You are here

Moon and Companions

January 23, 2011

If you look at them from space, the north and south poles of Earth look a lot alike -- they're both covered with ice. But if you probe beneath the ice, you'll find a big difference. The northern ice cap floats atop the ocean, while the southern cap floats atop the continent of Antarctica.

The poles of some other planets are pretty much the same no matter how deep you look. An example is Saturn, the second-largest planet in the solar system. It's high in the sky at first light tomorrow, well to the upper left of the Moon. The star Spica is a little farther to the Moon's left.

The Cassini spacecraft has found that giant storms swirl around both of Saturn's poles. They're thousands of miles across, with winds that top out at close to 350 miles an hour -- about twice the speed of even the most powerful hurricanes here on Earth.

The storms are a lot like the hurricanes on Earth. As water from thunderstorms falls deep into Saturn's atmosphere, it releases heat. The heat drives the storms -- just like Earthly hurricanes.

There's one difference between the storms at the north and south poles: The one at the north pole is surrounded by clouds that form a hexagon -- a shape that hasn't changed in at least a quarter of a century. Scientists have several possible explanations for the hexagon, but none of them has been confirmed, so the difference in Saturn's poles remains a mystery.

We'll talk about one of Saturn's moons tomorrow.

Script by Damond Benningfield, Copyright 2010


Get Premium Audio

Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.