Q: In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
One type of this phenomenon was measured using a Fe-57 detector in the Harvard Tower experiment. This effect produces the first-degree anisotropy in the CMBR. Recombination of hydrogen atoms occurred at a value of approximately 1100 for the quantity associated with this effect, whose cosmological variety increases with age and distance; that is because the universe is (*) expanding according to Hubble's law. A few objects, such as Andromeda, exhibit the opposite of this effect, because they are moving towards us. For 10 points, name this phenomenon, in which the wavelength of astronomical objects receding from Earth broadens, producing a namesake change in color.
A:
Science