Astronomers who used NASA's Chandra X-ray Observatory will host a media teleconference at 1 p.m. EDT Monday, Aug. 21, to announce how dark and normal matter have been forced apart in an extraordinarily energetic collision.

Reporters must call Megan Watzke at the Chandra Press Office at: 617- 496-7998 or e-mail: mwatzke@cfa.harvard.edu for participation information. Shortly before the start of the briefing, images and graphics about the research will be posted at:

http://chandra.harvard.edu/photo/2006/1e0657/

Briefing participants:

- Maxim Markevitch, astrophysicist, Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.

- Doug Clowe, postdoctoral fellow, University of Arizona, Tucson, Ariz.

- Sean Carroll, assistant professor of physics, University of Chicago, Ill.

A video file about the discovery will air on NASA TV at noon, Aug. 21. Audio of the event will be streamed live on the Web at: http://www.nasa.gov/newsaudio. For NASA TV streaming video, schedule and downlink information, visit:

http://www.nasa.gov/ntv

For information about NASA and agency programs, visit:

http://www.nasa.gov/home