What keeps the Galaxies apart?

Answer 1

The immensity of space keeps the galaxies apart, although it's not at all rare for galaxies to collide. As a matter of fact our own galaxy will collide with the Andromeda Galaxy sometime in the future. Right now they're moving towards each other at about 186 miles per second. To see a computer simulation of what will happen visit this website ==>http://www.space.com/scienceastronomy/astronomy/galaxy_collides_020507-1.html

To see an actual photo of two galaxies colliding visit this website ==>http://antwrp.gsfc.nasa.gov/apod/ap020506.html

Answer 2

They sometimes crash into each other. For example, Stanford recently (2006) discovered the glow of so-called "dark matter" around two galaxies colliding with each other. In fact, colliding galaxies are not that rare. [See source.]

The good news is that, even in the densest parts of galaxies, the constituent stars are so far apart, they rarely collide with other stars. However, their gravitational pulls can vastly alter the shapes of the colliding galaxies.

Although the paths of galaxies can meet, on the whole, galaxies are getting farther apart. This results from our expanding universe. As a model, think of our universe as sitting on the skin of a blown up balloon. The galaxies dot the skin around the area of the universe we are able to observe.

Now start blowing up the balloon even further. The galaxies (the dots) on the skin of the balloon will move farther apart from each other because the skin of the balloon (our universe) is stretching out.

Thus, even though those dots move about independently on the skin of the balloon, on average they are drawing apart...making collisions less likely over time...a very long time.

Answer 3

Nothing keeps them apart. Galaxies collide.