Harry Potter and the Moons of Jupiter
K.A.Cassimally
1330 It is in the latest Harry Potter novel, Harry Potter and the Order of the Phoenix, that readers get the confirmation that the 'Boy who lived' is indeed interested in a science that even some Muggles are good at: Astronomy, the study of celestial objects, of space and of the physical universe as a whole. Maybe the awful Dursleys did do some good things with Harry when they let the wizard, who did not yet know he was one, learn Astronomy.

At Hogwards School of Witchcraft and Wizardry though, Harry and his two best friends, Ron and Hermione, seemed to be going on more with the giant of the giants: Jupiter but to be more precise with its moons.

But unluckily for the wizards and witches, Astronomy was making life difficult. As Harry and his friends would be sitting for their O.W.L.S (Ordinary Wizarding Level) at the end of the year, they were bombarded with homework. This was fortunately corrected by Hermione before being actually handed to the teachers. And believe me, this was a good thing too as both Harry and Ron were making terrible mistakes. If it were not for Hermione, both boys would be getting a 'D' standing for Dreadful on the top corner of their parchment rolls. An would be:
'“Harry, you must have misheard Professor Sinistra,” says Hermione,
“Europa's covered in ice not mice!”'

Europa as you might have guessed is way too cold for mice. Spacecrafts have taken photos of this natural satellite and Europa does look lifeless.

If you are a Harry Potter fan though, you may well say that Harry went on Europa by magic and then saw living organisms there. Well coming to think of it, maybe he did find life on Europa if of course he ever went there.

This is because below Europa's ice coating, scientists think that there may well be a big ocean of liquid water. The biggest ocean in the Solar System in fact and that says something. Here on Earth, life and water appear to go together. So it is logical to think that there may be life in that ocean of Europa, is it not? Of course life in the form of microbes or some sort of alien fish is expected. And maybe swimming mice!

Unfortunately the mystery of life in Europa cannot be solved by this generation and I personally think nor can the next. This is because of the technology which still needs to take a big step forwards.

Back at Hogwarts, Hermione who was correcting one of Ron's essay about Io, another of Jupiter's numerous satellites, when she spotted yet another mistake. She remarked,
“And it's Io that's got the volcanoes.”

She was right again. Some people (I'll say including Ron) say that Io looks like a pepperoni pizza because the satellite is dotted with volcanoes.
“Io has more pepperoni-coloured volcanoes than Ron Weasley has freckles,” says Dr. Tony Phillips.
At this very moment dozens of these volcanoes are vomiting the hottest lava in the Solar System. The plumes rise so high into space that volcanic ash freezes before falling back to the ground as sulphurous snow. NASA's spacecrafts have actually flown through these plumes and survived.

Back on Earth and at Hogwarts more precisely where Hermione told Ron over the latter's shoulder,
'“Jupiter's biggest moon is Ganymede, not Callisto.”'

Ganymede is the largest known satellite discovered in the entire Solar System. It is a little wider than Mercury, which is the closest planet to the Sun in the Solar System.

Ron's mistake is not of those terrible ones though because Callisto is only a little smaller than Ganymede. Like Europa, Callisto may be concealing an ocean.

These four satellites were all discovered by Galileo Galilei in 1960. Galilei was astounded when he observed Jupiter through his primitive telescope as he saw four little 'stars' near the giant planet. He was even more amazed when he discovered that these 'stars' were moving in what seemed to be an orbit around Jupiter from night to night. Astronomers now call these four natural satellites the Galilean satellites.

Almost everything that is known about the Galilean satellites comes from NASA's spacecraft, especially the two Voyager probes.
But Hogwarts is a school of magic whereas Astronomy is simply magic.

About the Author

K.A.Cassimally is the editor in chief of Astronomy Journal, a small publication of the RCPL Astronomy Club, Mauritius.
Check out the new website (to be launched in February 2004): http://www.rcplastronomyclub.zik.mu