New Horizons at Jupiter
On its way to reach Pluto in 2015, the New Horizons spacecraft swung by Jupiter for some gravitational assist. As practice, it took the best picture yet of the Great Red Spot and the new Spot. Little Spot was formed from the merger of 3 smaller spots, and continues to grow. As in a tub of water, smaller vortices eventually merge into one big one.
The Great Red Spot was first observed by Domenico Cassini around 1665. It is shaped like an Earthly cyclone, but has lasted far longer. These storms form coloured spots because they extend deep into the atmosphere. They are signs of some unknown phenomena inside Jupiter. We recently saw that brown dwarfs, which occupy a size range between Jupiter and stars, are home to massive sources of energy. There is more inside Jupiter than meets the eye.
Below in 3-D is the eruption of volcano Tvashtar on Io. This moon itself emits a lot of heat. New Horizons also discovered a new volcano just reaching the surface of Io. Near Hawaii we have a submerged volcano named Lo' ihi that will someday form a new island. Objects from gas giants to little moons like Enceladus contain sources of energy. Something is going on literally beneath our feet.
Io is one of the four satellites discovered by Galileo. Objects circling a body other than Earth were a direct threat to the old Ptolemaic system. Scholars of the day refused to peer into Galileo's telescope for fear of upsetting their world view. Galileo spent the last 10 years of his life under house arrest for promoting heresy. (A bit like saying the speed of light isn't constant.) Despite his persecution, a Jupiter probe and a STAR TREK shuttle would be named for Galileo.