Comets are objects in the Solar System composed mainly of ice and dust. When their irregular orbits bring them near the Sun, comets give off a trail of gas and dust. This tail is called a coma, and is visible from Earth. Although they are similar to asteroids, comets are a different class of orbiting object, based on their visible tails.NASA-JPL: Near Earth Object Program FAQ

In February 2009, the comet Lulin, discovered by a teenager in China in 2007, is passing by the Earth. Lulin appears to be green; the color is from toxic gases.FOXNews.com: Strange Green Comet Passing by Earth Next Week (February 18, 2009) For those in United States, the comet was closest to Earth on the evening of February 23, 2009.The Tech Herald: NASA's Swift Gamma-ray Explorer monitors comet Lulin (February 23, 2009)

Lunin was first discovered in 2007, by Quanzhi Ye, a teenage student of astronomy in China.ScienceNews: A Green Visitor Makes its Approach (February 18, 2009) For Americans, the comet Lulin was closest to Earth on Monday, February 23, 2009, at 38 million miles away. Lulin's greenish hue is caused by the gases cyanogen and diatomic carbon.ScienceNews: A Green Visitor Makes its Approach (February 18, 2009) According to NASA, Comet Lulin's tail appears to be in front of the comet; a phenomena caused by an optical illusion.FOXNews.com: Strange Green Comet Passing by Earth Next Week (February 18, 2009)

Lulin is probably on its way out of the solar system and might not be seen again from Earth.Fox News: http://www.foxnews.com/story/0,2933,498705,00.html (February 24, 2009)

For Americans, Lulin can be seen to the right of Saturn, between the constellations of Virgo and Leo.Fox News: http://www.foxnews.com/story/0,2933,498705,00.html (February 24, 2009)

1. P-type: Periodic comet
2. C-type: Non-periodic comet
3. X-type: A reliable orbit cannot be calculated
4. D-type: A comet which has broken up into pieces or has otherwise been lost
5. A-type: An object that was mistakenly classified as a cometInternational Astronomical Union: Cometary Designation System

• NASA: Close Up Pictures of Comets

• Pbase: Amateur Photos

• SpaceWeather: Comet McNaught swung by the Sun in mid-January 2007

• YouTube: "Hubblecast 01 The Comet Galaxy" Video

• Flickr: Comet Photos

• • This page was created by Bernice S., a Part Time Guide in the Mahalo Greenhouse (see the original), and curated by Mike.

• If you'd like to help us create the best spam free search results on the Internet, apply to be a Part Time Guide!</em>