The first Trump administration defended cluster munitions as “legitimate,” but on Monday, Adm. Brad Cooper condemned them as “inherently indiscriminate.”

Globular clusters are ancient, spherical groups of stars that are often as old as the galaxies they orbit. The stars in a globular cluster orbit the center of mass of the cluster, and the angular momentum of the stars as they move in their orbits keeps the ...

Current theories say young galaxy clusters should be relatively cool compared to older ones. But researchers recently found a very young cluster that was shockingly hot. Study author Dazhi Zhou says it's the first time a galaxy cluster this hot has been ...