True colour image of Jupiter taken by NASA’s Cassini spacecraft. The Great Red Spot forms a distinct feature in the planet’s southern hemisphere. (Image: NASA)

As each passing day brings news of the discovery of yet another unknown and exotic exoplanet, it is with some regret that I have to report the strange disappearance of an old friend. It would seem that the planet Jupiter has been seriously lost… Now, you might think that this is not a particularly important event. After all, we do have seven other planets in the Solar System (eight if you still have an old-fashioned attachment to Pluto). But Jupiter is a bit special. It is by far and away the biggest planet in the Solar System. In fact, it has a mass two and a half times greater than all the other planets combined. Because it is so massive, it has been a major influence on the development of its nearest neighbours. The asteroid belt, for example, might have been the location of a reasonably sized rocky planet, had Jupiter not stunted its growth, so that instead it consists of a zone of rubble and a few dwarf worlds like Vesta and Ceres. Jupiter has at least 63 moons and a Great Red Spot, that is in fact a storm that has been raging since at least the 17^th century.

Yes, Jupiter is (well was) an amazing planet and now it’s gone, vanished, disappeared without a trace! At least that is what seems to have happened… How do I know? Well, on a recent family trip to the French theme park Futuroscope, near Poitiers, we paid a visit to an attraction called “Chocs Cosmiques”. It’s the French version of a Robert Redford production called “Cosmic Collisions”, and great stuff it is too! You sit back on reclined seats and look up at a curved ceiling onto which are projected images of the catastrophic collisions that have shaped the Solar System, including the Giant Impact that produced our own Earth-Moon system.

The Solar System (Image: NASA)

In the foyer, where you wait before going in to see the big feature, there is a display of all the planets in the Solar System, giving facts and figures about each. The exhibit shows the planets in a long line ordered according to their position relative to the Sun. First Mercury, then Venus, Earth, Mars and the asteroid belt: so far, so good. Next, the gas giants: Saturn, Uranus, Neptune. Finally Pluto, not officially a planet anymore, but still shown for old times’ sake. But, hang on, where is Jupiter? Gone! No sign of it anywhere! My eldest daughter and I were in a state of shock. We looked for it everywhere. Not a trace, completely written out of the script! I guess that, with all the new exotic exoplanets, Jupiter has become a bit passé. Its big spot and stripy orange face no longer swing it on Strictly Come Orbiting or Celebrity Big Planet. Ah well, not to worry, now we have Gliese 581 g and who knows what other exciting worlds out there…

The funny thing is that not many people seem to have noticed that Jupiter is gone. In fact, the advice from Jodrell Bank is that October is a good month to view the planet, particularly because “the Great Red Spot has intensified its colour, so is now standing out very well!” It’s all a bit embarrassing. Should I tell them what’s happened? Perhaps not…