Asteroids are minor planets, especially those of the inner Solar System. The larger ones have also been called planetoids. These terms have historically been applied to any astronomical object orbiting the Sun that did not show the disc of a planet and was not observed to have the characteristics of an active comet, but as minor planets in the outer Solar System were discovered, they were often distinguished from traditional asteroids.[1] Their volatile-based surfaces were found to resemble comets. They are grouped with the outer bodies—centaurs, Neptune trojans, and trans-Neptunian objects—as minor planets, which is the term preferred in astronomical circles. In this article the term "asteroid" refers to the minor planets of the inner Solar System.

Weird Alien Worlds Beyond Our Solar System:http://youtu.be/ofxY-mb503Y

Black Holes And The Faith of Our Universe:http://youtu.be/SvaeuL8tamw

The Cosmos:Narrated By Morgan Freeman:http://youtu.be/s1f4AoMkN0g

Biggest Most Complex Machine in History:http://youtu.be/ttoahynG184

Lightning Sprites at the Edge of Space:http://youtu.be/pYVr2XH_1FU

Biggest Things in The Universe:http://youtu.be/qsc4kzYpmkQ

Can Mars be Colonized ?:http://youtu.be/f1Q9CPe1JIw

Wild and Destructive Weather:http://youtu.be/v5E06fg1y2Q

Hubble:Exploring the Universe:http://youtu.be/CW2d32Go7yk

Hubble:Exploring the Milkyway:http://youtu.be/iR-cnY-Rq7Q

Neil Armstrong the First Human on The Moon:http://youtu.be/yqQgrGQnYQM