“In the year 3,000,002,012 the Andromeda Galaxy may collide with our Milky Way. At first this sounds miserable, like a collision of two bird flocks. But galaxy members fly farly, not tip to tip. In a galactic collision the stars do not actually collide—as with crisscrossing marching bands, only the interstices collide. (Oh to be like a galaxy, to mingle without wrecking. But then we would have to be composed of so much more sky.) The spaces between stars are so wide that thousands of galaxies have to converge before the stars will crash.”
Book:Things That Are