Every galaxy has a supermassive black hole at the centre of it.
The galaxy NGC 6240 within the Ophiuchus constellation, is a super galaxy that was formed as a result
of two smaller galaxies colliding with one another.
As a result, NGC 6240 has not one, but two supermassive black holes at its centre.
Astronomers believe that one day these two black holes may very well collide with one
another.
So what would happen if two black holes collided?
The collision of two black holes is such a rare event that it has never actually been
observed by scientists here on Earth.
We have however, ran extremely complex computer simulations to determine what the result would
be if two black holes did collide.
Firstly it's important to understand the enormity and sheer density of black holes.
A typical supermassive black hole can have a mass anywhere from many millions to several
billion times the mass of our sun.
The largest black hole we have ever found is in the galaxy Holmberg 15A.
The blackhole at it's core is 15,000 light years across and has an estimated mass of
170 billion times that of our sun - or most properly referred to as 170 billion solar
masses.
So what would happen?
Well there's basically two possible outcomes of such a catastrophic event.
Which possibility depends on the speed at which the two black holes are traveling, how
fast they are spinning, and the angle of their collision.
If the two black holes are spinning at very high speeds and come together at just the
right angle, the smaller black hole will be slingshotted away from the bigger black hole
and sent hurtling through space.
Similar to how two spinning tops bounce off each other when collided.
But the second, more likely outcome is that they will slowly come closer and closer together
until they can't escape each other's gravity and they eventually become one.
This process would be unbelievably violent.
When this happens the resulting black hole is known as a "Binary Black Hole".
As the two black holes start to merge they would appear to be a distorted mess of matter.
But as they come closer and closer together the resulting black hole goes through a process
known as "ring-down".
This is when any distortion in the shape is slowly dissipated and the new binary black
hole becomes more and more circular.
Until any asymmetry is lost and the black hole, once again becomes a nearly perfectly
circular disk of swirling death.
The energy emitted from the collision would be so great that it would send ripples through
the space-time fabric of the Universe.
Just think about that for a second, two black holes colliding would cause the very fabric
of the Universe, space and time, to ripple, like a gigantic pebble in a pond.
These ripple are known as "gravitational waves".
Gravitational waves have never been observed here on Earth.
In recent years we have built large instruments on Earth that are capable of detecting gravitational
waves far away in space.
And even more powerful instruments are currently under construction.
Why is it so important that we detect these waves?
Well gravitational waves are a fundamental component of Einstein's theory of general
relativity.
Detecting them and thus proving their existence would be irrefutable evidence to backup Einstein's
theory.
As well as increasing our understanding of gravity and how it behaves.
So to summarise, if you see two black holes about to collide, get the hell out of there.