Because it is a lighter gas
hydrogen
hydrogen
hydrogen
Yes. Hydrogen is a gas, and all gases tend to diffuse. Whether or not air is present is irrelevant.
0.00005% of the atmosphere is hydrogen.
At high altitudes, Neptune's atmosphere is 80% hydrogen and 19% helium.
The planet has a deep, dense atmosphere of hydrogen and helium. Below the upper cloud layers, the Sun would not be visible.
Hydrogen is found in the atmosphere.
* 22% of Mercury's atmosphere is hydrogen. * Venus does not have pure hydrogen in its atmosphere, but does have hydrogen chloride and hydrogen fluoride. * Earth has almost no hydrogen. * Mars does not contain any significant amount of hydrogen in its atmosphere. * Jupiter's atmosphere is roughly 90% hydrogen! * Saturn's atmosphere has even more: about 97% is hydrogen! * Uranus' atmosphere is 83% hydrogen. * Neptune's atmosphere contains 74% hydrogen.
To the point of being unbreathable to almost all organisms. Including us.
Jupiter's atmosphere is primarily composed of hydrogen and helium, with smaller amounts of methane, ammonia, and water vapor. The high concentration of hydrogen and helium gives Jupiter its characteristic colors and properties.
Although there is an enormous amount of hydrogen contained in Earth's crust and in the waters of the oceans, the free hydrogen in the air is only about 55 parts per million by volume. Because it readily combines with a number of other elements, concentrations are quickly dissipated. Any free hydrogen will rise rapidly into the atmosphere, to be ionized into space : the lighter elements such as hydrogen and helium readily escape the pull of gravity. (Nitrogen and oxygen are heavy enough to be held more readily.)