# Galactic Ejections & Black Hole Explosions: Exploring Cosmic Queries

An episode of [Space Nuts: Astronomy Insights & Cosmic Discoveries](https://invisiblenetwork.ai/podcast/1080090608), 26 Oct 2026, 31 min.

Audio: https://dts.podtrac.com/redirect.mp3/pscrb.fm/rss/p/op3.dev/e/api.spreaker.com/download/episode/75989472/galactic_ejections_black_hole_explosions_exploring_cosmic_queries.mp3

Space Nuts: Ejected Stars, Black Hole Deaths, and Astronomy Resources In this engaging Q&A episode of Space Nuts, hosts Andrew Dunkley and Professor Fred Watson tackle a variety of intriguing questions from listeners. The episode kicks off with Clark from Auckland, who wonders about the possibility of stars and planets being ejected from galaxies, and what that means for rogue celestial bodies. Next, Scott from Hobart delves into the life cycle of black holes, asking what happens when they can no longer hold back light and how they ultimately meet their end. Rusty from Brooklyn poses a thought-provoking hypothetical scenario about the sun disappearing and its effects on Earth's gravitational tether. Finally, Bea from Sydney seeks advice on resources for beginners in astronomy, prompting a discussion on apps, books, and equipment to kickstart a cosmic journey. Join Andrew and Fred Watson as they explore these cosmic curiosities with their signature blend of wit and insight. Key topics - The mechanics of stars and planets being ejected from galaxies and the existence of rogue celestial bodies. - Understanding the final stages of black holes, including Hawking radiation and potential explosive endings. - The implications of the sun's sudden disappearance on Earth's gravitational stability. - Resources and tips for beginners looking to dive into the world of astronomy. Timestamps 00:00 - Introduction and overview of listener questions 01:20 - Clark’s question about ejected stars and planets from galaxies 15:30 - Scott’s inquiry on the life cycle and death of black holes 25:00 - Rusty’s hypothetical scenario about the sun disappearing 35:15 - Bea’s request for beginner astronomy resources 45:00 - Closing thoughts and listener engagement Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support. 00:00 - Introduction to Space Nuts and Listener Questions About Ejected Planets and Black Holes 01:56 - Can Planets and Stars Be Ejected From a Galaxy and the Nature of Intergalactic Space 04:24 - Understanding Stellar Ejection Mechanisms and Measuring Galactic Escape Velocity 07:37 - Comparing Earth's Escape Velocity to Our Galaxy's and the Impact of Galactic Mergers 09:04 - Analogy of Bank Mergers to Galactic Mergers and Universe Dynamics 09:50 - Exploring Black Hole Evaporation Through Hawking Radiation and the Final Violent Burst 11:17 - The Inverse Relationship Between Black Hole Mass and Temperature Leading to Evaporation 14:09 - Theoretical End States of Black Holes Including Gravitational Shockwaves and Information Release 15:13 - Summarizing Black Hole Endings and Thanking Listeners for Thought-Provoking Questions 15:44 - What Happens if the Sun Instantly Disappears and the Speed of Gravity 19:56 - Writing a Prequel and Speculating on Threats to Earth and Solar System Stability 21:11 - Concluding Questions and Addressing Beginner Astronomy Resources 21:43 - Recommended Astronomy Resources Including Podcasts, Websites, and Sky Apps 23:06 - Using Binoculars and Telescopes for Sky Observation and Visiting Astronomy Optics Stores 24:30 - The Value of Planispheres and Considering a Smart Telescope for Modern Astronomy 26:07 - Smart Telescopes with Built-in Filters and AI Image Enhancement Capabilities 27:26 - Enhancing Astronomical Images with AI Software and Affordable Smart Telescope Options 29:04 - Concluding the Episode and Discussing Time Dilation and Future Episodes 30:11 - A Humorous Ejection Analogy and Farewell from Space Nuts Hosts 30:42 - Podcast Availability and Production Credits for Space Nuts

## Transcript

[0:00] Andrew Dunkley: Hello again. This is Space Nuts, a Q and A
[0:03] edition where we talk. Well, whatever you
[0:05] want to talk about. Basically, it's your
[0:08] show. This part of it, uh, every, uh, Monday
[0:10] we release these online. But, um.
[0:13] Yeah, uh, so what questions are we going to
[0:15] be dealing with today? Well, uh, we've got a
[0:18] question from Clark asking about the ejection
[0:20] of planets and stars. It's like being kicked
[0:23] out of a nightclub, really. Scott, uh, is
[0:26] asking about the death of black holes.
[0:28] Rusty wants to know about the, uh. Uh, this
[0:31] is an old chestnut, this one. We've done it a
[0:32] few times, but I really like this question,
[0:34] so we'll, we'll do it. It's a what if about
[0:37] the sun and a story or a
[0:40] question about resources for getting into
[0:42] astronomy. If you want to be, uh, uh, you
[0:44] know, a beginner, we'll tell you all about it
[0:46] on this episode of space nuts. 15
[0:49] seconds.
[0:50] Professor Fred Watson: Guidance is internal. 10,
[0:52] 9, ignition sequence. Star
[0:55] space nuts. 5, 4, 3, 2. 1, 2,
[0:58] 3, 4, 5, 5, 4, 3, 2, 1.
[1:01] Andrew Dunkley: Space nuts. Astronau Feels
[1:04] good. And unravelling the
[1:07] unravel, ravelable is
[1:09] Professor Fred Watson Watson. I thought I'd
[1:11] try that. Didn't work. Astronomer at large.
[1:14] Professor Fred Watson: Hello, Fred Watson. Uh, unravelling
[1:16] the ravioli, is that, uh.
[1:18] Andrew Dunkley: Yeah, that might be easier. Yeah, might be
[1:21] easier to say too.
[1:22] Professor Fred Watson: Yes.
[1:23] Andrew Dunkley: Uh, how are you, Fred Watson?
[1:24] Professor Fred Watson: Very well, thank you. Andrew. Good to see you
[1:26] again as always. And, um, looking forward to
[1:28] hearing what our listeners have dished up for
[1:30] us today.
[1:31] Andrew Dunkley: Yes, why don't we get straight into it? Um,
[1:34] our first question comes from ORK Auckland,
[1:36] New Zealand. Beautiful city. If you've never
[1:38] been there and you're thinking of a holiday,
[1:40] that's not a bad choice. Love Auckland.
[1:43] Um, and get out on a boat and go and visit
[1:46] one of the islands where all the vineyards
[1:48] are. It's awesome. Anyway, Clark, uh,
[1:51] asks, um. Hi, guys. Love the podcast.
[1:54] And I have a question.
[1:54] Professor Fred Watson: Good.
[1:55] Andrew Dunkley: Cause this is the Q and A edition.
[1:56] Clark, your timing's perfect. Uh, can a sun
[1:59] or planet be ejected from a galaxy or
[2:02] is the gravity from the galaxy centre too
[2:04] strong for this? Uh, I've always wondered if
[2:07] a lonely star or planet could be sitting
[2:10] between us and, say, the Andromeda galaxy.
[2:13] Thanks. That comes from Clark. Uh,
[2:15] we've kind of talked about this before. We
[2:17] know there are rogue planets, we know there
[2:19] are stars that get bumped around. But, um,
[2:22] this is kind of within the
[2:25] galaxy. Could they be ejected
[2:28] beyond? I mean, let's do the whole spectrum
[2:30] of ejection. You know, you're not good
[2:32] enough. Get out.
[2:35] Professor Fred Watson: Um, and in fact, uh, there's more of these
[2:37] things than you might think. And the ones
[2:40] that we can detect are all stars. I'm not
[2:42] sure that there's been any detections of
[2:45] interstellar, sorry,
[2:47] intergalactic rogue planets or
[2:49] orphan planets. I think they're all stars.
[2:52] But yes, the space in between the galaxies,
[2:54] the intergalactic medium
[2:57] as it's called, uh, you kind of imagine
[3:00] it would be empty, at least empty of stars.
[3:03] There's quite a lot of stuff in there
[3:05] actually. Um, one of my
[3:07] colleagues, Ken Freeman for a while was
[3:09] really interested in, uh, what are called
[3:12] extra galactic planetary nebulae. These are
[3:14] stars that have basically died, uh, shed
[3:17] their, uh, outer layers and formed what we
[3:20] call a planetary nebula. Nebula, nothing to
[3:22] do with planets. It's a name given to it by
[3:24] William Herschel because they look like
[3:26] planets, they're round. Um, so
[3:29] those are obviously things where a star has
[3:31] been ejected from a galaxy.
[3:34] Uh, and indeed there are some between
[3:35] ourselves and the Andromeda
[3:38] galaxy, um, as Clark
[3:41] mentions. Uh, but, um,
[3:44] more to the point, we can
[3:47] measure the velocities of stars
[3:50] in our local neighbourhood and when you do
[3:52] that, there are some that are going
[3:55] fast enough that they will be
[3:58] ejected from the galaxy as a whole.
[4:01] Uh, in other words, um,
[4:04] planets, sorry, stars that are
[4:06] disappearing. And the usual ejection
[4:09] method is probably, uh, a
[4:12] star that gets too close to the supermassive
[4:14] black hole in the middle of the galaxy gets
[4:17] this gigantic gravitational kick,
[4:21] uh, that hurls it out of the galaxy.
[4:24] Uh, uh, often if stars interact with one
[4:26] another, particularly when you've got binary
[4:29] stars, stars that come in pairs, um,
[4:31] something might perturb that, the fact that
[4:33] they're orbiting each other around the common
[4:35] centre of mass, um, and one might get
[4:38] booted out, the other might wind up
[4:41] going somewhere else. Uh,
[4:45] but that would not necessarily give you
[4:47] enough energy to leave the galaxy,
[4:50] uh, as a whole. And in that regard
[4:53] Clark's point is well made. Is the gravity
[4:55] from the galaxy centre, uh, too strong for
[4:58] this for a star to be ejected from the
[5:00] galaxy? Um,
[5:03] and it's not, but it
[5:06] needs a kick by something as massive as a
[5:09] black hole to give you the impetus, the
[5:11] energy to leave the galaxy. Uh,
[5:14] so we essentially have
[5:17] used that, certainly with, um,
[5:21] what we call the RAVE survey. The Radial
[5:24] Velocity Experiment was carried out on, um,
[5:27] the UK Schmidt telescope in the early 2000s,
[5:30] finished it in 2013. The survey that
[5:33] I was the project manager for,
[5:36] uh, we measured the velocities of half a
[5:38] million Stars altogether. And one of the
[5:41] first papers that came out of
[5:44] um, um, that survey when we
[5:47] didn't have all that many stars that we'd
[5:49] measured their velocities for. But
[5:52] uh, it was a paper that was basically about
[5:55] looking at stars that have been
[5:58] ejected from our Milky Way galaxy,
[6:02] uh, or are going to be ejected from the Milky
[6:04] Way galaxy. They've got enough speed to do
[6:06] that um, and work out
[6:09] what the escape velocity of the galaxy is.
[6:12] It sounds like picking yourself up by your
[6:14] own bootlaces but you can do it. Once you
[6:17] know the escape velocity of the galaxy you
[6:19] know its mass. So this was a way of weighing
[6:21] the galaxy which we did very early on in the
[6:24] rave survey. I think the numbers have changed
[6:27] slightly now because we've got far far more
[6:30] particularly from the Gaia ah survey uh,
[6:32] which was um, a
[6:35] spacecraft that was measuring um, very
[6:38] accurately the speeds of stars across the
[6:40] line of sight, not necessarily along
[6:43] the line of sight. Anyway, the bottom line is
[6:46] to cut a short question, uh,
[6:49] a long answer to a short question shorter,
[6:52] the answer is yes Clark, you can uh, and we
[6:54] see them and we can measure them and we can
[6:56] actually get useful information from them.
[6:58] Andrew Dunkley: M. Uh, the escape velocity of our galaxy
[7:02] uh, at the centre is roughly 220 to
[7:05] 230 kilometres per second.
[7:08] Uh, an object would need an additional boost
[7:11] of about 317 to 330
[7:14] kilometres a second in the direction of
[7:15] motion to completely break free of the
[7:18] galaxy's gravitational pull.
[7:20] That's pretty heavy stuff, isn't it?
[7:23] Professor Fred Watson: Yeah, and that tallies with my recollection
[7:25] uh, about um, in
[7:28] what we call the solar rays radius, the sun's
[7:30] position in the galaxy because the escape
[7:33] velocity varies depending on where you are in
[7:35] the galaxy.
[7:37] Andrew Dunkley: By comparison, Earth's escape velocity is
[7:39] only 11.2.
[7:41] Professor Fred Watson: Correct. That's right. Um, but the
[7:44] galaxy's escape velocity in the region of the
[7:46] sun is about 400 kilometres per second.
[7:49] Uh so yeah, it's because it's a bigger
[7:52] object.
[7:53] Andrew Dunkley: Yeah, that's tough going.
[7:57] Professor Fred Watson: Yep. But stars do it. We've got
[7:59] something.
[8:00] Andrew Dunkley: Oh they do. It prompts a question in my mind
[8:02] that slipped out of my head but now it's
[8:04] jumped back in again. Uh, are there
[8:06] likely to be ejections as a
[8:09] consequence of the merger between the Milky
[8:12] Way and Andromeda galaxies?
[8:14] Something's going to get kicked out.
[8:16] Professor Fred Watson: Yeah, I think whenever you have a
[8:17] Andrew Dunkley: company merger someone gets the boot.
[8:22] Professor Fred Watson: Um, yeah, it will be um, look, it'll
[8:24] be kicked out uh city. I think
[8:28] when that happens there will be
[8:31] such high, um, levels
[8:34] of gravitational interactions between
[8:37] stars and stars, stars and giant molecular
[8:39] clouds and stars and black holes that
[8:42] we'll probably see, um, the resulting
[8:46] galaxy, which, as you know, will be called
[8:48] Milcomeda, uh, the Milky Way and the
[8:50] Andromeda galaxy combined. Milkomeda, uh,
[8:53] will probably eject a very large number of
[8:55] stars, many more than we see being ejected
[8:57] from the Milky Way.
[8:58] Andrew Dunkley: Yeah. Ah, well, before I got into radio, I
[9:00] was a banker, believe it or not, and I
[9:03] actually worked.
[9:04] Professor Fred Watson: Yeah.
[9:05] Andrew Dunkley: Yeah. And I,
[9:08] I, I worked for a bank that merged with
[9:10] another bank. And it was kind of like
[9:12] Milkometer, because we had twice as many
[9:14] tellers, twice as many managers, twice as
[9:17] many examiners, twice as many,
[9:20] uh, general hands, um, all those, those
[9:22] banking positions that, uh, yeah, we had
[9:24] twice as many people, um, because, you know,
[9:27] they closed half the branches because you
[9:28] didn't need two branches of the same bank in
[9:30] the same street of every town and city in
[9:31] Australia. So, yeah, we eventually it
[9:34] created this conglomeration of people and
[9:36] there weren't enough jobs for them, and it
[9:39] got, yeah, it's part of the reason I got out
[9:41] and got into radio, because there wasn't much
[9:43] of a future for me there. So
[9:46] it's just how the universe works sometimes.
[9:50] Indeed. All right, thank you, Clark.
[9:53] Um, that was a great question. Lots of fun to
[9:55] tear that one apart. Boom. Boom. Question,
[9:57] uh, two today comes, uh, from,
[10:00] um, Scott in Hobart,
[10:02] Tasmania. Hello. Fred Watson and Andrew have
[10:05] a question for you. I understand that Hawking
[10:07] radiation will cause black holes to
[10:09] eventually evaporate. I think I heard 10
[10:12] to the 76 years. Uh, what I
[10:15] haven't heard described is what happens to
[10:17] the black hole once the mass falls below the
[10:20] threshold where light can escape. Will the
[10:23] loss of equilibrium between mass and light
[10:25] pressure result in an explosion? Perhaps you
[10:27] can talk us through the final process in the
[10:30] life cycle of a black hole. Thank you both
[10:32] for a terrific podcast. Thank you, Scott, for
[10:35] the good wishes and the great question. Yeah,
[10:38] um, I've never thought about a black hole
[10:40] getting to the point where its gravity can't
[10:42] hold back the light anymore.
[10:45] What happens then?
[10:48] Professor Fred Watson: Um, so actually,
[10:51] uh, um, um,
[10:55] Scott. I beg your pardon? I'm trying to get
[10:57] my nose here. Yeah, Scott is
[11:00] right. Uh, there's an explosion
[11:03] and it's very violent. Uh, and
[11:07] sometimes it's got a name. It's called the
[11:10] Final burst, which is, uh,
[11:13] a bit modest really, for what kind of
[11:15] energies that they're talking about.
[11:17] Um, and so it comes about,
[11:20] and we've talked about this before, Andrew,
[11:23] A uh, black hole's temperature is
[11:26] inversely proportional to its mass.
[11:29] So the more massive a black hole is, the
[11:31] cooler it is. And the ones we've talked about
[11:33] in the past have been very cold indeed, uh,
[11:35] just a few degrees above absolute zero.
[11:39] But as the mass gets less, uh,
[11:41] it gets hotter. And um, and
[11:44] so that produces
[11:48] a radiation from the black hole.
[11:51] And we're talking now about a time, yes,
[11:54] when it can no longer hang on to everything.
[11:57] And you get this sort of runaway, uh,
[12:00] effect, like a runaway greenhouse effect,
[12:02] except it's not the same. But basically
[12:05] that runaway causes um,
[12:08] the explosion. Um,
[12:13] I mean the theory, you know, this is all
[12:15] theoretical of course, but the theory
[12:18] predicts that the temperature of a dying
[12:21] black hole right at the end of its life
[12:23] will increase to billions of degrees.
[12:27] And in the final second
[12:30] the evaporation rate becomes so extreme
[12:33] that you get this enormous amount of energy
[12:35] that comes from uh, the
[12:38] dying black hole. Uh, and
[12:41] there are possible different
[12:44] end states. Um, and I guess
[12:47] the one, the most logical one
[12:50] is that it totally evaporates, so it
[12:53] becomes nothing. Uh, all the mass has
[12:56] gone in a flash of
[12:59] really high energy particles, probably
[13:01] gravitons as well as photons and other stuff.
[13:04] It basically uh, just
[13:07] flashes out everything, uh, and
[13:10] once again leaves nothingness behind.
[13:13] There is one, uh, I mean we're talking now
[13:16] about theoretical stuff. Some others
[13:19] have suggested that it shrinks to
[13:23] something called uh, the Planck
[13:26] mass, uh, where
[13:28] quantum gravity effects
[13:31] become the dominant feature. Um,
[13:34] and essentially you get, and that
[13:38] sort of stops the evaporation, if I can put
[13:40] it that way. Um, so there's
[13:43] something gets left behind, a sort of
[13:46] quantum element. And then
[13:49] finally, um,
[13:54] Again, when you look at the details, uh,
[13:57] it's probably uh, another
[14:00] possibility rather than all these things
[14:02] happen as well. I think, uh, we're talking
[14:04] about separate cases here that may have
[14:07] different, different starting points.
[14:09] I'm not sure, I'm not actually sure how uh,
[14:11] robust this theoretical stuff is as well.
[14:14] But some authors have suggested that
[14:17] you get gravitational shock waves as
[14:20] well. Basically when it gets
[14:23] to the end, uh, you get a shockwave as well
[14:25] as that explosion. Uh, and
[14:28] so what you might call trapped
[14:31] information, the stuff that Hawking argued
[14:34] about with another well known cosmologist, I
[14:36] can't remember who it was, uh, that trapped
[14:39] actually gets blown out into the universe
[14:41] because of a gravitational shockwave. All
[14:44] these things sound like, you know, using posh
[14:47] names for something dramatic that happened.
[14:49] And I'm not sure how many of them are really
[14:53] very robust theories, but it seems to be the
[14:55] case that the likelihood is there will be a
[14:58] violent explosion at the end of the Hawking
[15:00] radiation period as
[15:03] um, uh, Scott says, you know, 10 to the
[15:06] 76 years. It's a huge number of years down
[15:08] the track.
[15:09] Andrew Dunkley: Yes. A black hole doesn't go out quietly.
[15:12] Professor Fred Watson: That's the bottom line.
[15:13] I think that's the succinct way of expressing
[15:16] what I've just taken half an hour to say.
[15:17] Andrew Dunkley: Yeah, that's fine, yeah.
[15:21] It's our job to take half an hour to say
[15:23] something that takes and
[15:24] Professor Fred Watson: it's your job to make it succinct. So that's
[15:26] good. And you do it very well. Andrew, I have
[15:29] to say.
[15:30] Andrew Dunkley: Oh, thank you Fred Watson. Uh, and thank uh,
[15:33] you Scott for your question. Lovely to hear
[15:34] from you. This is Space Nuts, a Q and A
[15:36] edition with Professor Fred Watson Watson and
[15:39] Andrew Dun.
[15:44] Space Nuts. Uh, now Fred Watson, we have an
[15:47] audio question. This is an old chestnut, but
[15:49] I, I do like uh, these what if questions.
[15:52] This is Rusty.
[15:53] Professor Fred Watson: Hey guys, this is Rusty Mac from
[15:56] Brooklyn, New York. Uh, they say that the
[15:59] speed of light is the fastest thing known to
[16:01] man. And if the sun instantly
[16:04] disappeared, we would still have light for 8
[16:06] minutes and 20 seconds because that's how
[16:09] long it takes for light to get from the sun
[16:11] to the Earth. So if the sun
[16:14] disappeared suddenly, would the Earth
[16:17] still be gravitationally locked to the solar
[16:19] centre? Or would Earth, uh, and all the
[16:22] other planets get flung off into interstellar
[16:25] space immediately or would there be a
[16:27] delay? And if that happened instantly,
[16:31] what would that mean? That gravity was
[16:35] faster than the speed of light and that
[16:38] gravity waves are actually the fastest thing
[16:40] in the universe. Mhm.
[16:43] Andrew Dunkley: Okay, thank you Rusty and uh, hope all is
[16:46] well in Brooklyn. I walked across the
[16:47] Brooklyn Bridge last year from Brooklyn into
[16:50] Manhattan and uh, it's a heck of a walk,
[16:52] which is worth doing if you're a tourist.
[16:55] Um, lovely, lovely place. Love the
[16:58] buildings around that part of the world.
[17:01] Yeah, gee, it's, it's a. Yeah, it's
[17:03] just so different to anything we have here
[17:05] really. Well, parts of Sydney probably
[17:08] resemble it, but nothing out where I live.
[17:10] Um, the vanishing of the sun
[17:13] instantaneously. We have had that what if
[17:15] question once or twice before over the last
[17:18] ten years or so. Uh, but it's worth
[17:19] revisiting. I wouldn't like to think what
[17:22] could cause such a horrible thing to happen
[17:25] because I don't imagine that we would be
[17:28] around long to witness the long term
[17:29] ramifications.
[17:32] Professor Fred Watson: No, that's right. Uh, it would be
[17:35] cataclysmic. Um, but it's a good thought
[17:37] experiment to say, okay, what happens if the
[17:39] sun vanishes? And Andrew, you know the answer
[17:42] to this because we've talked about it before.
[17:44] So.
[17:45] Andrew Dunkley: Well, we'd have 8
[17:47] minutes and 20 seconds of sunlight and then
[17:50] we would be uh, plunged into
[17:53] eternal darkness and all the dogs and cats
[17:56] would start living together and um,
[17:59] everything would, would, would die. There'd
[18:00] be no photosynthesis, we'd uh, we'd not be
[18:03] able to produce food. We'd um, we'd, we'd, I,
[18:06] I, because we are not being held into a
[18:08] gravitational orbit around the,
[18:11] the sun, uh, everything would start to drift
[18:14] off into the Never, never uh, never
[18:17] to be heard from again. And, and we wouldn't
[18:19] last very long at all.
[18:21] Professor Fred Watson: Um, that's certainly true.
[18:22] Andrew Dunkley: And it would become cold. It would become
[18:26] very cold.
[18:27] Professor Fred Watson: Absolutely. Um, a bit of
[18:30] radiation from the Earth itself because of
[18:33] the nuclear processes that are going on
[18:35] inside it. But they're pretty low level.
[18:38] We're not a star, we're a planet. Uh, and so
[18:41] yeah, you wouldn't be that warm. Um, but
[18:45] in answer to the question though,
[18:48] uh, actually you
[18:51] would still be attached to the sun
[18:54] for the 8 minutes and 20 seconds that it took
[18:56] gravitational waves, waves to reach our uh,
[18:59] planet. So uh, gravitational waves have been
[19:02] demonstrated a number of times and
[19:03] theoretically this was predicted by Einstein.
[19:06] They travel at the speed of light.
[19:08] Gravitational waves travel at exactly the
[19:11] same speed. So that means that yes,
[19:13] gravitational waves are the fastest thing in
[19:14] the universe along with light and radio waves
[19:17] and all the rest of it. So um, there will
[19:20] be an 8 minute 20 second delay before we
[19:24] not only went dark, but also wandered off
[19:26] into the wide blue yonder. Uh, without the
[19:28] sun to hold us in orbit, we'd be zooming off
[19:30] at 30 kilometres per second in some straight
[19:33] line depending on it would be heading,
[19:35] depending on where the when, at what point
[19:38] in its orbit. The sun in the Earth's orbit,
[19:40] the sun disappeared. But it beliked a
[19:43] horrible thought. Slingshot effect. Yeah, it
[19:44] is a horrible thought. You should write a
[19:46] science fiction story about this.
[19:47] Andrew Dunkley: I think probably could. You know what I'm
[19:50] doing at the moment? I'm writing a prequel to
[19:52] um.
[19:52] Professor Fred Watson: Yeah, you said.
[19:53] Andrew Dunkley: Yeah, the Human Epoch. Yeah.
[19:56] I'm halfway through the first book. I'm
[19:58] trying to uh. Cause the hero of the
[20:01] Human Epoch trilogy is um, a fellow
[20:04] by the name of Gary Forrester. And I made him
[20:07] Canadian because the Canadians never get
[20:08] mentioned anywhere a lot of the time. And
[20:11] I thought they're such nice people, they
[20:13] certainly deserve a mention. So I made my
[20:15] hero Canadian. Could have made him
[20:17] Australian. Could have gone down the American
[20:19] road. But I think we've had enough American
[20:20] heroes in science fiction for the time being.
[20:23] So I went Canada, and, um, I've decided to
[20:26] write his story leading up to the beginning
[20:28] of the human epoch, um, because I like the
[20:31] character so much, um, but I don't
[20:34] think he could even save us from, uh, from
[20:36] something as cataclysmic as the sun
[20:38] vanishing. I wonder what
[20:41] could cause that. And I don't think there's
[20:43] anything that could wipe it out instantly.
[20:45] But maybe a black hole venturing into our
[20:47] vicinity would not be a good thing.
[20:50] Professor Fred Watson: That's right. But if the black hole was black
[20:53] hole worth its salt would be, uh, seized into
[20:56] orbit around that, uh, long before it gobbled
[20:59] up the sun. So we'd know about it.
[21:02] Andrew Dunkley: Yes. We'd also get a lot heavier.
[21:05] Maybe.
[21:06] Professor Fred Watson: Indeed. Probably so. Yeah.
[21:09] Andrew Dunkley: Yeah. All right. I, uh, think we covered
[21:11] that.
[21:11] Uh, Rusty, thanks for the question. Great to
[21:13] hear from you. Love the accent.
[21:17] Okay, we've had a problem here.
[21:19] Professor Fred Watson: This is Houston.
[21:19] Andrew Dunkley: Say again, please. Houston, we've had a
[21:22] problem. We've had a main beam. Roger,
[21:24] maineville. Okay, standby 13. We're looking
[21:26] at it. Stay smarts. Our
[21:29] final question today is, um,
[21:32] more of a. An educational query.
[21:35] I've, uh, recently gotten into astronomy.
[21:38] What are some of the resources for a
[21:40] beginner? Thanks. I, uh, haven't got a name.
[21:43] Just B, from Sydney. Thanks. Bea
[21:46] wants to get into astronomy, or has just
[21:48] started. Um, what would you recommend,
[21:50] Fred Watson, as somebody who's had a
[21:53] wonderful career in that exact
[21:55] science?
[21:56] Professor Fred Watson: Well, I'd start with, um, there's this
[21:59] really good podcast called spacenots that
[22:02] anybody wanting to get into astronomy could
[22:05] perhaps listen to as a resource.
[22:07] Um, ah, a lot depends on what you
[22:10] mean. Whether you want to be observing
[22:13] the sky, uh, or whether you're more
[22:16] interested in the stories that we often
[22:18] cover on space nuts about the way the galaxy
[22:21] behaves and whether stars can be ejected from
[22:23] galaxies and all of that sort of stuff. Um,
[22:26] and there's certainly plenty of
[22:29] material on the World Wide Web,
[22:32] uh, from reliable sources, um,
[22:35] including NASA, including Universe Today,
[22:38] an old friend of, uh, this podcast, including
[22:41] Ars Technico, another good friend, and
[22:43] phys.org, uh, they're all places where
[22:46] you can get good information that's P, P, H,
[22:49] Y, S, not F, I, double Z.
[22:52] Um, so, uh, those are the sorts of things.
[22:55] Now, um, I also would point you
[22:58] if you're interested in learning your way
[22:59] around the sky to some of the
[23:02] sky apps that there are. There's
[23:05] several of them.
[23:06] Um, I have one on my phone that
[23:09] I'm a cheapskate, so I never went for
[23:12] the higher version, figuring that because I'm
[23:15] an astronomer I should know my way around the
[23:16] sky anyway. But sometimes when you can only
[23:18] see one object because of the cloud clouds,
[23:20] it's a good way of finding out what it is.
[23:23] Um, lots of stuff like that. Um, hardware,
[23:26] of course, telescopes, binoculars. I'm
[23:29] always, uh, a, uh, fan of,
[23:32] in terms of astronomy, because even if you've
[23:34] got a site where you've got some light
[23:36] pollution and you're in Sydney B,
[23:39] so that, uh, it means you probably
[23:42] do have. It is. But you can still
[23:45] see, you get lovely views of the moon,
[23:48] uh, bright objects like the Orion Nebula.
[23:50] Even in light polluted, you can see them.
[23:53] Uh, and the planets. Binoculars are not good
[23:56] enough to show up the rings of Saturn. Um,
[23:59] but a powerful pair of binoculars will
[24:02] show you some of the satellites of Jupiter
[24:04] and see the way they're moving, they look
[24:05] like little stars right next to Jupiter. Uh,
[24:08] and then if you want to get into telescopes,
[24:11] there are one or two companies which
[24:12] specialise in optics for astronomy.
[24:15] Um, and they are for the most part,
[24:18] and certainly the one I'm thinking of, which
[24:20] is in Glebe, Sydney, uh,
[24:23] I won't give because that would be
[24:25] advertising, but, uh, they all know who I
[24:27] mean. Uh, it's, uh, not far from the fish
[24:29] market. There you go.
[24:30] Uh, that's a great place, uh, to get good
[24:33] advice on what you might need for what
[24:36] interests you and for what you can afford.
[24:39] Uh, it's a place where, uh, the
[24:42] staff are not just there, uh, because it's a
[24:44] job. They're there because they're passionate
[24:46] about astronomy themselves and they want to
[24:48] enthuse, uh, other people in the same way
[24:50] that they are. So you get really good advice.
[24:52] And that's true, I think, with other people.
[24:54] Um, uh, astronomy
[24:57] optics centres around the country. There's
[25:00] several I can think of some in Melbourne and
[25:02] in Brisbane and elsewhere too.
[25:06] Of course, then you're starting to spend big
[25:08] money and it really depends
[25:11] on what your resources are like and what your
[25:13] interests are. I still
[25:17] love, um, a planisphere,
[25:20] which is a piece of hardware, goes back
[25:23] at least 2,000 years. Uh, it's a little
[25:26] analogue computer, usually two cards, one
[25:28] with a hole in it, one with a star map on it
[25:30] and you can dial up the date and time on the
[25:32] edge and it gives you what the stars look
[25:34] like, of course, you can do the same thing
[25:36] online now. Um, and they're much more
[25:39] accurate. And of course they show the planets
[25:40] the online versions, which the old cardboard
[25:43] or plastic ones don't. But I've always been
[25:45] very fond of planispheres.
[25:46] Andrew Dunkley: I'm just looking at some pictures of them
[25:48] now. Yeah, I know what you're talking about.
[25:53] Professor Fred Watson: Sometimes called a star wheel. Um, I've still
[25:56] got the first one I ever bought when I was, I
[25:58] think 15. Uh, it's a Phillips
[26:01] planisphere. Uh, it's the 5 inch version.
[26:04] It was the small one, but it still works.
[26:07] Um, of course I see the sky from a different
[26:09] hemisphere now, so I've also got ones from
[26:12] the southern hemisphere too.
[26:14] Andrew Dunkley: That's pretty cool. Another thing B that you
[26:17] may want to consider, given our current level
[26:20] of technology is, um, something like I've got
[26:23] now, which is a smart telescope. Yeah.
[26:26] And, um, you know, on a clear night you can
[26:28] put this outside in your backyard and then
[26:30] sit in the comfort of your lounge room,
[26:32] especially if it's a cold night, and
[26:36] photograph, uh, things you can't see with the
[26:38] naked eye and would struggle to see with
[26:40] binoculars. Um, and
[26:43] keep the images that you've taken with it.
[26:45] And um, it. A lot of them have built
[26:48] in educational information. They can tell you
[26:50] what you're looking at and explain who found
[26:52] it, when they found it, what it is, why it
[26:55] is. It's incredible technology. And
[26:58] they've built them so well that they
[27:01] actually have light pollution filters
[27:04] built into them. So even, um,
[27:07] the last few nights here, as we record,
[27:11] have been very, very m. Uh,
[27:14] bright nights with the moon. We had a full
[27:16] moon a few nights ago. Um, doesn't bother the
[27:18] smart telescopes. They just filter all that
[27:21] out and, um, you can still
[27:24] see a really good image.
[27:26] Uh, and I've found a good trick. Um,
[27:29] when you get your image, I actually adjust
[27:31] the image as it is being, um, recorded by
[27:34] the system because it does stacking. Um,
[27:38] uh, I'll then put it through an
[27:40] AI, um, piece of AI
[27:43] software and say, I want you to just
[27:46] tidy this up. I'm paraphrasing. I tell it
[27:48] exactly what I want and
[27:51] it will enhance the image even further.
[27:54] I showed you Fred Watson. I took a photo of
[27:56] the moon with it the other day and then I put
[27:58] it into ChatGPT and said, can you enhance
[28:00] this, sharpen it up, show me a bit more
[28:02] detail in the cratering. And it just went
[28:05] bang. And the image I got was, was
[28:08] stunning.
[28:09] Professor Fred Watson: I thought it is, it's remarkable. Yeah,
[28:12] it is, absolutely.
[28:12] Andrew Dunkley: So that's something to consider. And it's a
[28:15] really inexpensive way of actually getting
[28:17] into astronomy. Uh,
[28:21] I didn't mention the brand of mine, but
[28:25] they're all very, very popular. They're all
[28:27] very good. There are a whole bunch of them.
[28:28] Some of them are, um, in the hundreds of
[28:30] dollars. Some are in the thousands of
[28:32] dollars. It just depends what you want to
[28:34] spend. But for someone like
[28:36] me, who, who doesn't want to spend
[28:39] hours and hours outside in the dark in the
[28:41] cold because it gets damn cold out here in
[28:43] winter, um, that's the perfect solution.
[28:46] So, yeah, might, um, be worth considering.
[28:49] That's just my piece of the pie.
[28:52] Professor Fred Watson: Well, I'm glad you put that in as well
[28:54] because that's a very important resource in
[28:56] today's day and age.
[28:59] Andrew Dunkley: Indeed. And, uh, thank you
[29:02] for the question, uh, Bea.
[29:04] And um, good luck with your future in
[29:06] astronomy. And that brings us to
[29:09] the end of the show. Fred Watson, thank you
[29:11] so much.
[29:12] Professor Fred Watson: A, uh, great pleasure, Andrew. I'm glad we
[29:14] made it without a hiccup. And, uh,
[29:17] great to have all those questions as well.
[29:18] Thought provoking as always.
[29:20] Andrew Dunkley: And please send us more questions, uh,
[29:23] because it's going to sound weird. This is
[29:25] time dilation at its absolute best. Um,
[29:28] Fred Watson and I will talk again next week,
[29:30] but we won't see each other for a month.
[29:35] I'll leave you to figure that one out. But
[29:37] yeah, go online to our website and, uh, send
[29:40] your questions through the Ask me Anything
[29:42] Anything tab. Uh, that is
[29:43] spacenutspodcast.com or
[29:46] spacenuts IO.
[29:48] And Fred Watson, we'll see you real soon or
[29:51] in a month. Whichever comes second or first.
[29:54] Professor Fred Watson: Whichever. Whichever. Is time dilated?
[29:56] Yes.
[29:57] Andrew Dunkley: I'll tell you about our travels when, when I
[29:59] get back next week.
[30:00] Professor Fred Watson: I'm looking forward. I'm looking forward to
[30:02] hearing that. Yes. Thanks,
[30:05] Fred Watson.
[30:05] Andrew Dunkley: We'll see you soon.
[30:06] Professor Fred Watson: Cheers for now. Bye.
[30:08] Andrew Dunkley: And, uh, thank you.
[30:09] Professor Fred Watson: Thanks.
[30:10] Andrew Dunkley: Yeah, thanks, Fred Watson.
[30:11] Yeah, I appreciate it. It's gonna be a long
[30:12] haul. Uh, and thanks to Huw in the studio.
[30:15] Uh, you're gonna love this one, Fred Watson.
[30:16] Uh, Huw couldn't be with us today. He, ah,
[30:19] was ejected from our galaxy.
[30:21] Wait for it. Because he's lactose
[30:24] intolerant. Uh, you
[30:26] gotta think about it.
[30:28] Professor Fred Watson: But I get it. I get it.
[30:30] Andrew Dunkley: I like that one. And from me, Andrew Dunkley.
[30:33] Thanks for your company. We'll see you on the
[30:34] next episode of Space Nuts. Bye. Bye.
[30:38] You've been listening to the Space Nuts Po.
[30:42] Available at Apple Podcasts, Spotify,
[30:45] iHeartRadio or your favourite podcast
[30:48] player. You can also stream on demand at
[30:50] bytes.
[30:51] Professor Fred Watson: Com. This has been another quality podcast
[30:54] production from Bytes. Com. Um.

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