Stars whose brightness changes periodically are known as variable stars. In 1912, Henrietta Leavitt discovered that the rate at which the brightness of a variable star changes is related to its overall brightness. Ejnar
Hertzsprung used this finding to calculate distances between far away stars. This later allowed Harlow Shapley to estimate the size of the Milky Way Galaxy and Edwin Hubble to detect the motion of galaxies. Hubble often
said that Leavitt deserved the Nobel Prize for her work, but she died before she could be nominated. What does the history of research on variable stars suggest about scientific knowledge?
Physicists prefer to build new knowledge based on their own work
Physicists do not like to use knowledge from scientists of the past.
Physicists build on the ideas of others to expand scientific knowledge.
Physicists are best when developing new ideas that will lead to individual recognition