Can humans breathe the air on Mars?

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Can humans breathe on Mars? -Jack J., age 7, Alexandria, Virginia

Suppose you were an astronaut who just landed on the planet Mars. What would you need to survive?


For starters, here’s a quick list: water, food, shelter — and oxygen.

Oxygen is in the air we breathe here on Earth. Plants and some types of bacteria provide it for us.

But oxygen isn’t the only gas in Earth’s atmosphere. It’s not even the most common. In fact, only 21% of our air is made up of oxygen. Almost everything else is nitrogen – about 78%.

Now you may be wondering: if there is more nitrogen in the air, why do we breathe oxygen?

Here’s how it works: Technically, when you breathe in, you take in everything that’s in the atmosphere. But your body only uses the oxygen; you lose the rest when you exhale.

The sky on Mars

The atmosphere of Mars is thin – its volume is only 1% of the Earth’s atmosphere. In other words, there is 99% less air on Mars than on Earth.

That’s partly because Mars is about half the size of Earth. Gravity is not strong enough to prevent atmospheric gases from escaping into space.

And the most abundant gas in that thin air is carbon dioxide. For people on earth this is a poisonous gas in high concentrations. Fortunately, it makes up far less than 1% of our atmosphere. But on Mars, carbon dioxide is 96% of the air!

Meanwhile, Mars has almost no oxygen; it’s only a tenth of a percent of the air, not nearly enough for humans to survive.

If you tried to breathe on the surface of Mars without a spacesuit that supplies you with oxygen – bad idea – you would die in an instant. You would suffocate and the low atmospheric pressure would make your blood boil, both at about the same time.

Life without oxygen

So far, researchers have not found any evidence of life on Mars. But the search has only just begun; our robotic probes barely scratched the surface.

Mars is without a doubt an extreme environment. And it’s not just the sky. There is very little liquid water on the surface of Mars. Temperatures are incredibly cold – at night it’s over -100 degrees Fahrenheit (-73 degrees Celsius).

But many organisms on Earth survive extreme environments. Life has been found in the Antarctic ice, at the bottom of the ocean and miles below the Earth’s surface. Many of those places have extremely hot or cold temperatures, almost no water, and little to no oxygen.

And even if life no longer exists on Mars, perhaps it was billions of years ago, when it had a thicker atmosphere, more oxygen, warmer temperatures and significant amounts of liquid water on its surface.

That’s one of the goals of NASA’s Mars Perseverance rover mission — to look for signs of ancient life on Mars. That’s why Perseverance searches the rocks of Mars for fossils of organisms that once lived – most likely primitive life, such as microbes on Mars.

Do-it-yourself oxygen

One of the seven instruments aboard the Perseverance rover is MOXIE, an incredible device that takes carbon dioxide from the Martian atmosphere and converts it into oxygen.

If MOXIE works the way scientists hope, future astronauts won’t just make their own oxygen; they could use it as part of the rocket fuel they need to fly back to Earth. The more oxygen humans can make on Mars, the less they need to take from Earth — and the easier it will be for visitors to get there. But even with homegrown oxygen, astronauts still need spacesuits.

Right now, NASA is working on the new technologies needed to send humans to Mars. That could happen in the next decade, maybe sometime in the late 2030s. By then you’ll be an adult — and maybe one of the first to step onto Mars.

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This article is republished from The Conversation under a Creative Commons license. Read the original article here: https://theconversation.com/could-people-breathe-the-air-on-mars-180504

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