What is the worst planets in the Milky Way galaxy?

Answer 1

We only know a handfull of planets of all of planets in the Milky Way galaxy, but there are pretty bad planets even in our own solar system.

Mercury is so hot, that all life would die in there, if life would have ever been able to emerge there. Venus is too hot for life too, it's atmosphere is full of corroding acid rains and it's surface covered with numerous volcanoes. Earth is the only planet suitable for life in our solar system. Mars is dry and too cold for living, all of it's water is frozen in its polar caps and under the rocky surface. Mars doesn't have an atmosphere either, so there is no air to breathe and all the dangerous space radiation comes straight to its surface. Jupiter is completely inhabitable, as well as Saturn, Uranus and Neptune. All four are huge gas planets, they don't have a solid surface at all, only gas is surrouding their cores, and they are also so far away from the sun that they are very cold. Those planets many many times bigger than Earth also have immensely heavier gravity, which would crush a human body if it would stand on some surface. Also huge cyclonic storms are wandering on Jupiter and Neptune, the Jupiters "eye" storm is so big, it could swallow three whole Earths.

Pluto which used to be a planet, but is better to categorize as a planetoid since it's so very small, is only a tiny ice ball so far away that the sun doesn't look much different than the other stars on Plutos sky. So it's extremely cold place with eternal night.

There are still worse planets in the Universe and in Milky Way, every planet which doesn't have a sun, if their sun has gone to an end, are completely impossible for life to exist, since they don't have light, which makes all life possible. Also it would be pretty horrible to be on a planet which' sun would die as a red giant turning to a supernova and destroy the whole planet and every life form on it. Everything would burn, oceans boil and mountains melt and the planet would turn into a giant ball of lava until the supernova would blow everything away.