Scientists have detected two collisions between a neutron star and a black hole in the space of 10 days. 

Researchers predicted that such collisions would occur, but did not know how often.

The observations could mean that some ideas of how stars and galaxies form may need to be revised.

Black holes are astronomical objects that have such strong gravity, not even light can escape. Neutron stars are dead stars that are incredibly dense. A teaspoonful of material from a neutron star is estimated to weigh around four billion tonnes.

Both objects are cosmological monsters, but black holes are considerably more massive than neutron stars...

BBC: Rare black hole and neutron star collisions sighted twice in 10 days