Just a thought but...from our galaxy I think we can see a few others,
Andromeda springs to my ignorant mind. I bleive the nearest is thousand
light years and the furthest a few million. But...

If I built a ship and started off to Andromeda, how would I know when I had
left the Milky Way? I understand that the edge of the solar system is
defined by lack of solar wind etc, but the galaxy?

David