Scientists of Laser Interferometer Gravitational Wave Observatory, which is generally known as LIGO have announced that collision of two black holes is possible. According to them, ” when two black holes come close to each other, a huge amount of force of attraction is produced between them due to the gravitational force present in each one which results in merging of both black holes to become a bigger black hole”
Such an event would be extremely violent.It will produce tremendously large amount of energy in the form of gravitational waves.This gravitational waves are similar like waves of ocean, and it’s detectable from more than a billion light-years.
This is exactly what happened earlier this year in 2016. In Laser Interferometer Gravitational Wave Observatory ,the sensitive instrument which is used to detect gravitational waves had detected the gravitational waves which was generated when two black holes of 30 solar masses each collided about 1.3 billion light-years away.
According to some scientists, when two black holes are about to collide, the objects around them travels back in time. Einstein predicted this gravitational waves earlier, but now LIGO had observed them for the first time. As better tools are developed, we would learn more and more about these extreme events.