A broadly accepted theory for the origin and evolution of our universe. The theory says that the observable universe started roughly 13.7 billion years ago from an extremely dense and incredibly hot initial state.
System of two stars that revolve around a common center of gravity.
Stars that are very massive will collapse under their own gravity when their fuel is exhausted. The collapse continues until all matter is 'crushed' into what is known as a singularity. The gravitational pull of a black hole is so strong that from a certain distance not even light can escape.
An exploding meteorite