NASA and GLOBE, an international student Earth science program, invite the public to join in a scientific experiment on Thursday, Oct. 13. It’s simple: observe the sky over your area and report on the presence or absence of contrails.

Teachers, students and anyone interested in helping to develop a better understanding of the Earth are welcome to participate in the second annual Fall Contrail Count-a-Thon by submitting contrail observations through an Internet Data Entry Form. Designed to give students and adults an opportunity to collaborate with scientists in a hands-on, real-world science experiment, the Count-a-Thon will also teach participants about contrails, a unique feature of our atmosphere.

Contrails are cirrus clouds formed when water vapor condenses and freezes around small particles (aerosols) in aircraft exhaust. Some of the water vapor comes from the surrounding air; some from the aircraft exhaust itself. Contrails, especially thin ones, are very hard to see from satellites and may have an impact on Earth’s atmosphere.

“To augment what we can see from satellite, we hope to receive visual observation reports from lots of people all over the world. Both reports of contrails and reports with no contrails are equally valuable for this research,” said Lin Chambers, director of the GLOBE contrail education project at NASA’s Langley Research Center, Hampton, Va. Contrails increase Earth’s cloudiness while impacting the atmosphere and climate. Observations in the U.S. and around the globe may help scientists better understand the atmospheric conditions that enable the formation of contrails.

Similar to last year’s event, the 2005 Fall Contrail Count-a-Thon will be held during Earth Science Week, Oct. 9 -15. Earth Science Week, sponsored by the American Geological Institute, Alexandria, Va., is an international event to help the public gain a better understanding and appreciation for Earth sciences and to encourage stewardship of our planet.

“We thought spotting contrails would be a fun and educational activity that could include more schools and the general public since no instruments are required,” said Peggy LeMone, chief scientist for the GLOBE program. The program is based at the University Corporation for Atmospheric Research, Boulder, Colo. “The distribution of sightings tells us about where jets are flying and where weather conditions favor contrails forming. We can also compare the contrail patterns with satellite images,” she said.

GLOBE is managed as a partnership between University Corporation for Atmospheric Research and Colorado State University, Fort Collins, through a cooperative agreement with NASA and sponsorship by the National Science Foundation and the U.S. Department of State.

GLOBE brings students, teachers, and scientists together to support achievements in science, technology, engineering and mathematics. It also helps gather important data for the global Earth science community. As of September 2005, students reported more than 13 million scientific measurements using methods and standards developed by GLOBE scientists.

NASA’s Science Mission Directorate also provides funding for the Count-a-Thon. The directorate is dedicated to understanding the Earth as an integrated system. Through the study of Earth, NASA is helping provide sound science to better life here, while developing the technologies needed to explore the universe and search for life beyond our solar system.

For information about the Fall Count-a-Thon event on the Internet, visit:

http://www.globe.gov/earthsciweek2005

For information about Contrail Education on the Internet, visit: http://asd-www.larc.nasa.gov/GLOBE

For information about NASA and agency programs on the Internet, visit:

http://www.nasa.gov