I am puzzled of the “Andromeda–Milky Way collision”, when everything is moving away from the center of the Big Bang?
In: 3
Things don’t move away from the “center” of the big bang, there’s no center of the big bang. Everything moves away from every other thing. [Balloon analogy](https://www.youtube.com/watch?v=mnENgtCdObo) for further information.
As for how galaxies collide…As you can clearly see, not literally everything moves away from each other. The solar system isn’t expanding nor does the milky way. That’s because of Gravity!
Gravity(and other forces like electromagnetism) gets weaker as the distance increase but the expansion is the opposite, it gets faster the further things are apart. At some point, things are so far apart that the expansion rate won against gravity. On the other hand, if things aren’t too far apart, like between the earth and the sun, or between nearby galaxies, Gravity will be strong enough and the expansion rate will be low enough that it won’t expand or even move toward each other.
Latest Answers