Ologies with Alie Ward - Cosmology (THE UNIVERSE) Part 2 Encore with Katie Mack

Episode Date: September 12, 2023

Dr. Mack returns with a new introduction and updates on… listener questions! The universe, dimensions, asteroid bags and cosmic vertigo with the amazing Astro Katie, AKA Dr. Katie Mack. Part 1 was a... primer on all things cosmological, from particle physics to black holes, so listen to that first then hop to this episode to get all your questions answered.Visit Dr. Mack’s website and follow her on Instagram, Twitter, YouTube and TikTokBuy Dr. Mack's new book: The End of Everything (Astrophysically Speaking)More episode sources & linksSmologies (short, classroom-safe) episodesSponsors of OlogiesTranscripts and bleeped episodesBecome a patron of Ologies for as little as a buck a monthOlogiesMerch.com has hats, shirts, masks, totes!Follow @Ologies on Twitter and InstagramFollow @AlieWard on Twitter and InstagramEditing by Steven Ray Morris and Mercedes Maitland of Maitland Audio ProductionsTranscripts by Emily White of The WordaryWebsite by Kelly R. DwyerTheme song by Nick Thorburn

Discussion (0)
Starting point is 00:00:00 Hey everyone, this is once again your friendly neighborhood cosmologist Katie Mac. I am giving a little bit of an update to this episode. This episode is mostly answering questions about astrophysics and cosmology things and since it was recorded in 2017 there have been a couple of changes, a couple of updates. One of the things that I answered questions about was asteroid searches, and I mentioned that there is a big part of the sky we're not really looking at. That has gotten better in recent years. There are some new observational projects. We have a much better survey of the sky for finding potentially dangerous space rocks.
Starting point is 00:00:44 finding potentially dangerous space rocks. There's some caveats though. One of them is that because of things like these new constellations of satellites that are going up, some of that is making those observations a little bit more difficult. I think we're still in a much better place than we were, and we're finding way more potentially hazardous objects.
Starting point is 00:01:01 Nothing is a big threat at the moment, don't worry. But yeah, it'll be interesting to see how that develops in the next few years. The other update is just that my social media stuff is all different now. I'm still on Twitter as at Astro Katie, though I'm using Twitter less these days. I'm on Instagram at Astro Katie Mac. So check those out and just check out my webpage astro Katie dot com that hasn't changed. You can learn about stuff like my book, the end of everything astrophysically speaking, where I talk about how the universe might end and what that would look like if we could
Starting point is 00:01:34 see that. And I have a newsletter now that you can also check out. There's a sign up on my website. It's called Watch this Space Time. So thanks for listening and I hope you enjoy the show. Hey, this is Ali Ward here with allergies. Now a few things up top. If you like allergies, I personally myself would love it. If you took a second to rate and or review it on iTunes, have you done that yet? It doesn't cost any money, you just do it.
Starting point is 00:02:05 And I also totally read all of your reviews. I'm thrilled by them. Today someone named Smile Miss, there are six S's in that, said the actual best. Yep, the actual best. When things get all jargony, alley fills in the gaps. Great guests, great topics, and a genuinely lovable host, which by the way I read that while walking into the post office and I almost started crying or skipping so thank you everyone for these when you leave reviews and you rate it. Other people say hey what's this thing? No. Cosmology part two. If you listen to the very very end of part one last week with the just phenomenal Dr. Katie
Starting point is 00:02:46 Mack, aka Astro Katie. Then you learned a lot about particle physics and the large heart on collider, um, string cheese, black holes, the world's most expensive selfie, and your own aching insignificance, all of ours. If you haven't listened, give it a go. I also tell you a somewhat embarrassing secret at the very end of the podcast. Maybe I'll do that again.
Starting point is 00:03:10 So part two with Dr. Mack means getting right into the nitty-gritty, your questions. And trust me, I had a million. But Katie and I were late to meet up with friends to see Murder on the AuriniXpress. So I could only ask about half an hour's worth of questions.
Starting point is 00:03:27 So I may have to nab her in the future to ask the rest because there's so many questions for you. It's like a rapid fire round. Sure. Yeah. I'm here for it. I'm going to throw a bunch of questions at you. If you want to skip any of them, you can just pass. First question is I'm going to ask her from the Patreon page.
Starting point is 00:04:01 Okay. So people are patrons. We appreciate them very much. They are great people. They are great people. They are fantastic and we want them to continue and ask lots of questions, which are all very good questions. Yes, exactly. Yes. You can be a patron for 25 cents in episode. Which is an amazing deal. Is it a good deal? People should totally do that. I want to make it accessible. If you did feel like tossing a dollar a month, then get yourself over to patreon.com slash allergies. I post calls for questions, some behind-the-scenes photos, or some patron-only videos, and for $25 a month, I'll be your emergency contact,
Starting point is 00:04:37 which I hope you never need. And also, I may not be reliable. This is a question. I'm just going to say one of the questions, but three different people asked a variation of it. Erin Hirdman and Alex Entroini. Entroini, Alex? Did I do that right? I'm sorry. Both wanted to know. Is there a name for the disorientation and panic
Starting point is 00:04:56 one feels when considering the vastness of the universe? Also, do you know of a way to get past it? There is a name. So, but there are a couple of names. One is Cosmic Vertigo. Okay. And the other is Cosmophobia. And I don't know if these are like official names, but these are names that I've heard.
Starting point is 00:05:20 There's so a couple of friends and colleagues in mine have a podcast called Cosmic Vertigo where they talk about cosmology and stuff and space and things, but it's based on that topic. And Cosmophobia, I know about because I occasionally get emails from people who say that they have severe cases and want my help. So it is a thing. Sometimes people get really, really upset about the vastness of space or just the fact that we have no control over these huge forces. I mean, that is something like, I have moments where I'm like, whoa, right? Because there are things like, you know, black holes are colliding with each other. And the universe is expanding and it's accelerating in its expansion. And it's getting bigger and bigger and faster and faster.
Starting point is 00:06:05 And like sometimes, you know, that stuff is really, you know, I mean, you think about your little life and what's going on in your day to day. And at the same time, like stars are exploding. And, you know, and we have, we can look at the Big Bang. Like we can actually see the primordial fireball at the Big Bang. Like we can actually see the primordial fireball of the Big Bang.
Starting point is 00:06:28 We can see that. How? Ladies and gentlemen, Alley Ward, Zero Chill. The reason is that the whole universe was hot and dense and smaller than it is now. So the Big Bang theory is just the idea that the universe in the past was smaller and denser and hotter than it is now.
Starting point is 00:06:44 And so if you kind of dial back the current expansion of the universe, then you get to the universe being very, very small and dense and hot. And so every point in the universe now was at some point much hotter and filled with like radiation, right? So like this part of the universe now in in the very distant past, was full of radiation and very hot and very dense, right? But so, when we look out into other parts of the universe, because light takes time to travel, every time we look farther away, we're looking farther into the past.
Starting point is 00:07:17 And so, we're looking at that part of the universe as it was, maybe a billion years ago, or five billion years ago, or whatever. And there's a part of the universe that's so distant that when we look at it, we're looking at it as it was during the time when it was still on fire. Right. So we look as we look into the distance in any direction, we're seeing that part of the universe as it was when it was still in that primordial fireball kind of state, which was how long ago. Well, that was around, so the fireball started to cool around 380,000 years after the big bang, whatever, after the moment of the beginning, whatever you call that, because that's still part of the hot big bang, which is like the hot phase. So we can actually see radiation coming from every direction
Starting point is 00:08:05 in the sky that is the radiation of that heat, like that radiation from that early time, just reaching us now from really distant parts of the universe. And so we can look at it. And we're looking at like the fireball universe. We're looking at that primordial plasma. I can just go ahead.
Starting point is 00:08:26 And so we see the big shows. Yeah, and so we know that it happened because we can see it and we can watch it. We can actually see parts of the universe that are still there as far as we're concerned. And that can give you cosmic vertigo. Yeah, just thinking about that was a big, important event. And like, so this sort of like nice, gentle, stable universe is not that's not how it always was. And we don't know, you know, we think that most cosmologists think at the beginning of
Starting point is 00:08:58 the universe before that hot phase, there was a period of very rapid expansion of the universe called inflation. We don't know why that started, we don't know why that ended, we don't know that that couldn't just start happening again right here right now. There are theories of the theories where you can have the universe like, and right here right now in this room, oh god, oh god. So this is an idea called vacuum decay where you can you can have like the universe like have a quantum event happen where one point in the
Starting point is 00:09:33 universe like transitions to this other state. It's called another vacuum, a true vacuum state. And that would create this bubble of like, again, bubble of death. That expands out at the speed of light in every direction, so you would never see it coming. It sucks. And it's a probabilistic event. It's a quantum event, so it could happen at any moment. It probably won't. Oh, God.
Starting point is 00:10:00 You know, it probably were just wrong about the theory. And even if we weren't wrong about the theory Like the the sort of timescale that we calculate for it would probably take like, you know, trillions of years or something But like it's a probabilistic event. I could have in an a moment technically. It's just with very low probability So like that could freak you out and I've gotten emails from people like they read about that and they're like I can't sleep And I'm like, I'm sorry Do you have any advice for that? I mean they're like, I can't sleep. And I'm like, I'm sorry. Do you have any advice for that?
Starting point is 00:10:26 I mean, I tell them like, so about vacuum decay, I can tell them like a few things. One is that we don't know, we don't have any, we don't know for sure that this is even possible. If it were possible, it probably would have happened in the very beginning of the universe because the conditions for it happening then were much more favorable So it probably would have already happened if it was gonna happen already or if it was possible at all
Starting point is 00:10:51 And then I say well if it's gonna like you it's nothing you can do. Yeah, I mean like it's it's traveling at the speed of light You won't even see it coming. That's the best way to die. Yeah, you won't I mean you won't notice like it basically like That's the best way to die. Yeah, you won't, I mean, you won't notice. Like, basically, like, so it is absolutely the best because you don't see it coming, so you can't be scared of it. You don't even really notice it because it's happening at speed of light.
Starting point is 00:11:12 And you're not like around afterward. And everything is around. Yeah, everyone you love dies at the same time. Yeah, everything dies. Everything's gone at the same time. There's no, there's no FOMO, right? There's nothing you're not missing out on anything because the whole universe is done now, right? And so it's kind of, in the same time, there's no FOMO, right? There's nothing you're not missing out on anything because the whole universe is done now, right?
Starting point is 00:11:27 And so it's kind of, in some sense, it's really inconsequential because there's no consequences of it. It's just, so it doesn't matter. Like you could just blink. And then you blink and maybe you open your eyes again, maybe you're consumed by a vacuum bubble of death, but who cares?
Starting point is 00:11:44 You don't know. If I could vote on a way for everything to end, I would be like, Oh, totally. Yeah, vacuum decay. Vacuum decay. That's gonna be my platform. It's a run chart.
Starting point is 00:11:55 But 2020 vacuum decay is my platform. It is the best way to end the universe. Okay, so that's one way to chill out. Paula Herrera wants to know, how scared should we be of a giant asteroid destroying Earth? Are any of the sci-fi movie methods to save the planet plausible? Are we basically doomed? Should an asteroid come our way?
Starting point is 00:12:15 Yeah, that's a little bit of a sadder point. Because like, okay, so we're basically not really monitoring about half the sky right now. What? Okay, no big deal. No big deal. Because we used to have some monitoring stations that have a Southern hemisphere and they lost funding. Oh, so we don't have as good a handle on the number of objects out there that could cause really big problems.
Starting point is 00:12:46 There's some kind of goals about how many, what fraction of objects above a certain size we should be aware of, right? It's like you're supposed to see 90% of objects above some size or whatever, and we're not really there. Oh, no. So I think there are programs being put together now and there's efforts to have a better catalog. It's not like we're due for a giant impact or anything.
Starting point is 00:13:17 These are still things that are probably not gonna happen anytime soon, but I can't honestly tell you that we're on top of it. Wow. We have, we're monitoring a lot, but we're not monitoring enough to say that we definitely don't have anything coming. Okay, so whether or not we could stop it. There are a couple of methods. If we find out about it early enough,
Starting point is 00:13:47 like five years ahead, 10 years ahead, then there's a possibility of sending a spacecraft to it and changing the course of it in some way. You don't want to just blow it up partially because some of these things are like kind of loose rubble piles. And so it wouldn't really work to try to blow it up but also because like if you have a huge asteroid and then you blow it up then you have like a bunch of smaller asteroids and that's not always better. Yeah, but
Starting point is 00:14:17 but there are a bunch of really cool ideas for just nudging a little bit and if you find out about long enough in the you know before it comes then you don't have to nudge it very far at all to get it totally off course, it will miss the earth. So like one of them is to take a really, really massive spacecraft and just like park it next to the asteroid in the orbit for a while. And so then it gets like, pulled a little bit by the gravity of the spacecraft. And that can, if you get it early enough, that's called a gravitational tractor. Yeah, if you get it early enough, that can work.
Starting point is 00:14:51 There are other ideas about like creating a giant sack and like, capturing it in a sack because you can't necessarily, let's not necessarily like a solid thing. How are you going to make a bag big enough to put it on an asteroid? I mean, it depends on the size of the asteroid, right? But I mean, I don't know. Like, is there... What is that made out of like mylar?
Starting point is 00:15:11 Uh, cap don't tape? I don't know. I'm sorry. I'm a little activated by this. I looked up asteroid bags. I was distracted for a few minutes on some galaxy printed totes and duffles and I was like, oh, that's nice. And then, okay, I realized that space people called these capture bags like this is just no big deal like just used to collect
Starting point is 00:15:30 fallen leaves or a dog doodle but NASA introduced a plan a few years ago and I asked a search engine gods what the bag might be made of and I found out it could be inflatable could be metal mesh or could just be high strength material. Sounds like they're figuring that out too. My guess is it's just a very large blue IKEA bag. Toe that fucker in. Those things are strong.
Starting point is 00:15:53 It's another idea, which is also really cool, where you spray paint half of the object so that it changes the reflectivity. And then that means that the solar wind will push a little bit more on one house than the other in some way. And that can change the trajectory. So there are a couple of possibilities. Those are some good options. Yeah.
Starting point is 00:16:12 Yeah, but you need a lot of lead time. And a lot of paint and a really big bag. Yeah. Yeah. Oh my God. I just can't believe that we're kind of sleeping on the job there. I mean, it's like we're not, I mean, there are people,
Starting point is 00:16:24 there's a lot of, a lot of these things are being monitored and there's nothing that we know about that's anytime soon coming as a threat, but there's also like we're not fully on top of this in the way that I feel like we should be. Oh, man, good to know. Yeah. Russell Kelly wants to know,
Starting point is 00:16:41 will the universe expand forever or will it eventually collapse in on itself? That is a great question. Based on our current understanding and the data that we have now, it looks like it will expand forever, which will lead to something called the heat death, which is the most depressing way for the universe to end, which is that we have dark energy, dark energy is whatever is making the universe expand faster and faster. If it's a cosmological constant, which is just a kind of dark energy that first invented by Einstein, but it seems to be the case, then what'll happen is that over time
Starting point is 00:17:15 the other galaxies will get farther and farther away, not in dramatic. The endromania galaxy is coming for us now. It's on its way. It's gonna collide with the Milky Way in about four billion years. That'll be fine, whatever. But then the more distant galaxies, they'll just get farther and farther away. And eventually we won't be able to see any other galaxies outside of our little local group. This is like when all your friends grow up
Starting point is 00:17:38 and move out to the suburbs, or get rich and go to Santa Monica. And then we won't be able to see the cosmic microwave background anymore, that after glow of the big bang, so the universe will just get really, really dark and really empty. And then our little group of galaxies will kind of be combined into one big blob, but eventually all the stars will burn out,
Starting point is 00:17:59 because they'll run out of fuel, and there's no more gas coming in to make new stars from other galaxies. So the stars will burn out, and then a bunch of things will collapse into black holes and the black holes will evaporate and the protons will decay and everything will just kind of decay into nothingness. And there will be this really empty, cold, dark universe with nothing in it and just like this tiny amount of radiation and no ability for any new structures to form, except maybe through some kind of quantum process, which is kind of a cool thing, but that's another topic. That's so goddamn lonely.
Starting point is 00:18:39 Yeah, that's called a heat death. So what happens when the indromino galaxy collides with Milky Way, though, you glanced right over that. What the hell is that about? That's really cool, actually. So the indrom in a galaxy is a spiral galaxy like around. It's got about a trillion stars. It's more massive than the Milky Way.
Starting point is 00:19:00 And it's got a super massive black hole. And they're all coming toward us at something like, I think it was like a hundred kilometers a second. Anyway, they're all coming toward us right now. And is it going to smishy smash? Yeah, it's going to come. And in about four billion years, it'll get here. And it'll, it'll collide with the Milky Way galaxy. The way that galaxies collide is kind of cool. They like sort of merge and they make these long trails of stars coming out.
Starting point is 00:19:30 And it'll be this sort of like really spectacular light show of like gaspled collide and make new stars. And there'll be this burst of star formation. And the black holes might like turn on and start like pulling in matter and like getting really bright. And stars will be flung out into space and on these long tails. This sounds like a warehouse space rave.
Starting point is 00:19:51 I'm not gonna lie. I'd be down for this. But because galaxies, because there is so much space between stars in galaxies, probably our solar system will not be affected. Okay. Like probably we'll just like this, this guy would get really interesting. But you know, it'll also be four billion years from now.
Starting point is 00:20:08 So the sun will be burning out and, you know, the earth will already have its oceans boiled away and life on earth will be possible. But if you know, we left something here to take pictures, they would be really pretty. Yeah. Mike, uh, Mel, Mel Choir, Mel Choir wants to know are Uranus jokes still funny? It's really Uranus, isn't it?
Starting point is 00:20:27 So actually, I don't know which is a better pronunciation. I usually say Uranus just because I don't want to deal with it, but then it's got the name Uran in it too. I know, it doesn't really help. No, they're not, they're not particularly funny. Okay, just checking out. So I use an AI for transcription for this podcast, and it transcribed to your NAS. And I'm sorry, but yes, that, no. So I use an AI for transcription for this podcast and it transcribed to your and ask. And I'm sorry, but yes, that is funny.
Starting point is 00:20:49 Megan Gerard wants to know slightly more on a local, practical level. She loves Stargazing, but even in a small city, it's hard to do because of light pollution. So can you recommend any tactics, resources, organizations for helping reduce light pollution. Also she thinks maybe light pollution is bad for us and animals. And so good way to stargaze and good way to reduce light pollution. So there are there are national organizations for like dark skies. I don't remember the names, but if you if you look them up, there's they have their charities charities that their whole purpose is to try to get better lighting in cities so that more of the light goes down and not up and changing what the lamps are made of and stuff like that.
Starting point is 00:21:35 So you can get involved in these campaigns and they're really helpful. Yeah, I can't remember the name of the organizations right now, but there are a few of them out there. DarkSky.org has a bunch of information on getting involved in DarkSky Advocacy and membership in this kind of a Dark Sky club. So hit that up. I will try to do my part and stop falling asleep with lights on. I fell asleep with them on again last night, but tonight, tonight, International Dark Sky Association. I'm going to do my part. If you want to go stargazing and your city's too bright, you just have to go somewhere else,
Starting point is 00:22:11 basically. So, when I was living here, when I was growing up in LA, in Long Beach, I was part of the LA Astronomical Society, and they would have Dark Sky Star Parties where we would drive like four hours into the mountains, and it would be dark skies out of star parties where we would drive like four hours into the mountains and It would be really dark. Yeah, so you don't have to get that far out of that out of city to do good stargazing So getting the fuck out of Dodge. Yes, got it. Yeah, that's pretty much it There's there's a really great film called the city dark, which is about It's about light pollution and what it does to us and what it does just astronomy And I'd recommend checking that out. I felt so little light on last night It's not good for you. Yeah, and now this set of questions comes from the Facebook group. There's okay
Starting point is 00:22:52 Allegis podcast Facebook group But before we take questions from you we're gonna take a quick break for sponsors of the show Sponsors why sponsors you know what they do? They help us give money to different charities every week. So if you want to know where Allegis Gives are money, you can go to alleyword.com and look for the tab Allegis Gives Back. There's like 150-year-from-charities that we've given to already with more every single week. So if you need a place to go, donate a little bit of money, but you're not sure where to
Starting point is 00:23:21 go, those are all picked byologists who work in those fields, and this ad break allows us to give a ton of money to them. So thanks for listening and thanks sponsors. Okay. Isabelle Lourian wants to know, what do you think the shape of the universe is? Hyperbolic, Toroid? What do you think? Did I say Toroid, okay? You said Toroid, okay. Okay. Toroidle is the adjective. Okay. But yeah, it's, so Toroid, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, the, also, a Taurus, apparently, technically, would be like an inner tube. Hollow. And a solid Taurus is a donut. But I want to say, I was on a desert show called Unique Suites. For like, a lot of seasons, I have to say, a cake donut seems like a solid Taurus. But if it's a fluffier yeast donut, there's all kinds
Starting point is 00:24:24 of air pockets in there, and the volume and density seems somewhere between a torus and a solid torus. And I need a physicist to get on this for me. Thank you. Okay. Oh, yeah. Back to the ship of the universe. The universe, the way she's asking the question, the answer is the universe is probably flat. Okay. Which just means, it just means that there's no large-scale curvature to the universe. So I said that matter curves space. So you get these like dense in space. On the very large scales, the space is flat in the sense that it's not large-scale curved.
Starting point is 00:25:00 It's still probably three-dimensional. I mean, the space part is three-dimensional, and then there's time. That's a force to mention. But it's flat in the sense that if you had two beams of light that were parallel, they would stay parallel forever. OK. That seems to be the case. At least as far as we can measure, there could be some larger scale curvature that we don't measure,
Starting point is 00:25:20 because it's just so big. Like, if you have a ball that's big enough, enough it looks flat like the surface of the earth looks flat but But the universe on the whole as far as we know Here's to be flat. There's no evidence for curvature, but it could be curved around on some really large scale Okay, we'll find out in before the stars all collapse on themselves. Hopefully maybe We'll find out before the stars all collapse on themselves, hopefully. Maybe.
Starting point is 00:25:46 No, no, no, no. I don't know. T.J. King and Laurie March both had kind of the same question. Is there a reason why some stars appear to twinkle more than others? Oh, yeah. Well, so stars appear to twinkle when you're looking through the atmosphere, because the atmosphere is bending the light a little bit just by being like a little bit hotter a little bit wetter or something in different parts. And so when you look through that sort of, you know, messy air, it makes the position of the star move around a little bit from your perspective. And that means that
Starting point is 00:26:25 sometimes it'll look a little bit brighter and sometimes a little bit dimmer and that makes the twinkling. So the brighter a star is, sometimes that makes it look less twinkly or more, it depends on kind of what the air is doing. But planets don't twinkle. Why not? So the reason planets don't twinkle is because so the the the reason planets don't twinkle is because the twinkling of a star comes from the fact that it's just a point of light. From our perspective, it's just a single point of light. And so it can be moved around, and that little point of light can be magnified a little bit, and that makes it look brighter
Starting point is 00:27:01 or less. But a planet is a disc of light from our perspective. It's really, really small disc, but it's a disc of light that's big enough that the little sort of turbulence cells or whatever in the atmosphere only just move the light around within the disc mostly. And so it doesn't get significantly brighter or dimmer because the motion of the air is not
Starting point is 00:27:26 enough to really change the sort of size and shape of that disc. So if you twinkles, you got to star. If it doesn't twinkle, you got to plant it more or less. Yeah. Yeah, more or less. So if you see something pretty bright in the sky and it's not twinkling and other things are, then you've probably seen a planet and they're probably seeing Jupiter, Saturn, Mars, or Venus. That's so great. Yeah. If you end if that does happen and it's the first time you've heard this, then you should high five Katie on Twitter.
Starting point is 00:27:54 Lauren Oaks wants to know, what is the deal with other dimensions? This might not be the right person to ask, but I still want to know. Okay. So we have three dimensions of space. So that's forward, backward, left, right, up and down. We also considered time to be about dimension. So when you think about things like relativity, you have to include time as part of your coordinate grid, basically. And so that coordinate grid has to have four dimensions. So the time is the fourth dimension.
Starting point is 00:28:28 And the reason for that is that space and time can kind of affect each other. Like moving through space at a higher speed changes the way you move through time. And when you're close to a gravitating object that changes the way you move through time. And so it has to be part of the same sort of malleable fabric in some mathematical sense. There could be other dimensions of space. And that we just can't interact with, we can't see, we can't perceive.
Starting point is 00:29:01 And in some cases, those other dimensions of space might be kind of wrapped around themselves. Okay. Which is a weird concept. But it's kind of like if you imagine, like, like if you imagine a string, right? A string is a three-dimensional object. Two of those dimensions are kind of wrapped around, really tight. So it only has a little bit, a little direction you can go in two of the dimensions. you can go a really long way in the other one. And so it might be that in space, in our universe, we can go as far as we want in our three dimensions, but the other dimensions are so small that we don't notice them because they're all wrapped up. And one of the reasons that those extra dimensions are hypothesized is that it might be that all
Starting point is 00:29:45 of our sort of particle interactions of stuff can only happen in this three-dimensional space, but gravity can leak out into the other ones a little bit. And so if that were happening, that would explain why gravity is so weak compared to all the other forces. So that's a hypothesis, you know. So there could be other dimensions that might solve that problem. But what about multiverses, and is there another me with a better life living in a different dimension?
Starting point is 00:30:12 So, that, so when people say dimension in that sense, they just mean another universe. The dimensionality, like the dimension doesn't mean space anymore, it means something else. So there could be other universes depending on how you define a universe because you could just define a universe to be everything and then everything is part of the universe by definition. There can't be a second everything. Yeah, okay. But you can define a universe as just the observable universe. So what's within our sort of the distance out to which we can observe anything, which is a set distance.
Starting point is 00:30:51 And then there could be stuff beyond that. We know there's stuff beyond that. So that's kind of outside of our universe. You can think of that as another universe. And then you can have other universes that are separated by higher dimensions from us. So you can have like, like, you can imagine our universe is a flat sheet and there's another flat sheet. So we've just taken one dimension down and they could collide maybe. And this is like, there's a theory for the big bang that comes from these two sheets collide and that makes a big bang and then they come apart
Starting point is 00:31:17 and then they collide again later on. It's called the ecopirotic model. My thesis advisor was one of the people who came up with that. a psychopirotic model. My thesis advisor was one of the people who came up with that. And then there are other ways to have other universes, like with the many worlds idea of quantum mechanics, which says that every time a quantum event happens, basically, another universe branches out from ours in a way that somehow makes sense mathematically, but sounds ridiculous when you think about it.
Starting point is 00:31:46 Is that kind of like an alternate reality? Kind of, yeah. Is there another me in another universe, in another reality who brushes her hair more regularly? Well, in the many worlds hypothesis, I guess technically, that would be the case. But, so if that's a good rabbit hole that you want to go into just like we start googling Because in many worlds like there's another universe where like a photon just went through that Window-ordent and that's the only difference. Oh my god. Oh my god. So like every possible thing Ricka land wants to know is there actual scientific proof that there might be life beyond our planet? Aliens, yes, no.
Starting point is 00:32:26 Probably. Okay. So what is Katie hate about her job? What does she hate? So one is the uncertainty of the kind of academic career letter. Okay. So I spent the last eight years as a postdoc, which means I had my PhD and I was doing research, but I didn't have a permanent job and I didn't know where I was gonna go next or how long I would be there or whether or not I would be able to continue in science because it was just, you know, applying for jobs. And it's a difficult thing to be doing.
Starting point is 00:33:00 And I, you know, all jobs have some uncertainty at some stage, but I feel like in academia, that uncertainty and that sort of tenuousness lasts a really long time. Yeah. And if you get to the stage where you're definitely not going to get an academic job and you wanted one, then you have spent many years making not very much money when you could have done something more lucrative and it would have been better off in like every way. So, I mean, I enjoyed doing the research.
Starting point is 00:33:34 And so for me, it was like, well, I'll just keep doing science as long as I can. I enjoy it. I'm willing to make that sacrifice. But for a lot of people, it's just so disruptive and it's so difficult that it's like, it's a really high anxiety time and it's really hard and a lot of people it's just so disruptive and it's so difficult that it's a really high anxiety time and it's really hard and a lot of people leave because that
Starting point is 00:33:49 is just really hard to deal with. That's the main thing. And then the other thing is that it's just, it's really easy to have a lot of self-doubt and you have to be very kind of self-driven and it's hard to know if you're doing a good job. And like it's, academia can be very competitive and you don't get a lot of like positive feedback. And so it can be just hard to kind of like,
Starting point is 00:34:20 keep doing what you're doing and know that you're doing it well or know how to do it well or you know, all of that stuff can be difficult. Which is great that you're doing and know that you're doing it well or know how to do it well or you know all of that stuff can be difficult. Which is great that you're a science communicator as well because you get to get a lot of feedback from the public. I can't imagine right? Yeah, I mean that does help a lot. Like if I'm you know sitting in my office banging my head again and something that I feel like I really should know this thing or I really should understand it, this should come more easily. And then you know I feel like I'm a total failure,
Starting point is 00:34:47 and I don't know anything. And then I go talk to room full of school kids, and suddenly, I'm an expert. And then I feel like I know a lot of things, and then it helps a lot. So yeah, for me, it's made a big difference, and just keeping me from getting too depressed about not understanding the universe, as well as I wanted to.
Starting point is 00:35:07 What about your favorite thing about the job or cosmology or physics or? My favorite thing is that I get to ponder the deep questions of reality as my job, you know? Yeah, like I was at a conference a couple of weeks ago and it was most of the topics in this conference were not stuff I work on. So it was like really deep questions about the nature of reality and like whether or not
Starting point is 00:35:34 space time is really a thing and how particles really work and all of that. And I was just like, like, I didn't, it's not the area I work in. So there was a lot I didn't understand about it, but I could grasp some of it. And I felt like, I just felt so privileged to be able to be in that room and to think about these things and to have some grasp of these huge concepts. And like, I get that was part of my work, you know. And that was just an amazing, that's just, every time that happens, it's an amazing feeling
Starting point is 00:36:08 that I get to do these mental exercises and learn about the fundamental properties of the universe. And that's my job. That's your job. I mean, writing the papers and teaching and all of that stuff is also my job. So there's a lot of other aspects to it, but just learning about the universe is a big part of my job, and I love that. It's so baller. Yeah.
Starting point is 00:36:32 Alright. Thank you for letting me talk to you for so long. I'm so sorry. It's the longest interview I've ever done, because there's so many questions. Okay, let's go to a movie. Okay, bye. So we barely made it to the movie, which was a very forgettable mystery romp about a train stuck in the snow, but stellar moustaches and I will remain forever shooketh by this
Starting point is 00:36:52 conversation. I'm glad we took it as long as we did. Now, to follow Dr. Mack, you can find her on Twitter as Astro Katie or on Instagram at Astro Katie Mac. And this podcast is at Allligis on Twitter and Instagram, and I'm at Allie Ward on both, and for T-shirts and Toads and Mugs and to support the podcast, while also covering your new body,
Starting point is 00:37:14 go to Oligismerch.com. And of course, if you like the podcast and want to support, just tell a friend, or make a post about it, or rate it on iTunes. That's huge. And yeah, I'll give you a secret. This week's secret is that I record all the narration in my closet because the sound is pretty good. There's all these clothes to dampen it. But the real nugget here is that I have a real laundry situation. And about half my body, currently sitting on a pile of towels, which I will get to this weekend
Starting point is 00:37:45 about half my body, currently sitting on a pile of towels, which I will get to this weekend after I obtain some soap. So yeah, I'm podcasting from a laundry nest. I'm like a cozy little woodland rodent. Talking at you through a machine! Big huge thanks to Stephen Ray Morris, patron saint of podcasts for editing this episode and to Shannon Feldes and Bonnie Dutch for all of their help with merch and Aaron for running theology's podcast Facebook group and the theme song was composed never formed by Nick Thorburn aka Nick Diamonds of the band Islands he's great check out his music until then ask smart people all the dumb questions you want. The universe is big, and regret is maybe the scariest thing there is. Okay, bye bye! Technology, technology, technology, and seriology.
Starting point is 00:38:45 It's a technology.

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