The great age of planetary exploration began back in the early 1960s with simple (!) probes to the Moon and Mars. Probably the best-known planetary explorers (to the public, anyway) have been the Vikings to Mars, the Mars Global Surveyor, the Mars Pathfinder, the Voyager missions to the outer planets, and the recently-ended Galileo mission. Today we have more spacecraft on the way to Mars, scheduled for arrival in early 2004, and the Cassini Mission to Saturn.
Cassini has not been sleeping on its way out to the ringed planet. Its most recent picture is of Jupiter and as you can see, it’s a beauty! This true color mosaic of Jupiter was made from a series of 27 images taken by Cassini’s narrow angle camera on December 29, 2000. At the time the spacecraft was doing a flyby of the planet and gaining a gravity assist to help it on to Saturn. This is the most detailed global color portrait of Jupiter ever produced. The smallest features you can see in this image are about 60 km (37 miles) across.
My favorite bits about Jupiter are the Great Red Spot — the storm just below the center of the image — and the swirling cloud tops in the belts and zones of the planet. Three Earths would fit comfortably across the spot — it’s that big. The smaller storms would be huge by Earth standards, covering most of one hemisphere in clouds and battering it with high winds.
In the range of strange in this solar system, Jupiter seems weird to us — but when you think about it, four planets in the solar system are gas giants (Jupiter, Saturn, Uranus, and Neptune). Four are “hardbodies” (Earth, Mars, Venus, Mercury). Pluto is a hardbody with a covering of ice. So, really, Jupiter isn’t all that weird. But, to us on Earth, used to breathable air, reasonable winds (as opposed to the highest windspeeds of around 650 kilometers per hour (about 400 mph)), and a solid surface, Jupiter probably does seem like kind of a colorful, but alien place.
While this is a close-up view from a spacecraft near Jupiter, you can get your own view (just not as detailed) of the planet in the night-time sky. This time of year (November), it’s low in the eastern skies right around 10 p.m., smack in the middle of Gemini. If you can (and you’re dressed warmly enough), wait until midnight, when it’s a little higher in the sky. It will look like a really bright star, but it won’t be twinkling and if you look at it through binoculars or a small telescope, you’ll see that it’s a planet! I’ll write more on it later on this year, but don’t hesitate to go check it out. Here’s a finder map:
