Is there air on Mars?
Mars has an atmosphere. It just will not help you take a single breath, will barely carry a whisper, and gives every gust of wind a fraction of the punch the same speed has on Earth.
5 min read
Yes, technically. Mars is wrapped in a real atmosphere, made of real gas, that behaves in ways nothing on Earth quite does. It just would not keep you alive for long.
Thin does not begin to cover it
Earth's air presses down at about 1,013 hectopascals at sea level. On Mars, the average surface pressure is about 6 hectopascals, roughly 0.6% of Earth's. Standing on Mars is like standing 35 km above Earth's surface, far higher than any airliner flies.
Almost none of it is oxygen. Mars's air is about 95% carbon dioxide, with a little nitrogen and argon mixed in. There is no breathing it, thin or not.
What that thin air does to sound
In 2021, Perseverance landed carrying a microphone, the first ever sent to record real sound on Mars. What it heard was strange.
Sound travels slower there: about 240 metres a second for low-pitched sounds, against 343 on Earth. Higher-pitched sounds travel about 250 metres a second, a genuinely different speed. Mars is the first place scientists have ever measured two separate speeds of sound in one atmosphere, a direct result of that thin, cold, carbon-dioxide air.
So does the wind actually blow?
It does, and Mars even gets storms big enough to wrap the whole planet in dust. But thin air pushes weakly no matter how fast it moves. A 100 km/h gust on Mars would feel like a gentle breeze on Earth, not the gale the number suggests.
That thinness is also why every robot sent to the surface, from tiny Sojourner to Perseverance and its helicopter Ingenuity, has needed its own sealed instruments and, eventually, will need its own air supply for any person who lands there.
Common questions
Is there really air on Mars?
Yes, a real atmosphere, but a very thin one: about 0.6% of Earth's surface pressure, made mostly of carbon dioxide with a little nitrogen and argon.
Could a person breathe on Mars?
No. The air is far too thin and has almost no oxygen. Anyone visiting would need a full sealed suit and their own air supply, the same as in open space.
Can you hear anything on Mars?
Yes, but it sounds different. Sound travels slower than on Earth, fades out within about 8 metres, and high and low pitches even travel at different speeds, something never observed anywhere else.
Does it get windy on Mars?
Yes, including planet-wide dust storms, but because the air is so thin, even fast Martian wind pushes far weaker than the same speed would on Earth.