(Click for larger view. Shots of Uranus’ ring system as it gradually turns its edge to us (it does this once every 42 years). The final image was taken in August 2007. (I de Pater/H Hammel/W M Keck))
There’s a BBC news story about the research this enables astronomers to do, along with more information about the evolution of the ring itself. That was taken with the ground-based Keck telescope. Here are some images of the same from the Hubble space telescope:
(Click for larger view. More information here. (NASA, ESA, and M. Showalter (SETI Institute)))
[Update #1: Phil has an excellent post on this, including (at the end) a reminder of an excellent (unashamedly juvenile, but clever) Futurama joke which is about the standard Uranus joke.]
[Update #2: Here’s a rather interesting BBC news story from a while back about how Uranus’ rings -officially discovered in 1977- may well have been discovered by Herschel way back in 1789, eight years after he discovered the planet itself. There’s some interesting -and not entirely unconvincing- speculation about why he might have been able to see it and why it had not been noticed in the intervening years.]
-cvj
Clifford: Hobby-ist is different from ring expert! And alot has happened in the planetary rings field since the Voyager days. Remember I was a scientific programmer for astronomers for almost 20 years (with my jobs driving my education) before I got my PhD. One big missing gap (and I’m sure I can think of others): I did not work on planetary atmospheres, i.e. radiative transfer problems.
Thanks Amara… I did not know you were a ring expert. Is there any aspect of solar system physics you have not worked on?!
-cvj
I have a special place in my heart for the Uranian rings. For ten years, as a kind of spare-time hobby (i.e. most of the time unpaid, in between my school and paid jobs), I made an analysis of the Voyager 2 PPS, RSS, and radio science Uranian ring data, in particular, studying the change of eccentricity of the Epsilon ring, the largest of the rings. At the time, it was the most interesting ring because its sharp edges indicated that some gravitational bounding process was in effect, but those theories were not well-tested yet. (Ah ha! now I know that electrostatic braking could presumeably do the same thing.) And Mark Showalter was my coauthor on the work, which was finally published in 1995 in AJ, so I couldn’t have done any better with an expert guiding my work. I would say that Mark is the world’s best observational planetary ring astronomer, and he just keeps getting better and better.
Since the Voyager days, the Keck (from the ground) with its adaptive optics is producing as good, if not better, data than Voyager. Imke de Pater, is the Keck rings expert, and, with Mark Showalter providing complementary data from the HST, have already have found several new Uranian rings. And more, with their dynamics colleague: Jack Lissauer, they have tracked the interactions of the many new Uranian moonlets and rings, resonances and all. The Uranian rings are a fascinating young system evolving on time scales from 10 to 10^7 years of dusty rings, big particle rings, embedded moonlets, …. it has everything!