Which process explains why the terrestrial planets do not have hydrogen and helium in their atmospheres?
thermal escape (??)
condensation
out gassing
solar wind
Yes, I would guess those light gasses would exceed escape velocity due to heat.
Thanks much!!
yes, here
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCQQFjABahUKEwjI1qjtttzIAhVLGz4KHfxjBKY&url=http%3A%2F%2Fwww.atmos.washington.edu%2F~davidc%2Fpapers_mine%2FCatling2009_SciAm_AtmEscape_Preprint.pdf&usg=AFQjCNE-vlUw54iLGlGBqrCfCQJ1CQHcIw&sig2=09z2PlaTuIUXxwPV5ia5jQ
You are welcome.
The process that explains why the terrestrial planets do not have hydrogen and helium in their atmospheres is called thermal escape.
To understand why this process occurs, we need to explore the characteristics of hydrogen and helium. These two elements are very light, which means that their atomic/molecular velocities are relatively high. Additionally, the terrestrial planets in our solar system have relatively low gravitational escape velocities. This means that the velocities of hydrogen and helium atoms/molecules in the upper atmosphere can exceed the escape velocity of the planet, causing them to escape into space.
To calculate the escape velocity of a planet, you would typically use the formula v = sqrt(2GM/R), where v is the escape velocity, G is the gravitational constant, M is the mass of the planet, and R is the radius of the planet.
In the case of hydrogen and helium, their high velocities enable them to achieve escape velocity relatively easily, allowing them to escape the gravitational hold of the planet. Over time, this leads to the loss of these light elements from the atmosphere of terrestrial planets.
In contrast, condensation refers to the process by which a substance changes from a gas to a liquid or solid state. This process does not cause the loss of hydrogen and helium from a planet's atmosphere. Outgassing refers to the release of gases from a planet's interior, which can contribute to the composition of its atmosphere, but it does not explain the absence of hydrogen and helium. Solar wind is the flow of charged particles from the Sun, which can interact with a planet's atmosphere but does not specifically explain the absence of hydrogen and helium on terrestrial planets.