This image, taken over 9 years ago by the Cassini-Huygens spacecraft on its way to Saturn, is still hailed as one of the best photos ever taken of Jupiter.
Actually a carefully crafted composite of 27 images, this image took more than an hour to capture. It later had to be painstakingly adjusted to account for planetary movement, lighting differences, etc., but what you see here is an accurate true-color view of the gas giant from December 29, 2000.
Jupiter is almost entirely atmosphere. Its colors come from the compostion of its clouds….some water, but a lot of ammonia, methane and hydrogen sulfides. Its winds, powered by internal heat and pressure and its incredibly fast rotation – the entire planet rotates in 10 hours, as compared to our 24 – clock in at over 30o mph. These factors combine to create high-powered jet streams, swirling eddies and massive storms. Some, like the famous Great Red Spot seen here, have lasted for hundreds of years and could cover the Earth several times. In fact, at 11 times the diameter of Earth, most of the storms seen here would cover much of our planet. The storms on Jupiter also generate massive lightning, many times larger than the kind seen on Earth.
In August 2011 the Juno mission will launch, its objective to exclusively study Jupiter’s atmosphere and magnetic field, and look further into the existence of a metallic hydrogen and icy-rock core. It will reach the giant planet in 2016.
Image credit: NASA/JPL/Space Science Institute