When Hubble First Calculated the Recessional Speeds of Galaxies in the 1920s

question 123

Multiple Choice

When Hubble first calculated the recessional speeds of galaxies in the 1920s, he used

• A) the Doppler shift relationship. This was an error, and the calculations had to be repeated using the cosmological redshift relationship.
• B) the Doppler shift relationship. This was an error, and the calculations had to be repeated using the gravitational redshift relationship.
• C) the Doppler shift relationship. This was correct because the nonrelativistic cosmological redshift relationship gives the same result.
• D) the cosmological redshift relationship. This was an error, and the calculations had to be repeated using the Doppler shift relationship.

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