image credit: NASA, Troy Cryder; image source;    larger image

Kepler Mission

The NASA Kepler observatory searches for extrasolar planets by monitoring about 100,000 stars in a small patch of sky. The observatory looks for stars that periodically dim as a planet passes in front of the star. Kepler was launched in 2009, and by January, 2012, it had already found 33 confirmed extrasolar planets and about 2300 candidates. To learn more, visit Kepler Mission, then click on "Mission Overview."

(This feature was updated on September 21, 2013.)

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Nebraska Astronomy Applet Project: Extrasolar Planets Lab

Visit Nebraska Astronomy Applet Project: Extrasolar Planets Lab to try to simulations of how extrasolar planets are detected indirectly--that is, without making an image of the planet.

Also, check out Planet Quest Interactives, and click on one of the simulations. You can choose from Extreme Planet Makeover, Planet Quest Timeline, and Alien Safari.

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image credit: D. Lafreniere, R. Jayawardhana, M. van Kerkwijk (University of Toronto); image source; larger image

APOD: Companion of a Young, Sun-like Star Confirmed

You are looking at the first telescopic image of a confirmed planet in orbit around a Sun-like star. The young planet is still quite warm, and therefore radiating considerable energy, which makes it relatively easy to detect. To learn more, see APOD: Companion of a Young, Sun-like Star Confirmed.

Space Topics: Extrasolar Planets--Searching Methods

There are five ways to detect an extrasolar planet:
--observing periodic changes in the frequency of the spectra lines at the star emits
--observing the periodic dimming of the star when the planet passes in front of the star
--observing periodic changes in the position of the star the planet orbits
--observing an enhanced image of the planet with gravitational lensing
--making a "direct" image of the extrasolar planet

Astronomers now believe our galaxy has more planets than stars--see this BBC Report.

(This feature was updated on September 21, 2013.)