An astrophysicist measures the redshift of a distant Type Ia supernova to be z=0.45z = 0.45z=0.45. Based on a model of the universe with a constant rate of expansion, the expected apparent magnitude of this supernova is m=21.8m = 21.8m=21.8. The actual measured apparent magnitude is found to be m=22.2m = 22.2m=22.2.
Which row correctly describes the observed brightness of the supernova compared to the model's prediction, the implied dynamic state of the universe's expansion, and the hypothetical entity proposed to explain this state?
Dimmer than expected; accelerating expansion; dark energy
Brighter than expected; accelerating expansion; dark energy
Dimmer than expected; decelerating expansion; dark matter
Brighter than expected; decelerating expansion; cosmic microwave background
66 exam-style questions on OCR A A Level Physics Astrophysics and cosmology, covering Stars, Electromagnetic radiation from stars, and Cosmology. Each one has a worked solution and a mark scheme showing where the marks go.