You are here


August 23, 2011

It is a world like no other. Geysers of gas and dust spew high into the sky. Flowing ice carves a landscape that looks like the skin of a cantaloupe. And it's so cold that water freezes as hard as granite.

This is Triton, the largest moon of Neptune, the outermost planet in the solar system. It's a little smaller than our own moon, but a lot more interesting. It has a polar ice cap, a thin atmosphere, and a global coating of ice. And it's so far from the Sun that temperatures hover around 390 degrees below zero Fahrenheit.

Most of what we know about Triton came from a spacecraft that flew past it more than 20 years ago. It photographed a landscape of subtle shades of pink, brown, and blue. Much of it resembles a cantaloupe, with ridges thousands of feet tall. This wrinkly terrain may have been carved by flowing ice.

The most intriguing discovery was the geysers. They shoot about five miles high, where high-altitude winds blow them parallel to the surface. Dark spots on Triton's surface may have been created by other geysers over the past millennium -- eruptions that help make this frigid moon one of the most interesting in the solar system.

If you have dark skies and a telescope, this is a good time to look for Neptune. It lines up opposite the Sun, so it's brightest for the year, and it's in view all night. It looks like a tiny blue-green star in Aquarius. To see Triton, though, you need a bigger telescope -- or your own spacecraft.


Script by Damond Benningfield, Copyright 2011


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.