the pressure of atmosphere is 1 atm while there is not any air pressure in the space and then molecules of air gases tend to escape from the earth to the space(gradually though).but why after millions and millions of years, we have still air on the planet.
And will be one day when there is not any air left on the planet earth?
2006-10-30 09:35:58 · 7 answers · asked by Ormoz 3 in Science & Mathematics ➔ Physics
I can not imagine that the gravity is so high to sustain atmosphere over this long period of time. Because I think the status of atmosphere on the planet is thermodynamically unstable.
2006-10-30 09:51:26 · update #1
Yes it is gravity. Oxygen, Nitrogen, CO2, Argon etc are too heavy to escape the atmosphere, even after billions of years.
However gasses like Hydrogen and Helium are too light to be held by Earth's gravity so they escape into space.
Jupiter and Saturn have higher gravitational pull than Earth and they hold onto their Hydrogen.
2006-10-30 09:57:11 · answer #1 · answered by amania_r 7 · 1⤊ 1⤋
Well it is very simple. It is basically gravity and you can prove it by calculating the escape velocity for each gas.
If you calculate the mean velocity of the molecules you will find that most of the gases in the atmosphere will have a velocity which is less than the escape velocity.
In fact, only one gas has a mean velocity which is greater than the escape velocity. This gas is Hydrogen. That is why there is almost no hydrogen in the atmosphere despite the fact that is going out from volcanoes all the time.
So gas can not escape the gravitational pull of the earth unless their velocity is bigger than the escape velocity. That is why you can also run without "escaping" into outer space, unless you start running real, real fast (and then you are spaced out).
2006-10-30 17:57:13 · answer #2 · answered by Dr. J. 6 · 1⤊ 0⤋
The threat to earth's atmosphere is not the strength of earth's gravity but rather the strength of it's magnetic field. The magnetic field acts like a force field to shield the earth from most of the solar winds which could strip the atmosphere away.
There was a recent television show that addressed this problem.
2006-10-30 18:57:39 · answer #3 · answered by oil field trash 7 · 0⤊ 0⤋
Gravity. The mass of the Earth is large enough that it has a gravitiation pull strong enough to sustain an atmosphere.
2006-10-30 17:38:57 · answer #4 · answered by Anonymous · 2⤊ 0⤋
Gravity is the main force but the lighter gas as it gets to the ozone layer IT will oxidize and as CO2 and water vapor it Will return to earth where some green plant will reprocess it to OX.
2006-10-30 18:32:12 · answer #5 · answered by JOHNNIE B 7 · 0⤊ 0⤋
uh... plants are constantly producing more "air"??? Also, the atomsphere is made of different layers, with different composition of "air" (gases).
2006-10-30 17:43:58 · answer #6 · answered by mom_of_ndm 5 · 0⤊ 0⤋
gravity
2006-10-30 17:38:30 · answer #7 · answered by t_roy_e 3 · 0⤊ 0⤋