Question: galaxies look stationary, so why do they rotate

Lucien Heurtier answered on 23 Mar 2023:

Nice question 😉

Well, you may not know, but actually galaxies turn pretty fast! The sun and the solar system appear to be moving at 200 kilometers per second! But the galaxy is so much bigger than the solar system, that even at this rapid speed, the solar system would take about 230 million years to travel all the way around the Milky Way, that’s why it looks quite stationary at first sight…