Can food grow on Mars?
This post is edited from an episode of the Is That True? Podcast, where host Arionne fact-checks different kid facts and questions. Today’s episode talks about growing potatoes on Mars, a fact submitted by Anaya.
Arionne: Today’s fact is out-of-this-world. Seriously, it’s really that good!
Anaya: Hi. My name is Anaya (Uh-Nay-Ah) Griffith and I am 8 years old and I’m from Oregon.
Did you know that potatoes can grow on Mars?
Arionne: Potatoes? On Mars? Wow, Anaya. I honestly have no idea.
It’s been a while since I learned about Mars in school. I was probably as young as many of you! And because science is always working on learning new things, I can assume that there is a lot of new research about Mars that I don’t know. Some things could even be different.
When we think about facts and what is true, things change. And sometimes, they change a lot. When it comes to astronomy, the study of space, this is very true. The more we can go explore, the more we learn.
Just think about the number of planets. When I was in school in the 1990s, we were taught that there were NINE planets in our solar system. And at the time, that was thought to be true. It was based on what we knew and what the science of that time could tell us.
But in 2006, things changed. The International Astronomical Union, which is this huge group of really smart people in astronomy, said that Pluto should not be considered a planet, but something called a “dwarf planet.” So now, our facts are different: We have EIGHT planets in our solar system.
It’s important to always get the most up-to-date information about space. So, I looked for an expert who studies it. And I found the perfect person!
Voula: So, hi, my name is Voula Saridakis, and I'm a curator at the Museum of Science and Industry in Chicago. And I'm part of a team at the museum that takes care of thousands of artifacts, some of which are. A hundred or even 200 years old and I helped put exhibits together. And I'm also historian of astronomy and space history, which means that I learned a lot about space and the history of space flight after college.
Arionne: That is so cool. Can you tell us about how did you get into this?
Voula: I always loved space when I was a little girl. I remember the first thing I saw, I think I was in third grade, was a book about the planets in the solar system. And that really made me so excited to learn more about space. And then I was watching film clips of Apollo missions that were landing on the moon.
And it was just so exciting that I knew this is what I wanted to study, and this is what I wanted to do.
Arionne: Ah, I love that. So of course you are the perfect person to help us see if this fact is true. So, is it true that potatoes can grow on Mars?
Voula: Well, the short answer to that question is yes, we should be able to, under the right conditions; which actually have a lot to do with something called habitability.
Arionne: Oh, wow. Wow. So what does habitability mean?
Voula: Research groups around the world are exploring this thing called habitability. We also study it here on earth and that means too.
Degree or extent, can we inhabit other worlds, not just Mars, but the moon or other planets in the system, solar system and even beyond. So in addition to how much oxygen or atmosphere exists on these other worlds, this would determine how much or little we can breathe and the technology needed to help us breathe.
But there's another really important aspect of habitability. Which has to do with food and water. So if we started long-term colonies on Mars, we really couldn't bring enough food and water onto our spaceships because they just simply wouldn't last long enough. But if we could find ways to create food and water on these other worlds and make them sustainable, then that would make it much more likely that we would be able to not only travel there, but also create inhabitable costs.
Arionne: Ah, got it. So that is kind of what would need to happen so that we could live there. And so, although we have not grown potatoes on Mars, we are trying to figure out how we could, and we think that we can.
Voula: Yeah, absolutely. So for anyone who might've seen the movie The Martian, you might have some idea of how to grow potatoes on Mars. Now in the movie, and it's based on a book, an astronaut becomes stranded on Mars and to keep himself alive, he starts growing potatoes.
So in the movie, we see him, you know, using Martian soil, but you still need fertilizer. And the only organic material fertilizer available to him is human waste. Now that can be dangerous because human waste carries bacteria and other pathogens, we call them, that could make us really, really sick.
But in the middle [of the movie], he freeze dries and exposes this human waste to sub-zero temperatures on Mars. And that way you wind up killing off anything harmful. He kills off anything harmful to himself, but there is another potential problem. Now, Martian soil contains a group of chemical compounds. Perchlorates which are in fact toxic to humans, but scientists think that we can get beyond this problem.
If we soak Martian soil in water and we wash it. So the idea is that the toxins would wash away and then you could eat potatoes, or anything for that matter, grown on Martian soil, but this has to be tested first. Now potatoes also love the sun and they need to be planted somewhere with plenty of sun, which is a problem on Mars because as we already know, Mars is further from the sun than earth.
Arionne: And one important thing scientists are studying on Mars: gravity! You know, the thing that helps pull us toward the ground so we don’t float away.
And finally, there is the issue of gravity. So Mars is only one third of Earth's gravity. So the question is can plants with roots that grow down into an inch of the ground, grow down into the marsh and ground?
If there's so little gravity and tests have been done on the international space station that showed that plants can still grow vertically in space. And they do this because they have a hormone called auxin, a-u-x-i-n, that helps them do exactly that. So we can also use special machines here on Earth to test plants with a simulated Martian gravity.
And so these tests suggest that Mars’s gravity is not an issue or should not be an issue. But again, you know, just like, uh, with the temperatures, this has to be tested on Mars to be absolutely positive.
Arionne: And what other work is being done to test habitability on Mars?
Voula: Sure. Recently, the latest Mars Rover Perseverance or Percy, we call it land, which landed on Mars this past February.
Is also performing some really important tests and experiments that will eventually help us learn more about habitability on Mars. So perseverance is the first mission to, uh, designed to see. Signs of past microbial life by collecting rock and soil samples that will actually one day be returned to earth.
And Percy we'll also look for just evidence that there was once a possibility of life and a possibility of water. And finally it has a special experiment, equipment on board that is going to try to convert carbon dioxide into oxygen, which is something that we would need to breathe.
So all of this is designed to help us learn more about the planet.
Arionne: So, Dr. Saridakis was our perfect expert for this fact because she loves space history and astronomy and space flight. And if you do too, there are TONS of ways you could work in this industry when you grow up.
Voula: There's so many opportunities when you grow up, what you are able to do in the space industry.
It's great to be an astronaut. A lot of people think, you know, the first thing they think about is, Hey, I want to be an astronaut. And if that's what you want to be, that's great. And I say, go for it. But there's so many other ways you can contribute to our understanding of space and the future travel to space, whether it's travel by humans or even robotic probes.
So then an astronaut, if you want to be an astronaut, or you can also be a biologist. You could be an engineer, a geologist, an astronomer over a bot, or assist a technician. You could even be a space journalist if you want it to. So really a whole universe of options out there, and maybe even one day you'll be testing those first Mars soil samples that will be coming back to earth from the Perseverance.
Arionne: Wow. I love that. Maybe it is time for a career change because a space journalist sounds like an amazing opportunity. Right? Thank you so much. We are just so happy to have you today.
Voula: Thank you. Thank you. It's been a pleasure.