Who was johannes kepler, and why is he known today?

Johannes Kepler (Weil der Stadt, December 27, 1571-Regensburg, November 15, 1630), a key figure in the scientific revolution, was a German astronomer and mathematician; known primarily for its laws on the movement of the planets in their orbit around the Sun. He was a collaborator of Tycho Brahe, whom he replaced as imperial mathematician of Rudolph II.

a historian researching the immigration policies of the early 1900s would expect a source written today,rather than in 1910 to :

( a ) be more interested in objective data and statistics.

agree with wilson that weakening the treaty would threaten world peace.