cosmology - What's dark matter and who discovered it?

I have heard about dark matter that's called the Master Of The Universe. What's this and is the dark matter the reason galaxies exist?

Answer

It's everywhere! Astronomers have found that supermassive black holes live in the heart of galaxies and pull stars with incredible speeds, but that they are not strong enough to hold all the stars in the gigantic galaxies together.

So what does hold them together in the spiral? Swiss astronomer Fritz Zwicky wondered why galaxies stayed together in groups, so he concluded that there must be something that no one detected before, and he named it "dark matter".

To prove it, scientists build virtual galaxies in computers, with virtual stars, and virtual gravity. Astronomers were looking forward to this simulation experiment returning the integrated galaxy similar to our galaxy. Instead, they found it disintegrated! The gravity of the galaxy is not enough to hold it together, so scientists added virtual gravity from virtual dark matter to the simulation experiment. And it solved the problem, the gravity from dark matter held the galaxy together.

So we can say that "dark matter is the Master Of The Universe". This is a short story about dark matter. To explain it in detail, I would need lots of books.