Out of This World

The scientific theory I like best is that the rings of Saturn are composed entirely of lost airline luggage.
-Mark Russell

I'd like to end this year with an amazing image from the Cassini spacecraft orbiting Saturn. The large moon in front is called Dione. In the background you can see Saturn’s rings on the left, nearly edge-on, and two more moons as well: Epimetheus, only 130 km (70 miles) across, and Pandora, slightly smaller at 104 km across.

Pandora was discovered in 1980 by the Voyager 1 probe, Epimetheus was discovered by astronomers in 1966. Dione was discovered long ago in 1684 by the astronomer Cassini (for whom the space probe is named). At 1122 km in diameter, Dione is the 15th largest moon in the Solar System and is more massive than all known moons smaller than itself combined.

Bottom Line

This so reminds me of covers of Sci-Fi magazines of the 1950's with an imaginary sky of a planet far away but this is real and Cassini is there; seven years imaging Saturn and its moons.

May 2012 bring amazement and wonders and joy to one and all.

Bonus Image

Another excellent photo from Astronomy Picture of the Day. You may recall that a lunar eclipse is caused by the moon passing through the Earth's shadow but this multiple-exposure really makes that shadow visible. (And gives one a feeling for the size of the moon compared to Earth)