A live videocast and chat from NASA's Jet Propulsion Laboratory, Pasadena, Calif., offers a unique opportunity for viewers to ask questions of scientists with NASA's Near-Earth Object Program Office about how NASA discovers and tracks asteroids.

The live event will air on the "NASAJPL" channel available on Ustream TV at: http://www.ustream.tv/channel/nasajpl on March 25 at 4:30 p.m. PDT (7:30 p.m. EDT and 23:30 UTC).

NASA detects and tracks asteroids and comets passing close to Earth. The Near-Earth Object Observation Program, commonly called "Spaceguard," discovers, characterizes and computes trajectories for these objects to determine if any could be potentially hazardous to our planet.

Participants include:

-- Don Yeomans, manager, NASA's Near-Earth Object Office at JPL
-- Steve Chesley, scientist, NASA's Near-Earth Object Office at JPL
-- Paul Chodas, scientist, NASA's Near-Earth Object Office at JPL

If you are unable to take part in the live chat, you can submit questions in advance to chatquestion@jpl.nasa.gov and watch the archived video at a later time.

More information about NASA's Near-Earth Object Program Office is available at: http://neo.jpl.nasa.gov/

NASA's Jet Propulsion Laboratory, managed by the California Institute of Technology, Pasadena, manages the Near-Earth Object Program Office for NASA's Science Mission Directorate, Washington.