Today Saturn is at perihelion. In other words, today the ringed planet is as close as it ever gets to the Sun, a mere 1.2 billion kilometres away. This doesn't happen very often. It takes 29½ years for Saturn to orbit the Sun once which means that the last perihelion was over ten thousand days ago, way back in January 1974. UK readers, think three day week; US readers, think Watergate. And the next perihelion will be in 2033. Whatever you do, don't think how old you're going to be then.
A few facts about Saturn. It's the second largest planet in the Solar System (it's huge), it's the sixth in line from the Sun, the Romans named it after the god of agriculture, the Greeks called it Cronus, it's mostly gas, it weighs 95 times more than the Earth, it spins on its axis once every 10 hours 39 minutes (that's very fast), it's the furthest planet that can be seen with the naked eye, it has 31 known moons (18 of which have names), Gustav Holst wrote a nice piece of music about it... oh, and it has rings. The famous rings are 250,000 km in diameter but less than one kilometre thick, they're comprised primarily of tiny particles of water ice, and they're gorgeous.
The first space probe to reach Saturn from Earth was Pioneer 11, way back in 1979. Voyagers1 and 2 passed by during 1980 and 1981 on their way to the outer planets (and beyond) but it's been a bit quiet out there ever since. Now at last a fourth spacecraft called Cassini is on its way to Saturn and is due to arrive there next year. There was a lot of fuss back in 1997 when NASA launched the plutonium-powered probe (what if it had exploded on takeoff?) but Cassini is still on course to enter orbit around Saturn next July. It will then continue to take readings and pictures for many years, while a small probe will be despatched for a 2½ hour descent onto the surface of Saturn's largest moon, Titan. Watch this space.
Saturnday
