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Name: Elias G.
Status: student
Age: 8
Location: N/A
Country: N/A
Date: 9/15/2004

How do galaxies hit each other if they are moving away from each other?

Hi Elias,

Think of this as two different forces. One of the forces causes the galaxies to separate (expansion of the universe) and the other force causes the galaxies to get closer to each other (local gravity). The separating force acts about at the same strength everywhere, but the one that brings galaxies closer together is stronger if the galaxies are close together to begin with. So what is happening is, the galaxies that are close together, tend to come together and collide, while those that are far enough apart continue to get farther away.

Greg (Roberto Gregorius)

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