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Neptune discovery in physics class: activities and simulations. Hezi Yizhaq, Environmental High School, DAT Fulbright Teacher from Israel Email Address: email@example.com Matthew Bobrowsky, Department of Physics, University of Maryland Email Address: firstname.lastname@example.org.
Hezi Yizhaq, Environmental High School, DAT Fulbright Teacher from Israel
Email Address: email@example.comMatthew Bobrowsky, Department of Physics, University of Maryland
Email Address: firstname.lastname@example.org
Kepler's laws of planetary motion are three scientific laws describing orbital motion, each giving a description of the motion of planets around the Sun (1619).
Kepler's laws are:
1. The orbit of every planet is an ellipse with the Sun at one of the two foci.
2. A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.
3. The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between them
distance from the Sun is: 19.22AU.
apparent between the planet position as predicted by theory and as measured in the sky
Discrepancies between calculated
to observed longitudes
Two possible explanations:
Independently, two astronomers, John Couch Adams in England and Urbain Jean Josef Le Verrier in France, calculated the position of this yet unknown planet.
Le Verrier was already a know scientist whereas Adams was a young Cambridge undergraduate, 26 years old, who seems to have taken on a own personal quest to search for an explanation for the apparent misbehavior of Uranus.
Urbain Le Verrier
John Couch Adams
In October 1845, Adams wrote to George Airy, the Astronomer Royal of Greenwich Observatory, claiming that he had solved the problem of Uranus' orbit, and stating the position where the unknown planet could be found. Now, if Airy had pointed a telescope at that spot, he might have found Neptune (however, not at the exact spot that Adams had pinpointed).
Although, he tried to conceal it, Airy had a strong negative reaction to Adams paper. His altitude later turned out to be of critical importance to the fact that Neptune was not discovered in England. The problem was that Airy was strongly opposed to theoretical investigations and skeptical of the abilities of younger scientists. He was not the sort of man to take a leap into the scientific unknown.
“God forgive me for writing in this way – The truth lies on the other side & Adams is the 1st theoretical discoverer of Neptune. The whole thing was parried [?] and perverted by Airy’s indefensible reticence. On him be the responsibility of the (temporary) transfer of one of the brightest stars in Britain’s Scientific fame to
France. “ British Astronomer John Herschel-1846
Numerical Solution of the Corrected Orbit of Uranus
(unperturbed orbit=19.22AU,R2=38.8AU )
Rotation Curves in the Milky Way
Rotation Curves in the Solar System
Modified Newtonian Dynamics