Definition: In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
Input: A doppler effect happens because the Sun , and the Milky Way are moving at nearly 600 km / s .
Output:
Such a Doppler effect arises because the Sun , and in fact the Milky Way as a whole , is not stationary , but rather is moving at nearly 600 km / s with respect to the last scattering surface .