It’s possible to measure the distance stars are from us, and knowing that plus their direction from us we can plot out a map of our galaxy. We can’t get any actual photos of it from the outside obviously, but we can find galaxies that look similar to the map of our galaxy, so we tend to just use those images when talking about the Milky way.
togocann49 on
I always wondered this myself. I think (do not know for fact) that extrapolate from the parts we do see, and with computer assisted imagery, we have what they show us as the Milky Way galaxy. The problem of course is when we discover new variables for equations, the result may change (or not enough to make a difference)
flowersonthewall72 on
The same way you can generally know what the outside shape of a house is when you are inside of it.
We can explore the different rooms and walls and doors and windows of the Milky Way and draw out where these features are. We might miss some fancy decor or shutters but we get 95% of the way there.
We map out our location compared to galactic center and stars and measure distances and motion.
Also, look up at the night sky in throughout the year. Two distinct arcs of the Milky Way come and go throughout the year. Just by that, we know the Milky Way has two arms.
Bezbozny on
We can *see* every star, we can see where they are in the night sky *relative* to us and eachother, all we need to do is plot them on a 3d graph and then see what that graph looks like from the outside
thomil13 on
As some of the other posters have already mentioned, a lot of it is down to mapping the positions of stars within our galaxy sand then looking at their positions relative to us, as well as their velocities. This way, we can see where stars or star clusters are bunched closer together, indicating the position of a spiral arm, or where there’s a relative lack of stars, which would indicate the presence of a gap or void. With enough stars, this allows us to get a pretty good impression of the structure of our galaxy, at least the parts we can see.
Based on other galaxies we’ve observed and using educated guesswork the milky way galaxy can be interpreted as yet another spiral galaxy and is depicted as such in artistic renditions of it. Really we have no images of the whole of our own galaxy, so any depictions of the full milky way is going to be a recreation from an impossible perspective.
8 Comments
It’s possible to measure the distance stars are from us, and knowing that plus their direction from us we can plot out a map of our galaxy. We can’t get any actual photos of it from the outside obviously, but we can find galaxies that look similar to the map of our galaxy, so we tend to just use those images when talking about the Milky way.
I always wondered this myself. I think (do not know for fact) that extrapolate from the parts we do see, and with computer assisted imagery, we have what they show us as the Milky Way galaxy. The problem of course is when we discover new variables for equations, the result may change (or not enough to make a difference)
The same way you can generally know what the outside shape of a house is when you are inside of it.
We can explore the different rooms and walls and doors and windows of the Milky Way and draw out where these features are. We might miss some fancy decor or shutters but we get 95% of the way there.
We map out our location compared to galactic center and stars and measure distances and motion.
Also, look up at the night sky in throughout the year. Two distinct arcs of the Milky Way come and go throughout the year. Just by that, we know the Milky Way has two arms.
We can *see* every star, we can see where they are in the night sky *relative* to us and eachother, all we need to do is plot them on a 3d graph and then see what that graph looks like from the outside
As some of the other posters have already mentioned, a lot of it is down to mapping the positions of stars within our galaxy sand then looking at their positions relative to us, as well as their velocities. This way, we can see where stars or star clusters are bunched closer together, indicating the position of a spiral arm, or where there’s a relative lack of stars, which would indicate the presence of a gap or void. With enough stars, this allows us to get a pretty good impression of the structure of our galaxy, at least the parts we can see.
I highly recommend [Dr. Becky as a brilliant consulting astrophysicist](https://youtu.be/yq0zyA6Yr7o)
take every object in the room you are in and pretend it’s a white dot.
back away far enough.. and the dots will be in the shape of the room.
we have ***two thousand million*** dots to work with.
[https://gea.esac.esa.int/archive/](https://gea.esac.esa.int/archive/)
Based on other galaxies we’ve observed and using educated guesswork the milky way galaxy can be interpreted as yet another spiral galaxy and is depicted as such in artistic renditions of it. Really we have no images of the whole of our own galaxy, so any depictions of the full milky way is going to be a recreation from an impossible perspective.