Why is Hubble's constant uncertain?

1 Answer
Dec 9, 2016

What Hubble uses is redshift for determining expansion, but the redshift can also be caused by galactic collapse.


Because of this we can't always tell how correct redshift is in determining expansion. Redshift is the displacement of spectral lines toward longer wavelengths (the red end of the spectrum) in radiation from distant galaxies and celestial objects.

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