Exam-style question
Try this first
What does a high redshift in the light from a quasar indicate?.
- A.The quasar is moving towards us at high speed.
- B.The quasar is moving away from us at high speed.
- C.The quasar is stationary relative to us.
- D.The quasar is located within our galaxy.
Model answer
What a good answer should say
- The quasar is moving away from us at high speed.
Explanation
Why this works
A high redshift indicates that the wavelengths of light from the quasar are stretched due to the Doppler effect, which occurs because the quasar is moving away from us. This stretching of light results in a shift towards the red end of the spectrum, confirming that the quasar is receding, which implies it is located at a large distance from us as part of the expanding universe.
Common mistake
No common mistake is linked to this question yet.