If over billions of years of time and many collisions with other galaxies, would the collection of supermassive black hole be enough to destroy all the mass of the billion of years of collected stars?

Apr 23, 2016

It is possible but unlikely that all of the Universe will become one supermassive black hole.

Explanation:

Black holes are small. If the Sun were compressed into a black hole it would have a radius of about 3km.

The supermassive black hole at the centre of our Milky Way galaxy has a radius of about $1.27 \cdot {10}^{10} m$ which is smaller than our solar system.

If the entire mass of the Milky Way galaxy was consumed into a black hole it would have a radius of about $2 \cdot {10}^{15} m$ or 0.2 light years which is tiny on the galactic scale.

If the observable Universe was consumed into a very supermassive black hole it would have a radius of about 13.7 billion light years. The radius of the observable Universe is about 45.7 billion light years.

Given the small size of even supermassive black holes the chances of them colliding are small. Only galactic collisions can cause this. There are theories that galactic super black holes can't grow to much bigger that about 10 billion solar masses unless they merge with another.

So, it is very unlikely that the entire mass of the observable Universe will fall into a super super massive black holes about one 37th of its current size. Given that the Universe is thought to be expanding this makes the likelihood of this happening almost impossible.