Suppose that we look at a photograph of many galaxies. Assuming that all galaxies formed at about the same time, which galaxy in the picture is the youngest?
A)the one that is bluest in color
B)the one that is reddest in color
C)the one that is closest to us
D)the one that is farthest away
E)the one that appears smallest in size

Question

Quizplus · Accepted Answer

Galaxies that are farthest away from us are seen as they were in the past, due to the time it takes for their light to reach us. Therefore, the galaxy that is farthest away would appear as it was at a younger stage in its development, making it the youngest in appearance in the photograph.

Suppose That We Look at a Photograph of Many Galaxies