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Gas giants hold onto their gases, not because they're cold, but because they're massive. I doubt you could get a planet to form with liquid or solid helium on t
by malfist 3y ago
Gas giants hold onto their gases, not because they're cold, but because they're massive. I doubt you could get a planet to form with liquid or solid helium on the surface. Building a planet generates a great deal of heat and pressure.
And we'd know if there was another gas giant in the kuiper belt. I couldn't find estimates on how much mass is in the oort cloud, but probably not enough to form a orbit with enough mass to make a gas giant.
Edit: Just found the wikipedia section on the mass of the oort cloud. Roughly estimated at 5 earth masses. Neptune, which isn't quite massive enough to be a gaseous planet, is 17 earth masses. Saturn, our smaller gas giant is 95 earth masses
- wredue 3y agoAll planets and moons hang on to their gasses through gravity. I would think our understanding of solar system formations and solar winds makes the likelihood of lots of helium being in the outer system being quite high. The temperature is not related to holding on to the helium, but to its density for higher efficiency farming.
- pfdietz 3y agoThe temperature at the exobase does have an effect on retention of helium. If it's high enough (relative to the escape energy of the planet) the high energy tail of the thermal distribution will leak atoms into space.