Why isn't the earth's atmosphere sucked into the vacume of space?

Answer 1

As the answers so far have pointed out: Earth's gravity is strong enough to hold it in place. It's the same as the water in the oceans. If you suck on a straw, water flows up the straw because the air pressure on the surface of the water raises the liquid to equalize the forces.

There's a limit to this though. With a long enough straw, even a perfect vacuum in the straw can only lift the water to a certain height above the surface. You will have then created a barometer. As the air pressure around rises and falls, the height of the water in the straw would rise and fall accordingly.

Air, being a fluid, is ultimately held in place because the gravity of Earth is stronger than the kinetic energy in the gas molecules can escape.

There is one more factor keeping Earth's atmosphere in place: The Earth's molten core. The convective currents in the metallic core generate Earth's magnetic field. This in turn protects Earth from the bulk of the solar winds. Without it, over time, the solar wind would strip the Earth's atmosphere out into space. Mars is our example of this case.

Mars once had a molten core, and surface studies by robots like the Mars Exploration Rovers shows that the atmosphere there was once much thicker than it is today. The presence of dead volcanoes (huge ones actually) shows us that the core was once molten. Once it cooled off, there was be no more magnetic field to deflect the solar wind, and the sun just blew it away.

Answer 2

The earth atmosphere is a gas and gases can be compressed and is denser at lower levels. The lightest element floats not because of gravity but because its less dense than all the rest. The other elements that are denser push on H2 and give it lift.
The reason why the Earth has an atmosphere and the other planets have lost theirs is because the mass of Earth has enough gravity unlike mars to hold the atmosphere.

Answer 3

Have you ever made a rapid vacuum in a tin can, well if you find a way, (I forgot how I did this in one of my labs) the tin can crushes like some semi-truck is on it. This shows how heavy the air in our atmosphere truly is. It is this weight what we call (barometric) pressure, on a surface like Mars where the atmosphere is a lot less dense the weight per volume is a lot less, so the pressure form your insides will push your skin apart and you will explode, (like a over filled water balloon). It is also this immense mass that allows gravity to hold it to our surface. Finally, air is a fluid so there are bounds between atoms that hold it together (take an air bubble underwater, it stays in a sorta spherical shape right and doesn't disintegrate into a billion pieces like you would expect, this is why its' mass as a whole is important). And lastly (I promise this time) what would blow our atmosphere off the surface? I can't even picture the atmosphere leaving the surface even if there was no gravity because it would take another mass with velocity to move the gas. ( I left off rotational velocity, omega, inertia of a moving fluid, bla bla bla, I just did not want to sound too nerdy) Hope this gives a better mind picture of the scenario.

Answer 4

Gravity from the Earth keeps the gas from floating into space. Bodies with lower gravity (such as the moon) have no atmosphere because they do not have enough gravity to hold down the gas molecules.

Answer 5

Space may be a vacuum but it is not suction. The Earth's gravity holds our atmosphere to its surface. Small amounts of gas are lost to space due to the speed of molecular movement at the uppermost part of the atmosphere, but this loss is negligible.

Answer 6

Gravity

Answer 7

gravity

Answer 8

Because its under the influence of Gravity...which is different to what im under ther influence of...hic...

Answer 9

earth's gravity is holding it in