Milky Way. Every star we see in the sky is part of the Milky Way, but a brighter center exists some light-years away. The Milky Way is about light-years in diameter and contains 200 to 400 billion stars.
A new kind of cosmic flash may reveal something never seen before: the birth of a black hole. When a massive star exhausts its fuel, it collapses under its own gravity and produces a black hole, an object so dense that not even light can escape its.
This artist's concept illustrates a supermassive black hole with millions to billions times the mass of our sun. Supermassive black holes are enormously dense objects buried at the hearts of galaxies. Image by NASA/JPL-Caltech