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Because almost all galaxies show redshifted spectra, we know that?
Because almost all galaxies show redshifted spectra, we know that?1) Our understanding of redshift is wrong
2) We must be at the center of the universe
3) The universe is expanding
4) The sky must be dark at night
5) The universe is closed
Final answer:The redshift observed in almost all galaxies is a result of the expansion of the universe, indicating that the universe is expanding. The redshift is seen in the hydrogen spectra of galaxies, and it is proportional to the distance of the galaxies from us. This suggests that space itself is stretching, causing the wavelength of light to be stretched as well, resulting in a redshift.Explanation:The redshift observed in almost all galaxies is a result of the expansion of the universe, indicating that the universe is expanding. The redshift is seen in the hydrogen spectra of galaxies, and it is proportional to the distance of the galaxies from us. This suggests that space itself is stretching, causing the wavelength of light to be stretched as well, resulting in a redshift.The idea that all galaxies are moving away from us is based on the work of Edwin Hubble, who observed that the redshift in spectra increased with distance from our galaxy. The expansion of the universe is not centered at a specific point; instead, all observers see themselves as stationary and other objects as moving away from them. This supports the understanding that there is no center of expansion in the universe....