Super voids, satellite noise and asteroid navigation

0:00This is a Triple J podcast. Hello, welcome to another episode of Science with Dr. Karl. My name is Lucy Smith, and I want to give you a little peek behind the curtain of what goes on when we record this podcast. It happens live on my show on Triple J Mornings, and we get questions through via text on 0439757355, and while I'm playing the music during the show, Dr. Karl and our guest will look at the questions as the song is playing. And I just want to say, one of my favorite parts of hosting this show is being able to see the way that their faces light up when they read your questions, the way they start having conversations amongst themselves and getting so excited to answer these questions, and for you to bring them to them live on air. Dr. Laura Driesen joined us today. She's an astronomer, she works among the stars, and every time she's on, she's so impressed by the questions that come through. You know, she said this morning off, Mike. You know, usually I'll get the same old questions, but every time I come on science with Dr. Karl,

1:02it's always so in-depth, so different. So that's just a taste of what you can expect in this episode. Dr. Karl, Dr. Laura, nerding out over the world of space. Let's get into it. Shh! Dr. Karl, we've got a very special guest in the studio with us. Yes, when I go to astronomy people who I ask for advice, as I asked her, what's this story about dark energy is explained by black holes, and she turned it into English, and so let me introduce you to the microphone, Dr. Laura Driesen. Is that the correct part? Driesen, it's not. Driesen, yeah. Because it's Dutch, right? Okay. And we've had you on before. Yes, a little while ago. I was on it, always happy to chat with people about space. Yeah, you know, and that was the thing. I feel like you got into, like Dr. Karl said, the nitty gritty of some of these big scientific space concepts, right? But you put them in language that people understand. I want to know, what's something that's kind of blown your mind recently that you've had to wrap your head around? Ooh, that's a great question.

2:02So at the moment I'm working on something, it doesn't have a very good name. We need to get, sometimes we're good at naming, sometimes we're very bad. This time I think we're on the bad side. Long period radio transients. Okay. So these are things that spin, and we can see them sort of as flashes of light, but they're too slow. They're way slower than we would expect for something like this, and we're trying to work out what they are. Hang on, hang on, hang on. So what does that look like in the sky? So it looks like, if you imagine looking at a lighthouse, and as the light spins around, you see a flash of light going past. So that's what we see. We see a flash of light. And because the lighthouse is spinning the same speed every time we see this really regular flash. And we usually see this in something called a pulsar, a very small star left over after a star explodes, but those spin really fast. Lots of times per second, the slowest known one is about 24 seconds, for one rotation. So imagine all of Sydney rotating once in 24 seconds, a full rotation in 24 seconds. That's what these stars do. But now we have things that are minutes to hours.

3:03And that sort of for physics doesn't make sense, because we think these spinning stars, when they slow down the light turns off. So it's like a lighthouse that's spinning, and then once it gets a bit too slow, the light loses power and switches off. So we shouldn't see these flashes. It's spinning too slow. So that's why I'm working on. Don't some of them, this is the right object. I'm thinking of have absolutely huge amounts of energy way beyond what we expect. These do have huge amounts of energy, and it's because the light is something that we call coherent. So if you think about the light that you usually see around you, that light, all the waves are sort of just random everywhere. But in a laser, all the waves are aligned, and that boosts the brightness. And we call that coherent emission, because it's coherently lined up. So this light that we're seeing is coherent. So it's like a space laser. I suppose it does not mean it then comes from a small, in space source, you know, something like, no, not light is across, but centimeters. Yes, so usually when we see something that doesn't last for very long, and is bright, that tells us that the thing that creates it,

4:03or the area it comes from, must be small, because we can't have something that lasts for a very short time, come from something very, very big. Wow. So we've seen these things, it's small. We think it might be related to a different kind of dead star called a white dwarf. So when a big star explodes, it can leave behind a black hole all these neutron stars. But when a smaller star just kind of lives out its life, it can turn into a white dwarf. So it's kind of an older star. So we think that's the sort of path we're exploring at the moment. So they're like the senior citizens of the space. But my favorite thing is I feel like this is a good naming example. I've called mine WD40, because it's a white dwarf. And the post code, because a lot of stars have like a post code instead of an actual name, ends with 40. So I was like, it's right there. I've got to go for it. Perfect. So what was the concept? What was it called? Something transient. A long period radio transient. Because we see them with radio waves. Right. Yeah. That sounds like a playlist, like a study playlist, like chill beats. Yeah. Maybe we should make one. Maybe I think we should. Maybe we should.

5:03A long period radio transient is a playlist. Fine music to match. Well, that's just the beginning. Laura, Dresden, can obviously speak to anything in the space world. 04397575, we'll start with Matt in Alfred's point. Matt, what is your question about super voids? Good morning, doctors. I was actually watching a YouTube video on my curves because last night with my son. And we're talking about super voids. And they're just like an incomprehensible size and how big they are. But I was wondering how do they actually detect these voids of hundreds of millions of light years across? Like my comprehension is you look at the aeroplane window when you see a cloud, I can't see what's behind the cloud. So in that void, surely there's like stars and galaxies in front of it. So how do they detect the void behind those galaxies? Wow, good question. This is a really great question. And super voids, it sounds very cool too. We like to add super to things. So a super void is kind of these undidense regions of space. So space usually has a certain amount of stuff in a certain area.

6:04And then there are other parts of space that just has less stuff in the same region. And we can kind of see these because space, if we look on really big scales. So we're not talking looking at individual stars. We're kind of zooming out almost as far as you can. There's structure to how things are. And it almost looks like a giant web. And we call it the cosmic web. So there's this giant web of galaxies and streams of particles in between them. And we can kind of make maps of where the material is because we can see the material. So we can make a map of where it is. And a map then that reveals where it isn't as well. But with astronomy, we can see through things by looking at different wavelengths of light. So different wavelengths can see through different things. If you look through a window right now, you can see through it. That's optical light. But in infrared, you might not be able to because infrared light doesn't travel through glass. Whereas infrared, on the other hand, if you hold up a garbage bag, a black one, you can't see through with your eyes, but infrared can see through it. So different wavelengths of light go through and around things.

7:05And we can see different wavelengths that light at different distances. So we can see through things, not necessarily individual galaxies, but those are very small. Individual galaxies in the whole of space. It's like little tiny pinpricks. So sometimes we don't need to see around things as well. And it's just a little definition of a void. Oh, yes. Yeah, take it away. No, no, you go for a car. OK, so we live on a third rock from the sun. There are 300,000 million stars in our galaxy. Our galaxy is part of a small group called the local group of maybe 20 or 30 galaxies, which in turn is one over 1,000 or so local groups in the thing we call the local cluster. And that cluster is one of 1,000 clusters in what we call the local supercluster. OK, you might have thought the Earth is a basic unit. The supercluster is the basic unit of the universe. And imagine you get a sponge, and you cut through with a very sharp knife. And you can see voids and walls.

8:05The walls are made of superclusters, and the voids are what you're talking about, but they're not true voids. They've got stuff in them, but relative to the walls of this sort of sponge-like structure, they're relatively empty. Yeah, and I think it is similar to a sponge because we see the sponge is kind of solid, but in between. We know there's air, right? We just know that that's a lot less dense and has a lot less going on in those voids as well. So it is actually a very good analogy. Great. Thanks, Mark. Cool. That was massive. It really is. Hey, we've got tea from Melbourne, Dr. T. What do you want to know? Hey, Drs. I just wondered if there's any science behind small practices like naming three gratitude or taking four slow breaths. And I guess it's a two-part question. What happens to the brain and nervous system when we do these things regularly? Are you fitting into this in the category of meditation and mindfulness?

9:06Yeah. There is evidence that shows that it is good for you, which surprisingly makes perfect sense. Part of you is what you get from the outside world. And you learn mathematics, you learn the times tables, you learn to be kind to people, and a whole of other things. And also part of you is what is innate inside you. But if there's always stuff coming in, like you're continually scrolling, what's inside you doesn't get a chance to come out. So we call this meditation or mindfulness. And the science shows that it will, if you do it regularly, reduce slightly, stress and symptoms and anxiety, it'll give your working memory higher ability to work and make you more flexible, and it'll help you better with your emotions. And when we actually do brain scans using EEGs, with the other little electrodes on your head, we look at something called the default network. And you think, what sort of name is that? They discovered this in the 1990s, early 2000s, and it's what is active in your brain when you're doing nothing.

10:08So if you just switch off your TV, switch off everything, switch off the scrolling, and just sit there and stare out the window, and then you stop looking at what's out there, there's just nothing going on. Your default network is active, and it relaxes even more when you go into meditation. So yes, meditation, mindfulness, a bit of that every day is definitely good for you. Thank you so much, Dr. Karl, for explaining that. You know what I've been doing as well, rather than three things you're grateful for, I saw this TikTok, and apparently, it's really good for your brain before you go to sleep. And if you're someone like me who maybe ruminates a little bit or, you know, it's apparently, so there's T, there's three steps. The first one is, you write down something that you did today that maybe your past self would not have been able to do. Then the second one is, you write down something that you can consciously let go of right now, that you can just let it go, you don't need to worry about it during your, you know, your sleep, and then your third thing, one thing you're proud of yourself for today,

11:10even if it's small. So it's a little less like, I'm grateful for this, and more just kind of like consciously doing a bit of a recess, an assess really, and then a reset before you go to sleep. I've been, I've been doing it, I've been liking it. Ah, what I love doing is the fleshing the three lights for a bus when it's got a blinker on or when it's to come out, and about three quarters of the time when you give them lots of room and let them know that you're slowing down and let them come in, they'll open the window and you get the hand. And the hand is from the fingertips to the base of the thumb, and they must have all go to hand school because they all do it exactly the same. And I'm really proud of that. What about you, Dr. T? What if you don't today that you're proud of? Um, having the confidence to have this phone call, would you believe? Love it. Exactly. One thing that you're past self, maybe wouldn't have done, Dr. T. Yes, how this? Dr. Laura, I want to ask you, you know, you're someone who is probably in the books, looking at screens, is there something that you do for daily mindfulness or to reset? Well, I do find it really hard because I feel like when we do this sort of work

12:10where you are reading and absorbing a lot of information, you do put your head down to sleep and then your brain's like, no, remember that thing from today and it's really frustrating. I'm more of an active mindfulness person, so I sow and I really feel like getting into that, doing something with my hands, because of course during the day, everything is my brain. It's just at 100, you know, it's going so fast, but I really like to do that kind of active, just slow yourself down, do something with your hands. Kind of repetitive. Yeah, yeah. And it's also nice because you do end up with something at the end. So I feel like that's kind of nice. It feels so good. Dr. Laura, we are going to put you back to work. Frank and you're a Sydney. What's your question? Okay, Dr. Carl, Dr. Dr. Laura, I was just wondering about a couple of things. The actual spent atoms on a star, if it's dead, do they actually weigh a ton of peace? And if so, could you move them with the bulldozer? And I also would like to give a shout out to Gressford, because that's where I'm heading to my farm and that should be where you have the one night stand. Ooh, okay.

13:11Frank, making a really good point there, we announced yesterday that we are bringing back the one night stand. It is going down, laded this year, and we're currently taking submissions for rural towns to have it. Frank, I like this from you. We're at Gressford. Well, I'll start to calm. Yeah, well, I'm just outside in place called Glendentbrook. Okay, all right. Well, Frank, we'll add it to the list. I think you might need to send in an application, but we'll get to that later. For now, you are wondering how heavy are the atoms in a dark star? Dr. Laura, where do we start with this? Well, I was wondering, Frank, because you said something about spent atoms. What do you mean by that? Well, my version of a dark star, which also is a great rest there, soul of the Grateful Dead song. Yes, very cool. Exactly. The dead star, or is it a cold star where it no longer produces light? Or it's Dr. Paul Connett back in 1995, told me this since bottom, they ever since. Right, I see. So there's a couple of things, because a dark star, there's a few different thoughts on this. The dark star, theoretically,

14:12is kind of similar to a black hole, but that maybe isn't sound like what you're talking about. And maybe you're talking about something like a neutron star or a white dwarf, some of these old remnants left over from stars. Yeah, yeah, yeah. So I think the interesting thing here is that the atoms don't get really spent. The atoms are still atoms. It's the star itself that's not really doing anything anymore. So what happens when a star reaches the end of its life? So a star like our sun is never gonna explode. Instead, it's sort of just gonna slowly run out of fuel. Yeah. So what happens is that the fuel in the core, right? In a normal star, we've got gravity pushing in that then helps the fusion happen in the core. That's like the engine. And then the energy from the fusion in the core pushes out. So that's why stars around, because we've got gravity pushing in and the fusion, the energy from the core pushing out. So as these stars run out of fuel, they just kind of just get smaller and smaller and colder and they eventually just run out of fuel and then we assume they're just kind of floating around dark.

15:14So they're dense and they're, could you move an atom to the atoms? It does one atom way at a time. So at atoms, I mean, I suppose now we're thinking about weight versus mass, right? Because we're adding gravity into the equation. Ooh, I have to do the maths. I'm looking at Carl to see, Dr. Carl to see if he's got a further explanation. Well, I'm trying to also out by saying that in some cases, especially in a neutron star, the mass can be so great that the atoms tend to kind of break down into neutrons and then apparently quarks underneath and it gets real messy. It does and we don't actually know. Wow. Oh. Oh. Oh. Now we're talking particle physics. So we got, you know, good old electrons and all that sort of stuff, but fundamental particles include the electron, but it's basically we have matter and then we know matters made up of atoms and then atoms are made up of protons and things like that. And then there's even the next level down is all of the much smaller stuff, including quarks. So we used to think that the atom was the end, then the nucleus was the end and we used to think that protons were as small as you can get.

16:14It turns out that they're made of three quarks and there's how many quarks altogether, half a dozen or so. Oh, there's the up quark of the down quark and the strange quark. And in charb, I'll have a name here. The charb quark, yes. There are real names that the scientists came up with. There's water. Yes. And so a neutron is made of two down quarks and one up, where the proton is made of two ups and one down. And they seem to be the end of the line with our knowledge as of the 12th of March, 2026, that it might be different. And so a neutron star doesn't have atoms. It has neutrons on the top. It might have atoms, but definitely there are neutrons near the top and then it goes into quarks, we're fairly sure. But I don't know about a white dwarf, does a white. So our sun, after a few conceptions, we'll shrink down to a white dwarf where it weighs 80% of its current mass and is 100 times smaller, so roughly the size of Earth. Does that have atoms? Are they still at a point where they are? Yes, let's not quite get into the density of a neutron star

17:15so things are still relatively what we expect. Thanks for your question, Frank. Thank you. Now, Luke and Mount Dandenong, you saw something in the sky recently. Tell us about it. What happened? Hi, hey, gang. It's a bit of a weird one. So I hope I do it justice. So we were camping out at Garouin and it was a new moon and we were just stargazing couple of mates and I. And we saw this, it happened twice. So we saw this like weird blip in the sky. It's hard to explain. It's kind of like you're looking at a reflection and someone's dropped a pebble in. And so it's a black sort of flash and then it rippled outwards and distorted the stars around it. And a mate and I both saw it. So it wasn't going insane. Can I ask you, before it or around the same time, were there any satellites visible in the sky? So in 2017, there were about 1,000 working satellites.

18:15Currently there's 10,000 and in just four years we're going to 50,000. So did you see a satellite go across the sky near that before it? No, not that we noticed. Like we saw heaps of satellites because it was like a new moon. But yeah, nothing just before it. Well, in that case, the second thing is that the astronomers have a thing called first light. So they wake up at a telescope for the first time and they get first light. And then when you're meeting a astronomer and they've been doing some viewing, you say, oh, how was it last night? How was the seeing? S-E-E-I-N-G? If only we had an observational astronomer on board to talk to us about their carousel scene. Yes, very interesting. So I suspect this is an atmospheric effect. So seeing is kind of the density of the vapor in the sky and it moves things around and makes things look blurry. So when we talk about seeing, good seeing means that everything looked really nice and sharp

19:17because we had sort of clear skies but also dry skies is really important for that. So when we're talking about telescopes and in terms of seeing, we're thinking about whether things looked fuzzy or sharp and whether things kind of wobbled around a little bit because of different densities in our atmosphere. So I suspect this was probably something similar but maybe something that was a little bit more extreme, I guess, like a pocket of vapor or something like that passing across the sky just as you were looking. And it happened twice? Yeah. Yeah, it happened twice in the same spot in the same part of the sky. So it's like the black flash was round and then it's breaking out, it's from that. It's just kind of like it just went black in a section and then after that, it rippled outwards. Like you've dropped a stone in a reflection and then it distorts the image as it radiates away from it. Okay, if this was a trick science fiction movie,

20:18I would immediately think of a very large alien space. Oh yeah, must be. I probably, I mean, I'm an astronomer not an atmospheric scientist but it sounds like something atmospheric must have happened and we do have weird atmospheric anomalies and I'm sure lots of people have seen something weird in the sky before and often it is something to do with the atmosphere. And you said that it did happen in the same part of the sky. So if it's related to local things, well then you are in the same area both times. In the case of my neighbor at the street, she's had lightning come through her front window and land on the kitchen twice. What? In the same spot, whereas I'm about 200 meters down the road and I've never had lightning hit my house. So in the same way, if there's a set of wind currents and you've got mountains around you or valleys or whatever, then that could create chaos. What was the topography like where you were? Was it flat? Oh, we're in Geroane National Park. So it was like, yeah, mountainous. Okay, you could have had wind currents, maybe. Thanks Lou. How do you spell that thing again, sorry? S-E-E-I-N-G.

21:20So when somebody says there an observational astronomer, you casually drop in. So how is the seeing last time? Yes, the seeing, you sound very fancy. Thanks Lou. All right, thank you. Have a good day. You mentioned lightning striking twice, Dr. Carl. Jackie in Melbourne, what's your question? Yeah, hi, Dr.. I'm just wanting to find out, actually, it's more from my son. How come lightning or can be different colors? This is a great question. We're back to the atmosphere, but this is something I do know a little bit about. It's to do with scattering of light. So when light travels through our atmosphere, it bumps into all sorts of particles. And how the light behaves depends on the type of the particle and how much of that particle is in there. So all different chemicals and dust and things like that. And some light bounces more. So that means it gets what we call scattered away. So blue light, in particular, when it gets scattered, it sort of disappears because it gets scattered in so many random directions that we don't see anymore. That's why sunsets are red as well,

22:21whereas red light travels through. So depending on what sort of particles are in the atmosphere, what density there is, that light from the lightning kind of travels in a different way. And some of the light gets scattered, sometimes it doesn't. So the kind of effect in the end is that sometimes it might look more reddish, sometimes it might look more blueish. And astronomers and physicists use the word scattering different from the normal people. So scattering is where you've got a bunch of balls and you throw them at a pole and they all go from different directions. For a physicist, scattering is when subatomic particle or light, or say a photon, is absorbed and then does something to what is absorbed by a normalian atom and then is re-emitted. And usually in a different direction with some changes, optical properties. So scattering involves absorption and re-emission. Is my memory still correct on that? Yes, and there's a few different types of scattering as well. I know, I know, we have, this one is called Rayleigh scattering. And it's also why the moon, when it's eclipse, looks red.

23:23Wow. It's because of scattering. Yeah. And if you want to get really into it, look up me scattering, M-I-E. That was Gustav Me. And so he there was scattering of all ranges of particles, sizes, and different frequencies and wavelengths. Yes, and we even talk about scattering differently, depending on what type of astronomy you are. So I talk about scattering off electrons, specifically. Wow. What else could they base it off? Well, so I'm a radio astronomer, and the type of scattering that happens causes the light to arrive at a different time. So a flash goes off in the distant universe, and it travels through just a bunch of electrons, basically, which is actually not that many, because the universe is pretty empty. But if it's traveling from far away enough, that means that the light that's a higher frequency, so the shorter wavelength arrives first, and then we see it kind of like a parabola. So we see this curve as the light arrives later and later. Yeah, parabola. I don't know that word. I've never heard that word in years. So we've got, I'm bringing it back, bringing back the parabola. We've got Simon instructing here, Dr. Simon. What do you want to know?

24:24Hey, guys, I was just wondering if there's no up and down in space. Why is it that all the planets seem to follow the same plane around the sun? And if they follow the same plane around the sun, do they follow all the planets in the Milky Way follow that same plane? This is a multi-part question, but I love it. So the planets are all in the same plane, roughly the same plane. There's a little bit of wobble, but roughly the same plane because of how they formed. So when a star forms, it starts actually as a big cloud of gas and dust. And then that gas and dust gets a little bit dense in one spot and everything starts falling in because of gravity. And as it falls in, it forms a disc, pretty much like water going down your drain. Things don't fall in in all different directions because there's often a bit of rotation in there. So just like water going down the drain, everything all this dust ends up falling in in a disc like a whirlpool. And the star forms in the middle where most of the stuff falls in, but you end up with this disc of dust

25:25and that forms then into the planets. So they everything started in this disc going around in a circle. So that means at the end, everything sort of stays in a disc. Not perfectly because some things whack into each other, but we end up with everything pretty much in a disc. So that means every solar system will roughly have its own plane. But no, not everything's the same way. And actually, the solar system is kind of almost perpendicular to the Milky Way. So it's traveling sort of face on through the Milky Way. So no, not everything's on the same plane, but within each solar system, we would expect most things to be roughly in the same plane. And in fact, so the solar system is traveling around the center of the galaxy at around 220 kilometers a second, but it's sort of going square on. And do we still reckon that there's roughly 7,000 of these stellar nurseries in a Milky Way where stars and planets are born? Oh, I don't know the exact number, but yes, they're most galaxies. So younger galaxies like the Milky Way

26:27that it sort of disc galaxies compared to the older galaxies that have sort of run out of the star forming material that you need will have a whole bunch of what we call star forming regions. The closest one is called the Roe of Fear Key Complex. Yes, and it's a blob of gas and dust where lots of little baby stars and solar systems and that far is it? Ooh, that's a good question. It's actually pretty close, I know this, because it's in my sample of radio detected stars. So it's a couple of hundred pasex, I think, I think. Which is, this is really unusual. Yes, I said pasex. Which is three times that for light years. Three times that for light years, yes. It's really unusual, because when you talk to most astronomers and you say, how far is that they go, I have no idea. Yes, we do. We don't think that much about everything's far away. It's all far away. You have discovered one solar system where there's a planet going north-south over the... Over the rotational pole? So the star's rotating, oh, there you go. So most of the planets are following the equator. But we have found at least one case

27:28where it's going north-south, and you would expect that. We've discovered 5,000 solar systems and there's all sorts of things going on and near collisions and so on. There's always a weirdo, you know. You get all that Simon? Yeah, I guess so. Thank you. Some sort of space butterfly effect going on. You sit in... Yeah, it's like as everything, every solar system is like a space drain. All the water going down in a plane. Perfect. Yep, so good. Dink, in San Gate, Dink, what is your question? Hi, I'm just wondering how spacecraft gets through the asteroid belt. Did I navigate through it? Straight line, what happens? Ah, so obviously the way it is is the way it is in Star Wars, where there's an asteroid every four meters. That must be it, I'm sure that's what it is. No, so I can see where this comes from because we do see in pretty much every sci-fi movie. They're ducking and weaving and, you know, warping into it suddenly, there's rocks everywhere and they have to get around it. So actually, the asteroid belts are pretty empty. So compared to a lot of space, we would say they're full, but that's sort of astronomy speak.

28:29In reality, they're actually very empty and the satellites and things like the Voyager spacecraft, which are the two spacecraft that are outside the solar system, the furthest anything man made has traveled from Earth. They just went straight through because there's not much in there. Oh, hey, odd. You've forgotten about 18412, Crystal Niskey. I have, you tell it. Is that your star? No, that's my asteroid. Asteroid, yeah. We can't name stars after people. I did just make a, a, a, a, a, a, Braden article and make a website about that lately because you can't name stars after people, but comets you can and asteroids you can. Yeah, so, yeah, it's about six kilometers in diameter. Oh, that's pretty, pretty decent. And it's not expected to wipe out humanity as we know it. 18412, Crystal Niskey. That is your asteroid. Hey, Dink, thanks for your question. All right, have a good day. Ben, in my engine, you have a pretty big question. Talk us through it. So my question's for Dr. Laura. I'm just wondering with the sort of increase in the number of satellites that are getting sort of leased into the atmosphere these days,

29:30I think it's some, some targeting around 50, or 1000 and X, few years. How's that impacting radio astronomy and things like the square kilomeray and, and ASCAP and for people like yourself and how are you sort of, and what are we doing about those things? Dr. Laura, do you want to give us some context to what ASCAP is? Yes, I was going to say, Ben, you definitely know your staff because your name dropped my two favorite telescopes. So I love that. So the SKA, or the square kilometer array, is the biggest telescope in the world. It's been built right now. And part of it is in Australia and WA. And in the same sort of spot, there's ASCAP, which is the Australian SKA Pathfinder. It's 36 dishes out in Western Australia about eight hours drive from Perth. So it's a big radio telescope. And that's the one that I use all the time, all the data are public as well. So if you want to download it, you can. And these radio telescopes look for radio waves. And this is what we use for communications on Earth. And we have, for over 100 years, right? So if you listen to this on your car radio, your car radio knows what to play because of radio waves, Wi-Fi, Bluetooth,

30:32all of that is radio waves of light. So you're right, Ben, it does have a really big impact on us. There's more what we call radio frequency interference. Now, if you imagine like in between the TV channels or in between the radio channels, you hear that fuzz. It's sort of like that. We see, instead of seeing space, we see a mobile phone, or we see a satellite, or we see all these things that we don't want to see. And it means that we can't actually see what we want to see because it completely blocks it out. It's like when you try and take a photo of the sun and it just blows everything out. It means you can't recover it, right? So it does have a really big impact. Some frequencies of light are protected, but it's very tiny, very tiny little slices of radio frequency. So we do have a lot of people who work, who their main job is to try and get rid of this mess that comes from satellites. But the other side of it is, of course, is we know where all the satellites are because we can see all of them even if we don't want to. So there's a lot of satellite tracking and things like that that you can do with radio telescopes, which is kind of cool, but not really what I want to do.

31:34So it does have a really big impact. I suppose that was a long-ancidio question, but there's a lot of algorithms and people doing whole PhDs to work out how to what we call mitigate this RFI. So we can either prevent it from getting to us in the first place or trying to slice it out after we've already got the data. That's awesome. Thank you. Thanks, Ben. Matt, in Ginne de Bain, what is your question? Hey, doctors. My question is, the sun changes its poles quite regularly, every seven or so years. I've not noticed anything. Does anything happen on Earth, noticeably? And what happens when the Earth changes its poles, every 10 or 11, 12,000 years? So the sun changes its poles every 11 years. It's part of the solar cycle. And the swap happens during the solar maximum. So we do notice it because that's when we get a lot of big flares and what we call coronal mass ejections when the sun shoots out a chunk of plasma. So if you're lucky and you're in a good spot,

32:35you get might get to see the pretty lights of the Aurora. So lots of things happen at that pole swap time of the sun because it's also the solar maximum. There's actually been lots of those coronal mass ejections recently. So are we due for a swap? So we've just had it. So we're on the other side. And we actually find that on the other side, so when we come in down out of the maximum, that's when we see more of these coronal mass ejections. And is there a period when there is no North Pole, no South Pole? And if so, how long does that last for? Oh, that's a good question. I'd have to look that one up. I'm not sure. I don't think so. I think I've probably heard about it. And then the Earth swapping its poles. What happens to our weather and location and? There's a whole lot of papers on that. So certainly, when we swap the time that we can have known North and South Pole, and therefore we have no protection from the charged particles from space, and therefore the Aurora is going to happen down to the equator, that can last up to 70,000 years. Now, the weird thing is that the magnetic pole

33:37reversals of the Earth are random. They don't follow a bell shaped curve. Like if you go and measure the height of humans, or the diameter, or height of trees, and a forest, you'll find an average value, and then equal numbers each side. Whereas it's just a bunch of spikes with regard to the reversal of the North-South poles. And so I'm guessing we don't ask a physicist about that. Well, we don't really know when it's going to happen, but I do, I have read a little bit about it, and it does mess up with the animals, because a lot of animals do get impacted by the magnetic field. Oh, yeah. So I think it can mess with animals and things. And in that book Quantum Life by Jim Al Haif and Khalili, he talks about how they have birds, have little magnetic particles near their eyes that use quantum chemistry, quantum physics, to be able to navigate. Wow, incredible. Thanks, Matt. Thank you. We've got Tom in X-Muth here, Dr. Tom. You've got a question about black holes. I do. Are they really a hole? Or is it a 360? Do we know what the shape of it is? I love this question, Tom, because I actually did a lot of digging

34:38into why black holes are called black holes. And it's not, so on the Wikipedia, it says it's because a guy said it in a lecture, but it's not. It was a different bloke who, I don't remember the name of, but you can look him up. And he used to say to his kids when they were younger that if they lost something, it must have fallen into the black hole of Calcutta, which was a horrible prison in Calcutta. And if you went in, you were never coming back out again. That's right. Just like a black hole. If you go in, you're never coming back out again. So black holes are not holes. They're an extremely dense, ridiculously dense, sort of undefined density of stuff. So if you went around to the back side of a black hole, it would just look like a black hole. So they are similar to a lot of things in space, spherical, unless there's rotation and magnetism, so they can be slightly a little bit off spherical. But yeah, the other side of a black hole around the other side would look the same. Just a different background. Thank you very much for your time. No worries. Thanks, Tom. And that wraps us up for this week's episode, Dr. Laura. Thank you so much for coming through. We love having you on. Thanks for having me, and thanks for the amazing questions.

35:39Yeah, they were really good at great. If we want to learn more about what you're doing, what you're up to, what you're researching, where should we go? So on Instagram and TikTok, I'm AstroLauraD. AstroLaura is taken. So I had to go with AstroLauraD. Damn. And astroLaura.com, if you want to find all the other socials like Blue Sky and LinkedIn and all that sort of stuff. Amazing. AstroLauraD for Laura Dreson. Thank you so much for hanging out with us. Hey, Dr. Carl, we'll do this again next week. Did she came? Yeah. Thanks so much for listening to this week's episode of Science with Dr. Carl. And if space is your jam, you want to learn a little bit more about the stars and the planets. You can tap back into the podcast feed. We've got episodes with people like Catherine Bernelpeg from NASA, Australian of the Year, who talks through what it is like venturing into that world. A big thank you again to Dr. Laura Dreson for joining us. We'll have her handles for you in the show notes, if you want to check out more of her work. This episode was produced by Josh Brennan. My name is Lucy Smith. We'll catch you next week. Bye.

36:39Dave Marquesi here from the TripleJ hack team. Hey, if you love Dr. Carl's podcast like I do, you might enjoy the hack podcast as well. Each day, we bring you the news that matters to you from the latest science on climate change to what's happening in politics and news around the world. The hack podcast, it's your daily fix of the news you need to know. Get it wherever you're listening now.