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  • SciShow Space is supported by Brilliant.org

  • [♪INTRO]

  • Lately, there's been a lot of talk about building a colony on Mars.

  • There's still a lot to do before we get to that point, like,

  • we should probably figure out how to get people there.

  • But even if we did set up a human habitat,

  • we'd still have some huge challenges to overcome.

  • Because traveling to, and living on, the Red Planet

  • would be more dangerous than basically anything we've ever tried.

  • Here are three of the biggest challenges the Mars colonists would, or will, have to face.

  • The danger starts long before reaching the Martian surface.

  • Depending on exactly when and how our astronauts launch,

  • it will take the crew somewhere around seven months to get to Mars.

  • And as soon as they leave the protection of Earth's magnetic field,

  • they'll be exposed to the intense radiation environment of space.

  • This radiation is mostly made of tiny subatomic particles like protons and neutrons.

  • Many stream out of the Sun as part of the solar wind, while others,

  • called cosmic rays, come from all over the galaxy.

  • And sometimes, these particles can strike a bit of DNA

  • as they pass through the human body.

  • Each hit can randomly change a little of someone's genetic code, and that can lead to mutations

  • in new cells that ultimately cause problems like cancer or heart disease.

  • Thankfully, because we're protected by the Earth's magnetic field and atmosphere,

  • we aren't exposed to most of these particles.

  • But things aren't the same in space.

  • Although astronauts take precautions, spending six months on the International Space Station

  • results in absorbing about three times as much radiation as the U.S. annual legal

  • limit, and a trip to Mars would be over twice as much as on the ISS.

  • And, if there happened to be an explosive solar flare during the trip,

  • the crew could receive a lethal dose of radiation in just a few hours.

  • Since Mars lacks a global magnetic field and doesn't have much of an atmosphere,

  • things don't get a lot better once the astronauts land, either.

  • Over about 500 Earth days, they would receive about as much radiation as on the trip there,

  • and that would really add up over a lifetime.

  • To protect our first interplanetary settlers, scientists have a couple of ideas

  • that would make MacGyver proud.

  • First, it turns out that water is very effective at absorbing radiation,

  • because it's rich in hydrogen, which is just the right size to block these subatomic particles.

  • And water is something the astronauts will already be bringing with them.

  • So one option is to line their spaceships and habitats with tanks of it.

  • Another option is tunneling underground to escape the radiation, or setting up shop in

  • giant, empty lava tubes left over from when Mars was volcanically active.

  • Of course, astronauts don't need to worry about radiation if they starve to death first,

  • and growing food on Mars won't be a picnic.

  • Well, actually, growing food might not be too terrible.

  • Laboratory experiments suggest that it is possible to grow plants in the powdery Martian

  • soil, and Mars' atmosphere is full of yummy carbon dioxide for photosynthesis.

  • What might be more tricky is not dying from the food you grow.

  • See, Mars' surface is full of perchlorates,

  • a class of salts considered industrial waste here on Earth.

  • Perchlorates overwhelm the body's thyroid gland by blocking its ability to absorb iodine,

  • which is normally used to produce a hormone that regulates your metabolism.

  • In the U.S., it's regulated in things like groundwater at the state level.

  • Massachusetts, for example, sets the legal limit at two parts per billion by mass.

  • Meanwhile, on Mars, perchlorates are found at a rate of

  • around 6 million parts per billion.

  • Which is just a tad higher.

  • Just like we can clean up soil here at home, it's possible to do the same thing on Mars,

  • like by introducing microbes that eat perchlorate as an energy source.

  • Which, of course, would run the risk of contaminating Mars with even more Earth life.

  • And that's a whole different problem.

  • So, either way, I'm gonna let you take the first bite.

  • To power all that soil cleanup, plus basically everything else,

  • settlers will need a reliable source of electricity.

  • The obvious answer is to just throw up a bunch of solar panels and call it a day,

  • but that could be a big mistake.

  • See, every year, Mars suffers from dust storms the size of Earth's continents,

  • and, on average, those cover the globe about twice a decade.

  • The thin Martian atmosphere means these windstorms wouldn't blow over the solar panels,

  • but all that dust flying around blocks an enormous amount of sunlight.

  • When the Mars rovers Spirit and Opportunity got trapped in the last global dust storm in 2007,

  • they were reduced to operating just a few minutes each day.

  • That's okay if you're a robot, but not so good if you need to do things like,

  • I don't know, breathe or see at night.

  • To get around this, the first Martian colonists will need to bring a different kind of power source,

  • like something based on plutonium,

  • because plutonium doesn't care if the Sun is out.

  • So, it's not that there aren't solutions to these problems.

  • We could clean up the soil, build radiation-proof habitats,

  • and figure out a reliable power supply.

  • The thing is, there are a lot of problems, and finding the answer to each of them

  • in a way that doesn't break the bank will be a real challenge.

  • But, hey.

  • People.

  • On Mars.

  • If we can get that far, we'll figure out the rest.

  • Now, even though solar energy may not be the perfect fit for a Mars colony,

  • it would still be useful.

  • And if you want to dive deeper into the quandary of powering a planet with solar,

  • our sponsor Brilliant has a cool lesson about just that.

  • Brilliant takes you through puzzles and quizzes as a good refresher on

  • how much solar energy we really have to work with here on Earth,

  • and how much we'd need to collect to power current human consumption.

  • Let's see if we can figure it out.

  • So one of the things I personally love about a Brilliant quiz

  • is that it starts off with some really basic information,

  • and then dives into some really interesting details before the quiz even starts.

  • So for example in the Solar Power quiz, it talks about how, of course,

  • all plants and animals are kind of connected with the sun, as far as their power goes, if you will,

  • but also how things like windmills depend on the sun,

  • as the wind fundamentally results from uneven heating of the Earth's surface.

  • Which I think is cool!

  • So then when you start the actual quiz, what's great is that it gives you all the information

  • that you really need to find the answer, and if you need to cheat you can just view the

  • solution, then go back and figure out how you would have gotten there in the first place.

  • And the first 200 people that sign up at brilliant.org/scishowspace

  • will not only be supporting our show, but will get 20% off an annual subscription.

  • [♪OUTRO]

SciShow Space is supported by Brilliant.org

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