eli5 How do we know how our galaxy looks like if we’re part of it ?

Question

We can only see ourselves if we look in the mirror or our photos or like we can see how our planet looks because of the satellites . But how can we see our galaxy

In: 10

Answer 1

A lot of answers here seem to forget that we can see other spiral galaxies … everywhere. So we’re starting with a very strong hypothesis of roughly what it should look like. There are details to work out of course (e.g., how many spiral arms, density gradients, etc.), but being able to see other galaxies is a real strong clue