Light has travelled from ALL of them. How do we know? We can see...

Light has travelled from ALL of them. How do we know? We can see them. All light has a beginning and travels at a set speed. It begins when the star starts sending light, the light takes light years to reach us. So Andromeda is 2 million light years away. What that means is that the first light from that galaxy took 2 million years to reach us. Before that we could not see it.

I would like to know how this question has arisen.