Questions I’d like to ask a physicist

Considering how massive Jupiter is, and how strong the gravity must be, how come Jupiter is so gaseous? In other words, why doesn’t Jupiter solidify? Seems like that would happen with all that gravity. For that matter, why doesn’t that happen with the sun? Is it that high gravity creates so much heat in the core that even though the gas is highly condensed it still can’t solidify? Or is it something to do with the freezing point of hydrogen?

If there was a steel beam 6 inches thick but a million miles long, and it was floating in space with nothing nearby to exert gravity on it, what would gravity generated by that beam do to the beam itself? Would it collapse in on itself and become a sphere? Since this beam would be so massive, would it have massive gravity? Or would it have very little gravity due to its thinness, the fact that all of its mass is spread so thin?

Considering the positive charge that protons carry, and the negative charge that electrons carry, how come atoms don’t just collapse in on themselves? What prevents this?

If you put an object that has no water whatsoever in the microwave, would it heat up?

If we travel toward a light source (such as the sun) at very fast speeds, will the increased frequency of the electromagnetic waves change the light from visible light to gamma radiation, and therefore become deadly? Does this put a physical limit on how fast humans could ever travel toward a star (go too fast toward the light and we get cooked)?

If the universe is always expanding, and therefore everything in the universe is always moving further away from everything else at all times, why have the stars that we can see from earth always remained in a fixed position since the time of the Ancient Greeks? Or have they not?