If you've seen pictures of Jupiter in the past, you've probably seen one of its most distinctive features - a lively red spot in the lower hemisphere of the gas giant. But that isn't a blemish or a geographical feature - it's a terrifyingly powerful storm.
It would be impossible to stand on Jupiter - there is no surface, and the planet is comprised mostly of gas, with some liquid elements. The gases - a non-breathable blend of ammonia, ammonia hydro-sulfide, helium and hydrogen - are whipped across the surface at speeds of up to 400mph, giving the planet its striped appearance. The storm that comprises the red spot is self-contained, though, and nobody knows why. What we can tell you is that it spins, like a cyclone, and is enormous; at its widest it is more than three times the diameter of Earth. First noticed by astronomers in the 1600s, the storm has been raging for well over 400 years and possibly more, but in recent years does seem to have shrunk. It may one day finally end and disappear.