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[[Image:Comet wild 2.jpg|right|thumb|Photograph of the comet code named ''Wild 2''|250px]]

[[Image:Comet wild 2.jpg|right|thumb|Photograph of the comet code named ''Wild 2''|250px]]

Comets in orbit around stars may be highly eplitical rather than circular ( such as planets ) which takes them past the orbit of pluto.  Some mass of the comet will sublimate with each pass by the sun and after many passes the comet may no longer be active and be simply an asteroid.

A '''comet''' is a ball of frozen gases, ice, and dust, typically having a diameter of less than five kilometers. A comet develops a tail composed of its constituent materials, in gaseous or liquid form, when it is close enough to the sun for some of the frozen material to melt. Comet tails can be millions of kilometers in length and always "point" away from the sun due to the pressure of the [[solar wind]].

 

Comet [[orbit]]s around the sun may be highly [[elliptical]], rather than nearly circular (such as planets), which takes them out past the orbit of [[Pluto]].  Some of the mass of the comet will [[sublimate]] with each pass by the sun and after many passes the comet may no longer be active and be simply an [[asteroid]].

 

[[category:astronomy]]

[[category:astronomy]]