Using sophisticated math and the Hubble telescope, NASA has determined that the Milky Way and the Andromeda galaxies are on a collision course.....in 4 billion years. Computer simulations taken from Hubble's data show that it will take an additional two billion years after the collision for the two galaxies to completely merge and reshape into a single elliptical galaxy.
"In the worst-case-scenario simulation, M31 slams into the Milky Way head-on and the stars are all scattered into different orbits," said Gurtina Besla of Columbia University in New York. "The stellar populations of both galaxies are jostled, and the Milky Way loses its flattened pancake shape with most of the stars on nearly circular orbits. The galaxies' cores merge, and the stars settle into randomized orbits to create an elliptical-shaped galaxy."
Throughout all of this though, there is no real danger for our sun or solar system. It is more likely the sun will be flung into a new region of our galaxy. Maybe when this happens we can finally get an answer to the "Is there life in our Galaxy other than us?" question. But by then we will probably be gone.....
Here is a computer simulation of the collision made by NASA:
photo courtesy of space.com