More Cassini at Enceladus
A perfect place for some future Winter Olympics might be Enceladus, one of the moons of Saturn. Its entire surface is coated with ice. The ice reflects almost all of the sunlight that strikes the little moon, so it shines pure white. And the average surface temperature is around 330 degrees below zero Fahrenheit.
But there's also a good place for a lodge -- near the moon's south pole, where liquid water squirts from cracks in the crust. These regions are far warmer than the rest of the globe. And like bigger versions of Old Faithful, the geysers may erupt on a schedule.
Four long, wide cracks known as "tiger stripes" mar the crust near the south pole. Researchers say they appear to open and close on a regular schedule as the moon orbits Saturn. When Enceladus is closest to Saturn, the planet's gravity forces them open. When Enceladus is farther away, the strain is reduced, so the stripes close up.
As the stripes open, they release streams of liquid water that jet thousands of miles into space. One research team says the water may come from the edges of the tiger stripes themselves. The researchers say that as the sides of these fissures rub together, they generate heat, melting some of the ice.
We should know more about the tiger stripes pretty soon. The Cassini spacecraft is scheduled to fly just a few miles above Enceladus's south pole today, providing the best views yet of the moon's intriguing stripes.
Script by Damond Benningfield, Copyright 2008
For more skywatching tips, astronomy news, and much more, read StarDate magazine.