How different is Mars from Earth
Jupiter is the 5th farthest planet from the sun after mercury, Venus, Earth and Mars respectively. Beyond mars, the vast chunk of space is composed of asteroid belt, which contains many small sized rocks up to a few km in radius.
Beyond these tiny rocks revolves the planet Jupiter around the sun at a distance of 700 million km, making it 11 times the distance of the sun and earth. At such a distance from its host star, it is bound to be cool with an average temperature of -150 c. Still, it is much warmer than thought to be.
It has been measured that its iron core, having extraordinary pressure, is hotter than the sun. That is why, Jupiter, emits heat more than it receives. Extreme central pressure is the reason its core is still in the solid state.
Unlike, the 4 planets mentioned, its non-terrestrial in nature, which means it does not have solid surface. Only its small solid core is made up of iron and silicon compounds. The rest, mantle and surface, is made up of liquid hydrogen. Above the liquid hydrogen seas, floats the thick ammonia and hydrogen clouds, with some presence of ice too.
If an astronaut by chance, in the future, lands on Jupiter, he would have to do so in a boat type spaceship, which could float on the seas.