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Shrinking Storm on Jupiter（星)
It's snowing, but the clouds are red. The wind howls at 400 miles an hour, faster than a hurricane.And it's colder than the North Pole. Named the Great Red Spot , this storm is on Jupiter, the largest planet that goes around the Sun.The storm is shrinking. No one knows why—or what it will do next.
Astronomers discovered the Great Red Spot by looking at Jupiter through telescopes.The spot, once estimated to be 25,500 miles across, was just 10.250 miles wide when the Hubble Space Telescope last observed it."It 's at the smallest size that we've ever seen." says Dr. Amy Simon,an astronomer who studies the storm.It's also changing shape.looking more like a circle than its usual oval.
Jupiter differs greatly from Earth It 's made mostly of hydrogen and helium(氦). But most of the hydrogen and helium on Jupiter is not in the form of gas. Instead, Jupiter 's great gravity squeezes the hydrogen and helium, turning most of these elements into a liquid. Only the outer part of Jupiter is gas.And that 's where the Great Red Spot is.No one knows why the Great Red Spot is red. Like Jupiter's air, the spot is made mostly of hydrogen and helium gases. But they lave no color. So something else must color the spot red.
Mysteries abound about the spot, such as what powers it and why it is so red. Now another one arises. The Great Red Spot has lasted longer than any storm on Earth.On Earth, hurricanes weaken when they move from sea to land. and when they move north or south.Neither of these things happens on Jupiter. Yet the storm is shrinking. "Could it disappear?"
asks Dr. Simon. "Would I bet money on it one way or the other? Probably not."
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