Astronomers had used Sir Isaac Newton's laws of motion to calculate the orbits of the known planets and shown that every 113 years, the relative positions of the planet Venus and the Earth would put Venus between the Earth and the Sun. Edmund Halley had proposed that, if the transit of Venus were to be observed at two points on the Earth, the difference in timing and the distance from one point to the other could be used to compute the distance from the Earth to the Sun. In the eighteenth century, the Royal Society of London collected observations from adventurers who went to different places in the world in order to time the transit of Venus across the Sun, which occurred in 1761 and 1769. A committee was formed to examine these reports and use them to determine the distance from the Earth to the Sun.