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Space scientist and astrobiologist Erika DeBenedictis joins WIRED to answer the internet's burning questions about The Red Planet.
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00:00I'm Erika DeBenedictis, a space scientist and astrobiologist.
00:04I'm here today to answer your questions from the internet. This is Mars Support.
00:13Second Fret asks, why is Mars red if not for the devil's light?
00:18Explain that, science. Mars is red for the really simple reason that it's basically rusty.
00:23So it has metals that make it look red. It's not because of the devil's light, nor is it because
00:31it's too hot.
00:32Sometimes I've heard that. People think Mars is red because it's literally boiling or something like that.
00:37Mars is cold and rusty, and that's why it looks red.
00:41Big Booty Bear asks, why did Elon Musk say you can only depart to Mars once every two years?
00:48Mars and Earth both orbit the sun, and that means that they're different distances apart from one another at different
00:55times.
00:56So here's Earth and here's Mars. Earth orbits close to the sun pretty quickly.
01:01Mars is farther away, and it orbits the sun more slowly because it has more distance to go.
01:08That's why a Mars year is two Earth years. It takes Mars twice as long to get all the way
01:15around the sun relative to Earth.
01:18So you want to go between Earth and Mars when they're closest together,
01:22rather than when Earth and Mars are on opposite sides of the sun.
01:27Fundamentally, that difference in the length of the year is where this idea of launch windows comes from.
01:36Timothy Dooner asks, how realistic were the crop growing scenes in The Martian?
01:42The Martian is such a good movie. It was also a great book.
01:45I really like The Martian, and in general, with just a couple exceptions, both a fun and pretty realistic depiction
01:51of what it might be like to be trapped unexpectedly on Mars.
01:56There's a famous scene where the main character realizes that maybe he could grow potatoes to keep himself alive and
02:02wait for rescue.
02:03And so he mixes Mars regolith, the dirt, with his own poop to fertilize it, and he grows potatoes.
02:12It's very close to correct with one big problem.
02:17At the time that The Martian, the book, was written, we didn't know about the toxin that is in Mars
02:24dirt called perchlorate.
02:25Chemically really similar to bleach, which you probably have in your house because it kills things.
02:30Like, you use it to sterilize stuff.
02:32Had he eaten those potatoes, he would have died because it would have killed his thyroid.
02:38It's ever so slightly wrong.
02:46Terraforming refers to this idea that we might be able to take somewhere else in the universe,
02:51some other planet, and make it more like Earth, gentler conditions, more amenable to supporting life.
02:59A bunch of changes in new technology mean that big parts of terraforming Mars might happen way faster than you
03:08might expect.
03:09Mars might be green in our lifetime, so it could be covered with a complex ecosystem of mostly plant life,
03:17doing photosynthesis, making oxygen, and evolving.
03:21Russian Roulette Time asks, any scientific inaccuracies in The Martian?
03:26Maybe one nitpick.
03:28There's a scene where there's a big storm that, like, causes a rocket to, like, vibrate because of the wind.
03:35That's not a thing.
03:37Mars has really, really low pressure.
03:41Although the wind speeds can be very high, the air is just so thin that it doesn't pack a punch.
03:47Um, Bertha Coombs asks, question for literal rocket scientists, how long is the trip to Mars,
03:54and how will we ever have enough energy fuel to get people back to Earth?
03:59This is a great question, and the challenge of sending people to Mars and bringing them back,
04:05that second part, is so hard.
04:08That is the reason why we haven't gone to Mars.
04:11We barely have the technology to bring people back.
04:14Getting there, in the very best case scenario, takes six months.
04:18Consider that when you go to Mars, you get to launch from Earth with fresh humans who are perfectly healthy.
04:25You get to launch with a rocket that you got to tune up with all of your equipment.
04:30You get to fuel it with rocket fuel that you made with all of our wonderful industry we have on
04:35Earth.
04:35When you launch from Mars, you have none of that.
04:37You have people who might be less healthy.
04:41You have a rocket that has now been reused once with very few tools to fix it.
04:45And the hardest part is the fuel.
04:48It's very hard to either bring enough rocket fuel to Mars to come back or to make it on site.
04:54The crux of the challenge is how to enable that return trip,
04:57which is so much harder than getting there.
05:01Bastalim asks, why are there mountains on Mars that are much higher than the highest mountains
05:07on other planets in the solar system?
05:09Mars does have really tall mountains. Famously, it has a mountain called Olympus Mons,
05:15which is this really big shield volcano, more than twice as tall as Everest on Earth.
05:21There's a combination of reasons. One reason is that unlike on Earth, where we have tectonic plates,
05:29so all the continents are kind of floating on top of this magma soup.
05:33And that means that when you have a volcano, the spot that it erupts will move.
05:37That's why Hawaii is a chain. That's one volcano that kept erupting and made this chain.
05:43On Mars, that wouldn't happen. There aren't tectonic plates.
05:46And so that volcano would just stay in the same spot and keep erupting and keep getting taller
05:52and taller and taller. And on top of that, because Mars has somewhat less gravity,
05:57you can like stack rocks kind of higher. And so together, Mars ends up with really tall mountains.
06:03Maki J. Fran 93290 says, does Mars have seasons? Yes, Mars has seasons. It also has different
06:12locations on the planet that have different climates, same as Earth. In the middle of the day,
06:18at the equator, during summer, the temperature could be 50 degrees Fahrenheit. So a little chilly,
06:24but you just need a jacket. Like it's not that cold. But at night, things cool off really fast. It
06:30could get
06:30down to negative 100 Fahrenheit. It gets even colder during the winter. On the edge of the ice cap,
06:36it can get down to negative 200 Fahrenheit. Corrupt Boomerang asks, why is everyone obsessed
06:44with colonizing Mars? In a word, curiosity. Humans are explorers. We like to push the limits of what's
06:51possible and learn about the world we live in. Of places in our solar system, Mars is in many ways,
06:59the most intriguing target. It's a place that a long time ago looked like Earth. It has all the
07:06essentials that are needed for life. Today, it's very hostile, but perhaps with technology,
07:12we could make it a really nice place to live. Manria4 asks, what happened to that water on Mars? Are
07:19we
07:19going to do anything with that or what? It's actually a common misconception that Mars doesn't
07:24have water at all. Mars has a ton of water. It's just locked up as ice just beneath the surface.
07:31So
07:32most of the whole northern hemisphere of Mars is permafrost, meaning it has like a really thin layer
07:38of dirt dust that makes it look like a desert. But if you scrape down, and one of the rovers
07:44did this,
07:44if you scrape down just a tiny bit, there's ice just below the surface. Benhansen00 asks,
07:52what kind of batteries do the Mars rovers use? That's what I want to power my cell phone for 13
07:58years.
07:58Christmas gift ideas. All of the modern Mars rovers actually use lithium ion batteries just like your
08:05phone. The difference is they have like a built-in solar panel that they use every day to recharge. The
08:12solar panels can last actually way longer than NASA thought they would. So famously, Spirit and
08:20Opportunity were originally scheduled to have like 90-day missions because NASA thought that their
08:27solar panels would fail after 90 days. The thought was they would like basically get covered with dust
08:33and they would stop working. And instead, it turns out that the dust would settle on the solar panels,
08:40but sometimes it would also get cleaned off of the solar panels. And so instead of lasting three
08:45months, these rovers lasted years. And NASA had to appropriate like more funding to fund scientists
08:52to like run these rovers for years longer than they thought they would work. Weston B Dev asks,
09:00wait, how are humans going to breathe on Mars? Has anyone considered this NASA? All caps.
09:06Yes, this is a big area of research. NASA is on it. And there's broadly two options. Mars actually does
09:14have an atmosphere. It's almost entirely carbon dioxide and it's super thin. So it's like 1% of the
09:23density of Earth's atmosphere. Carbon dioxide, so there's oxygen in there. And also even as a solid,
09:30it has dry ice, which is carbon dioxide. Mars also actually has a lot of water. It has tons of
09:36ice
09:37that's just beneath the surface. It's permafrost. Water also, H2O, oxygen. You could take either of
09:44these plentiful resources and get the oxygen out. NASA actually demonstrated on Mars a technology called
09:51MOXIE that takes the carbon dioxide, splits it, and gets the oxygen out of it. And that is the current
09:57idea for how the first humans on Mars will breathe. Another option is to do it the old-fashioned way
10:04with plants. So plants breathe oxygen into the atmosphere as they do photosynthesis. And that
10:10oxygen comes from water to make breathable air on Mars. Vection says, 12 midnight, body, go to sleep,
10:20brain. I wonder how much I weigh on Mars. Mars is a little bit smaller than Earth. And that means
10:26it has
10:27less gravity. You weigh about 40% of how much you weigh on Earth. You could jump, like, really high,
10:34but you still have the same mass. If you were to, like, go and tackle someone by running really fast
10:41and slamming into them, you still have the same amount of energy that you're knocking into them with,
10:47even though the gravity is less. PSdists1324 asks,
10:54How fast would you die on Mars without a spaceship? If you find yourself outside on Mars, you're in a
10:59lot of trouble.
11:00You probably could survive very brief exposure. You won't be able to breathe, which is sort of your first problem.
11:05And in under a minute, you're going to probably go unconscious. Mars is also far colder than you could tolerate
11:12for a long period of time. There are other things, too, on Mars that would kill you, but over a
11:19much longer time frame.
11:21Mars has quite a lot of radiation, so it has UV radiation. The dirt on Mars is literally toxic.
11:27In general, if you're on Mars, you do today need a spaceship or a habitat of some kind.
11:39Earth and Mars are about the same age. Our solar system formed because it was this big glob of mass
11:45that was kind of orbiting the sun, and over time, the gravity of different parts of that mass started
11:52coalescing into planets. And so both Earth and Mars formed into these circular globs of rock.
11:59About four and a half billion with a B years ago, like a really long time ago.
12:04Four billion years ago, they actually probably looked really similar. They both had liquid water,
12:08so they were both these beautiful like water-filled worlds with rivers that carved canals into the surface.
12:28The simplest answer is that there wasn't ever any life there, but that's not fun. We are still
12:36looking for evidence of life, despite the fact that we still haven't found anything that's like
12:43obviously a smoking gun. So far, what we know is that Mars is like not obviously covered with plants.
12:50We also know that there's not like obvious fossils or anything that we found, although again,
12:55it's a really big planet and we've only had rovers sort of spot check just a couple spots.
13:02One sign of life that we've looked for is basically oil. One of the ways that we know that there
13:10were
13:10dinosaurs 200 million years ago is that the bodies of carbon-based life, both the dinosaurs and plants
13:17that lived then, have turned into oil today because they got compacted and pressurized. The hydrocarbons
13:23are themselves evidence of ancient carbon-based life. Mars basically doesn't have oil and it was a huge
13:32news story when people found like the tiniest, tiniest trace amounts of hydrocarbons. So again,
13:39it's like exactly in this tantalizing place. The signs are pointing to probably not and yet we're
13:46looking for like the tiniest indications and like maybe finding some evidence of certain types of
13:52chemistries that could have been produced by life. But I think my favorite hypothesis is that Mars
14:01maybe did used to have life and today it's no longer growing. Mars is just too extreme, but it could
14:09be
14:10that it's hibernating. It's locked up, either trapped in the ice or maybe dried out, desiccated. If only we
14:19went to Mars and we warmed it up, we made it possible for there to be liquid water, perhaps we
14:25would be able to
14:26revive life that once lived on the surface of Mars. That style of experiment, that style of search for
14:34life is what we use on Earth in really extreme environments. So when people go to Antarctica,
14:40often they don't look directly to see if things are growing and instead they take a sample and see if
14:47when put into less harsh conditions something grows and sort of becomes obviously alive.
14:54Workbot1 asks, have we learned anything new from Mars that we didn't already know before landing
15:00there with a rover? Scientists before we sent rovers figured out a lot of stuff just from pictures of
15:07Mars. The fact that there used to be some sort of liquid on Mars is like obvious from just orbit.
15:14You can do like a satellite image and just like look and you can see river deltas. Like it's really
15:19obvious that some liquid was there carving its way on the surface. That conclusion was then followed up
15:26on with supporting evidence of many different sorts by actually sending a rover down to look at the
15:33chemistry of the rocks that very conclusively point to the fact that that liquid water was once there.
15:38But there are some things that you can't see from space. The existence of perchlorate in the dirt on
15:45Mars was something we had no idea about until like the 2010s when rovers went there and we only know
15:53that this is a huge problem we need to solve when we go to Mars because we had rovers. Eric
16:00Joram asks,
16:01How are people going to build a base on Mars when they can barely stand after they are pulled out
16:06of
16:07a space capsule after nine months? Being in space is not good for your body. If you spend a long
16:13time
16:13in space you become frail and sort of weak very quickly. It's so relaxing to your body, your body
16:19doesn't have to hold itself up, that your muscles start wasting away and your bone density goes down.
16:25We know this because astronauts on the ISS have been under a lot of medical observation
16:31so that we can try to figure out what to do to fix it. Folks have figured out ways of
16:36exercising
16:36astronauts in microgravity that help a lot toward maintaining muscle mass and bone density. So
16:42people on the ISS spend like two hours a day exercising every day. Constructivism asks,
16:49What type of material is the surface of Mars primarily made of? So unfortunately we have never
16:56brought samples of Mars dirt back to Earth, which I would love because then we could run lots of tests
17:02and know exactly what's in it. Instead we have data from rovers of what the regolith or Mars dirt is
17:09like
17:09in a couple different spots. So what scientists use to study Mars dirt is we use what's called regolith
17:16simulants. And they mimic like the mineral composition of the dirt at the Perseverance landing
17:24site, that's one rover, or the Curiosity landing site. This is another rover. And this is obviously
17:29not real Mars dirt because if it was it'd be under armed guard. I mean this would be incredibly valuable.
17:35What this actually is is someone went out on Earth and found some rocks that have similar mineral
17:42composition to what the rovers saw on Mars. They ground them up to the right size and they send it
17:47to us in a little tube. There's a couple big differences between Mars dirt and Earth dirt.
17:53One is there's a toxin in Mars dirt called perchlorate. It will kill you. The other really big difference
17:59is that nothing has ever lived and died in this dirt. It's literally just ground up minerals. That is a
18:05problem for things like agriculture. Most plants require that there's all sorts of things in the
18:13soil. Soil has a whole microbiome. There's bacteria in the dirt that create nitrogen to feed the plants.
18:22There's degrading organic matter from things that have grown before. And Mars dirt has none of that.
18:27It's basically sterile rock dust. Let's Andrea asks, what would a habitat look like on Mars?
18:35I'll maybe describe two possible habitats. The first is sort of the equivalent of like an adobe
18:41building but on Mars that most makes use of the local resources which is important because you don't
18:48want to have to schlep heavy stuff to Mars. You could basically make these like dirt covered huts that
18:54protect you, the human inside, from radiation by having really thick mud bricks. As another option
19:02that is a little more high-tech, maybe more aesthetic, people are actually thinking about using advanced
19:09materials to make greenhouses on Mars. And I brought a sample of one of the materials people are considering.
19:15So this is aerogel, this very light substance. It's transparent and it's really good at blocking radiation.
19:22And so people are thinking about creating greenhouses that use this sort of material
19:29to protect the people inside from radiation, insulate them, and allow us to look outdoors.
19:35All right, that's all the questions. Thanks for watching.
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