Monday, August 6, 2012

Jupiter and its Moons


Jupiter with Ganymede and Europa minutes after Io is eclipsed.
Jupiter, the most massive planet in our solar system, contains a current count of 50 "permanent" moons. Of these many moons, the four largest are Callisto, Europa, Ganymede, and Io. These four are known as Galilean satellites, having first been observed and recorded in 1610 by Galileo Galilei. Europa is thought to have a liquid ocean under its frozen crust, but the possibility may also lie with Callisto and Ganymede. Ganymede is also the largest planetary moon and the only moon with its own magnetic field. Io, on the other hand, is the most volcanically active body in the solar system.

Another capture of Jupiter, Ganymede, and Europa.
The Great Red Spot is not the only interesting feature of Jupiter. The rings of Jupiter were first discovered in 1979 by NASA's Voyager 1 spacecraft. These are a flattened main ring, an inner cloud-like "halo" ring, and a third gossamer ring. The gossamer ring, call such due to its transparency, is actually three rings of microscopic debris. That debris came from the three small moons Amalthea, Thebe, and Adrastea. Perhaps the most interesting fact of Jupiter is that is can technically be called a failed star. It lacks the mass needed to graduate to a brown dwarf and has cooled below the threshold for fusion; however, enough heat, mass, and pressure remain to cram together atoms resulting in new behaviors. With this limbo state of chemical and nuclear reaction, oddities such as liquid metallic hydrogen are possible. It is with the launch of and arrival of Juno to Jupiter that we may finally see below the clouds of Jupiter.

As a celebration for the successful landing of Curiosity, I decided today was a good day to share what may be my favorite photo I've ever taken. It was with the aid of a wonderful astronomer and telescope during an amateur astronomy night in Australia that I had this opportunity, and success.