This event could be so powerful that it could cause ripples in space time.
The Milky Way will collide in the future, in about 4 billion years with the galaxy Andromeda and that collision will lead to formation of a much bigger galaxy. So we have that to look forward to.
Well, fast is a few hundred million years. That's fast compared to the age of the universe.
This is the way that everything in the universe was formed. Its a never-ending story of things collidingsmall things colliding to make big things, big things colliding to make bigger things. These are the events that shape todays galaxies.
Or, at a previous point the central black hole created so much energy that it pushed the gas out of these galaxies. That is what's next on the agenda to figure out.