The rings of Saturn are the most extensive planetary ring system of any planet in the Solar System. They consist of countless small particles, ranging in size from micrometres to metres, that form clumps that in turn orbit about Saturn. The ring particles are made almost entirely of water ice, with some contamination from dust and other chemicals.
On October 6, 2009, the discovery was announced of a tenuous disk of material in the plane of and just interior to the orbit of Phoebe, which can be loosely described as another ring. This ring is tilted 27 degrees from Saturn's equatorial plane (and the other rings). It extends from 128 to 207 times the radius of Saturn; Phoebe orbits the planet at an average distance of 215 Saturn radii. The ring is about 20 times as thick as the diameter of the planet. Since the ring's particles are presumed to have originated from impacts (micrometeoroid and larger) on Phoebe, they should share its retrograde revolution, which is opposite to the orbital motion of the next inner moon, Iapetus. Ring material migrates inward due to reemission of solar radiation, and would thus strike the latter's leading hemisphere, possibly causing the two-tone coloration of that moon. Although very large, the ring is virtually invisible—it was discovered using NASA's infra-red Spitzer Space Telescope. The existence of the ring was proposed in the 1970s by Joseph Burns of Cornell University.The discovery was made by Anne J. Verbiscer and Michael F. Skrutskie (of the University of Virginia) and Douglas P. Hamilton (of the University of Maryland, College Park) and published in Nature.
This artist's rendering released by NASA's Jet Propulsion Laboratory on Tuesday Oct. 6, 2009 shows the biggest but never-before-seen ring around Saturn, spotted by NASA's Spitzer Space Telescope. The inset shows an enlarged image of Saturn, as seen by the W.M. Keck Observatory at Mauna Kea, Hawaii, in infrared light. The bulk of the ring material starts about six million kilometers (3.7 million miles) away from the planet and extends outward roughly another 12 million kilometers (7.4 million miles). The newly found ring is so huge it would take 1 billion Earths to fill it, JPL said. (AP Photo/Artist's Rendering courtesy NASA's Jet Propulsion Laboratory)
On October 6, 2009, the discovery was announced of a tenuous disk of material in the plane of and just interior to the orbit of Phoebe, which can be loosely described as another ring. This ring is tilted 27 degrees from Saturn's equatorial plane (and the other rings). It extends from 128 to 207 times the radius of Saturn; Phoebe orbits the planet at an average distance of 215 Saturn radii. The ring is about 20 times as thick as the diameter of the planet. Since the ring's particles are presumed to have originated from impacts (micrometeoroid and larger) on Phoebe, they should share its retrograde revolution, which is opposite to the orbital motion of the next inner moon, Iapetus. Ring material migrates inward due to reemission of solar radiation, and would thus strike the latter's leading hemisphere, possibly causing the two-tone coloration of that moon. Although very large, the ring is virtually invisible—it was discovered using NASA's infra-red Spitzer Space Telescope. The existence of the ring was proposed in the 1970s by Joseph Burns of Cornell University.The discovery was made by Anne J. Verbiscer and Michael F. Skrutskie (of the University of Virginia) and Douglas P. Hamilton (of the University of Maryland, College Park) and published in Nature.
This artist's rendering released by NASA's Jet Propulsion Laboratory on Tuesday Oct. 6, 2009 shows the biggest but never-before-seen ring around Saturn, spotted by NASA's Spitzer Space Telescope. The inset shows an enlarged image of Saturn, as seen by the W.M. Keck Observatory at Mauna Kea, Hawaii, in infrared light. The bulk of the ring material starts about six million kilometers (3.7 million miles) away from the planet and extends outward roughly another 12 million kilometers (7.4 million miles). The newly found ring is so huge it would take 1 billion Earths to fill it, JPL said. (AP Photo/Artist's Rendering courtesy NASA's Jet Propulsion Laboratory) 
No comments:
Post a Comment