Background:
Uranus is the seventh planet from the Sun, unknown to the Greeks, Egyptians and all ancient civilizations, since it is at the limit of detection with the naked eye under dark skies and therefore undistinguishable from a dim star. Uranus was named by Johan Bode (the same as in Titius-Bode law). In Greek mythology, Uranus was the personification of Heaven and ruler of the world, regarded as the husband and son of Gaea (Earth) and father of the Titans, Furies and Cyclopes; he was overthrown by his son Cronus (Saturn), who was also Jupiter's father.

William Herschel discovered this planet in 1781 when he was doing a survey of the stars in the constellation Gemini with his 6-inch telescope.


Science Daily — As the rings of Uranus swing edge-on to Earth - a short-lived view we get only once every 42 years - astronomers observing the event are getting an unprecedented, glare-free view of the rings and the fine dust that permeates them.

This series of images from NASA's Hubble Space Telescope shows how the ring system around the distant planet Uranus appears at ever more oblique (shallower) tilts as viewed from Earth - culminating in the rings being seen edge-on in three observing opportunities in 2007. The best of these events appears in the far right image taken with Hubble's Wide Field Planetary Camera 2 on August 14, 2007. (Credit: NASA, ESA, and M. Showalter (SETI Institute))

The rings were discovered in 1977, so this is the first opportunity astronomers have had to observe a Uranus ring crossing and perhaps to discover a new moon or two.

While the Keck II telescope and the Hubble Space Telescope have been looking at the planet for years in anticipation of this event, ground-based telescopes in Chile and southern California have targeted the planet during the actual ring crossing.

The inner rings are much more prominent than expected, revealing material in otherwise empty regions of the system of rings.

"People tend to think of the rings as unchanging, but our observations show that not to be the case," said de Pater, a UC Berkeley professor of astronomy. "There are a lot of forces acting on small dust grains, so it is not that crazy to find that the arrangement of rings has changed."



Full story at:

http://www.sciencedaily.com/releases/2007/08/070823141039.htm