Combining Newton's and Kepler's laws, we can weigh the Sun, provided we know:

Question

Quizplus · Accepted Answer

Combining Newton's law of universal gravitation with Kepler's third law allows us to calculate the mass of the Sun if we know the astronomical unit (A.U.)—the average distance from the Earth to the Sun—and the exact length of the year, which is the period of Earth's orbit around the Sun. This combination does not directly require knowledge of the Sun's density, temperature, Earth's mass and circumference, or the details of Venus's transits.

Combining Newton's and Kepler's Laws, We Can Weigh the Sun