From the December 2007 issue

Does redshift increase over time?

R. Schultz, Chester, Ohio
By | Published: December 1, 2007 | Last updated on May 18, 2023
Yes, it does. Many people think of redshift as due to a Doppler effect from a distant galaxy’s “recession velocity.” In fact, it is more accurate to think of a photon’s wavelength as being stretched by the expansion of space.