Question #c4320
1 Answer
Jan 18, 2018
Well, several things ...
Explanation:
They are all composed of dust, gas and stars as well as quite a lot (possibly five times more) dark matter.
They all rotate.
Beyond the local group (which is gravitationally bound together) they are all moving away from us (and each other.)
Last, but not least, they are all beautiful (in their own way)
