To the unaided eye, its translucent clouds are simply ... By far the most common type of galaxy, spiral galaxies have a bright, dense core of stars collected in a central globe, from which two or more ...
The black hole resides at the heart of a galaxy about 7.5 billion light-years from Earth ... Such jets, not visible to the naked eye, start out small and grow over time. "We've known for a while that ...