why doesn’t Earths atmosphere just float off into space?

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Why doesn’t the atmosphere (air we breathe) just float off into space?

Some objects in space have atmospheres like Earth and Jupiter. Others like asteroids and the moon don’t have an atmosphere.
Why doesn’t earth atmosphere just drift away into space?
What am I missing about the concept of atmosphere?

In: Planetary Science

30 Answers

Anonymous 0 Comments

Air is matter. Matter has mass. Mass has weight (in Earth’s gravity) so it is pulled towards the Earth.

WHen they say atmospheric pressure is “14.6 pounds per square inch,” that’s literally the weight a column of air above a square inch of surface. That’s the force gravity is exerting on that column of air keeping around the Earth.

In the same vein, the air pressure gets lower as you go higher up because there’s less gas above a given square inch. Less pressure, lower density. The amosphere gets thinner and thinner as you go up and just gradually transitions into “empty” space. There’s no real end to the atmophere. It jst gets to a point where it’s thin enough to call “space.”

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