Suppose that astronomers discover an error in our understanding of Cepheid variable stars,such that stars of a given oscillation period have a smaller luminosity than previously assumed.How would that change the estimated distances to other galaxies?
A) The distance estimates would not change.
B) The distance estimates would have greater variation.
C) The distance estimates would become larger.
D) The distance estimates would become smaller.

Question

Quizplus · Accepted Answer

Cepheid variable stars are used as standard candles to estimate distances to other galaxies. If their luminosity is smaller than previously assumed, then their intrinsic brightness would also be smaller. This means that the calculated distance to those galaxies would be overestimated, and would need to be corrected by making the distance estimates smaller. Therefore, the correct choice is (D) the distance estimates would become smaller.

Suppose That Astronomers Discover an Error in Our Understanding of Cepheid