* Jupiter is a gas giant: It doesn't have a solid surface like Earth. It's mostly made up of hydrogen and helium, with a swirling, dense atmosphere.

* Extreme atmospheric pressure: As you descend into Jupiter's atmosphere, the pressure increases incredibly rapidly. Even if a spacecraft could withstand the heat and radiation, it would be crushed by the immense pressure before reaching any kind of "surface".

* Extreme temperatures: Jupiter's atmosphere is incredibly cold at the upper layers, but temperatures increase rapidly as you go deeper. The core is thought to be incredibly hot.

* Toxic atmosphere: Jupiter's atmosphere is composed of toxic gases like ammonia and methane, making it impossible to breathe.

Instead of landing, spacecraft can fly through Jupiter's atmosphere. The Juno spacecraft, for example, orbits Jupiter and has gathered valuable data about its atmosphere, magnetic field, and composition.