If Jupiter was 80 times more massive it would have been a star. Due to gravitational compression Jupiter was hot when it first formed. It is still cooling off even today. Jupiter emits about twice as much energy as it receives from the Sun. In the absence of sunlight Jupiter would have a temperature about 100 degrees above absolute zero and would glow dimly in the infrared part of the spectrum.
Strong winds blow at the boundaries between the belts and zones.
The brighter bands are regions of upwelling atmosphere capped by bright white ammonia clouds. Jupiter is mainly made of hydrogen and helium. At the high pressures of Jupiter's interior hydrogen gas becomes a liquid. Jupiter's magnetic field is the strongest of any planet in the Solar System. The strong magnetic field produce intense radiation belts near Jupiter and polar aurorae .