Could our position in the universe affect our perceptions of the expansion? (Intermediate)

Also couldn't our position in the universe be affecting our perceptions of the expansion say like someone being in the bleachers of an expanding arena as opposed to someone at the pitcher's mound?

It's possible that we could have been given a universe that looks very different for different observers. But this doesn't appear to be the case. In cosmology, we assume that the universe is both homogeneous and isotropic (looks the same everywhere on large scales, the structure has no preferred direction). This appears to be true if you look at the distribution of galaxies (or gamma ray bursts, or anything that we can see out to large distances) on the sky, it looks pretty uniform across the entire sky (look at this slice of the sky from the APM Survey)

So while we can't go to another galaxy and measure the expansion of the universe there and compare it to what we measure here, we have pretty good reason to believe that the universe "looks the same" wherever you are, so the expansion should work the same way.

This page was last updated June 27, 2015.

About the Author

Christopher Springob

Christopher Springob

Chris studies the large scale structure of the universe using the peculiar velocities of galaxies.  He got his PhD from Cornell in 2005, and is now a Research Assistant Professor at the University of Western Australia.

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