"Prepare the bunker, Earthlings. In T-minus 4 billion, our neighboring Andromeda galaxy will collide with our own Milky Way. Scientific American's Caleb Scharf offers a preview of the space fireworks we can expect."
In about 4 billion years these two galaxies will begin a ponderous collision lasting for perhaps 100 million years or so. It will be a soft type of collision – individual stars are so tiny compared to the distances between them that they themselves are unlikely to collide, but the great masses of gas and dust in the two galaxies will smack together – triggering the formation of new stars and planetary systems.
...So there it is. The end of the world we know is coming.
Does this change anything? I say, we have approximately 4Billion years to get our exit strategy in motion. BOOM!
The Race To Get Out Of Our Current Space Is On!
The recruitment, science education/training, and logistics challenge will be out of this world.
The time to get started is NOW, because before you know it 4B years will pass and moving the Human Race + Baggage off of a plant in a safe and orderly fashion--well, there it is.