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.

2004 October 13

Contrail Clutter over Georgia
Credit: MODIS, Terra Satellite, NASA
Explanation: Artificial clouds made by humans may become so common they change the Earth's climate. The long thin cloud streaks that dominate the above satellite photograph of Georgia are contrails, cirrus clouds created by airplanes. The exhaust of an airplane engine can create a contrail by saturating the surrounding air with extra moisture. The wings of a plane can similarly create contrails by dropping the temperature and causing small ice-crystals to form. Contrails have become more than an oddity - they may be significantly increasing the cloudiness of Earth, reflecting sunlight back into space by day, and heat radiation back to Earth even at night. The effect on climate is a topic of much research. You can help NASA measure the actual abundance of contrails by participating in a contrail counting exercise that runs over the next two days.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.

http://antwrp.gsfc.nasa.gov/apod/image/0410/contrails_nasa.jpg