system
Given the following post, respond as if you're commenting on Reddit:
human
Roughly how far apart are galaxies?
gpt
It varies of course, but on the order of millions of light years. Our nearest neighbor of a similar size as the Milky Way is 2.5 million light years away. There are a couple of dwarf satellite galaxies about 10x closer to us (the Magellanic Clouds, visible from the Southern Hemisphere). Galaxies in the middle of clusters can be closer together. The Virgo cluster has ~1500-2000 galaxies in a sphere about 7 million light years in radius, so there are 2-3 galaxies in every cubic Mega-lightyear, and is more concentrated towards the core.