Newton best known for:

Formulation of Gravitational Theory (Newton's three laws)

Discovered prism of light

Discovered Differential Calculus

A Body remains at rest or moves in a straight line at constant speed unless acted upon by an unbalanced forces

Acceleration of a body is directly proportional to amount of force acting on it

Whenever one body exerts force on second body, the second body exerts an equal, opposite force on the first

Uranus was unknown to the ancients, even though it is just visible to the naked eye. It was discovered by Sir WilliamHerschel, a musician who at the time was only an amateur astronomer interested in hunting comets. In 1781, he observed a pale blue object whose position in the sky changed from night to night. Herschel at first thought he had discovered a comet, but observations over several months showed that the body's orbit was nearly circular, and he therefore concluded that he had found a new planet. For this discovery, King George III named Herschel his personal astronomer.

  Solution:

JOHN ADAMS—Britain

J. URBAIN LEVERRIER—France

Must be a new planet

In Britain, prediction ignored (Airy)

1846 - Neptune discovered (Berlin)

Orbit - 164.8 yrs - 301 A.U.

Neptune was discovered in the 1840s from predictions made independently by a young English astronomer, John Couch Adams, and a French astronomer, Urbain Leverrier.

Adams and Leverrier both noticed that Uranus was not precisely following its predicted orbit, and they therefore inferred that its motion was being disturbed by the gravitational force of an as yet unknown planet. From the size of these orbital disturbances, Adams and Leverrier predicted where the unseen body must lie.

Adams completed his calculations in 1845, but when he reported his results, the astronomer royal, Sir George Airy, was unconvinced and gave a low priority to the search for the unseen planet. In 1846, however, Airy was startled to read a paper by Leverrier detailing calculations nearly identical to those made by Adams. This spurred Airy to begin a search in earnest, but by then it was to late: Leverrier had given his predicted positions to Johann Galle, a German astronomer who that same night pointed his telescope to the predicted location and saw Neptune.

Assignment of credit for the discovery of the new planet led to a rancorous dispute tinged with national pride that lasted decades, and the discovery is now credited equally to Adams and Leverrier.

Ironically, Galileo had seen Neptune in 1613 while observing Jupiter's moons. His observation notes record a dim object whose position changed with respect to the stars, as would be expected for a planet. Galileo failed, however, to appreciate the significance of that motion, so Neptune eluded discovery for another two centuries.

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