In the early 2000s, Phil Plait wrote his first book, Bad Astronomy, which debunked conspiracy theories and fallacies, like the idea that NASA faked the moon landings in the 1970s or that planetary alignments can affect life on Earth. Twenty years later, he’s continuing his quest to quash astronomical misconceptions while sharing his love for the cosmos. Plait, an astronomer and science writer, has spent his career sharing space news and explaining complex concepts to the public through his popular blog and newsletter, both called Bad Astronomy.
In his new book, Under Alien Skies, out today, Plait brings his usual curiosity and humor to exploring 10 fascinating spots in our solar system and beyond. Plait delves into the science—and science fiction—of these space destinations, going beyond what telescopes and space photography can tell us about these strange worlds, and what it would actually be like to visit them in person.
This conversation has been edited for length and clarity.
WIRED: I always wanted to ask you. Why do you call yourself the Bad Astronomer?
Phil Plait: It’s because when I first started writing on the web—and we’re talking 1993 here—I started writing about misconceptions in astronomy. Over time I started calling that “bad astronomy,” and somebody started calling me the “bad astronomer” on bulletin boards back then. I thought that was funny, and the name kind of stuck.
You’ve referred to yourself as a “scientific skeptic.” Can you explain what you mean by that?
Scientific skepticism—what a lot of people call “critical thinking,” which is probably better—is basically just saying: “OK, here’s a claim, and here’s the evidence for it. Does the evidence support the claim or is there more going on? Is there evidence I’m not being shown? Is the claim a logical conclusion from that evidence? Is there some way I can falsify this claim? Is there some evidence that does not support it? And is there some other idea that might do better?”
And that’s what the scientific process is. That’s something that I think is sorely needed these days. There’s so many people making claims about climate change, about vaccines, about guns. The fact that people are uncritically accepting claims made by people they trust is not a good thing.
What was your motivation for writing Under Alien Skies?
Getting people interested in astronomy is not that hard: “Look at this gorgeous picture of a galaxy. Isn’t it awesome?”
And then I started getting this question [about images from space]: “What would this look like if you were there? Sure, there’s this picture from Hubble, but if you were actually floating in space, at Saturn or next to this gas cloud, would it really look like that?”
A lot of times the answer would be, “Yeah.” If you’re floating above the moon, the view would be like what you’re seeing from these satellites. But when it comes to gas clouds and galaxies and some other things, especially now with the James Webb Space Telescope, the answer is, “No, it wouldn’t look anything like that.”
I started thinking: What would it look like if you were actually in a gas cloud? Turns out, the answer is complicated. I decided to pitch an article to Astronomy magazine, basically covering three different scenarios, and wrote it, and it was a popular article. I thought: You know, this would make a good book! And boom, just 25 years later, I decided to finally get around to writing it.
It was interesting to write down what objects would be interesting to see up close. I had this huge list and I had to pare it down to 10 for the book, because I knew nobody would want to publish a book that’s 400,000 words. That was tough.
If there’s one thing you’d want people to take away from the book, what would that be?
If there’s an overarching concept—where I’d want people to close the book and go “huh!”—it would be that these places are real. These are worlds that exist.
For the first half of the book, it’s all solar-system places that we’ve visited with spacecraft. Saturn is a real place; it’s not a dot in a telescope. But also, in the last half of the book, it’s basically imaginary planets, like an Earth-like planet orbiting two stars, like Tatooine [in Star Wars]. What would you experience there? We have a ton of Tatooine-like planets that we’ve discovered. Maybe not desert planets with lightsabers. Maybe they’re gas giants like Jupiter or whatever. But binary stars have planets. They’re out there. It’s not just science fiction; this is for real.
How did you choose the 10 locations for this ride through the cosmos?
In some cases it was easy. I mean, Saturn, c’mon.
We know a lot about the moon, but there’s a whole generation that thinks about that like how I think about World War I: It was a long time ago. They don’t know all the particulars. They may not understand what it’s like to stand on the moon. It would be fun to talk about what an eclipse would look like on the moon. I thought: Yeah, that’s pretty cool, I want to write about that. Then, we’re talking about going to Mars, so why not [write about] Mars?
I added Pluto. Not necessarily because it’s a weird place, which it absolutely is, but because it’s sort of a signpost at the edge of the solar system. When I thought about all the images we got from the New Horizons probe, I thought: If you look one way, the solar system is this way, and the rest of the galaxy is in that direction.
A globular cluster is one of my favorite objects to look at through a telescope. They’re really gorgeous. It would be ridiculous if you were inside one. Our sky would look black compared to the sky there, filled with stars.
Let’s talk about some of the other locations. Tell us what it would be like to go to a planet orbiting around a red dwarf star.
Red dwarfs at first don’t seem like they’re very interesting: They’re these stars that are half the size of the sun, they’re cool and faint. There are no red dwarfs visible to the naked eye. One of the interesting things about them is that they’re really good at making small rocky planets like Earth, but it’s hard to detect them. I just wrote about this in an article in Scientific American.
[Red dwarf] Trappist-1 was only discovered a few years ago, and then people said, “Oh, this has seven small planets orbiting it, and three of them might be at the right distance to have liquid water on the surface.” We don’t know much about these planets, although new JWST observations came back showing that the innermost planet doesn’t appear to have an atmosphere. That’s not unexpected; it’s almost skimming the surface of the star. It’s really hot.
Trappist-1 is close enough to us that a lot of the constellations would look similar [in the night sky], but a little different. [The planets] will be tidally locked, so one side always faces the star and one faces away. From different points on the planet, the star is always there, it never rises, it never sets; it’s always right there.
How concerned are you about the solar storm activity on these red dwarf stars?
The thing about red dwarfs is, even though they’re small, because of their internal structure, they have incredibly powerful magnetic fields. That’s what generates these huge storms: solar storms, flares, coronal mass ejections, these immense explosions, what we see on the sun.
These red dwarf stars do this a lot, but they tend to do that when they’re young. When they’re less than a billion years old—which I know, sounds crazy. To an astronomer, it’s a kid, an infant—they’re very active. But as they age, due to various physical things, the magnetic fields tend to shrink and the activity tends to lessen. So after 5 billion years, which is maybe how long it takes for life to develop on a planet, these stars should be relatively calm. You may still get gigantic bursts from them, and they may sterilize the planets.
But one thing we know about the universe is that it’s very diverse. So yeah, sure, a lot of these red dwarfs may be very active, but a lot of them aren’t. Trappist-1 is older than our sun, and it doesn’t appear to be that active at all. So maybe after several billion years, things will be OK.
What are your thoughts on objects like Oumuamua, that weird interstellar comet that a few people speculated might be alien in origin?
It was shocking when it was discovered. There had been hints of interstellar material passing through the solar system, but nothing concrete we could point at and go: “This is it.” And then when it was discovered, it was like “Holy crap! There’s no doubt, this thing is screaming through the solar system way faster than anything could orbit the sun.”
Everybody’s first thought was that it’s probably a comet that started way far out from the sun, way past Neptune. There’s billions of these icy bodies and they’re so far out, it’s easy to disturb them and have them drift out into the galaxy.
But then it was close to the sun and not showing a lot of activity, so [people decided] it’s probably an asteroid. And then they switched it back to maybe being a comet. And then it was discovered to be speeding up a little bit: It’s not just flying away from the sun, its velocity was changing at an unexpected rate. There was outgassing: There was ice on it that was turning into a vapor and pushing on it like a rocket. There was this idea that it might be alien debris, and that was—I’m trying to think how to phrase this politely, because it was a professional astronomer who published that—that was nonsense. That was total speculation, and in my opinion, a little bit silly. Just because something is behaving in a way you don’t expect doesn’t mean aliens built it. That’s kind of a leap we don’t want to jump to.
We haven’t exhausted all the natural possibilities. A new paper came out that basically says: It’s just frozen hydrogen. That stuff comes off. It’s extremely difficult to detect. That’s a natural thing you’d expect some of these [interstellar objects] to have, and it makes sense. So it’s not aliens. “It’s never aliens” is sort of a rule of thumb astronomers should adhere to.
Going back to the moon and Mars, there’s this perennial debate about whether to send human or robotic explorers—as in, astronauts versus probes. What are your thoughts on that?
You hear arguments from people—which are correct—that robots are cheaper. It costs a couple billion dollars to launch a probe to Mars. If you send humans, humans need to eat and breathe and poop, and that’s inconvenient. We have a lot of baggage, literally. To go to Mars, we have to bring all this stuff with us, and a lot of that technology isn’t well developed yet. And even if it were, it’s still really expensive. And that’s not to mention the radiation issues: It takes months to get to Mars, and if the sun decides to flare, that could be a problem. You don’t want to deliver a bunch of corpses to the planet.
For me, the question should be: What is it we’re trying to do here? Are we interested in exploring the science of Mars? Do we want to know what its surface looks like, how its atmosphere behaves, what the interior is like? Yeah, robots can do that pretty well.
On the other hand, maybe your goal is to explore the solar system in a first-person sense and to get people really excited about this exploration. People get excited about these rovers and orbiters and space telescopes we send up, but there was never a moment like Neil Armstrong stepping on the moon. If that’s what you’re trying to do, you’ve got to send humans. NASA has this old expression: “No bucks without Buck Rogers.” You need to have people doing these sorts of things.
If your goal is to set up a human base on the moon or Mars and eventually develop that into its own self-sustaining civilization, then you’ve got to be clear about that, and that’s something NASA hasn’t been doing until recently. I think the new mission, Artemis, will do that better than Apollo did. Apollo was always: Get there to win, beat the Soviets. Now it’s more like: Let’s go there, let’s do this piece by piece, let’s do it the smart way, develop the technology, make sure we’ll go there to stay.
I’m OK with it, because honestly, even if this costs $100 billion, that’s not a lot of money. NASA’s budget of $25 billion or so is a half a percent of our national budget. It’s less than we’ve spent on a bunch of fighter jets that the military doesn’t even want. What the Pentagon loses in a few days would be enough to fund NASA for a long time.
If you were to make a prediction of what human exploration of Mars might look like 50 years from now, what do you think it could or should look like?
I’m glad you added that, because people ask me sometimes: “What do you predict?” Well, I don’t predict anything because that’s a bad bet. The political tides can shift like that, tossing your plans into the trash can. Fifty years from now, I have no idea.
If you project from where we are now, SpaceX is about to test their gigantic Starship rocket, which could take 100 people at a time to space, and you could launch 10 of these things for how much it would cost to launch NASA’s Space Launch System rocket. You could launch five of them just [carrying] fuel to orbit the Earth, and then you could launch five more to refuel [from these orbiting depots] and then go wherever you want. It seems like sending people to the moon is going to get a lot easier, and sending them to Mars becomes possible.
In 50 years, you could have more than one scientific base on Mars, and people living on the moon, in the sort of scenarios in my book. On the other hand, the 2024 election could go the wrong way, and everything falls apart, and the Earth will be a smoking ruin in the year 2073.
If you could visit any place in the solar system or in the cosmos, which one would it be? Or is there a place that you would say that has been underexplored?
If I could go anyplace, it would be Saturn, and I think I make that fairly clear in that chapter!
But a place that’s underexplored, my first thought would be Uranus and Neptune. We’ve only had flybys of them, and these probes shot past them at high speed and [people] basically said: “Here’s 5,000 things now we don’t know about these planets.” And we won’t until we go back there and orbit them to see what’s going on. There’s a lot of talk about that in astronomy right now, that we want a big flagship mission to go to these planets.
And then I think Venus. It’s this planet that’s the same size as Earth, has roughly the same composition, and yet couldn’t be more wildly different. Why? What happened to Venus? It’s not just the thick atmosphere and the broiling temperature on the surface. The structure of the surface is very different than Earth, and we don’t know why. We’ve sent probes and some landers, these Soviet tanks that have landed on the surface and basically melted after a few hours. But we just don’t understand this planet at all.
What would you imagine a possible encounter or communication with alien life to be like? Might it be like something in Carl Sagan’s Contact?
The way the science works out, if there’s life in space—and I strongly suspect there is—the vast majority of it is going to be what we would think of as simple life forms: single-celled algae and yeast and stuff like that covering these planets. That’s simply because, if you look at Earth, for 4.5 billion years, for most of that time, life was very simple. It didn’t start to become more complex until about a billion years ago. So just by statistics, three quarters of the planets out there, if they’re about 5 billion years old like Earth is, you’re just going to find goo on the planet. You’re not going to find aliens like us. That kind of life can’t contact us.
Humans have only been around for 200 years, technologically. We’ve been on this planet for 200,000; [it’s] only for the past couple hundred, maybe one hundred, we’ve been able to maybe communicate with life on other planets. One would expect that—if we don’t blow ourselves up or pollute our planet or whatever, if humanity lasts for a long time—we’ll become more advanced. So if there’s intelligent life in the galaxy. The odds are, they’ll be hugely more advanced than us. That’s why in Contact, the aliens were so beyond us that we could barely comprehend them. So if they’re interested in talking to us, it’s probably going to be them knocking on our door, which is kind of what happened in Contact. They waited for us to get to a certain point, detected that, and then said, “OK, we’re going to send you this message.” That’s science fiction, but I think it’s going to be like that.
The other aspect of this is, if they want to contact other species, if they want to explore the galaxy, the cheapest way to do that is sending out robots which can then land on a planet, build more of themselves, and then launch them to other planets. So honestly I think that may be the way first contact will be: We’ll see a probe coming into our solar system, a robotic probe from another civilization. That would certainly be cool, scary, and interesting.
