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Learn about planets outside our solar system through Exoplanets and Alien Solar Systems by Tahir Yaqoob, Ph.D., a book in our online store book collection.
Artist's concept of a rocky planet in orbit around a distant star.
Click on image for full size
NASA, ESA and G. Bacon (STScI)

Planets around other Stars

Did you know that about 200 planets have been found around distant stars? The first planet around a star like our Sun was found in 1995. Since then, a new planet has been found almost every month!

The star and its planet move around each other. The planet moves in a wide orbit. The star just wobbles slightly. This causes a Doppler shift of the light. Most of the distant planets were discovered this way.

Some of the planets pass in front of their star. This blocks out some of the light. It makes the star look dimmer. It's like a solar eclipse. The planet only covers a small part of the star. Only a few of the planets pass in front of their stars.

All of the new planets are too far away to see directly. We can only see their effect on the star that they orbit.

Last modified March 13, 2008 by Becca Hatheway.

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The Fall 2009 issue of The Earth Scientist, which includes articles on student research into building design for earthquakes and a classroom lab on the composition of the Earthís ancient atmosphere, is available in our online store.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA