Black hole

Black holes are regions in space with gravity so strong that nothing, not even light, can escape. They are invisible but can be detected by their effects on nearby objects. Some black holes may have formed after the Big Bang, while others are created when massive stars collapse.

What is a black hole?

Why can't black holes be seen?

How can black holes be observed?

What are some possible origins of black holes?

What happens when large stars collapse?