Solution: It is known that the universe is expanding, so all stars are moving away from us, and the further away they are, the faster they are moving away from us. For convenience, there is a quantity known as

It is known that the universe is expanding, so all stars are moving away from us, and the further away they are, the faster they are moving away from us. For convenience, there is a quantity known as redshift, z, that can describe how "far" an object is away from us. Redshift is given by the equation

1 + z = λ'/λ_{o}

where λ_{o} is the wavelength of light emitted at rest and λ' is the wavelength of light observered on Earth.

(a) Is redshift a distance measurement?

(b) If a star is supposed to emit light at a frequency of 4.57x1014 Hz, what would the observed frequency be if the redshift of this star were 0.1?