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

Those gasses aren’t nearly cold enough to be solids.

At low pressures, liquids can’t exist. That’s why dry ice (solid CO2) sublimates rather than melts. There’s not enough pressure for it to be a liquid.

Saturn’s moon Titan has lakes of liquid methane on the surface because it is cold enough and has enough pressure to keep it liquid.

The gas giants are mostly hydrogen, which doesn’t become solid at all as far as we can tell under any temperature or pressure. We believe that inside the gas giants, eventually, you will reach an ocean of liquid hydrogen due to the immense pressures.

Now, why are all the gas giants far away from the Sun? Early on in the solar system, when the sun first switched on, the radiation pressure of the light from the sun was able to push all the light gas particles out to the outer solar system, but the heavier dust particles didn’t get pushed out, so the rocky planets were made of this dust pressed together, and the gas giants were made of all of these gasses clumping together.