A quasar is the extremely bright core of a distant galaxy, powered by a supermassive black hole swallowing gas. A single quasar can outshine all the stars of its host galaxy combined, which makes quasars visible across billions of light-years. How quasars were found In the 1950s, radio astronomers found sources that looked like stars … Read more
Gravitational waves are ripples in the fabric of space-time, produced when massive objects accelerate. Einstein predicted them in 1916 but thought they would be too weak to detect. A century later, he was proven right on the first point and wrong on the second. The first detection On September 14, 2015, the two LIGO detectors … Read more
A black hole is a region where gravity is so strong that nothing, not even light, can escape once it crosses the boundary called the event horizon. Black holes are not cosmic vacuum cleaners: from a distance, their gravity acts like that of any object with the same mass. Stellar black holes: from dying stars … Read more
