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If I were traveling through space, could I see distant galaxies with my own eyes?

If I were traveling through space, looking at distant galaxies, what colors, if any, would I see with my own eyes?

Unfortunately, traveling through space, you probably wouldn't be able to see distant galaxies with your eyes, as your eyes are not strong enough. From Earth, you can see only Andromeda, the nearest galaxy, with your eyes, and that is only if you squint. In space, the visibility will be a bit better because the atmosphere will not get in the way. But that will only make a slight difference, as the galaxy is not that bright to begin with.

Andromeda is 2.5 million light years away, so let's say that with only your eyes you can see galaxies that are 2.5 million or fewer light years away. Galaxies are, on average, separated by between 2 and 3 million light years. So at any given time while you and your eyes were traveling through space, you would probably only be able to see one galaxy, unless you were in empty space (not inside a galaxy) and happened to be in the middle of a cluster, and then you would be able to see several.

In terms of what colors you would be able to see, galaxies are dominated by either red or blue colors, depending on whether they are dominated by either young (blue) or old (red) stars.

Since galaxies are, however, made up of stars, if you got close enough to see individual stars, you would see the colors of the individual stars, which can cover the whole visual spectrum (red, orange, yellow, green, blue, indigo, violet). Whatever colors of light stars and galaxies emit in the visible wavelengths, you would be able to see.

October 2008, Sarah Scoles (more by Sarah Scoles) (Like this Answer)

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