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Moon and Companions

StarDate: 
September 8, 2016

There are many great examples of how astronomy has progressed in recent decades, from the discovery of dark energy to the confirmation of thousands of planets in other star systems.

For another example, consider the bright light below the Moon this evening: Saturn. Until the late 1970s, astronomers knew of only about 10 moons for the giant planet. Since then, the number has jumped to the 60s.

Some of those discoveries came from the twin Voyager spacecraft, which flew past Saturn in the early ’80s. Their cameras detected several small, dark satellites orbiting far from Saturn.

Other discoveries came more recently, from ground-based telescopes, mainly in Hawaii. Researchers spent years searching around Saturn and the other giant planets for previously unseen moons. Their efforts were rewarded with dozens of new moons. And finally, the Cassini spacecraft found a half-dozen more moons of Saturn early in this century.

None of these recently discovered worlds is anything special. Most are only a few miles in diameter. They’re oddly shaped chunks of rock — perhaps debris from bigger moons, or asteroids captured by Saturn’s gravity. Even so, they tell us a lot about the environment of the outer solar system — and about how quickly the science of astronomy is advancing.

Again, look for Saturn below the Moon this evening. The star Antares is below Saturn, with the brighter planet Mars to their left — a beautiful grouping in the evening sky.

 

Script by Damond Benningfield

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