Observational first: physicists have used the ATLAS experiment at CERN to observe the production of top-quark and photon pairs. (Courtesy: CERN) For the first time, particle physicists have observed ...

When a star the size of 20 suns dies, it becomes, in the words of astrophysicist Zaven Arzoumanian, “the most outrageous object that most people have never heard of”—a city-size body of improbable ...