Mars has an atmosphere! #MarsIsCool
The air pressure is less than 1% of Earth’s. Though thin, it’s there. It’s composed of trace amounts or oxygen with carbon dioxide making up 96% of the atmosphere.
For comparison, Earth’s atmosphere is 78% nitrogen and 21% oxygen.
Ionized particles from Mars’ atmosphere trail behind it from the solar wind interacting with it ionosphere.
Obviously, no one is going to breathe on Mars unaided. Besides lacking oxygen, it’s too thin It would be like trying breath the air 20+ miles above the Earth’s surface.
All of this is today. I wonder what Mars was like millenia ago. Perhaps it had an atmosphere that supported life. We know it had water.