Black hole collisions

How gravitational waves form and how they’re detected on Earth

1 What is gravity?

On forming his theory of general relativity, Einstein revealed that gravity is the result of celestial objects distorting the fabric of the universe, which he called space-time, around them.

2 What are gravitational waves?

Really massive objects, like black holes, create a dent in spacetime. This ‘dent’ doesn’t produce gravitational waves, but if two black holes spiral towards each other they will lose energy, sent out as ripples in space-time.

3 Where the signal comes from

Black holes move closer and begin to merge millions of light years away from Earth.

4 A pulse of waves

The new, combined black hole settles down; the waves it releases radiate out through space at the speed of light.

5 Journey through space

The waves then begin their million light year journey to Earth, waiting to be detected.