Rings of Uranus
The rings of Uranus were discovered on March 10, 1977, by James L. Elliot, Edward W. Dunham, and Jessica Mink. William Herschel had also reported observing rings in 1789; modern astronomers are divided on whether he could have seen them, as they are very dark and faint. By 1978, nine distinct rings were identified. Two additional rings were discovered in 1986 in images taken by the Voyager 2 spacecraft. Two outer rings were found in 2003–2005 in Hubble Space Telescope photos.
About Rings of Uranus in brief
The rings of Uranus were discovered on March 10, 1977, by James L. Elliot, Edward W. Dunham, and Jessica Mink. William Herschel had also reported observing rings in 1789; modern astronomers are divided on whether he could have seen them, as they are very dark and faint. By 1978, nine distinct rings were identified. Two additional rings were discovered in 1986 in images taken by the Voyager 2 spacecraft, and two outer rings were found in 2003–2005 in Hubble Space Telescope photos. The rings are intermediate in complexity between the more extensive set around Saturn and the simpler systems around Jupiter and Neptune. They are probably composed of water ice with the addition of some dark radiation-processed organics. The ring system contains little dust overall; it consists mostly of large bodies 20 cm to 20 m in diameter. The Uranian ring system probably originated from the collisional fragmentation of several moons that once existed around the planet. After colliding, the moons probably broke up into many particles, which survived as narrow and optically dense rings only in strictly confined zones of maximum stability. The mechanism that confines the narrow rings is not well understood. Initially it was assumed that every narrow ring had a pair of nearby shepherd moons corralling it into shape. In 1986 ‘Voyager 2’ discovered only one such shepherd pair around the brightest ring.
Two more faint rings were revealed, bringing the total to eleven. The latter were dubbed 4, 5 and 6—according to the numbering of the occultation events in one paper. In 2003, an additional pair of previously unseen rings were previously unseen in 2003-2005. Uranus’s ring system was the second to be discovered in the Solar System, after that of Saturn, after the rings of Saturn. In the order of increasing distance from the planet the 13 known rings are designated 1986U2Rζ, 6, 5, 4, α, β, η, γ, δ, λ, ε, ν and μ. The majority of UranUS’s rings are opaque and only a few kilometres wide. The relative lack of dust in the ring system may be due to aerodynamic drag from the extended Uranian exosphere. In the two centuries between 1797 and 1977 the rings are rarely mentioned, if at all. This casts serious doubt on whether Herschel could have saw anything of the sort while hundreds of other astronomers saw nothing. The Keck Telescope in Hawaii has since confirmed that Herschel’s notes were published in a Royal Society journal in 1797. They deduced that a system of narrow rings was present. The former was dubbed 5 and 4, according to one paper, and the latter was dubbed 4 and 5. Later they found four additional rings: between the β and γ ring and three inside the α ring. These designations have been used as names since the rings’ names since 2003 –2005.
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This page is based on the article Rings of Uranus published in Wikipedia (as of Nov. 22, 2020) and was automatically summarized using artificial intelligence.
