Can a Black Hole swallow entire Universe?

Many people say No and many say Yes. It's my article, so here's what I think about this question. Can a Black Hole eat the entire Universe? Before I answer this question, we should understand the term Event Horizon.

What is Event Horizon?

According to general relativity, an Event Horizon is defined as the shell of "points of no return", i.e., the points at which the gravitational pull becomes so great as to make escape impossible, even for light.

The Theory

So the entire Universe will be swallowed by a black hole only if it enters the event horizon. This might be a theoretical possibility, but extremely rare to actually happen. The biggest reasons being the Hubble expansion of the universe and the mass of stars and galaxies.

No matter how big a black hole is, its gravitational pull will only be as strong and not infinite. Many people confuse that Black Hole has infinite gravity but it's not yet discovered. Yes, Black Hole definitely has an infinite density at its core because all of its molecules are closely and tightly packed. 

Now suppose a star is near a black hole. Due to the gravitational pull of the black hole, the gases from the star will get pulled towards the event horizon of the black hole. The high velocity of the gases will form an accretion disc around the black hole, which will gradually cross the event horizon (the point of no-return). This process, however scary, is very slow.

As an example, the fastest-growing black hole in the galaxy NGC 1277 consumes a mass of Sun every 2 days. It started at roughly the size of 5,000 suns within about 1 billion years following the Big Bang. Currently, it weighs 70 billion suns making up to 14% of its host galaxy’s mass. 

Despite this voracious appetite it grows at a pace of 1% every million years. So simple math will tell you that in order to twice the mass it needs 70 million years, and still wouldn’t even make one-third of its own galaxy. Now given that there are like millions of galaxies out there, and many of which are bigger than NGC 1277, the time required to consume the entire universe would exceed the life span of the Universe itself. Again, here we are not even accounting for the fact that the Universe is expanding! In that case, most of the mass will “outrun” the black hole by the expansion of space, thereby increasing the distance and decreasing the gravitational pull exerted on the nearby stars by the supermassive black hole.

The End Notes

Yes, it is theoretically possible for a supermassive black hole to eat up the entire universe, it won’t be the prime culprit of the universe’s death. There are higher chances of us dying by Big Rip instead!

So. Here are the sources of the information for this post.

https://en.wikipedia.org/wiki/Event_horizon

https://www.livescience.com/62581-supermassive-black-hole-could-eat-the-sun.html

https://www.space.com/18668-biggest-black-hole-discovery.html