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

The same way we could draw the shape of a house even if we were trapped inside it. We don’t have any “photos” of it from way outside, but from where we sit we can measure the distance to many many different stars and turn them into a rough map that shows us the shape and size. Then an illustrator or computer draws a pict based on that map