wiki Word: exoplanet

Definition: An exoplanet is a planet beyond our Solar System.

     An exoplanet is a planet that is found beyond our solar system. Most exoplanets are giant and are likely to resemble Jupiter.The first confirmed detections were made in the 1900's; Since 2000, more than 15 have been discovered every year. The frequency of detection is increasing with 61 planets detected in 2007. There are many different detection methods for exoplanets.

     NASA's Spitzer Space telescope has captured enough light from exoplanets to identify molecules in their atmosphere. This is a BIG step in searching for life outside of earth. Spitzer obtained the detailed data of two exoplanets called HD 209458b and HD 189733b. The "hot Jupiters" strongly resemble Jupiter, only orbit closer to their suns. The data indicate the two planets are drier and cloudier than predicted. Theorists thought hot Jupiters would have lots of water in their atmospheres, but surprisingly none was found around HD 209458b and HD 189733b. According to astronomers, the water might be present but buried under a thick blanket of high, waterless clouds.

     The right size, the right distance, the right temperature: we finally have evidence for the existence of extrasolar worlds that may be candidates for life-bearing planets as well. A search of the nearest 1,000 stars to our Sun may reveal evidence of planets very much like Earth. "Earth-type" planets, the most conducive to sustaining life, must be solid bodies (unlike the gas giant planets in our outer solar system) with masses roughly between 0.5 - 10 Earth masses. These planets need to be found at distances from their parent star such that the planet's temperature and atmospheric pressure are supportive of the existence of liquid water.

This is an example of one way to discover exoplanets. Through their stars. If a star has a planet, then the gravitational influence of the planet will cause the star itself to move in a tiny elliptical orbit around the common center of its mass. (see diagram above)

This is an artist's impression of the exoplanet Gliese 581 c.

SO WHAT??? SECTION:

An exoplanet is a planet beyond our solar system. Many have been found and the search continues. What are we looking for in these planets? Life beyond earth. Could these planets be terrestrial? And of not, could they be suitable enough to vist and learn more about our universe? The search continues for life, and these planets could possibly be the answer.

Bibliography:

"Extrasolar Planet." Wikipedia. 2008. 29 Apr 2008

http://en.wikipedia.org/wiki/Extrasolar_planet

Watanabe, Susan. "Spitzer: Studying the Universe in Infrared." NASA. 22 Nov. 2007. NASA. 9 May 2008 <Susan. \"Spitzer: Studying the Universe in Infrared.\" NASA. 22 Nov. 2007. NASA. 9 May 2008 <http://www.nasa.gov/mission_pages/spitzer/news/spitzer-20070221-full.html>. |http://www.nasa.gov/mission_pages/spitzer/news/spitzer-20070221-full.html>.