astronomy

AstronomersPart OneBrief Descriptions of the Following Astronomers:Walter Baade : Baade was a German-born American, whose work gave new estimates for the age and size of the universe. During the wartime, blackouts aided his observatons and allowed him to indentify and classify stars in a new and useful way, and led him to increase and improve Hubble's values for the size and age of the universe (to the great relief of geologists.) He also worked on …

…focus. (2) The speed of a planet in its orbit varies so that a line joining it with the sun sweeps over equal areas in equal times. (3) The squares of the planets' periods of revolution are proportional to the cubes of the planets' mean distances from the sun. These laws removed all doubt that the Earth and planets go around the sun. Later Sir Isaac Newton used Kepler's laws to establish his law of universal gravitation.