What would life on Earth be like if our planet were cube-shaped?

It’s coming home. In the season one finale of Dead Planets Society, our hosts Leah Crane and Chelsea Whyte are taking on everyone’s favourite planet: Earth. But fear not – they’re not destroying it entirely, just reshaping it a bit. Gravity naturally encourages objects in space to form spheres, but in this episode, Earth is getting cubified.

Transforming Earth into a cube is difficult, so our hosts have turned to geophysicist and disaster researcher Mika McKinnon for help. No matter how you do it, Earth’s going to be uninhabitable for a while. But once things settle down, life on our home planet would be drastically different.

For one thing, if Earth were molded into a cube but kept the same mass and the same amount of water, the oceans would pool up into six seas, one on each face of Cube Earth protruding from the surface like a huge lens. The atmosphere would behave similarly, not reaching the edges or corners. This would leave a narrow inhabitable zone around each of the six seas with bleak mountains beyond the atmosphere.

Space exploration would, in some ways, be simplified – all you’d have to do to get into the vacuum of space would be to build a shielded rover and trundle off towards the edges of the world. Those edges would be perfect for space launches and telescopes, with no air to hamper things, but the constant earthquakes as gravity tries to make the planet a sphere again might make things tough.

Then, in the second part of the finale episode, coming out on 22 November, our hosts and McKinnon take on what life will be like on Cube Earth. Days will seem different, as each sunrise and sunset would happen suddenly across each face of the planet. The world’s new shape and the six bubbles of atmosphere would encourage something like island evolution, potentially producing strange wildlife and enormous sea monsters.

Dead Planets Society is a podcast that takes outlandish ideas about how to tinker with the cosmos – from putting out the sun to causing a gravitational wave apocalypse – and subjects them to the laws of physics to see how they fare.

To listen, subscribe to New Scientist Weekly or visit our podcast page here. Dead Planets Society will be back with season two in 2024.

Transcript, part one

Mika McKinnon: So, think about if you want to go outside the magnetic field you have to be in your little fish bowl.

Leah Crane: Yeah, I want to cruise around in my all-terrain fish bowl.

Chelsea Whyte: Why are we outside Earth’s magnetic field? Because we’re making the planet a cube. Welcome to Dead Planets Society, everybody.

Leah Crane: This is a podcast where we imagine what it might be like if we were given cosmic powers to rearrange the universe.

Chelsea Whyte: I’m Chelsea Whyte, US editor at New Scientist.

Leah Crane: And I’m Leah Crane, physics and space reporter at New Scientist.

Chelsea Whyte: And welcome to the first episode of our two-part season one finale. This one is a doozy, folks.

Leah Crane: This week it’s time for the most dangerous game. We’re taking down Earth.

Chelsea Whyte: And in true Dead Planets Society fashion we’re doing it in glorious style.

Leah Crane: Glorious, geometric style. We’re making it a cube.

Chelsea Whyte: Cube Earth, Cube Earth, Cube Earth.

Leah Crane: Cube Earth, Cube Earth.

Chelsea Whyte: I truly love this idea and I can’t wait to find out how we could slice the planet’s faces off.

Leah Crane: Thanks, Hannibal.

Chelsea Whyte: You’re welcome. But also I’m curious what will it do to gravity, or time, what would it be like to live on Cube Earth?

Leah Crane: Well, I’ve done a little bit of research so one thing I do know is that it would be absolutely wild. Or should I say, it will be absolutely wild? We’ve also got geophysicist and disaster researcher Mika McKinnon to help us out, and we started by asking her what’s the best way to make Earth a cube?

Mika McKinnon: I think that’s actually the most challenging part, is trying to get the cube, and then once you have the cube just, kind of, assuming that it stays that way, because when left to its own devices, anything big enough is going to go in the spherical and/or lumpy potato direction. Just that’s how gravity works. So first you have to get it into a cube, then you have to keep it into a cube. So I thought that we would start and keep the same mass, because if you start screwing with the mass of the Earth then really you don’t have the Earth at all anymore. So I figured you need to, like, shave down the sides and stick them up in the corners, kind of like a big ball of clay going on. And if you really think about the Earth, it’s not exactly solid, you just have, like, a solid shell, so if you had enough force it is a giant lump of really warm clay, really warm green and blue clay at that. So I’m just going to be like, ‘Look, let’s just have, like, giant cosmic hands doing this. Like, I don’t know, maybe we’re using specially shaped primordial black holes? Why not? Giant chisels?’

Chelsea Whyte: Or it sounds like, like my first instinct was we need a cosmic chisel to slice off the faces of this cube but it sounds like it might be better to have, like, a mold, like a Playdough mold.

Mika McKinnon: Yes, and just smash it in.

Leah Crane: You know how they grow those, like, fancy watermelons?

Chelsea Whyte: Oh, yeah, the cube watermelon.

Mika McKinnon: Yeah.

Leah Crane: Could you just put a mold that’s gently squishing and wait? Because there is a lot of liquid.

Mika McKinnon: Yes, we can take the toddler approach and be like, round peg, square hole, we’re set. Just squish that nice, round planet into a square mold and push it down enough, then good enough.

Leah Crane: Oh great.

Mika McKinnon: So we’re going to take the same mass that we had before and if something kind of goes squishing out, that’s okay. It helps that the mantle of the Earth – so the Earth has the solid inner core, liquid outer core, then the big, gooey mantle and the tiny, thin little crust. And the tiny, thin, little crust is we’re just going to, like, shatter it like an egg shell on a freaking hard boiled egg, whatever, it doesn’t matter. We squish it then it will reform, it’s no big deal, we do that all the time.  The mantle-y bit, you’re probably thinking of it being like an ocean of lava because that’s how we draw it in text books but it’s not, it’s blue, and green, and gooey. So it’s more like oatmeal.

Chelsea Whyte: Literally blue and green?

Mika McKinnon: Yes, yes, yes, the inside of the Earth is blue and green. I mean, it’s really, really hot so it’s probably glowing red, but the rocks themselves are blue and green, if you had colour when completely surrounded by a solid which is like this whole philosophical problem of, like, what is the colour of the inside of a human, right? Like, are the insides of humans actually red or is it only red because you rip them open and take a peek? In this case we’re going to rip the planet open and take a peek so deep blue and green aside from the fact it’s glowing red hot. So, like, the whole concept of colour just kind of falls apart a bit. But, so blue and green squishy inside of the planet and we’ll just kind of squish it out and, like, the core will probably not get re-shaped during this.

Leah Crane: Once we cube it, it sounds like we’re going to probably have to wait a while for the crust to reform because every method we’ve thought of makes Earth, like, super unpleasant to be on for a bit. Like, you don’t want to be on the surface while we’re putting it in the mold.

Mika McKinnon: It’s okay because the earth is going to be super unpleasant no matter what for a while. So if we’re starting off and we’re going to try and keep things to be the same mass, then we end up with, like, a little cubical Earth with everything the same size in every direction, which it is not right now, like, you think Earth is a sphere, hey, we have a consistent radius. No, we don’t, we’re like a squished sphere that is actually really lumpy so it’s more like a potato. So we’re already going in to the realm of, like, hey, this is a more perfect planet than we have. But even if we squish everything, the gravity is still going to be pointing to the centre, so everything inside is still going to be all circular, so we’re still going to have, like, the magnetic field of the Earth, hot metal moving fast, it’s that our core is going to still generate a doughnut-shaped magnetic field. So you’re still going to get your northern and southern lights only above those parts of the cube. Oh, by the way, do we want to have the Earth rotating through a flat part? A face? Or do we want it rotating through a corner?

Chelsea Whyte: So, this was a good question that we were talking about. Like, yes, I think it’s interesting in both ways but I prefer, for some reason, aesthetically to be spinning through a corner. Like a little-

Leah Crane: I’m the exact opposite.

Chelsea Whyte: Yeah?

Leah Crane: I think that it’s a funner if it’s spinning like a cube because then you’ve got a whole edge that’s on the edge moving instead of just one little corner. You’ve got-

Chelsea Whyte: Also days would be really weird, right? Like all of a sudden the sun would hit an entire face if it was spinning with a-

Mika McKinnon: Oh yeah. Light and time are just going to be all over the place, but also magnetic fields are going to be all over the place because they’re still going to be doughnut-shaped, and that’s going to impact things like you still have your cosmic rays moving fast every time they hit the field, they light up, it’s like effectively northern and southern lights are this, like, ‘Hey, how you doing on hardening your electrical grid? It’s really beautiful and pretty up here, we’re ready to zap you all.’

So anything poking out of the magnetic field is not protected from the zappage, which is- we’ve talked about this in terms of concerns for when the Apollo missions happened we were like, ‘Hey, you know, just so everyone’s aware, if there’s, like, a coronal mass ejection towards the moon during the Apollo missions we’re just going to have a bunch of fried astronauts up there.’ And they had, like, the emergency speech set aside and everything. So that’s everything outside the magnetic field is just, kind of, death land.

Leah Crane: Screwed.

Mika McKinnon: Yes, well, I mean, it’s, you know, you can come up with ways to protect yourself from cosmic rays, like, you can wander around in giant tanks of water, would be one way of doing it. Or lead encasements.

Chelsea Whyte: I wish you could have seen our faces. That was incredible. I want to be in a giant tank of water.

Leah Crane: Fish tank, fish tank, fish tank!

Mika McKinnon: Yes, exactly.

Chelsea Whyte: One of my deep wishes is to live in the ocean, in the deep sea, and I could just take it with me.

Mika McKinnon: Exactly, and we talk about this in terms of, like, how would we do deep space exploration of humans, well, one of the things we have to talk about is how do we keep people protected when we’re going outside our magnetic field to somewhere else. And one of the concepts is, well, maybe you could just put all the water that you need anyway, put it on the outside of the spaceship, and store it on the outside to be a beautiful shield to absorb all the ways the universe is just trying to casually kill you as you explore deep space. So, we can do that. So, think about if you want to go outside the magnetic field you have to be in your little fish bowl or, like, giant lead aprons and X-ray machine style like, ‘Hey, let’s just put on the dentist robes and go for a stroll.’ But that’s not the only problem.

Chelsea Whyte: I prefer the fish bowl.

Leah Crane: Yeah, I want to cruise around in my all-terrain fish bowl.

Chelsea Whyte: So, let’s talk about what this would look like from afar. So that means we’d have this cubed planet but each face would have like a, like a half sphere, like a little contact lens of water on it. Is that right?

Mika McKinnon: Yes.

Chelsea Whyte: And then where would the atmosphere- would the atmosphere be also in that weird dome on each face?

Mika McKinnon: Yeah, so-

Chelsea Whyte: We’re living in the dome, we’re living in the dome in our fish bowls.

Leah Crane: We would have, like, six domes but they would not be connected.

Mika McKinnon: Yeah, there’d be six little domes on six little faces and each one would be surrounding a little sea, and if you look at the size of the ocean and you look at the size of the atmosphere and how much water and how much gas we’re working with here on Earth, we’re talking about all of humanity living in a little ten kilometre fringe around each of these lakes.

Chelsea Whyte: Incredible.

Mika McKinnon: So, space is defined by how much atmosphere you have, right? Like at some point you go high enough up that you’re like, ‘There’s not enough air, I’m in space.’ It’s not very high, it’s like 200 kilometres, right? And the edges of the cube are going to be, like, 1000 kilometres outside the atmosphere. So the edges of the cube will be in space by how we currently define things.

Leah Crane: We going to have to redefine space.

Mika McKinnon: Or we redefine spaceships so they have wheels, so you have a fish tank on wheels as your new spaceship because you can leave the atmosphere of your face, go up to the edge of the world, then go across the edge of the world to go explore the next isolated little bubble, right?

Chelsea Whyte: Imagine the tourism. Imagine it. I want to go on a trek to The Edge. Capital T, capital E, in my little fish bowl rover.

Leah Crane: I can picture it perfectly.

Chelsea Whyte: But gravity wouldn’t be that strong out there, would it?

Mika McKinnon: Well, you’d be dealing with mountaineering problems. So, going to space would also be mountaineering. It’d effectively be like Everest on extreme ends because gravity’s going to keep pointing towards the centre, but the centre when you’ve got a square is at an angle. So, when you’re at the- like, if you’re in the centre of the ocean, gravity’s pointing straight down. But by the time you get to the edges of the lake or of the sea, it’s going to be at a bit of an angle and you’re going to be, kind of, constantly walking uphill or downhill. Even though the surface is flat, your gravity is not. Your gravity is at an angle and the further you get from the centre, the bigger that angle gets.

You’ve only got, like- it’s a ten kilometre fringe so you can cross the entire width of your available coastline, breathable area, in, like, a two hour stroll. I mean, walking around the lake would take longer but you’ve got a very short distance before you’re going to need your fish bowl to keep going. Your, like, little oxygen bubble inside of a fish bowl on wheels to go to space. And the further you go towards the edge, the steeper your angle is going to be. We’re going to know that the edges exist because the horizon, if you’re in the middle of the ocean, the first thing you’re going to see is going to be the corners of the cube. And you’re going to be able to see them from, like, I think the fish bowl, or the little ocean lenses are, I think about 300 kilometres across. And if you’re in them, as long as you’re within 150 kilometres of the edge, or of the coastline, so as long as you’re not in the dead centre, if you’re, like, halfway to shore, you will be able to see a corner. But it’s not until you’re within, like, ten kilometres of shore, maybe fifteen kilometres of shore, that you’ll be able to see the flat areas actually nearby. So you won’t be able to see the human-inhabited portion unless you’re almost at the coast. You’ll only be able to see these corners jagging off, that are way out there, and have no air and no inhabitation, they’re just rock. So you see, like, these mountains off to the sides.

Chelsea Whyte: Would this look like a very large mountain or would it take up more of the sky?

Mika McKinnon: So, I’ve been trying to decide on that one and I think to some extent we’re going to have to play around with some optical effects here because right, like, you could tell things were flat, one of the first places you can tell that we have a round planet is in the ocean where you’ve got these beautiful horizons going on, and you can tell what’s going on with, like, sunsets and sunrises, why we have blue skies and red skies, from how much atmosphere you’re looking through. But that all gets muddled up when you’re dealing with, like, this tiny little bubble happening. And I think that you would end up still getting your red sunsets, but they’d be really close.

Leah Crane: It seems like it would be easier to do rocket launches from cube Earth, right? Because you have all those nice corners with no atmosphere.

Mika McKinnon: Instead of having all of our space ports at the equator like we do now where we can use the earth’s rotation to, like, fling things in to space, we’d instead probably have a two-stage spacecraft where stage one would be wheels and go to the corner of the earth, and stage two would be launch from the corner into orbit. And if you’re really lucky you can also do it with the rotations happening – depending where you have the axis of the Earth, you could shape it to be able to get that little gravitational assist anyway.

Leah Crane: I wonder if we got someone with mad hops, if they could jump off the corner of the earth in to space.

Mika McKinnon: If we could do, like trampolining?

Chelsea Whyte: Yeah, I want to pogo-stick into space.

Leah Crane: Oh my god.

Mika McKinnon: And we’re still dealing with the- it’s not that much lower, unfortunately.

Chelsea Whyte: Okay.

Leah Crane: Dang.

Chelsea Whyte: But these edges would also be, like, incredible places to do a whole lot of science. Like, I’m just thinking, put all the telescopes out there, right? Outside of the atmosphere.

Mika McKinnon: Oh, yeah, you have no atmosphere going on, you could actually walk out and repair them instead of having to deal with, like, the poor Hubble space telescope just slowly disintegrating as its stabilisers- you don’t have to worry about stabilisers. You have less gravity so you don’t have to deal with the mirrors warping as much. You have really predictable light cycles happening.

Leah Crane: Super- with a sharp edge.

Mika McKinnon: Yes, and you could do things like pick a corner and have a telescope on each side of the corner to have full coverage. And they could even share, like, a little processing centre just like we do in Antarctica right now. So yeah, you could do some really cool science with that.

Leah Crane: That seems pretty rad. I will say that it seems to me, and this might not be true, Mika, we’ll need your input, but it seems like if we’re cubing Earth and then we’re going to put some telescopes and stuff on there, it does seem like earthquakes might be a problem because of how much we’ve screwed up the planet.

Mika McKinnon: Yeah, I would say there’d definitely be a lot of, like, surface level earthquakes going on during the time where everything was cooling. All the bits that we destroyed would be cooling down and crunching, and as they cooled and crunched they would contract and you’d get some earthquakes from that but they’d be, you know, relatively surface-level earthquakes. But the whole planet would be trying to relax from a cube back into a sphere so it would always be trying to have, like, the corners crumble in and the flat bits bulge out unless we’re keeping it in our mold. So you’d definitely have some fairly large earthquakes from that as it’s all just trying to sag out. So I’d recommend we come up with, like, an Earth sized pair of Spanx to shove it in. Keep it, like, forcefielded into place. Because after you go through all the effort of building a cubical planet you, kind of, want to keep it.

Chelsea Whyte: Yeah.

Leah Crane: I like the idea of shapewear but the shape is a cube.

Mika McKinnon: Look, everyone has their own aesthetic preferences, we do no shaming here.

Chelsea Whyte: Okay, we’re going to have to end it there, but we’re not done at all. We had so much more conversation with Mika that we’re coming back tomorrow with Cube Earth, Part II, the last episode of season one.

Leah Crane: We’ll get into how Cube Earth is just mega-Australia, the absolutely wild climate that’ll happen there, and the inevitable sea monsters that cubing the earth would create.

Chelsea Whyte: Thanks again to Mika McKinnon for joining us, and to all of you for listening. If you have any questions or ideas for destroying the universe, get in touch at deadplanets@newscientist.com.

Leah Crane: Or if you just want to chat about what Cube Earth would be like, you can find us on X – I’m @downhereonearth and Chelsea is @chelswhyte. Bye!

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