# How far into intergalactic space would you have to go to see the Milky Way?

If in the distant future a ship were somehow able to move beyond the galaxy and into intergalactic space, how far would it have to go before we could look out a window and see the Milky Way in its entirety, rather than just edge-on as we see it from Earth?

## migrated from space.stackexchange.comJul 19 '16 at 16:49

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• This is a better question for astronomy than here, but I'm not going to migrate it there because as this question stands, it isn't very well defined. And I don't think it's the kind of question that can be well defined, unfortunately. The answer is a very long ways away, but it largely depends on which direction you go. – PearsonArtPhoto Jul 19 '16 at 16:40
• I don't think it's that unclear. He's basically asking how far away you would have to be in order to see the Milky Way like we see pictures of other galaxies. It's an angular size question, and it just depends on how large you want it to appear. Ultimately, it comes out to ~50,000 light years. – Phiteros Jul 19 '16 at 16:43
• @PearsonArtPhoto I was actually writing out an answer to this when you closed it. I agree, though, it might be better in Astronomy. – Phiteros Jul 19 '16 at 16:43

We can calculate the distance we need to be from an object in order for it to be any arbitrary angular size using the formula $$D=\frac{d}{2\tan(\frac12\delta)}$$. In this case, $$D$$ is the distance from the object, $$d$$ is its diameter, and $$\delta$$ is the angular size. The Milky Way's diameter is 100,000 light years. If we want the Milky Way to appear as large as the Sun appears from the Earth (0.5$$^\circ$$), we would need to be 5,700,000 light years away. If we want it to appear much larger, we could be closer. For the Milky Way to be the size of a 1 meter circle held at arm's length (90$$^\circ$$), we would need to be 50,000 light years away.