Astronomers and astrophysicists often refer to blue-shift and red-shift.
a. Outline what is meant by the terms *blue-shift* and *red-shift* and suggest why they are called as such.
b. In what way has our knowledge of the Doppler effect been able to help our understanding of cosmology?
c. Light from a distant star is observed using a telescope and a diffraction grating. One spectral line from the star is measured at a wavelength of 580.9 nm, whereas the same spectral line measured in a laboratory has a wavelength of 527.0 nm.
What can you say about the relative motion of the distant star and the Earth?
d. Light from a distant star is observed using a telescope and a diffraction grating. One spectral line from the star is measured at a wavelength of 580.9 nm, whereas the same spectral line measured in a laboratory has a wavelength of 527.0 nm.
Calculate the speed at which the distant star is moving relative to the Earth.