Credit & Copyright: International Astronomical UnionExplanation: How many planets are in the Solar System? This popular question now has a new formal answer according the International Astronomical Union (IAU): eight. Last week, the IAU voted on a new definition for planet and Pluto did not make the cut. Rather, Pluto was re-classified as a dwarf planet and is considered as a prototype for a new category of trans-Neptunian objects. The eight planets now recognized by the IAU are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Solar System objects now classified as dwarf planets are: Ceres, Pluto, and the currently unnamed 2003 UB313. Planets, by the new IAU definition, must be in orbit around the sun, be nearly spherical, and must have cleared the neighborhood around their orbits. The demotion of Pluto to dwarf planet status is a source of continuing dissent and controversy in the astronomical community.
1999 2000 2001 2002
2003 2004 2005 2006
2007 2008 2009 2010
2011 2012 2013 2014
2015 2016 2017 2018
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Publikacii s klyuchevymi slovami:
planety - planetnaya sistema - solnechnaya sistema
Publikacii so slovami: planety - planetnaya sistema - solnechnaya sistema
Vse publikacii na tu zhe temu >>