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Ceres: Asteroid or Planet?
| Title |
Ceres: Asteroid or Planet? |
| Explanation |
Is Ceres [ http://en.wikipedia.org/wiki/Ceres_%28asteroid%29 ] an asteroid [ http://www.nineplanets.org/asteroids.html ] or a planet? Although a trivial designation to some, the recent suggestion by the Planet Definition Committee [ http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_committee.html ] of the International Astronomical Union [ http://www.iau2006.org/mirror/www.iau.org/NEWS.55.0.html ] would have Ceres reclassified from asteroid to planet. A change in taxonomy might lead to more notoriety for the frequently overlooked world. Ceres [ http://www.pantheon.org/articles/c/ceres.html ], at about 1000 kilometers across, is the largest object in the main asteroid belt [ http://www.solstation.com/stars/asteroid.htm ] between Mars and Jupiter. Under the newly proposed criteria [ http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_release.html ], Ceres would qualify as a planet because it is nearly spherical and sufficiently distant from other planets. Pictured above [ http://hubblesite.org/newscenter/newsdesk/archive/releases/2005/27/image/a ] is the best picture yet of Ceres, taken by the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap010806.html ] as part of a series of exposures ending in 2004 January. Currently, NASA's Dawn mission [ http://dawn.jpl.nasa.gov/ ] is scheduled to launch in 2007 June to explore Ceres and Vesta [ http://antwrp.gsfc.nasa.gov/apod/ap060820.html ], regardless of their future designations. |
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A Map of Asteroid Vesta
| Title |
A Map of Asteroid Vesta |
| Explanation |
Vesta is a huge rock 500 kilometers across that orbits out past Mars [ http://www.seds.org/nineplanets/nineplanets/mars.html ]. In 1997, the above map [ http://oposite.stsci.edu/pubinfo/PR/97/27/9727c.html ] of Vesta [ http://en.wikipedia.org/wiki/4_Vesta ] created using the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap970306.html ] was released showing a rugged surface highlighted by a single crater spanning nearly the entire length of the asteroid [ http://en.wikipedia.org/wiki/Asteroid ]. The large crater dominates the lower part of the above false-color conglomerate image [ http://hubblesite.org/newscenter/newsdesk/archive/releases/1997/27/image/e ]: blue indicates low terrain, while red indicates raised terrain. Evidence indicates that Vesta [ http://oposite.stsci.edu/pubinfo/background-text/vesta.txt ] underwent a tremendous splintering collision [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1996A%26A...316..248M ] about a billion years ago. In October 1960, a small chunk of this rock believed to have originated on Vesta [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001M%26PS...36..501D ] fell to Earth [ http://antwrp.gsfc.nasa.gov/apod/ap050102.html ] and was recovered in Australia [ https://www.cia.gov/cia/publications/factbook/geos/as.html ]. Vesta is considered by some to be a candidate for reclassification into a planet [ http://www.iau2006.org/mirror/www.iau.org/iau0601/iau0601_release.html ]. |
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Small Worlds Ceres and Vesta
| Title |
Small Worlds Ceres and Vesta |
| Explanation |
Ceres [ http://www.planetary.org/explore/topics/asteroids_and_comets/ ceres.html ] and Vesta [ http://hubblesite.org/newscenter/archive/releases/ 1997/27 ] are, respectively, only around 950 kilometers and 530 kilometers in diameter - about the size of Texas and Arizona. But they are two of the largest of over 100,000 minor bodies [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/ asteroidfact.html ] orbiting in the main asteroid belt [ http://www.solstation.com/stars/ asteroid.htm ] between Mars and Jupiter. These remarkably detailed Hubble Space Telescope images [ http://hubblesite.org/newscenter/archive/releases/ 2007/27/ ] show brightness and color variations across the surface of the two small worlds. The variations could represent large scale surface features or areas of different compositon. The Hubble image data will help astronomers plan for a visit by the asteroid-hopping Dawn spacecraft [ http://dawn.jpl.nasa.gov/index.asp ], scheduled for launch on July 7 and intended to orbit first Vesta [ http://antwrp.gsfc.nasa.gov/apod/ap070525.html ] and then Ceres [ http://antwrp.gsfc.nasa.gov/apod/ap060821.html ] after a four year interplanetary cruise. Though Shakespeare [ http://www.phrases.org.uk/meanings/305250.html ] might not have been impressed, nomenclature introduced by the International Astronomical Union in 2006 classifies nearly spherical Ceres as a dwarf planet [ http://en.wikipedia.org/wiki/Dwarf_planet ]. |
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A Map of Asteroid Vesta
| Title |
A Map of Asteroid Vesta |
| Explanation |
Vesta is a huge rock 500 kilometers across that orbits out past Mars [ http://www.seds.org/nineplanets/nineplanets/mars.html ]. Last week, the above map [ http://oposite.stsci.edu/pubinfo/PR/97/27/9727c.html ] of Vesta [ http://www.hawastsoc.org/solar/eng/vesta.htm ] created using the Hubble Space Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap970306.html ] was released showing a rugged surface highlighted by a single crater spanning nearly the entire length of the asteroid [ http://izzy.online.discovery.com/DCO/doc/1012/world/starshack/starshack052296/starshack.html ]. The large crater dominates the lower part of the false-color conglomerate image: blue indicates low terrain, while red indicates raised terrain. Evidence indicates that Vesta [ http://oposite.stsci.edu/pubinfo/background-text/vesta.txt ] underwent a tremendous splintering collision [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996A%26A%2E%2E%2E316%2E%2E248M&db_key=AST&nosetcookie=1 ] about a billion years ago. In October 1960, a small chunk of this rock believed to have originated on Vesta [ http://stardate.utexas.edu/radio/StarDateDB.FM$RETRIEVE?value=12/24/1994&field=ScriptAirDate&html=Test+Request+Date ] fell to Earth [ http://antwrp.gsfc.nasa.gov/apod/ap960819.html ] and was recovered in Australia [ http://www.netinfo.co.uk/factbook/21e2.html ]. |
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