Question: How big is the collision of two neutron stars colliding

Laurence Datrier answered on 13 Jun 2019:

The two neutron stars themselves are quite small; they are about 10km in diameter. However the collision of two neutron stars is dramatic enough that even if it’s located 3000000000000000000000km away from Earth it distorts spacetime through gravitational waves enough that we can detect the gravitational wave here on Earth – and it’s not easy feat, because spacetime is very stiff and isn’t distorted easily! There’s nothing here on Earth that can produce gravitational waves we can detect. The kilonova (the “explosion”) that happens just keeps expanding. Elements like gold come from these explosions!