Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2001 November 28
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Extra-Solar Planetary Atmosphere Detected
Illustration Credit: Greg Bacon (STScI/AVL)

Explanation: By directly detecting the atmosphere of a planet outside our Solar System, humanity has taken another small step toward finding extraterrestrial life. The unexpected detection by David Charbonneau (Caltech) and associates came from Hubble Space Telescope observations of Sun-like star HD 209458. As an orbiting planet crossed between that star and the Earth, sodium in the planet's atmosphere absorbed starlight at very specific colors. The planet, originally discovered two years ago, has about 70 percent the mass of Jupiter but orbits very close in. A long-term goal of this type of research is the detection of planetary biomarkers that would indicate life, such as oxygen, water, or methane.

Tomorrow's picture: Into the Sun

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
& Michigan Tech. U.