University of Hawaii astronomer J. Patrick Henry, who studies clusters of galaxies, will give a free lecture on “;X-raying Dark Matter”; at 7:30 p.m. Tuesday at Manoa Valley Theatre, 2833 East Manoa Road.

Henry was one of four scientists this year to receive the Rossi Prize from the High Energy Astrophysics Division of the American Astronomical Society for his research.

He will explain how studying X-rays made by clusters of galaxies has given scientists new insights into the mysterious, unseen dark matter that makes up most matter in the universe.

He will also describe some of his adventures building and flying instruments for his studies.

For more information on the Frontiers of Astronomy Community Lecture, see the Hawaii Institute for Astronomy Web site at www.ifa.hawaii.edu/specialevents/Frontiers08.