Young Supernova Remnants
The remnants of recent stellar explosions in our galaxy are intense X-ray sources. An orbiting telescope has revealed their structure. One has a pulsar; others are expanding shells of shock-heated gas
Rich Clusters of Galaxies
Some 10 percent of all galaxies belong to rich clusters, systems with thousands of members embedded in hot gas. Such a cluster is a gravitational maelstrom with giant galaxies close to its center
Supernova Remnants
Radiation emitted by the debris left over from catastrophic stellar explosions may yield clues to many astronomical puzzles