Beautiful clouds swirl through the atmosphere of Jupiter, the largest planet in the solar system, in this view from the Voyager 1 spacecraft. The thin orange diagonal band in the top half of the image is a jetstream that blows at about 275 miles per hour (120 meters/second). Some of the cloud features in this image are larger than the contiguous United States. [NASA/JPL]
Cirrus clouds are a common sight at this time of year — high, thin streamers of ice.
Clouds are common sights on other worlds, too. But many of those clouds aren’t made of water. The clouds on Venus, for example, are made of sulfuric acid, while those on Titan, the largest moon of Saturn, are made of methane and ethane. And on Jupiter, the solar system’s largest planet, the clouds at the top of the atmosphere are made of ammonia.
Jupiter is basically a big ball of gas that consists mainly of hydrogen and helium, the lightest chemical elements, with a smattering of carbon, oxygen, nitrogen, and other elements. At the top of Jupiter’s atmosphere, the hydrogen and nitrogen come together to make ammonia, which condenses to form a layer of clouds that’s about 30 miles thick. A bit of sulfur in the atmosphere mixes with other elements to color the clouds orange, tan, and brown.
Sometimes, a gap opens in the clouds, allowing us to see the layer below them. That layer contains clouds of liquid water, which look white. The clouds produce big thunderstorms, with lightning a thousand times more powerful than anything here on Earth.
Jupiter’s clouds reflect a lot of sunlight, which helps make the giant planet one of the brightest objects in the night sky. Right now, it rises a couple of hours after sunset, and looks like a brilliant cream-colored star. And tonight, it rises just above the Moon — a beautiful sight for a cloud-free night.
Script by Damond Benningfield, Copyright 2012
For more skywatching tips, astronomy news, and much more, read StarDate magazine.