Question

Redshifts were used as supporting evidence for the big bang theory.

Which describes redshifts? Check all that apply.

The light source and observer move closer together.
Observed light shifts to a longer wavelength.
They indicate receding galaxies.
Observed light shifts to a shorter wavelength.
The light source and observer move farther apart.
They indicate approaching galaxies.

Answer 1

Check all that apply:

- Observed light shifts to a longer wavelength. ✔
- They indicate receding galaxies. ✔
- The light source and observer move farther apart. ✔

(Not true for redshift: "move closer together", "observed light shifts to a shorter wavelength", and "indicate approaching galaxies" describe blueshift instead.)