If an element becoming colder slows the atoms down, which makes them more likely to be solid, than why are all the gas giants furthest from the sun?

Question

If an element becoming colder slows the atoms down, which makes them more likely to be solid, than why are all the gas giants furthest from the sun?

In: Planetary Science

Answer 1

Temperature is not the only factor in states of matter. The other factor is pressure. You can look up a “phase diagram” to see how they relate. Something that is cold but low pressure may remain a gas, and something that is hot but high pressure may solidify.

Actually, there’s even another factor, which is probably more relevant here: each substance has different melting/boiling points. Liquid nitrogen is very “cold” to us, so why is it still liquid and not solid? Well, for a very simple reason: nitrogen freezes at an even colder temperature than that.

So in short: it’s cold by our standards, but not cold *enough* for the gases in those planets’ atmosphere, and the pressure is high but not high enough to squeeze them into a liquid or solid (though the core of Jupiter is in fact liquid because of the pressure).