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Sparkly Rings

December 28, 2011

The rings of Saturn may be the most famous feature of any planet in the solar system. Yet there’s not really much to them — enough rock, ice, and dust to make up a small moon. The rings span a couple of hundred thousand miles, though, so they reflect a lot of sunlight, making Saturn appear much brighter than the planet alone.

A system of rings around another planet may enhance its brightness, too — enough for us to see the planet across a distance of 25 light-years.

The planet orbits Fomalhaut, the brightest star of Piscis Austrinus, the southern fish. It’s low in the south at nightfall, but it’s the only bright star in that region of the sky, so it stands out.

Fomalhaut is only a few percent the age of the Sun. It’s still encircled by a giant cloud of dust — possible leftovers from the era of planet formation. In fact, a few years ago, images from Hubble Space Telescope revealed a bright object moving through that disk — a possible planet.

The pictures show nothing more than a dot of light. But it’s far brighter than any planet should be, even if it’s a giant like Jupiter, the giant of our own solar system.

The extra brightness could come from a giant system of rings around the planet — a disk of material similar to the disk that surrounds Fomalhaut itself. If so, the disk is so large and massive that it could be forming moons — tiny worlds born from the bright rings of a distant planet.

We’ll talk about another distant planet tomorrow.


Script by Damond Benningfield, Copyright 2011


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