I’ve been reading that Venus’ atmospheric pressure is something like 90x Earth’s…but since Venus’ gravity is almost identical to ours and with no magnetic field to keep the solar wind from stripping the atmosphere from the planet, what makes and keeps it so thick? How does it not just evaporate or blow off into space (if being continuously fed by volcanoes) to make it closer to Earth’s density under Earth-like gravity?
**Edit:** Thanks to all of you who took the time to answer here; I think I finally understand what’s at play and how it works. Made my night, and you’re all awesome, hey? 🙂
In: 11
Volcanism probably plays a major part. Venus seems to have active volcanoes; the sulfur and carbon dioxide that is found in the atmosphere quite probably came from them, as volcanoes on earth put out the same materials.
As you point out, Venus doesn’t have a magnetic field to keep the solar wind from stripping the atmosphere. Either this means that the output of volcanic gasses is able to compensate for losses, or that Venus’ current atmosphere is not stable over the long term. It is very possible that in billions of years the atmospheric composition of Venus will look very different.
The pressure/density of Venus’ atmosphere is very high at the surface, in fact it is not even a gas but a supercritical fluid, walking on Venus would be half similar to swimming! The height of the atmosphere doesn’t necessarily have a linear relationship with the density at the surface, because it is 90x higher pressure at the surface doesn’t mean the atmosphere reaches 90x as high. Gas compresses, so as you pile more gas into the atmosphere, the atmosphere sags under its own weight.
I’ve been reading that Venus’ atmospheric pressure is something like 90x Earth’s…but since Venus’ gravity is almost identical to ours and with no magnetic field to keep the solar wind from stripping the atmosphere from the planet, what makes and keeps it so thick? How does it not just evaporate or blow off into space (if being continuously fed by volcanoes) to make it closer to Earth’s density under Earth-like gravity?
**Edit:** Thanks to all of you who took the time to answer here; I think I finally understand what’s at play and how it works. Made my night, and you’re all awesome, hey? 🙂
In: 11
Volcanism probably plays a major part. Venus seems to have active volcanoes; the sulfur and carbon dioxide that is found in the atmosphere quite probably came from them, as volcanoes on earth put out the same materials.
As you point out, Venus doesn’t have a magnetic field to keep the solar wind from stripping the atmosphere. Either this means that the output of volcanic gasses is able to compensate for losses, or that Venus’ current atmosphere is not stable over the long term. It is very possible that in billions of years the atmospheric composition of Venus will look very different.
The pressure/density of Venus’ atmosphere is very high at the surface, in fact it is not even a gas but a supercritical fluid, walking on Venus would be half similar to swimming! The height of the atmosphere doesn’t necessarily have a linear relationship with the density at the surface, because it is 90x higher pressure at the surface doesn’t mean the atmosphere reaches 90x as high. Gas compresses, so as you pile more gas into the atmosphere, the atmosphere sags under its own weight.
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