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Announcements. Next exam is scheduled for Monday March 31. Due to icemaggedon , it will be delayed one week to Monday April 7. Tentatively will cover the rest of Chapter 5 (from Kepler) and all of Chapter 6 and some of Chapter 7 . Sample questions will be posted tomorrow.
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Announcements • Next exam is scheduled for Monday March 31. Due to icemaggedon, it will be delayed one week to Monday April 7. Tentatively will cover the rest of Chapter 5 (from Kepler) and all of Chapter 6 and some of Chapter 7. Sample questions will be posted tomorrow. • Dark Sky Observing Night Wednesday. Forecast looks good: clear but cold. Set-up starts at 7:30pm.
Isaac Newton1642 – 1727 Born at Woolsthorpe Manor in Lincolnshire three months after his father dies. He is raised by his maternal grandmother after his mother remarries. He isn’t nobility but he does have status above the peasantry
Early on, his mother wants him to run the farm Isaac absolutely hates farming and openly shows his dislike of it Fortunately, the local school master convinces Isaac’s mother to send him back to school. Eventually, he enters Trinity College at Cambridge in 1661.
In 1665 Plague hits London and Newton goes home to Woolsthorpe While at home he continues his studies on his own. It is during these two year that he forms his early ideas about light, motion, gravity and the foundations of calculus. He is still very much a Cartesian at this time but he is beginning to question it.
In1669 Newton is appointed the Lucasian Chair of Mathematics at Trinity College in Cambridge
Due to an early “run-in” with Hooke over the behavior of light, Newton becomes a recluse at Cambridge
By 1684 Hooke, Wren and Halley are in discussions on the nature of the force binding the solar system
After Newton sends Halley a 9 page proof that the orbits are ellipses, Halley starts pushing Newton to publish his work
Newton’s first draft contained his 1st Law of motion and an inverse square law of gravity He still had not figured out his 3rd Law and his law of gravity was a little fuzzy with only an inverse square distance relationship
His second draft brought him to his 3rd Law and the mutual nature of the force of gravity He immediately saw the problem that it would be impossible to calculate precisely the orbit of any planet with all the other planets and the Sun pulling on every other object
His biggest hurtle was determining the force of gravity of an extended object It is this problem that leads him to the invention of calculus
He proved the universality of his law of gravity by comparing the fall of an apple to the “fall” of the moon
Just before he was ready to publish, Hooke tried to interject himself As a result, Newton makes much of his work overly mathematically complicated, beyond anything Hooke could understand Halley must do a great deal of soothing to calm Newton down and convince him to complete the work
Finally, Principia is published in July 1687 It is an exceedingly difficult book to read with lots of overly complicated math. It is not a book that could be used to teach others physics.
Thanks to Samuel Clarke’s edition of Jacques Rohault’s Treatise of Physics an understandable bit of Newtonianism came out
Once others got into the act, more proofs of universal gravity and Newton’s laws came about The Paris Academy of Science attempted to decide between the shape of the Earth as predicted by Descartes and that predicted by Newton using the lengths of pendulums. Their results were inconclusive
The most triumphant proof was by Edmund Halley and his prediction of the return of his comet Halley noted the orbits of the comets of 1682, 1607 and 1531 were all very similar. His calculations show they are all one object and he predicts it will return in 1758
Halley’s prediction was improved by Alexis-Claude Clairaut The problem was the perturbing influence of Jupiter. Clairaut’s prediction was only a month off in perihelion
The biggest problem with universal gravitation was the 3-body problem
Many of the most famous mathematicians of the 18thand 19th Centuries worked on the problem Leonhard Euler Simon de Laplace Jean D’Alembert Joseph Lagrange
After the publication of Principia, Newton moves on He serves as Master of the Mint from 1699 for almost 30 years until his death in 1727
He is knighted by Queen Anne in 1705 He also serves two unremarkable term in Parliament as the member from Cambridge 1689 – 1690 and 1701 - 1702
Newton dies on March 20, 1727 He is buried in Westminster Abby