A theoretical astrophysicist by training, Ethan left a promising research career in cosmology and a job as a physics and astronomy professor to focus on science communication full-time. He revels in telling scientifically accurate, beautifully illustrated stories about the Universe with the widest audience possible. He believes this Universe is the one thing we all have in common, and knowing our shared cosmic story should be for absolutely everyone, regardless of age, gender, race, religion, nationality, sexuality, educational and economic background, or any other trait.
I met Ethan Siegel in 2015 at Midsouth Con in Memphis. I was walking through the halls and I see Zangeif and Chun Li rocking different fighting poses for the cameras. Fast forward a few hours and I find myself in a science panel. Here comes Zangeif taking a chair at the head of the table to lead the discussion on astrophysics, in his tiny red shorts. It was then that I thought, I have to be friends with this dude. And that friendship has been richly rewarding. Ethan is incredibly smart, loving, and funny. He is always ready to share information, talk space shop, and is so talented at discussing subjects that may go over your head in a down to earth manner. He is also fun at any type of game table, bringing smiles and jokes, enriching any environment he is in.
For this issue of the Saga, I sat down with Ethan over a beer and an energy drink and we just jumped right into multiple universes and our wild game worlds. Below are select parts of our conversation about life, universes, and everything.
Interview with Ethan Siegel
So let’s set the stage for our fantastical conversation with the real world first. What scientific evidence is there for parallel or other universes? And does that come into play at all at your table?
All right, so let me answer the second question first. The way I try to set things up is, there are going to be rules to how this thing works. And whatever the rules we set are, I want to make sure that they’re self consistent. Whatever we’re doing, I don’t want to have rules that change in the middle of the game. So whatever we’re going to set up, those are the rules. So, for example, our world, we don’t have a moon in the sky. So when it’s night, you can see the abyss of stars, but it’s also really dark. And this, I discovered, puts all the humans at a disadvantage because humans suck at seeing in the dark in a way that all the other species don’t. And so that’s fine, that’s just a part of the game. But that also means all the NPC humans struggle at night. And then you have things like, okay, so those are the rules you set up. And part of what we have is we know that there are orbs, these big black orbs that can be smashed because they smashed one that pretty much tie the worlds together or sever the connections and keep them apart.
I try to keep things rooted in physics, like there are seasons, there were years, they have a continent and oceans, and presumably beyond their continent that they know about there is more unexplored world out there. Maybe the world you game in is on a different continent on the same world that I game in. I don’t know. But one of the things that I think about when I think about parallel worlds and parallel universes is we know that there’s a lot of universe out there beyond our own Galaxy and we know beyond the limit of the universe that we can see. There’s almost definitely more unobservable universe, and we only have a lower limit on how far that goes on. It could go on for millions or billions or trillions or many orders of magnitude more of the volume that we have. So even though we think there are like 2 trillion galaxies in our universe, who knows how many zeros there are in the big unobservable universe? And then if you go even beyond that, because we have this theory for how the universe was created, about what came before the Big Bang.
And the way that theory works is it predicts. Hey, here are a whole bunch of wild consequences that you wouldn’t get if you just had the one Big Bang, and that’s the start of everything. And believe it or not, there are a few things that we can go and observe in the real universe that we live in to see is the Big Bang without this thing we call cosmic inflation. Does that give you correct predictions, or do you need cosmic inflation to precede and set up the Big Bang? And we’ve actually made four separate tests of things where we’ve been able to go out and measure. Is it like the Big Bang with no inflation, or is it where inflation goes and sets up and makes the Big Bang happen? And in all four of the ones we’ve been able to measure decisively, the one with inflation matches what we see, and the one without it doesn’t, which is very exciting because inflation predicts. Hey, if you start having this space that’s undergoing inflation, then what it’s going to do is it’s going to periodically pop off these giant universes that start with their own hot Big Bang, but all these different universes are going to be separated from each other.
It’s like if you imagine this expanding sea of bubbles, but the bubbles never collide. The bubbles only get pushed apart. So our universe, we think, is one of those bubbles. And I am certain if this is the correct story, then there are other Big Bangs and other universes that arose from them out there. We don’t know how similar or different they are to our own. We don’t know if you can travel between them somehow. But if you want to fold that into the mythology of your world, there are some physical reasons to suspect maybe the answer isn’t no. Maybe it’s possible. I don’t think that it’s likely that it’s exactly the way I’ve set it up (in my game). I think there are probably more than four universes out there, and I think that it’s probably not connected in the way. Like, oh, yeah, this one made all the living things in this world, and then when things die, they go to this other one. But there are a lot of unknown unknowns to get a little Rumsfeldian on you. And so maybe it’s possible.
What amazes me is the way you’re describing this, because there was an old D&D setting called Spelljammer (which they just recently announced they’re putting out a book for coming up this year). And the idea there is that all the different D&D universes are in Crystal Spheres, and you break through that sphere and go through the phlogiston, which is like, I believe, a medieval belief system of what binds the universe.
Oh! Phlogiston was what they thought made fire work before they discovered oxygen. They thought that instead of combustion taking place because oxygen combines with heat to release energy, they thought that everything contains phlogiston. And when you run out of phlogiston, your fire goes out.
Well, in D&D, they went with that old belief, so when you go between Crystal spheres you can’t have any flames because the phlogiston will explode around you. And for D&D it was a way to say, “oh, you can go from Dragonlance to Forgotten Realms”. But it is interesting that their idea has echoes in the real world. Now, the Crystal Sphere was much smaller than a whole universe, but just the wording there with the bubble and the Crystal sphere. That’s great how that lines up. And what a great fictional way of dealing with this topic. We want people to travel between these worlds and this is how we do it.
Yeah. I also don’t know how much of a role technology plays in your campaign, but in my campaign there is all of this technology in addition to magic. And so you have a bunch of non spellcasters people who don’t use magic, who just rely on technology. And there’s also something and this is like a spoiler, I guess. Hopefully none of my players are (reading) this. There is a special property that one hybrid species possesses that dwarfs and humans, when they have offspring, they can make half dwarves. So in the way I’ve developed it, dwarves and humans are from the same world and elves and elflings are from the same world. So elves and elflings can mate and produce offspring and humans and dwarves can mate and produce offspring, but not the other combinations. But when you have a half dwarf, half dwarves have this special, I’ll say power, that they can lock magic so that no magic can be used in a certain region around them. And there is a half dwarf city that is hidden that they have not been able to find because my players keep only trying to use magic to find it.
And magic is locked so it doesn’t work. And so I think it’s kind of funny because they’re all like, hey, what’s that big thing on the map over there? How come when we go there we can’t see anything? Maybe they’ll figure it out at some point, but it’s sort of that beauty of having a bigger open world.
So now I have to ask, in fiction, which one of the inter-dimensional or interstellar travel is your favorite? Warp speed, hyperspace, folding space, or a Stargate? Which one of those either captures your fictional love the most or makes you say, “oh, well, maybe we can actually do this.”
Well, the one that’s been worked on the most physically is Warp drive. Warp drive tends to be like, my go to, because I really like the idea of you make this stable thing around your ship so you can travel through it, and then you compress the space in front of you while expanding and rarefying the space behind you, and then you can move through that compressed space, and that’s how you can cheat the speed of light and beat it. And there’s actually been some physics work on that theoretically where people have worked out, oh, here’s how you do it. Here are the ingredients you’d need. So we don’t know that our universe has all of those ingredients that we need, but it’s at least plausible. I also like the idea. Just like, if you take a sheet of paper and you connect two points to one another, you can imagine, well, instead of getting from A to B by traveling along the paper, I can just poke through and instantly go from here to here. I like that from a mathematics point of view, but I’m also happy to go along with whatever system we’re working on.
If you just have a pirate ship that travels through space— because why wouldn’t it? — then that’s what we got, and that’s great. We’ll have a good time with it.
Definitely. A fun thing I’ve enjoyed in our gaming is that you’ve always taken up whatever’s put in front of you and said, all right, let’s do it. That leads into another question I’ve got. I have a professor who did a lot of research on the origins of the vampire myth, but he was completely, constantly sidetracked in his research because there’s been so much RPG stuff that is written so well in depth that he would be researching it and realize that it was just fiction for gaming. With so much popular media like Marvel with the multiverse and all these other fictional depictions of other planes of existence coming out these days, do you think that makes it harder for your job with hard science and research, because people get so informed with these fictions?
In my real life, where I’m a scientist trying to communicate science to the general public, yeah. I actually think all the way back to the Peanuts comic strip, because I remember this page, where Lucy is teaching Linus, the boy with the blanket. Like her little brother, she’s teaching him that when he puts sunglasses on, he causes the sun to eclipse. And that if you put your sunglasses on, then you see the sun is eclipsing. And if you take your sunglasses off, the eclipse is over. And the other characters are like, oh, poor Linus. He is going to have to go to school twice as long as everyone else because he’s going to have to unlearn all the stuff that Lucy taught him. And that’s kind of how I feel about some people, is they come to me with not just like, “I want to know what’s up and what’s true and what’s out there.”
They come with these misconceptions that you have to undo before you can teach them the actual correct thing, but in a way that’s not really a bug. That’s just a feature, because that’s how we work. We as humans, we try to make sense of the world. And if the world doesn’t make sense to us, we’re going to craft a narrative for ourselves where it does make sense, even if that narrative is wrong. So it makes my job harder. But I can’t fault people for being human. So I will just say, yeah, it comes with the territory. I decided that this was the route I was going to go with my life, and that means necessarily, this is a challenge I’m taking on.
So it looks like we got about three minutes left before our time is up. So final question, what would make your spirit sing to explore when it comes to other planes of existence at your tabletop?
Oh, boy. So, some of the things that they haven’t explored yet is there is an ice dragon ritual where they know it’s related to the dwarves and it’s related to cheese, the food. And they know that once a year, the ice dragon wakes up and he flies towards some island that’s in the west. And then from there, it’s almost like it just flies off into space. So there’s the potential to have things open up in that direction. They know that there are forbidden lands to the north, that when they sail to, they can see a tip of a new land at the edge of their map. They know there’s something to the east through the mountains. It’s radioactive, but they haven’t gotten there yet. And they also know that to the south there is an island, a solitary island inhabited by one person. And that person’s name is Island Joe, also known as Joe of the island. I think all of these things have the potential to be gateways to, let’s just say new adventures. And I’m open to these adventures that can take them wherever their imaginations do. And mine, too.
Thanks for talking with me tonight and I’m sure I’ll have some more questions in the future about universes and other cool science things that I’ll be coming to you for answers.
Well, the most important thing is that the saga continues.