In the context of the Doppler effect, which of the following is a difference between a blueshift and a redshift?
A) Unlike a redshift, a blueshift is caused by a velocity of recession.
B) Unlike a blueshift, a redshift is based on the Hubble's law.
C) Unlike a redshift, a blueshift is a shift toward shorter wavelengths.
D) Unlike a blueshift, a redshift is based on a light source moving closer to an object.
Question 2
Which of the following statements best describes one astronomical unit (AU)?
A) It is the distance from Earth to the Moon.
B) It is equal to the average distance of the Sun from Earth.
C) It is the distance that light travels in a vacuum in one year.
D) It is the average distance between two stars in the Milky Way.