Zach Weinersmith
Appearances
Short Wave
Should Humans Live On Mars?
How do you govern these communities? So like whenever someone talks about going to Mars on like Twitter, they post a gif of a guy walking toward the horizon dramatically. But most of life in the International Space Station is like scrubbing the toilets. and making sure there's not too much mold and cooking dinner and that sort of thing and managing interpersonal relationships.
Short Wave
Should Humans Live On Mars?
It's a lot like Earth. And so we need to have the solutions we have on Earth.
Short Wave
Should Humans Live On Mars?
Sure. So, you know, when you're in an orbital space station, you are under the influence of Earth's gravity, but you experience, like on a roller coaster, zero gravity. This reliably produces all sorts of terrible stuff for the body. The obvious stuff is loss of bone mass, which happens at a very rapid clip. Studies show about 1% bone loss in the hip per month. I want to emphasize per month.
Short Wave
Should Humans Live On Mars?
You may ask yourself why we don't turn into like Harry Potter when the bones got dissolved and no one has been up for more than 437 days. That was the maximum time. Only a few people have been up for a year. Muscles experience very similar effects. People often get motion sick right when they get up.
Short Wave
Should Humans Live On Mars?
They also lose what's called the baro reflex, which is that thing where you go from lying down to standing up and you get a little dizzy. That can happen in space so that when you get back to Earth... It's considered very impressive if you can merely walk after a few months. More subtle effects are things like higher rates of certain bacterial infections that we don't experience on Earth.
Short Wave
Should Humans Live On Mars?
Might be due to stress, might be due to the zero gravity allowing bacteria to just kind of float around. And then somewhat especially worryingly is that you reliably experience vision loss, and we don't know why. And this happens even on short trips. The best version of this is that we lose some vision and you have to send up what are called space adjustment goggles or glasses rather.
Short Wave
Should Humans Live On Mars?
The scary version is that there's some broader nerve damage that we don't understand yet that could cause cognitive effects if people were up in space longer.
Short Wave
Should Humans Live On Mars?
That's exactly right. Yeah. And that's important. So there's some world in which 40% Mars gravity makes things just fine. Like one of the things we worry about is having babies in space and zero gravity. You try to imagine like kids not developing bones normally, maybe 40% gravity is enough to make the body work out.
Short Wave
Should Humans Live On Mars?
Or maybe there's even some world in which you wear like a weighted suit and that's enough to handle it. But we don't know is the problem.
Short Wave
Should Humans Live On Mars?
Yeah. Often when this question comes up, if it comes up at all, it's like, can you have a baby in space? And the answer might well be yes. A bigger, trickier part is, can they develop to an age where they can have babies? Can they go through all the stages of development in this foreign environment? Gestation, birth, becoming teenagers, all this stuff.
Short Wave
Should Humans Live On Mars?
You know, Kelly mentioned the perchlorates on the surface, they disrupt hormones. Yeah. Right? And there's a bunch of subtle stuff that we haven't got into. Like, if you go to the ISS... The atmosphere is very high in carbon dioxide, orders of magnitude more than on Earth. We can tolerate it, but astronauts often complain of headaches.
Short Wave
Should Humans Live On Mars?
Many other chemicals are going to be at different concentrations than we have on Earth. This is the tip of the iceberg. You may have the idea that space stations are kind of like organized projects for answering questions, and they aren't. They're done for political reasons, and scientists get to throw experiments at them. So we have like a grab bag of experiments on reproduction in space.
Short Wave
Should Humans Live On Mars?
Some invertebrates, some vertebrates, a very small number of like rodent studies, nothing even close to human. And what we really need is like a generational study on vertebrate mammals in these environments. And it doesn't exist.
Short Wave
Should Humans Live On Mars?
Could I add one thing to that real quick? Yeah. We should have put a pin in earlier, which is most of the people who have ever been to space are middle-aged men, overwhelmingly. So when we say we know X, Y, and Z about bodies in space, we are mostly talking about middle-aged men from the U.S. and Russia.
Short Wave
Should Humans Live On Mars?
Certainly we know nothing about babies or teenagers, but even like the data on women is quite limited. Women were not allowed into the US program until 1978. Russia technically flew women earlier twice. To this day, it's something like 10% of all people who've been to space are women.
Short Wave
Should Humans Live On Mars?
So, you know, we can say we have this kind of data on bodies, but most of the bodies are bodies like mine, middle-aged men, except their bodies are a little more fit maybe. But so like there's very basic data we're still missing.
Short Wave
Should Humans Live On Mars?
You know, the way we like to say this is that there is no plan B. Elon Musk might want to put on a cowboy hat and fly off to Mars and start his Martian city and leave this polluted planet behind to its wars and devastation. And if he thinks that, he is a fool because Mars is so bad, you could not, for $10 trillion, make Earth as bad as Mars.
Short Wave
Should Humans Live On Mars?
You could zap us with asteroids and unleash every disease you can imagine and start a couple nuclear wars. It's still not even close. That's how desolated everywhere else in the solar system is. So we have to make it work here. It doesn't matter if you love it or hate it. This is the only option, and it will be that way for a very long time.
Short Wave
Should Humans Live On Mars?
The moon, Mars, we're creating an orbital space station. And among those, Mars is overwhelmingly the best option.
Short Wave
Should Humans Live On Mars?
She's a biologist and science writer. And she and her partner, Zach Wienersmith, spent four years researching space settlement for a book called City on Mars. And in it, they get into everything it would take to do this. They talk about the key real estate.
Short Wave
Should Humans Live On Mars?
So today on the show, we do a little thought experiment. What would it really take for humans to live in space, and specifically on Mars? Can we do it in our lifetimes? And more importantly, should we? I'm Regina Barber, and you're listening to Shortwave, the science podcast from NPR.
Short Wave
Should Humans Live On Mars?
Okay, so it feels like people's settlement obsession is mostly focused on Mars. Why is Mars the big candidate?
Short Wave
Should Humans Live On Mars?
Okay, let's start with the first hurdle, which is like keeping people alive in space for a significant amount of time. The longest someone has been in space is like just over a year. That's not a lot of data for us to have for long-term effects of people in space. What do we know about the dangers of living outside of Earth's protective magnetic field, like on the human body?
Short Wave
Should Humans Live On Mars?
So there's a sci-fi fantasy that, as an astrophysicist and a Trekkie, I've been watching percolate all my life. And in the last decade, it feels like it's become more than fantasy.
Short Wave
Should Humans Live On Mars?
Right. But this is, you know, a different acceleration due to gravity in space. orbit versus on Mars.
Short Wave
Should Humans Live On Mars?
Let's talk about radiation. So like when we have, you know, the ISS, we have some amount of protection from the magnetosphere of Earth. But now we go to Mars or even the travel to Mars, that protection is gone. So what does that mean for settlements outside of Earth?
Short Wave
Should Humans Live On Mars?
Another question beyond the mold people. Like, what do we know about how people eat? Like, how are they going to get enough food? Are they going to produce that food?
Short Wave
Should Humans Live On Mars?
Wow. Let's talk about babies because you've brought it up a few times. Let's say we can keep somebody alive for 20 plus years on the surface of Mars. Then we see them possibly reproducing.
Short Wave
Should Humans Live On Mars?
And like speaking of like very basic data missing, we haven't even talked about the issues with like child development. Like you were saying that there's this bone loss in space. And is that going to be a huge concern with babies?
Short Wave
Should Humans Live On Mars?
How has working on this book changed your attitude towards Earth? If it has...
Short Wave
Should Humans Live On Mars?
But I've always wondered, what would a space colony actually look like?
Short Wave
Should Humans Live On Mars?
Kelly, Zach, thank you so much for talking with me about if we could live on Mars. Thank you for having us.
Short Wave
Should Humans Live On Mars?
This episode was produced by Jessica Young. It was edited by our showrunner, Rebecca Ramirez, and the facts were checked by Tyler Jones. The audio engineer was Gilly Moon. Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Shortwave from NPR.