Saturn is like an old friend these days. From orbit around Saturn, the Cassini spacecraft has beamed back thousands of pictures of the planet and its moons and rings. It’s also probed their composition, and measured magnetic fields and radiation belts. That’s given us a pretty thorough dossier on the solar system’s second-largest planet.
The getting-acquainted process actually began long before Cassini, though. Thirty years ago today, Voyager 1 flew past the planet. During several weeks of observations, the craft told us more about the planet than centuries of ground-based observations.
Voyager’s close-ups showed that Saturn is encircled by thousands of narrow rings, not a few broad ones. They showed the hazy atmosphere of Saturn’s largest moon, Titan, and the icy surfaces of several smaller moons.
Voyager also measured the composition of Saturn’s atmosphere, and it measured wind speeds at the top of the atmosphere of up to a thousand miles an hour. And it measured the length of Saturn’s day -- something that’s tough to do for a planet that doesn’t have a solid surface.
After it passed Saturn, Voyager 1 headed away from the realm of the planets. Today, it’s exploring the fringes of the solar system -- three decades after providing an introduction to the planet Saturn.
And you can see Saturn at dawn this month. It’s well up in the east-southeast at first light, and looks like a bright golden star.
Script by Damond Benningfield, Copyright 2010