Home→Collections→Solar System
Discovery Of Icy Red Sphere Tests Limits Of Solar SystemMarch 16, 2004|By Guy Gugliotta The Washington PostAstronomers have identified an icy, red, planet-like object orbiting the sun 8 billion miles away, a distance that is nearly three times as far as Pluto and stretches the limits of the solar system far beyond anything yet discovered.Scientists said the object may the first visible evidence of the Oort cloud, a massive spherical shell of comets thought to be loosely orbiting the sun and extending outward almost halfway to the nearest star.Should the object prove to be part of the Oort cloud, it could also provide new evidence supporting the theory that the early solar system was formed when the sun was part of a closely knit cluster of stars.The discovery has already set off a debate about whether the object is a planet. "In my opinion [a planet] has to be more massive than any other object in a similar location," said astronomer Michael Brown, of the California Institute of Technology, who led the team that observed the object at California's Palomar Observatory. "Our prediction is that there are going to be many, many more of these."Regardless of the final determination, the discovery substantially enlarges the solar system and adds evidence that its nether reaches may be sprinkled with countless dwarf planets, planetoids and would-be comets far beyond the gas giants Saturn, Uranus and Neptune."There's absolutely nothing else like it in the solar system," Brown said in a telephone news conference from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We didn't think we'd ever find something in the Oort cloud this close."Brown said the team has provisionally named the object "Sedna," after the Inuit goddess of the sea. "We knew it would be the coldest, most distant object in the solar system," he said, "and we had decided that it would be right to name it after an Arctic deity."He said Sedna is between 800 and 1,100 miles in diameter -- at most two-thirds the size of Pluto, or one-seventh the size of Earth.The team identified Sedna from a series of three photographs taken with Palomar's Samuel Oschin telescope in a three-hour period on Nov. 14, 2003.Sedna appeared as a tiny red point of light, moving across the photograph in each successive exposure, a giveaway that it was a solar system object.Further observations determined that Sedna was moving in a pronounced elliptical orbit, and at its present distance of 8 billion miles was probably as close to Earth as it would ever be, Brown said. At its extreme, Sedna will be 84 billion miles from Earth, taking 10,500 years to complete an orbit."We don't know what it's made of," Brown said, noting that Sedna was one of the reddest objects in the solar system, rivaling Mars, and very bright. "We have been unable to figure out what sort of material is red and reflective," he said. "Our hypothesis is that it is half-rock and half-ice."Brown also said Sedna rotates slowly, an indication that it probably has a moon.Sedna was observed well beyond the farthest objects so far discerned in the Kuiper Belt, a shell of small icy bodies, including Pluto, between 2.8 billion and 4.7 billion miles from the sun.Brown suggested Sedna could thus be the first object ever seen from the Oort cloud."Not so fast," said planetary scientist Alan Stern, of the Southwest Research Institute, in Boulder, Colo. "This is quite an exciting find, but the jury is out on whether this is the Oort cloud or the Kuiper Belt. We don't know much about it yet. We need to do the work."Stern, lead scientist for NASA's New Horizons mission to Pluto and the Kuiper Belt, praised the Sedna discovery for demonstrating the outer solar system's large population of dwarf planets, of which Sedna appears to be one. "It's big enough for gravity to make it round," Stern said. "You can argue whether it's major or minor, but it's a planet by any definition."
 Bosh, Wade break out of their funk?Chavez Confession Numbs CourtroomDo nicknames on jerseys go against Heat "sacrifice" mantra?Do Heat appreciate magnitude of Game 5?Could Heat find value in NBA free agency?Would Heat give Peace a chance? Related ArticlesIf Sedna Isn't A Planet, Is Pluto?April 4, 2004Telescopic Sights Free Of Earth`s Murky Atmosphere, The...December 9, 1986Starry-eyed Optimism At NasaJuly 13, 1997Space Telescope Shows Birth Of Solar SystemsDecember 17, 1992Find More Stories AboutSolar SystemIndex by Keyword|Index by Date|Privacy Policy|Terms of ServicePlease note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.