Why does Earth's atmosphere stay close to the Earth?

Question

I know it has to do with gravity

Answer 1

You are right, the atmosphere has mass, so gravity holds it in place.

Mars is smaller than Earth, so it has lower gravity and it can only hold a very thin atmosphere. It might have had a thick atmosphere once, but it has dissipated into space.

The Moon of course is very small, and has no atmosphere at all.

Jupiter is huge, and has a very, very deep atmosphere.

Answer 2

You know it has to do with gravity - so you know the answer, why ask the question?

Gravity pulls matter towards the centre of an object, that includes you, water, baseballs, and the atmosphere.

Answer 3

Yes it's gravity and inertia (speed).  The Moon was once much closer to the Earth than it is today.  In the early days of the Earth/Moon system or after their formation the Moon once caused tides on the scale of tsunamis hundreds of feet high daily.  Since those early days the Moon has been moving farther away from the Earth by 3 centimeters per year.  Lasers reflectors left on the Moon by the Apollo astronauts are regularly used to measure the distance and is how this recession was discovered.  In millions of years the Moon will be too far away to affect the ocean tides as it does today.  The lack of the stabilizing effect of the Moon on Earths rotation will cause the poles to wobble causing the end of the four season as we know them.

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Answer 4

The Earth's gravitational field is what holds the atmosphere tight. Air does have mass but that is not necessarily why it gets caught in the Earth's grip. Gravitational fields actually bend space. Therefore light, which has no mass, is affected by gravity.

Answer 5

You answered your own question: gravity. The escape velocity determined by Earth's gravity is greater than the velocity of its air particles, so they can't escape.

Answer 6

Yes, it's gravity that keeps our atmosphere here.