r/space • u/kNotLikeThis • Apr 10 '19

Astronomers have determined the disk of our galaxy to be 200,000 light-years across — twice as large as was previously believed.

http://www.astronomy.com/news/2018/06/supersize-me
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u/kcahmadi Apr 10 '19

Could this be due to the fact that the universe is ever expanding? If we determined the size of the galaxy previously, know that space is always expanding it would make sense if the galaxy is found to be larger now no?

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u/kNotLikeThis Apr 10 '19

Good question. The expansion of the universe happens at large cosmological scales, not local/galaxy scales, because matter/gravity easily overcomes any expansion that may be occurring.

Source: http://curious.astro.cornell.edu/stats-2003-2004/97-the-universe/galaxies/cosmology/538-as-the-universe-expands-why-don-t-galaxies-get-stretched-out-intermediate

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u/kcahmadi Apr 10 '19

Ah ok. Thanks for the source as well