Jupiter’s magnetic field is bigger than the Moon. The region of space in which a mass’s magnetic field dominates is known as its magnetosphere. These regions surround planets, pulsars and even our Galaxy. The planets in our Solar System have magnetospheres that interact with and are shaped by the charged particles in the wind streaming from our Sun. The largest magnetosphere in our Solar System surrounds Jupiter. Jupiter rotates very fast and has a very strong magnetic field, and its magnetosphere is filled with plasma from its volcanically active moon, Io. These features, coupled with the fact that the solar wind is slower and less dense at Jupiter than at Earth, lead to a very sizeable Jovian magnetosphere. It is easily big enough to contain a body the size of our Sun and, if visible, would be larger than the Moon in our night sky; quite an achievement considering that it is over 1,500 times farther away.