"data-medium-file =" http://www.clarksvilleonline.com/wp-content/uploads/2011/08/NASA.jpg "data-large-file =" http://www.clarksvilleonline.com/wp -content / uploads / 2011/08 / NASA.jpg "class =" alignment line full "wp-image-85503" title = "NASA – National Aerospace Authority" src = "http://www.clarksvilleonline.com / wp-content / uploads / 2011/08 / NASA.jpg "alt =" NASA – National Aerospace Authority "width =" 200 "height =" 165 "/> Pasadena, CA – December 2018 Closely approached by the large, near-Earth asteroid 2003 SD220 gave astronomers an excellent opportunity to obtain detailed radar images of the surface and shape of the object and to improve understanding of its orbit.
The asteroid will safely fly past Earth on Saturday, December 22, 2018, at a distance of approximately 2.9 million kilometers (1.8 million miles). This is the closest approach of the asteroid in over 400 years and the closest to 2070, when the asteroid will be safe ely is approaching the earth a little closer.
These three radar images of the near-Earth asteroid 2003 SD220 were surveyed on the 15th and 17th December by coordinating the observations with the 230-foot (70-meter) antenna at Goldstone's Deep Space Communications Complex in California and the National Science Foundation's (NSF) 100-meter Green Bank Telescope in West Virginia. (NASA / JPL-Caltech / GSSR / NSF / GBO)
The radar images show an asteroid with a length of at least 1.6 km and a shape similar to that of an exposed section of a hippopotamus wading in a river
They were received from December 15-17 by coordinating observations with NASA's 70-meter antenna at the Goldstone's Deep Space Communications Complex in California, the 100-yard Green Bank of the National Science Foundation, and receiving a telescope in West Virginia the 305 meter long antenna of the Arecibo Observatory in Puerto Rico.
The Green Bank Telescope received the powerful microwave signals sent by either Goldstone or the NASA-funded Arecibo planetary radar known as the "bistatic radar configuration". The use of one telescope to transmit and another to receive can yield significantly more detail than a telescope, and it is a priceless technique to obtain high-resolution radar images of slowly rotating asteroids like this one.
These two radar images of near – Earth asteroid 2003 SD220 were shot on 18. and 19 December by coordinating observations with the Arecibo Observatory's 300-meter antenna in Puerto Rico and the National Science Foundation's (NSF) 100-yard Green Bank Telescope in West Virginia. The radar images show that the asteroid is at least 1.6 kilometers long. (NASA / Arecibo / USRA / UCF / GBO / NSF)
Photographers achieve unprecedented levels of detail and are comparable to those obtained from a spacecraft flyby, "said Lance Benner of the Jet Propulsion Laboratory in Pasadena, California, and the scientist who guided the observations from Goldstone.
"The Most Conspicuous Surface The feature is a distinctive ridge that appears to wrap partially around the asteroid at one end, covering approximately 330 feet [100 meters] over the surrounding terrain, with numerous small bright spots in the data The images also show an accumulation of dark, circular features on the right edge, which may be craters, "Benner explained.
The images confirm what was observed in earlier "light-curve" measurements of the sunlight reflected from the asteroid and the previous radar Arecibo Images: 2003 SD220 has an extremely slow rotation time of about 12 days.
It also seems to be a complex rotation similar to a badly thrown football. Known as "non-major axis" rotation, it is unusual for near-Earth asteroids, most of which revolve around their shortest axis.
With resolutions of up to 3.7 meters per pixel, the details of these images are displayed 20 times finer than what the asteroid had achieved three years ago in close proximity to Earth. The new radar data will create important restrictions on the density distribution of the interior of the asteroid – information that is only available for a few near-Earth asteroids.
"This year we were able to plan with our knowledge of the slow rotation of SD220 from 2003. A great series of radar images using the nation's largest single radio telescopes," said Patrick Taylor, senior scientist of the Universities Space Research Association (USRA) at Lunar and Planetary Institute (LPI) in Houston.
The new details that we have discovered in the geology of the SD220 of 2003 will allow us to reconstruct the shape and the state of rotation, as demonstrated by Bennu, the target of OSIRIS. REx mission, "said USRA scientist Edgard Rivera-Valentín at the LPI," detailed reconstructions of shape allow us to better understand how these small bodies have formed and evolved over time. "
Patrick Taylor conducted bistatic radar observations with the Green Bank Observatory, home of the Green Bank Telescope, the world's largest fully controllable radio telescope Rivera-Valentín will lead the reconstruction of the form of 2003 SD220 and head the observations of the Arecibo Observatory.
Asteroid 2003 SD220 was discovered on September 29, 2003 by astronomers at the Lowell Observatory near Earth (LONEOS) in Flagstaff Arizona (Arizona) – a NASA-supported project to explore a near-earth-object project (NEO), which is no longer in operation.
It is classified as a "potentially dangerous asteroid" due to its size and proximity to Earth orbit. However, these radar measurements refine the understanding of the orbit of the SD220 from 2003 and confirm that this is not a future threat to Earth.
The Arecibo, Goldstone, and USRA planetarium projects are funded by NASA's NASA's Near Earth Object Observations, the planetary planetary coordination office (PDCO), which manages the agency's planetary defense program.
The Arecibo Observatory is a National Science Foundation facility operated under a co-operation agreement with the University of Central Florida, Yang Enterprises, and the Universidad Metropolitana. GBO is a National Science Foundation facility operated under a collaboration agreement by Associated Universities, Inc.
. JPL hosts the Center for Near Earth Object Studies (CNEOS) for NASA's Near Earth Object Observation Program.
For more information on CNEOS, asteroids, and near-Earth objects, see:
others Information For NASA Planetary Defense Coordinating Office, see:
For more information on the National Science Foundation's Arecibo Observatory, see:
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Themes  Asteroid, Asteroid 2003 SD220, Earth, NASA's Goldstone Deep Space Communica, NASA's Jet Propulsion Laboratory, NASA's Near-Earth Object Program, National Aerospace Authority, Pasadena, Radar, Telescopes, University of Central Florida