What is meant by galaxies that are "interacting?"
When galaxies are said to be 'interacting' this usually means they are either colliding, beginning to collide or have collided.
This will happen in a few million years time I believe, the Andromeda Galaxy, our closest galaxy to the Milky Way, will collide with the Milky Way, this will increase the mass of our galaxy & in the lead up of the approaching Andromeda Galaxy, the skies will be glowing with the billions of stars with in it.
Another interesting feature of this time, infact will be gone technically, we will no longer have the moon, as it will have been catapulted out into space, much like the moons of mars will, and where it will either be caught by another planet, our own sun, collide with another body or begin travelling the universe.
So even if the Earth is (hopefully not) destroyed before the Andromeda Galaxy collides, we will have a piece of Earth, still around possibly.
Hope this help & the extra info.