What is the "cosmological redshift"?
A) The stretching of wavelengths of photons by the Doppler shift,because they are emitted by galaxies that are moving away from us
B) The loss of energy of photons as they interact with virtual particles in the vacuum,so that their wavelengths gradually increase as they travel toward us through space
C) The stretching of the wavelengths of photons as they travel through expanding space
D) The stretching of the wavelengths of photons as they pass through absorbing matter in galaxies between us and the emitting galaxy

Question

Quizplus · Accepted Answer

Cosmological redshift is caused by the stretching of the wavelengths of photons as they travel through expanding space. As the universe expands, the distances between galaxies increase, causing the wavelengths of light emitted by them to be stretched out, which results in a shift towards the red end of the spectrum. This phenomenon is different from the Doppler shift because it is not caused by an object in motion towards or away from us, but rather by the expansion of the universe itself.

What Is the "Cosmological Redshift