Galaxies are so big, and their separations are so small in the universe, that collisions between them are actually
rather common, especially in the dense cores of clusters of galaxies where they buzz around like bees in a swarm.
The Milky Way is currently making a meal of the Large and Small Magellanic Clouds and will probably finish digesting
them in about 100 million years or so. There are also several dwarf galaxies such as the Sagittarius System that are
waiting in the wings as the next meal. The biggest, and most spectacular, collision will be with the Andromeda Galaxy,
which will visit us in about three billion years give or take a few millennia! It is approaching the Milky Way at a speed
of roughly 700,000 miles per hour. By the time they are 300,000 light years apart, powerful gravitational effects
will tear spiral arms to shreds, and destroy the beautiful pinwheel shapes these two galaxies have had since
they were first formed. There are many examples of these intergalactic 'train wrecks' to be found in space.
What do you think the sky would look like with another galaxy plunging towards your own?
