jun 012012
 
Light 'Echo' Around Supermassive Black Hole

  Astronomers studying the galaxy NGC 4151 with ESA’s XMM-Newton space observatory have detected X-rays emitted and then reflected by ionised iron atoms very close to the supermassive black hole hosted at the galaxy’s core. By measuring the time delays occurring in these ‘reverberation’ events, they were able to map the vicinity of this black [continue reading]

mei 122012
 
Is a fifth force altering gravity on very large scales?

  Most people take gravity for granted. But for University of Pennsylvania astrophysicist Bhuvnesh Jain, the nature of gravity is the question of a lifetime. As scientists have been able to see farther and deeper into the universe, the laws that govern its expansion have been revealed to be under the influence of an unexplained [continue reading]