting rumors of UFOs again...” (B, 38:33)
• Jupiter: Still shining in Gemini, past opposition but full of dynamic moon events (shadow transits, Great Red Spot appearances).
• Special Event: Regulus (brightest star in Leo) occulted by the moon on March 29th, a rare sight. “It's a pretty surprisingly rare event that the moon passes in front of a bright star.” (B, 40:14)

Comet Watch

• Comet C/2024 E1 (Weirzchos?): Approaching northern skies, potentially visible in small telescopes at mag ~10 at month’s end.

Messier Marathon (March Tradition)

• Challenge: Attempt to observe all 110 Messier objects in a single dusk-to-dawn session. Preparation and horizon planning are key. “It is one of the greatest observing challenges that any backyard astronomer can ever attempt...” (A, 45:18)
• Strategy Tips: Go by right ascension, stay awake through “the three hour gap” after Virgo, and don’t nap!
• Book Recommendation: 110 Things to See With a Telescope (John Reed & Sey Vaughan).

Paul’s Deep Sky Tour: Targets in Gemini

• Open Clusters:
  • M35: “One of the finest open clusters in the sky... If you can have one Messier, this is a good one.” (B, 49:17)
  • NGC 2158: More distant companion to M35.
• Planetary Nebulae:
  • NGC 2392 (Clown Face Nebula): High surface brightness, striking face-like appearance.
  • IC 443 (Jellyfish Nebula): Supernova remnant, delicate arcs of gas—best viewed with OIII/UHC filters.
• Double & Notable Stars:
  • Castor: Splits into blue-white pairs; actually a sextuple system.
  • Pollux: Bright orange giant, potential exoplanet host.

Lunar Features (Day 10–12 Update)

• Sinus Iridium (Bay of Rainbows): Semicircular flooded crater.

• Copernicus Crater: Fully illuminated.

• Aristarchus Plateau & Crater: Highly reflective, standout white area.

• Gassendi: Remarkable fractured floor.

• Oceanus Procellarum: Largest lunar mare, “ocean-sized” basalt plain.

• Grimaldi: Dark-floored crater, striking near the lunar limb.

• Shikard: Massive, tie-dye patterned floor.

• Quote: “The Moon is so cool. It's always overlooked... But go back to [it,] it's such a cool object.” (B, 57:55)

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Notable Quotes & Moments

On the Vanishing Star:

“Regular main sequence stars don't do that sort of thing. No, they just don't.”
—Jeni, 11:44

On Data Archiving:

“If they'd thrown those plates away... wouldn't have known about this. You got to keep it all.”
—Paul, 12:56

On Dark Matter Galaxies:

“These globs are being tied together by something and you can't see that something. So it has to be dark matter.”
—Jeni, 29:24

Philosophy of Science:

“It's not science to say, yes, it absolutely, definitely exists because we haven't found like a particle.”
—Paul, 29:58

On the Messier Marathon:

“If you can get halfway, then you get a gold star, to be honest, because... you do a bunch at the beginning and then you... got this three hour gap in the middle while you're waiting for stuff to rise. Do not do what I did, which is go in and have a little nap...”
—Jeni, 46:56

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Timestamps: Key Segments

• Vanishing Star in Monoceros: 10:29–19:48
• Discovery of Dark Galaxy in Perseus Cluster: 19:49–33:12
• Artemis II Update: 33:12–36:52
• ALMA’s Large Image Release: 36:42–37:34
• What’s Up in March’s Sky: 37:34–59:01

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Closing

Paul and Jeni wrap up the show with lunar observing tips and a reminder:

“If you have any comments... send them over to us at the show awesome astronomy.com... So until next time, it's goodbye from Cydonia Base.” (A, 59:01)

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For more resources or to contribute, visit awesomeastronomy.com. For listener questions, reach out via the show email, Twitter (@AwesomeAstroPod), or Facebook.

Transcript

[A]

The quest we find ourselves upon is daunting, fraught with danger, cloaked in mystery. The long struggle and search is not for the faint of heart. The depths astronomers have gone to, plunging into the unknown, probing with strange, often homemade instruments, the constant questioning of whether this is right or going to answer the question. But enough about me and my blocks drains. For we are seekers of the secrets of the universe, from the visible to the invisible, space dust to space rocks, planets, comets, galaxies and everything in between. And talking of the in between, I'm pretty sure the answer to Dark matter sits about 2 foot down in my back garden. I'm Jenny.

[B]

And I'm Paul.

[A]

And welcome to episode 169 of Autumn Housekeeping for March 2020. Oh, good Lord, I've had a week.

[B]

Oh, you sound like it. You sound like it. You did, you did discover dark matter, didn't you?

[A]

Oh, my God. Yeah. So I've been having work done in my attic, first of all. So basically the melon who did the lost conversion, but, like, when I bought the house, didn't put any insulation in the apex, so it was always absolutely brassic up there. So I've now had insulation put in the apex. So I've had all of that noise and chaos right over simulation to the max, especially with all, like, the, like, gangster rap that they were playing. I was just, I. It's, yeah, not good. And then I went out into the garden, like, Tuesday, because just before we started recording, we commented on how, like, spring seems to have arrived. Maybe it has. And so, you know, it was, yeah, it was like a dry, sunny day. I was like, oh, my God, I'm gonna put washing on the line. So I went out with my towels and I was like, what's that? What's that? And, like, around my pipe, which is weird, like the toilet waste goes, there was all this grey. I was like, oh, what the f is that? Right? Put my towels on, went in, got the Barry Gold, started pulling up Astral Turf. And before anyone judges me, the Astral Turf is not my choice. It came with the house, right? Pulling up the Astroturf, all this, like, sludge underneath. I was like, oh, my God. Worked out it wasn't the poo pipe. Thank God. Turns out there's a breach in the concrete for the waste pipes that take the waste water from the kitchen sink and the washing machine, right? And so it was, like, leaking out. So then I was like, well, why is it leaking out? Right? Pulled that drain off, water level right up, panic foamed. My mum and dad they came down, we got the water out. And what I can only describe as black sludge that contains bioscience is just new to humanity. There must be organisms living in this thing that no one has discovered, no one's seen before. Literally about a foot of black crud.

[B]

Nice.

[A]

Me and dad scooped out with a ladle attached to a bit of. A bit of stick. Just like a wooden baton that you got from the garage. You strapped a ladle to the bottom of it. Oh, we were wearing face masks. Like, the smell like just ammonia was unbelievable. So this is not just me. There's no way that this is like less than a year of build up. This is. I don't know, I think I'm pulling stuff up from the last time we went to the moon. Like, honest to God, manhole cover is clean. We checked that. So we've isolated where the issue is. And now I have industrial strength, like biodegrade. Like the stuff you put down your sinks. But like industrial level.

[B]

A small tactical nuclear weapon.

[A]

Yeah. Essentially blast its way through to put down there. And then if that doesn't work, then I'm gonna have to call in the professional. So.

[B]

Nice, nice, nice.

[A]

You've had a much more pleasant week, though.

[B]

Well, this week's been just working and doing the things. I was on holiday last week. I was in. I was in that there Suffolk by. In Southwold, having a nice little just chill by the coast. It was nice. There's a nice brewery there and pubs and it's just nice. It's really lovely place. Go there regularly. And before that I was. It was Festival of Tomorrow, which is the big science festival in Swindon. And I was doing some shows there, doing. Doing my thang.

[A]

How did that go?

[B]

Good, good, yeah. It was just a. Well, I did a load of online shows for school. Well, it was one big online show for. I think we had over 600 like kids online watching.

[A]

Oh my God, that's amazing.

[B]

And doing like questions and stuff like that. And we did a whole thing. And then I did a day actually at the science fair on Monday of like stage shows, stuff like that, all about spish and stuff. Got my sparkly costume on and all the rest of it. So it was all Good, good. Yeah. So that was fun. And yeah, now I've just been quite. Being reasonably chilled, enjoying the fact that spring is. Is here. All the blossoms on the springs and the daffs are up and the lambs are bouncing around in the fields. It's all really, really spring, spring and it's warm. It was like 17 degrees on Wednesday.

[A]

Jesus. I didn't have 17 degrees, but I'm in double figures, which is nice.

[B]

Yeah, it was 17 here on Wednesday. Mad. It was like, literally I was just bloody like T shirt, shorts and stuff. I was like, this is mad.

[A]

So, I mean, to be fair, I am actually in a T shirt today, like for the first time in. I don't know, it's literally been months, I think, since the last time I just sort of sat around in a T shirt.

[B]

It's really nice. And poor old Dustin still, like, knee deep in snow.

[A]

I don't know, I think he's up to his tits, to be honest.

[B]

He keeps sending his film of, like, all this snow and then he goes on these big snow hikes and I'm sitting here going like, it's 17 degrees and the daft. Yeah, yeah. That's crazy.

[A]

So we've also been planning Astro Camp.

[B]

Yeah. Astro Camp is just about to go live.

[A]

It is. As of Sunday 1st March. The tickets are on sale.

[B]

Yep. Coincide with this podcast coming out. So if you're. If you're around anywhere, I mean, you know, get on a plane. Come here, come.

[A]

Oh, we'd love to break the record for the, like, most distant traveler. We had some come over from France once. I'm sure. We did.

[B]

We did, we did. So, yeah, be cool. Come, come, come, come. So, yeah, tickets on sales. It's all cool. We've speakers and guaranteed clear skies and, and, and beer and it's all.

[A]

Yeah. And people joke about our clear skies guarantee, but every astral camp, we've seen at least one star.

[B]

We have. We did have that. We did have. Actually, we did have that one washout, didn't we? So when we joked like it was one star, it literally was like a hole in the cloud. That was one star. With all the rain. With all the rain around.

[A]

Saw it. It's fine.

[B]

Yeah, we did have work. The only washout we've ever had, it was just in all the Astro camps we've done, which is quite a few now. And I've lost count.

[A]

I've lost count too. It's gotta be two dozen.

[B]

Oh, we're past 25, aren't we? 25 was last year's.

[A]

Oh, yeah, it was.

[B]

Yeah. So, yeah, we're venturing towards 30 soon. And yeah, we've had one washout, which is a pretty good record. It's a pretty good record, actually. So, yeah, it's not bad.

[A]

And also, we are solving the emails issue. Yes. So thank you to Everyone who has been sending us emails and helping us figure this out. We think that we're getting there.

[B]

Yes. With the emails message on another channel from Visto saying it's broken. I've been emailing you. So. Yeah, we know. We're fixing it. Next episode we will chunk into some emails and do all that. So it is being solved there actually there have been loads of people emailing, apparently.

[A]

Yes. And keep emailing us because it helps us figure out where the problems are. So the email is the showesomeastronomy.com. just send us anything, send us your latest photo, send us a question, send us your thoughts about something. It just, it helps us diagnose this problem. So thank you so much.

[B]

No, no.

[A]

Unless it's a dick dick.

[B]

A dick dick. A dick dick. A dick dick.

[A]

I like a dick dick, but not a dick.

[B]

Well, but, But yeah, email away. Email away. And you, you're. You're off again.

[A]

I'm off again.

[B]

You're off again on your journeys and your trips. Yeah, you're, you're.

[A]

We are sailing. Yeah. That's as much singing as you're getting off me. I am, I am preparing for another adventure with Fred Olsen and go stargazing. Off to Norway again. So fingers crossed for the northern lights. They're on a northern lights cruise now. Some of the ghost stargazing astronomers and they have had spectacular shows so I managed to see them last time, but I only had one clear night. So I would love to have, like, I'm not gonna be greedy and hope that every night is perfect. I would love to have.

[B]

Go for it.

[A]

I'd love to. 3. If I can have three good nights out of us. I think my cruise is like a 10 day cruise. Yeah. So if I can have. Yeah, three good. Three good. Yeah, I'd be happy.

[B]

Cool. Cool.

[A]

Yeah, that's. That's the hope. That's the dream. So can we all have a word with the weather gods, please? Sacrifice a goat or something.

[B]

Yeah, cool.

[A]

And so on to the news. Hang on, hang on, hang on.

[B]

You said that was all the singing we were getting?

[A]

Oh, yeah, I liked.

[B]

You like you're gonna sing all the way through the episode.

[A]

I liked. I just, I just. Yeah.

[B]

Oh, God, we're gonna do awesome. Awesome the Musical, aren't we?

[A]

Oh, my God.

[B]

Yeah.

[A]

I'd pay to see that.

[B]

Yeah, that would be. It'd be like kind of like Hamilton crossed with Phantom of the Opera.

[A]

And what's that one with the. When they're on the spaceship and they're like rocking and rolling. Return to forbidden Planet.

[B]

Oh yeah, yeah, yeah, that's good. Yeah, yeah, yeah.

[A]

We are onto the news and we are staying away from space exploration this time. Apart from one very quick word by Artemis later at the end. But we are all about the astrophysics this time.

[B]

We are, we are. Because how about a mysterious vanishing star? So this is a sun like main sequence star in Monoceros called A S, S N, which I always assumed is assassin.

[A]

That's what I was, I was trying to spell that out.

[B]

I was like, yeah, they were going for assassin. When they built that system, they were going for assassin, weren't they? And then they couldn't quite bring themselves to actually write the word assassin.

[A]

No. So they wrote, they just got it close.

[B]

So they made the acronym A S a s s n. So assassin 24 FW. Okay, so sun like star, it suddenly in September 2024 became 40 times dimmer. So essentially like pretty much vanished. I mean, 40 times diminishes these loads.

[A]

Jesus.

[B]

Yeah, yeah, yeah. I mean it's just.

[A]

And it's. This is a main sequence star.

[B]

Exactly. And this dimness continued for. Well, it's eight and a half months. Almost nine months. It was eight and a half months. Yeah, exactly. So you're right, regular main sequence stars don't do that sort of thing.

[A]

No, they just don't.

[B]

Dying stars. Yeah, absolutely, yes. You know, look at Beetle, Beetlejuice and all that. Yeah, exactly. It does stuff like that. Infant stars. Yeah, absolutely. They, they flare up, they calm down, they do all sorts of crazy things. But not your billions of years old, regular stable main sequence variety star. They just don't do this.

[A]

Was it a Dyson sphere?

[B]

Yeah. Was it a Dyson sphere? It just got in. No, no, you could just hear, you could just hear them. We are the Foil tin hat brigades.

[A]

Scrambling now.

[B]

They're scrambling, scrambling around. Yeah, yeah. So, and on top of that, there appears to be like an excessive amount of infrared observed.

[A]

Oh. But then that kind of says dust.

[B]

Ah, well, well, hold that thought. So. Well, this, it turns out, isn't the first time. So when astronomers look back at old plates, they discovered that this star did this in 1937 and it did it in 1981.

[A]

Is it like some, something that's orbiting?

[B]

Which means. Yeah, this is a 44 year long cycle of this sort of radical dimming.

[A]

This is why it's so important to keep all the old data.

[B]

Exactly, exactly that. Because if we, if they'd thrown those plates away, you know, some, some idiot gone like, oh, I don't use plates anymore. Let's just chucked them all out. Wouldn't have known about this. You got to keep it all. You got to keep it all. You got to have your archive. So yeah, 37, 81 and now 2024. There's a 44 year cycle going on of this. Quite dramatic. I mean this is the 40 times it, it's massive. There's a huge drop in magnitude. It basically vanishes. It basically.

[A]

Yeah, it is.

[B]

So what's going on here? Well, a team led by Professor Nadia Zakamaska, John Hopkins University, used optical spectroscopy with Cosmos at the Apache Point Observatory, Maggie on the Magellan Telescope and Ghost on the Gemini South Telescope. So they use three lots of spectroscopic instruments from different observatories to have a look at what's going on here because it looked really interesting and kind of what they discovered is quite surprising. The findings indicate a puffy, very gas rich, very metal rich as well, circumcellar disc.

[A]

Oh my goodness.

[B]

Rather than a dusky, dusty, thin disc.

[A]

Oh wow.

[B]

Yeah, yeah, yeah. So this is surprising in a couple of ways because firstly, your circumstellar discs are usually quite narrow. They're usually quite thin.

[A]

Yeah. And, and they dissipate quickly.

[B]

Yeah, exactly. And precisely. They really probably shouldn't be there at this, this stage. This starts at least 2 billion years old. So it probably should have gone by now. Yeah, but, but even if, even if it still exists, they're usually very narrow and very dusty. Is, you know, probably how you imagine a disk of dust and debris around a cosmic object that kind of, I would say like Saturn ring like, but that kind of thin, like egg white, round, a round of thing in the center. That kind of idea. But this is much thicker. Puffier is Right. They call it puffy in the, in the paper. And the other is the rich cocktail of elements and it's a gas rich, metallic rich thing which is very much the sort of disc you find around like an infant star for instance, like brand new, still forming star.

[A]

Yes. It hasn't formed planets kind of thing blob thick.

[B]

You've all seen the images of those kind of like, you know, blobs of gas where there's a star burning away, like starting in the center. And, and so, you know, the sort of disk that forms planets and things like that, that sort of idea. Well, assassin 24fw is definitely not young. It's at least 2 billion years old. As I said, main sequence star. It's not anything special it's very sun like it's, it's not, you know, it's pretty average star. So this is the sort of circumstances that shouldn't be present. It shouldn't be there. Yeah, really odd. So the team think the explanation. Well, they propose that this is debris from some sort of cataclysmic event. Like a large planetary collision for instance.

[A]

Ah, do you know what that was in my brain? I wonder if it's gonna be some kind of event.

[B]

Big planets crashing into each other like you know, really that kind of Hollywood styley like end of boom.

[A]

So surprising that.

[B]

Yeah.

[A]

That that would happen billions of years on.

[B]

Well, exactly. And so you know, this has left the star system filled with a sort of element rich, gaseous, metallic rich cloud.

[A]

Yeah.

[B]

Rather than your kind of, you know, leftover bits of dust and debris from formation, things like that. Which is then of course explains the infrared excess detected as well. Because if this whole system's got this sort of big puffy cloud of gas and metal and things like that, then it's going to absorb infrared and release it.

[A]

Yeah.

[B]

They point out that the grain size of the cloud does appear to be larger than a typical cloud of ism. So the average grain size was much larger than your typical interstellar medium. So it just indicated it's not, it's something else.

[A]

Yeah. So it's like things have either started clumping or they've like been fractured. But not down to the molecular level.

[B]

Exactly. So the periodic dimming though because of course. Okay, if it's just a big uniform cloud, why is there this dramatic dimming? They think that's a particular dense area of the disk. Perhaps even the collision happened or something. But it's, the team hypothesize is tied to a large planetary body that's orbiting. So like it's clumped it together in a, in a spot because been shepherded by the gravity and it'd be something in the order of several Jupiters. So there'd be a large planet that's orbiting the star that's, that's shepherding this, this debris into a lump. So you can think of it, think of it like a ring, I suppose like you know, a diamond ring. There's a sort of ring and then there's a big lump of it at one side and that's going around in a sort of 44 year orbit.

[A]

I love that.

[B]

Good, innit? It's really good. So post the dimming they're now following up the observations to check various signals from the star Itself. Because now the star's like, more. It's brightened back up again.

[A]

Yeah.

[B]

So they want. They want to unpick, like, what's coming from the cloud. What's coming from the star.

[A]

Yes. What's coming from the star.

[B]

Yeah.

[A]

I wonder if it's. Yeah. Because it's so interesting. It's like whether that dents a bit is where the collision happened or it's like reforming.

[B]

Yeah, exactly. Or. Yeah, yeah, well, exactly. Perhaps it's actually reformed. Who knows? Yeah, yeah, yeah, that's. That's a great. I don't think that's in the paper. That's a really interesting idea. So. Yeah.

[A]

Oh, well, if you're listening, dear Author, you should have seen the number for 10%.

[B]

I have to say, it was a very modern paper in that it had about, like, 13,000, like, listed authors. It's like, you know, the first page of the paper was like, everybody and their aunt and dog was listed on the front page.

[A]

I. I put Oreo in my acknowledgments in one of my papers once.

[B]

Yeah, but this wasn't even the acknowledgments. This was literally like, you know, the

[A]

author, as the author, the list of authors. Like.

[B]

Oh, God, that's like a page of all. Like, surely they kind of all written this.

[A]

No, it's. They'll put people on, like, who built the instrument, for example.

[B]

Yeah.

[A]

And. And it's. It's like. Because they never used to kind of credit those sorts of people, and. Which is unfair because without them building the instrument, the science wouldn't happen. So now it's like a lot more people.

[B]

Yeah, but, yeah, it's a big old list. Anyway, it's in the Astronomical Journal, if you want to. To follow that up and say it's the. As the lead author says it shows the universe is very far from static. That.

[A]

Yes.

[B]

You know, you think of systems around stable stars forming and then that's it. But actually, potentially, you still get, billions of years later, massive collisions between planets and bodies and things that create these kind of debris fields. And that would be, you know, almost like, probably putting the clock back to the beginning in terms of that. That system and its formation. Fascinating stuff like that.

[A]

Love it. It's a good story.

[B]

It's a good story.

[A]

So for my story, I'm actually going with something unusual and interesting and different as well. And this is. I think it's an amazing discovery in the Perseus Cluster, and astronomers think that they have found a galaxy that is made almost entirely of dark Matter. Right. Which is interesting on two levels, because first of all, a galaxy that's almost entirely dark matter, and then secondly, how do you find a thing you can't see?

[B]

Yeah.

[A]

Because if it's almost entirely dark matter, then that sort of says there's not really any starlights. And that is the case is there is hardly any starlight. There's just this like really fine, like a gossamer veil of starlight and then these little buttons of globular clusters. And that is what was key to finding this. I love this story. So this is, this is this whole new class of galaxies.

[B]

Right.

[A]

We're only just starting to find these dark matter dominated galaxies with very few stars. You know, we're still finding them, still trying to understand them. And it was found using globs. So globs, globular clusters. We love to look at them from our backyard. They're these like ancient balls of gravitationally bound stars. They can contain hundreds of thousands, millions of stars. They go back to the early days of the universe, some of them forming sort of 13 billion years ago. And by and large, many of them, say, seem to have formed in kind of one burst of star formation or with one major burst of star formation. And studying them gives us clues to kind of the earliest stages of star formation. Because they are so ancient, we find them in the outskirts of galaxies. We know our galaxy has got almost 160. That's how many we've cataloged anyway. There's probably more hiding behind our dusty disk. We've counted them around Andromeda, you know, all the big galaxies, we've counted them. The thing is, those galaxies are obvious, right? The, the big galaxies like ours and Andromeda and Triangulum and you know, the Pinwheel, anything like that. Right. They're ancient, they're full of stars, they're really obvious. Right. But not all galaxies are obvious. And about a decade ago en masse, we started finding what's called ultra diffuse galaxies. So ultra diffuse galaxies, they have a large physical size but very little starlight.

[B]

Yeah.

[A]

Like most of their mass is invisible. It's in the form of dark matter. And the way that they're found is with really specialized like camera equipment. Often it's like arrays of camera lenses that don't allow stray light in and have very dark interior. So there's no internal reflections of the light off mirrors and things like that. So that you can then find the very faint starlight associated with these galaxies and get like lost in the processing. So since, you know, from about A decade ago. Thousands have now been found. Right. We find them in galaxy clusters. We find them outside of galaxy clusters as well. But what was noted about these ultra diffuse galaxies is they have this really unusual property, is that they seem to have, for their given mass and size, five to seven times the amount of globular clusters, right? Yes. They have like this overpopulation of globular clusters and about a quarter of their stellar mass is in their globs. Like so much of their stellar mass is locked up in their globular clusters. And so then astronomers kind of got thinking and they were like, well, we found these ultra diffuse galaxies with like all these extra globs, but what if these are just kind of the bright end of the scale? What if there are ones which are even fainter? Are there starless galaxies out there? Are there dark galaxies? Right, right down at the fainter end. And so because of this unusual property of these over densities of globular clusters, astronomers were like, oh, we could maybe use this to like try and find them because we wouldn't be able to see them, but we could see their globs, right?

[B]

Yeah, yeah, yeah.

[A]

So using Hubble, this is actually a Hubble story, not a, not a James Webb look at Hubble doing.

[B]

Good old Hubble.

[A]

Good old Hubble. So the team of astronomers, they looked at this Hubble data and they found, because Hubble had looked at part of the Perseus Cluster and they found 10 over densities of globs in, in the field, in the images, and they had no associated starlight with them. So they were like, right, interesting. Did a lot of digging, found out that of those 10, they had all been sort of found before they were associated with galaxies. They were like, good, the method works because we found them not through their starlight, but through their globs.

[B]

Yeah.

[A]

So then they dug into the data a bit more and they found a clump of four globular clusters with no associated starlight and no known galaxy association. They called this one candidate Dark Galaxy 1. Now, follow up observations haven't revealed any starlight, so that one is still a mystery. But what they did is they went back to the data, went with more sophisticated statistical methods, factoring in things like the colors of the globular clusters to look for ones which are all like stuck together and found candidate Dark Galaxy 2. Now they noticed that Hubble had gone to that patch of sky twice. So they did the thing that astronomers always do and they stacked the photos together. And in that stacking, they then found Some very, very faint starlight. They went to Euclid. Euclid has also looked at the same patch of sky and they found some very faint starlight in Euclid with exactly the same morphology as was found in the Hubble data.

[B]

Right.

[A]

And so the fact that they have robustly detected starlight with two different telescopes shows it's not some kind of image processing error. And this is really strong evidence that now they have found the first, what they're calling dark galaxy.

[B]

That's really cool.

[A]

Yeah. And if you look at the picture of it, literally you can see the four dots for the glob.

[B]

Yes, you can. I was just looking at the picture. I just brought it up while you were talking, I thought, oh, yeah. And you can, you can absolutely see there's four little globs.

[A]

Yep. You can see though. And then you kind of squint and you're like, maybe there's some starlight.

[B]

There's like looking.

[A]

You're like.

[B]

Yeah. On the zoomed. On the very, very zoomed in image, there's a sort of triangular patch.

[A]

Yes.

[B]

Which you.

[A]

And that is the start you could

[B]

convince yourself is because you got like kind of that background fuzz that you get on very blown up images. But there's a, there's a sort of denser patch of it.

[A]

Exactly. And that is the starlight.

[B]

Wow.

[A]

So with this particular galaxy, it's at least 16% of the stellar mass is in the globs, but they think it could be a lot higher. They just. Because they've only got a couple of images to try and decipher the starlight from this galaxy. It's kind of like baseline minimum 16%. And so then the question becomes, how do you get these dark galaxies? And so what they think is that these are galaxies that have been stripped of their normal matter during interactions with other galaxies in the Perseus cluster.

[B]

Right.

[A]

But the globular clusters, see, they survive because as individual objects, because they are so tightly gravitationally bound that as individual objects they don't get shredded, but the matter has been ripped out of the galaxy.

[B]

Right.

[A]

Yeah. And so then you can also wonder through these interactions are they've got extra globs, is that because they're stealing them from other galaxies during the interaction? You know, like they lose their normal matter, but then they steal some globs, who knows? But then the question becomes, are these the still the, the bright end of dark galaxies? Because they still have starlight. Right. So they still have stars, they're not just dark matter. So Then it's like, are these still towards the bright end of dark galaxies? Because they clearly still have starlight, so they're not like 100% dark matter. So it's like, are there ones still yet to be found that don't have stars and don't have starlight? And maybe that's what the candidate Dark Galaxy 1 is because they couldn't find any starlight with that. And maybe that is sort of a true dark galaxy. So. Yeah, but I just, I love this story.

[B]

Yeah. And, and I suppose, I mean, are we saying this, this helps confirm dark matter, do you think?

[A]

So this is. It's like another part of galaxy evolution. I guess it is another argument for dark matter for sure, because there's no. These globular clusters would not randomly just be stuck together like their, their coincidence and their location is not a kind of randomly. These globs are being tied together by something and you can't see that something. So it has to be dark matter. But it's also kind of looking at another window into galaxy evolution.

[B]

Yeah.

[A]

And another's kind of, you know, part of it which we don't really understand yet and we haven't really thought about. And there's, you know, all these kind of galaxies out there which we, we haven't even started scratching the surface on.

[B]

No, no. Well, it's a really interesting part of astronomy, isn't it, because we, we still haven't confirmed dark matter.

[A]

No, there's lots of evidence for it and it's passed lots of tests.

[B]

There's loads of evidence for it. And we constantly on this show say, like, you know, we still can't absolutely go. Because that's not science. It's not science to say, yes, it

[A]

absolutely, definitely exists because we haven't found like a particle.

[B]

Yeah, exactly. That would be ridiculous to say absolutely exists because that, that would be unscientific to say that.

[A]

Yeah.

[B]

Which is kind of the point we always try and make over the years and we get accused of being like massive dark matter skeptics and the rest of it. It's like. No, it's just good science to say.

[A]

Yeah, well, actually, it's our leading theory, but we.

[B]

It's the leading theory. Yeah, well, it's not even, it's not even really the leading theory. It's a leading hypothesis. It's not, it's not strong enough to be a theory even, because there's lots of, there's so many competing ideas of what it is.

[A]

Yeah. And it is that, you know, there is so much Evidence for it. But it's like what it is. We haven't got clues there.

[B]

No, exactly. Is that we're almost kind of in that, I suppose that period where we, we know what gravity, you know, we know gravity is and things. But we don't actually hadn't worked out how it worked and you know, sort of.

[A]

Yeah.

[B]

All that sort of.

[A]

Yeah. It's like we know, we know it's there, something there and it does a thing. What is it?

[B]

But what is it?

[A]

Yes.

[B]

So it's just interesting because this, this is, this almost. It's sort of predicated on the idea that yes, these, these are dark matter galaxies. These are actually, you know, so this, this is dark matter. It's very interesting. It's.

[A]

Yeah.

[B]

And whether that then helps us discover what it is.

[A]

Yeah.

[B]

Because there's clearly a big lump of it here or appears to be. Yeah. I just find the dark matter thing, in fact, funny enough, it's Astronomy now magazine this month actually, which I do know. Have you been getting Astronomy now recently?

[A]

No, I haven't.

[B]

Big shout out to the Astronomy Now. It's been taken over. It's been, it's been a whole new team and they've got a new editor, Stuart Clark. Dr. Stuart Clark, who's. It actually has really become a much, I think a much better kind of kind of magazine.

[A]

Well, do you know what? Maybe I'll try a few mag. A few copies then a few issues.

[B]

Yeah, I think it's got a lot better. And they funny enough this, this month they have a whole article on the sort of dark matter.

[A]

Yeah.

[B]

Kind of exploration. What is it? Is it even actually a thing? There's a really good sort of little kind of, you know, deep dive into that which is.

[A]

I might have to try a few because, you know, I, Yeah, I get, I get sky at Night and Focus. But you know, sometimes it's nice to kind of switch them up and you know, it's like sporadically I buy new scientists and yeah, maybe I'll give this one a go.

[B]

Yeah, I'd say, I sure say I've been very impressed with it in the last, last little while. I think. I think the new editorial team's been very good for it. It's, it's, it's stepped up a gear. It's. It's a much, much more slick, professional looking looking art. And they put QR codes on for where all the science articles they quote and things are. So there's like QR codes. You go straight to the, you go

[A]

straight to the paper that's used for.

[B]

It's little, little things like that all the way through. It's like just a bit slicker. This is a bit better. This is a much better, better product and I've been really enjoying it. Really.

[A]

I like that.

[B]

But it's just because I had a dark matter article this this month.

[A]

So. From astronomy now to space flight. Not now.

[B]

You're well done.

[A]

Yeah, it's just a very quick mention. We're not gonna bang on about it, but it's just to say that Artemis 2 has rolled back to the vehicle assembly building. Although the second wet dress rehearsal went swimmingly, there were then issues post that rehearsal with helium, which is used to kind of pressurize tanks and maintain them. There were issues there. So. And they can't fix it at the pad. So they've got to roll back and investigate properly because they're not 100 sure what's actually gone wrong.

[B]

And all I can say is we said it wouldn't go.

[A]

Yeah. And I mean they're hoping to make April, but I don't think. And now I honestly, I don't think it will be. I think we're looking at May, June as. As a serious.

[B]

I'm gonna make a prediction, but I think it won't even probably be till the autumn. Like it would be later in the year. Much, much later in the year.

[A]

Well, I would quite like it to be June because that's probably when I'll go back out to the States. So it would be great if I could kind of time it so I can on my way back stop at Florida.

[B]

Yeah.

[A]

And actually watch it. Like that'd be sick.

[B]

I just feel like they won't keep wheeling out of the vab.

[A]

No.

[B]

To just like, oh, there we go. So you might just go like, you know what? Actually let's strip some of this down and actually just make sure it does work properly.

[A]

Yeah.

[B]

Actually they'll come to the. Oh, do you know what? Let's put a three month delay in to actually redo this bit and rebuild this bit and go to the. Because it was a problem on the pad as well, wasn't it? There was actually a problem with the stuff on the pad. So there'll be this kind of like big engineering kind of. Let's just go over everything again and just. And actually the. By the time you've done that, suddenly it's like April, May, June. You're looking at July and June, June, June. Yeah. But what I mean is then there's all. There's other launches going on.

[A]

Yes.

[B]

And they have busier because, you know, better weather and all this. You get lots and lots of other launches going on and there's lots of commercial launches. And so there'll be this, like. And of course, it's got to be a particular window with the moon.

[A]

And yes. It's only certain days in the month that it can.

[B]

And suddenly you're like, would it be September then? Actually like August. September getting into autumn. I, I, that's gonna be, I'm gonna. Okay, put a pint on that.

[A]

All right. So you're going, what, like September, Almost August.

[B]

I reckon kind of the end of summer into autumn will be.

[A]

I, I would like June. Thank you. Yeah. And then just to finish off, I, I want to just mention there's this really cool new image that's come out from, from alma. So the Atacama Large Millimeter Array down in Chile, and they have image. It's the largest ALMA image ever. So it spans about three full moons and it is focused on the central molecular zone of our galaxy. So this is the, the gas and dust that's swirling around our supermassive black hole. It's a region that spans about 650 light years. And you find the star formation in this region is really interesting. There's typically more massive stars. It's warmer, it's more turbulent, it's much more reminiscent, we think of what star formation was like and the kind of conditions of star formation in the very early universe because of this extra temperature and the turbulence and everything. So it kind of gives us an opportunity to study that kind of star formation up close. Because, you know, when we look at galaxies in the early universe, we see them as blobs. We can't study star formation in any kind of detail. It's a really, really cool image. They've looked at it over many wavelengths. It's a multispectral image.

[B]

Very cool image.

[A]

You get so much beautiful detail in it. I would recommend have a look at that if you can. It's ALMA and the Central Molecular Zone. That should bring it up.

[B]

And shout out to alma. You go on their website, they have a pride mode and you go, alma. You click on pride mode and your whole, the whole website just becomes sort of shimmering rainbow, like sort of spectra. So shout out to alma. That's good, good, good work. So, yeah, that's beautiful image. Really stunning. Yeah, really stunning.

[A]

Yeah. And it's like there's not too much science that's come out of it. Yeah, it's just kind of like an image release because they're gonna sort of analyze it now in detail. But it's a lovely image so would recommend people go and have a look at that.

[B]

Cool.

[A]

So now we should probably talk about things that we can look at in the sky with our eyeballs.

[B]

Right? Well, it's a lot of bright objects this month actually. There's a lot of bright, bright blobby things. Bright things to look at. So we have Venus in the evening sky returning to us. So initially quite low, it was putting in an appearance after sunset at the end of February. So if you were kind of had a nice low western horizon, you could probably see Venus just sitting there on just as the sunset. And as month goes on, the brightest thing in the sky bar the moon and sun is going to be starting rumors of UFOs again because where it's sitting like 10 degrees up, causing your non astro friends to start messaging you going Dave, what's that bright thing hovering over the park? But it's there, it's going to be climbing up. So it's not that kind of spectacular shooting up the sky saying you see Venus at like, you know, 30 degrees up in the sky. It's going to be kind of 10, 11, 12. It's going to be slowly climbing up as it comes up, but it'll be there. Be really bright and be actually quite or always think sometimes more spectacular when you see that close to the ground like that.

[A]

Yeah. And you're seeing it in the colors of twilight. You've got that pinky purple sky. Very cool.

[B]

It's very cool. So that's Venus. Venus is back. So that's good. And then Jupiter. Jupiter's still big and bright in Gemini and white's past opposition and fading a little in intensity now. So the mag's starting to now turn down a little bit. Very much the key go to object in the sky right now if you.

[A]

Yeah, still good.

[B]

Swing it, you know, every time and you can't miss it. It's like literally it's pretty much the only thing I see when it's been cloudy. It's like you see it burning through the cloud reaching its second stationary point on the 11th. Okay. So it's of course possible to get that nice little loop it makes. There are various moon events. The Galilean moon events are plenty to watch out for through the month. Shadow transits, transits, occultations, they are whole. There's just more than we could list. Very easy to find.

[A]

Yeah, you're better off looking especially from

[B]

your location and Things like that. What's a good time? I could sit here and list loads of them. And of course you know, don't forget the Great Red Spot transits and things like that. There's loads going on. It's really good Jupiter time. It's nice and high. Gemini's nice and high for northern Europeans. There is a spectacular Regulus occultation on the 29th in the early evening. So the moon, you know, depending on location, the waxing gibbous moon will blot out the brightest star in Leo which of course is. We said this before, it's a surprisingly rare event that the moon passes in front of a bright star.

[A]

Yes it is.

[B]

It's a pretty surprisingly rare event that the moon passes in front of a. Even the average like bright. It doesn't happen very often.

[A]

But regulus is so bright.

[B]

Exactly. This is going to be a spectacular one. Which means it'll be completely cloudy and raining where I am. So this would be after 7pm I think it's about 7:14 or 7:13 in London and a bit later about 7:18 I think it is in Edinburgh for instance. So depending where you are, your latitude. So just after seven and then it'll appear again about an hour later. So it's about an hour behind the moon now.

[A]

So what might we miss it disappearing because of sunset time.

[B]

Exactly. So now ingress is actually before sunset

[A]

in the UK but we can see it reappear.

[B]

Yeah, but actually good binos are a small scope. You'll see Regulus in, in the kind of twilighty just pre sunset sky you definitely see. It's a very bright star and in the way that actually you can see bright stars all day if you know where to put your telescope. If you know where to point a telescope you can see. I mean I've seen Venus at lunchtime.

[A]

I have heard of people doing planets but I've not heard of people looking at stars.

[B]

You can see some of the bright stars especially in that kind of later like when it's a bit dimmer like early morning.

[A]

Okay. So like just before sunset it's only

[B]

like midday you might get or something like that. But actually you can see the brighter stars when the sun is up. Just if you absolutely know where to point the telescope and you know, yeah,

[A]

you can do not point it at

[B]

the, don't point it at the sun. But they are, you know these stars are bright so it is possible. So actually this is, it's not long before sunset so you will actually see if you put binoculars on the moon you'll you'll find Regulus. You'll see it sort of just next to it. So you will see it. So just make sure you're prepared. Don't go out sort of naked eye going, well, I'm going to go still blue sky. You need a pair of, you know, 10 by 50s or something like that to see it. Yeah, but. Yeah. And then an hour later you'll definitely see it as it comes out. So that's a spectacular one to watch out for. Then we also maybe have a bit of comet action in the middle of the month.

[A]

Oh my.

[B]

It's actual month. But the moon would be kind of getting in the way until then.

[A]

Okay. Yeah.

[B]

A bit bright. And so this is Comet C 2024 E1. Now, I've been debating how this is said, but where's Chos. Where's. Where's Choss?

[A]

Wiz Charles?

[B]

I don't know. W E I R Z C H O S. Yeah, I happily be corrected on how that is said. But anyway, discovered about two years ago, it's probably an Oort cloud object that's taken millions of years to get here. And after it's in a solar system for a. It's gonna be ejected out into deep space. Poor little bugger. Off he goes. It's gonna like the speed it's achieved falling in from the Oort cloud.

[A]

Yeah, that. It's gonna kick itself out and ping

[B]

off and become an interstellar comet. It's off it will go. Perihelion was 20 January and the 17th was closest approach to Earth. But it's now venturing into northern skies because actually it was.

[A]

Yeah, because it's been a southern hemisphere, obviously.

[B]

Penguin fancy object. Exactly. And it moves from Eridanus into Taurus. You'll see it after sunset and it should be about Mach 10. So that'll be. That'll be nice.

[A]

So small telescope.

[B]

Yeah, exactly. So if you're out watching at the end of the month, you're out watching Regulus fall behind the moon.

[A]

I will look for a comment.

[B]

You're there at sunset, have a look for the comet as well. And it's about Mach 10. That's nicely reachable. You should be able to get a good strong pair of binoculars. Should be able to sort of perhaps even pick it up. So that's good stuff.

[A]

So before Paul does the deep skydive, there's another deep sky thing to do this month because it's March and that means it's Messier marathon time. I'm very excited.

[B]

So are you gonna try it?

[A]

Ah. Do you know what? I think if I've got clear skies, the problem is I'm gonna have to like, go somewhere for it.

[B]

Yeah.

[A]

What I'm thinking is I'm gonna have a go at Astral Camp. And I just, I know that by the time Astro Camp rolls around, because it's in April, some objects will not be visible. And I accept that. But I'm thinking this Astro Camp, I'm gonna go for round two, because I did try it.

[B]

You did try it. You did try a couple of years ago.

[A]

Yes. We got about two thirds of the objects and I was very pleased. So especially this time round, I'll have the sea star and I can try and photograph them. I would just do like a couple of minutes on each one.

[B]

Yeah, yeah.

[A]

Not to get the best images of them, but just to get something off them.

[B]

Oh, nice.

[A]

So the question now is, what is the Messier Marathon?

[B]

Go for it.

[A]

It is one of the greatest observing challenges that any backyard astronomer can ever attempt at in their life. And I will deny anyone to say otherwise. It's just brilliant. You don't need a giant telescope to have a go. You need either a large pair of binoculars or a small telescope. Because what we are doing with the Messier Marathon is we are hunting all 110 objects of Comet hunter Charles Messier's catalogue, which was Originally published in 1774. Not with 110 objects. 110 objects was kind of finished like in a few decades ago. But because Charles Messier found them with his crappy like 18th century optics, it means that you can definitely see them with your modern day 21st century or 20th century, depends on when your telescope was built. Optics. It is a mixture of stars and nebulae and star clusters and galaxies. And it's just excellent. Yeah, it is. It is difficult because it is a dusk till dawn event. You have to start shortly after sunset. You do not go in numerical order. There isn't? No. And that is critical. You have to go in order of right ascension, essentially across the skies. You have to catch things before they set to begin with, and then later on you're waiting for things to rise. There are all sorts of lists online that will tell you the order that you need to go in. And the clearer your horizon, the better if you miss some at the beginning because you don't have super close clear horizon, who cares? Like, so few people have actually completed the Messier marathon. If you can get halfway, then you get a gold star, to be honest, because it is the Trick is, the problem is that you do a bunch at the beginning and then you kind of clear Virgo. And then you've got like this three hour gap in the middle while you're waiting for stuff to rise. Do not do what I did, which is go in and have a little nap and think you'll come back up later, because you will not.

[B]

That's deadly. That's deadly.

[A]

That is deadly.

[B]

And then you just, you're just too warm and it's too nice and you're like, no, no, I, I've never actually attempted the full, the full thing. I've never done it. And I keep. Okay, maybe this is the year. Maybe this is the year I'll do it. I, I can recommend a book I think we mentioned before. It's 110 things to see with the Telescope, the world's most famous stargazing list, and that has, like, advice on how to do the marathon.

[A]

Okay.

[B]

And that's by John Reed and Sey Vaughan. And, and it's, it's a really good book and it's not expensive. You can get it. And it's a nice little book as well. And it's got some really good kind of guides on how to find the objects and things like that. So I'd recommend that. But yeah, no, I, Maybe this is year I'll have a go. Maybe this is it. Because the problem is it's just such a big, long night. That's it.

[A]

It's all night. It's an all nighter.

[B]

You've got to clear your diary because you won't, you won't be fit for service the next day.

[A]

No, no, no, absolutely. Because it's literally. And you got to prepare, you got to kind of sleep as late as you can in the day before.

[B]

Yeah, yeah, exactly, exactly.

[A]

But the Mercier catalogue is not the only list of deep sky objects out there. There are many, many other catalogues. And we're gonna tour some of the objects from some of those other catalogues with Paul's deep sky suggestion.

[B]

Right. And this one is Gemini. Deep sky gem likes, it's nice and high. You've got Jupiter sitting there. So you're in the area already because let's face it, you're gonna have a look at Jupiter while you're out there. So you might as well have a look at some of the other. And it's a, it's that kind of great constellation for winter. Spring, sitting right on the edge of the winter. Milky Way only contains one messy object, though. So in your marathon you're only gonna visit visit it once. But it's home to several iconic nebulae and star clusters are great for the sort of visual and astrophotographers alike. So let's start with that lone Messier M35, which is one of the finest open clusters in the sky, to be fair. I mean, if you can have one Messier, this is a good one.

[A]

Yeah, have a good one.

[B]

It's visible to naked eye under dark skies. It appears in binoculars as a large fuzzy patch in a telescope. It just explodes into hundreds of bright blue white stars ranging sort of curving chains. To find it, look near the foot of the twin caster, the upper of the two twins, near the star Eta Geminorium. Now bonus here is that right next to it is NGC 2158, a much older, more compact cluster. Now why they look like a duo, they might have them next to each other. Actually, 2158 is actually four times further away at about 11,000 light years to M35, 2800 light years. Well, thereabouts, it's still a fair way away. It's still fair away. Yeah, exactly. And it appears a few faint golden smudge in small telescopes. So have a look out for that. Next object on our tour of the Twins is NGC 2392 or the Clown Face Nebula. This is a bright, high surface brightness planetary nebula. It looks like a small bluish green fuzzy star at low power. So look out for that. But with higher magnification you can see the bright central area, which is the nose of the clown, surrounded by a double shell of gas that resembles a face.

[A]

Oh yeah, yeah, yeah.

[B]

It's about 2 degrees southeast of the star Delta Geminorium or Wasat. Wasaat.

[A]

Wasaat.

[B]

You've got to be a certain age to know what that is. A more difficult observation and a great imaging target is IC443 or the jellyfish Nebula. Now this is a supernova remnant from a star that went supernova sometime probably at the height of the last ice age 20,000 years ago, and is similar to the more famous Veil Nebula insignia. It's very similar. It is possible to see this visually with a dark sky, good aperture, no. 3 and UHC filters. So you need. Unlike the veil, whereas veil you can see completely naked eye through a telescope. Say naked eye through a telescope without filters. Through a telescope, I should say.

[A]

Yeah, I got one naked eye through a telescope. We got you.

[B]

You got me. But it improves with O3 and UHC and things in the Veil. The jellyfish, you have to be in a really dark sky with a lot of aperture to get a decent hint of it without filters. So really throw an.03 in and you should see it appears as like delicate sweeping arcs of gas with tendrils that can look a bit like a jellyfish. If you've never seen a jellyfish before,

[A]

it makes me think of those, like the late medieval drawings of animals that they've heard descriptions of. Completely never seen. Like, giraffes are always brilliant.

[B]

Completely. Completely, yeah. I mean, indeed. I can see where people are coming from. That looks a bit like. It's a blobby bit and there's kind of tendrils and if you squint, you're like. It's kind of like a jellyfish, I suppose. Sort of, yeah. But it's fun. It's a really lovely object if you get to see it. And a great imaging target because, of course, you don't have to worry about the sort of power of your eyes. Couple of extras to mention. Here are the heads of the twins, Castor and Pollux. Castor is a superb double star that splits even in a small telescope to two bright blue white stars. So it's actually a sextuple system. It's actually six in there. And those of you, more power and girth for now, will, yeah, will get three stars. But you won't. That's what you'll get, I'm afraid.

[A]

Yeah.

[B]

Pollux is an orangey giant star, though not a binary, but it is currently the brightest star, thought to have a planet about twice the mass of Jupiter, is debated, actually, but it's even got a name, Thestius.

[A]

I like that. So, yeah, like that. Looking at that. Be like naked. I star with a planet, maybe.

[B]

Yeah, exactly, exactly. So on for our moon guide. Yes, our new moon guide. That we were.

[A]

This is a lovely section.

[B]

Yeah. Suggested. I liked it. I thought it was a really good idea.

[A]

Yeah.

[B]

So this is day 10 to 12. So, okay, we got 10, 11 and 12 wexing gibbous phase of the moon. And here are some of the sort of most dramatic sort of land sea, he says in inverted commas, land sea boundaries on the lunar surface with stunning changes in relief and albedo. Day 10 and the sinus iridium, the bay of rainbows is now very clear. This is a massive impact crater flooded by lava, appearing as a semicircular bay on the edge of the Mare Imbrium. Copernicus Crater. We talked about this last time. Now fully illuminated, it's complex terrace walls, massive central peaks cast long Jagged shadows across the crater floor, though perhaps not quite as dramatic as the previous 24 hours. So if you go back to day nine, that's, that's probably the better day for it. Look out for Bully Aldus, which is a perfect sharp edged crater. It's like absolutely stunningly perfect. It looks like someone's actually like built it in. The Mare Nubium stands out beautifully against the dark basaltic plains. Really beautiful. By day 11 we're moving on to the Aristarchus plateau and of course we've got Aristarchus, bit of most reflective, highest albedo area on the Moon. It's that white patch. You can see it looks white, it's just really, really bright. And that's sort of even on the terminator as it's coming out the terminator, it glows. It just seems to sort of almost radiate its own light. It's really, really impressive. Keep an eye out for the Valis, which is sort of massive. Cobra headed is how it's often described. Sort of sinuous rile, this lava channel that's nearby, which is a great, great thing to find. It's quite, quite small. I mean this is when people look for these objects they think they're going to be as big as the craters. They're quite small and you have to kind of search for them and you find them.

[A]

Yeah, but then that's the fun of the hunt.

[B]

That's the fun of the hunt and that's what's fun about the moon. Then you've got. Gassendi crater is located on the northern edge of the Mare Humerum. Always love these Latin names, they're brilliant. This is a fantastic floor. Fractured crater. Ah,

[A]

interesting.

[B]

That is kind of how to describe. It's like delicate web of cracks on its floor and it's kind of as the sun hits you got these little like shadows and they're actually, if you're physically there, they'd be a lot deeper but from our perspective they just look like little tiny scratches, sort of shattered glass kind of thing. It's really cool. Then Marihoorim Self Humaram or the rather saucy sounding sea of moisture that's very moist.

[A]

I don't like that word. It's the bad word.

[B]

And yeah, so the sea of moisture appeared fully out of the gloom and is framed by these smaller craters like Vitello on its southern edge. It's really cool. Then we're on to day 12 and the moon approaches approaching full. Now we're getting towards that, that full moon and the terminator is kind of nearing the limb. You're getting very close. It's that, that point where people think they. It's a full moon. Yeah, that's that. You know, people say, oh, it's full moon last night. No, actually it's almost. Almost. Almost, but not quite.

[A]

Yeah.

[B]

It means that the shadows, because the curve, as you're getting towards the edge, like the limb, from our perspective, the shadows are getting shorter. They're not getting quite as long sort of shadows. And so the big star here is Grimaldi. Large strikingly dark floored basin near the western limb. Because it's floor is made of dark lava, it looks like a black hole rather than the crater. If you like catch it. When it's really dark in that crater, it actually looks like there's a hole in the moon. It's really cool. Like all these highlands around, it's very, very cool. Then we have the Oceanus Procalarium or the Ocean of Storms on show that's now like kind of fully out. This is the, the largest of the lunar mare. And day 12 kind of reveals just, just how vast of an ocean is. Just a huge, huge area. What a big bit of the moon is. It is, yeah. Look out for the various wrinkle ridges across its surface caused by the cooling of that kind of ancient lava. As it cooled, it shrinks and stuff. Real favorite mine is the crater Shikard, which is massive wall plain near the southwestern limb. It's unique because its floor has patches of varying darkness, like sort of stained surface. It looks like it's kind of like tie dyed. It's really cool.

[A]

Oh, I like that.

[B]

See, the moon's so cool. It's really, really.

[A]

The Moon is so cool. It's always overlooked.

[B]

People get obsessed by deep sky and I'm, I'm one of those people all the time. But go back to Moon's really cool. It's such a cool object.

[A]

It's just. And the thing is, the moon is always there.

[B]

Yeah.

[A]

Like, you know, you can only see certain objects at certain times of year, but the moon and every month is

[B]

there and it's reliable. And actually it's one of those objects that even on a not so good night.

[A]

Yes. You can really enjoy it too.

[B]

You can still go and have it. So even if it's a bit cloudy, but you can still go to the moon and actually get a really good night's astronomy regardless. Whereas, you know, you, if you want to do deep sky and things, it's cloudy. I'm written off for the evening. Actually, the Moon's always there. It's really good. And the Moon itself begins bright with full on the 3rd, last quarter on 11th, new on the 19th, and first quarter on the 25th. So all that remains to wish you clear skies and happy hunting.

[A]

Right, there we are. Mystery solved. I'm waiting for the Astronomer Royal to turn up any moment and present me with my medal for discovering what dark matter truly is all about. If you have any comments, queries, suggestions, thoughts, send them over to us at the show awesome astronomy.com we now have a bunch of your emails through which we can address next time, but we're still diagnosing the issues. So please get in touch, send us some more, help us stay in contact with you. And so until next time, it's goodbye from Cydonia Base.

[C]

Awesome Astronomy is produced by Ralph Paul, Jen, John Damian and Dustin and is free to use with attribution. Theme music by Star Salzman with stinger variation by Rin Jorgensen. We promote general science, astronomy, space exploration and rational thinking with more resources on our [e-mail] if you want us to read your thoughts and comments out on the show, send us your views, opinions, critiques or questions to the [e-mail] tweet us @awesomeastropod or give the awesome Astronomy Facebook page a like and leave your comments there. Thanks for listening. From Cydonia Base Head of Transmission.