Phys 3250: Topics in RelativityInstructor: Dr. Spencer BucknerOffice: SSC B-326Office Hours: MWF 10:15 – 11:30am

and MWThF 1:30 – 2:30pmor by appointment

Email: buckners@apsu.edu

Website: www.apsu.edu/buckners/relativity

Class Meeting Time:Wednesday 12:20 – 1:15pm

Class Meeting Place: SSC E-109

Textbooks

Schaum’s Outline for Modern Physics by Ronald Gaurteau & William Savin

Grading

Exams………45% A…90 – 100%Homework…35% B…80 – 89%Project………15% C…70 – 79%Participation…5% D…60 – 69%

F…<60%

ExamsThere will be three exams during the semester: one about every fourth class meeting. The exams will consist of a number of numerical problems similar to the homework and at least one essay question. The exam dates are:

Wednesday September 16Wednesday October 14Wednesday December 2

HomeworkHomework will be assigned each week and will be due the following week. Most problems will be out of the Schaum’s Outline for Modern Physics but additional supplemental problems from other sources may be assigned. Solutions to the homework will be posted in the class D2L shell within a day or two of the due date.

First Homework Set: Schaum’s Outline Chapter 1 Supplementary Problems #1.11, 1.13, 1.17, 1.18, 1.19 & 1.20

ProjectThere will be one project on a topic in relativity, either special or general, during the semester. The results of the project will be presented in a poster format to be displayed during the final exam period on Thursday December 10 @ 1:30pm (or whenever we agree upon a time). You must be available next to your poster to defend it during the entire exam period. A project abstract (prestract?), worth 15% of the project grade, will be due Wednesday October 14.

The Need for Relativity

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First published in a four part paper by James Clerk Maxwell between 1861 and 1862. Maxwell showed that light was an electromagnetic wave whose propagation speed was equal to the inverse square root of the product of the two fundamental constants in his equations.Question: What is the medium through which light travels?

The Need for Relativity II

Performed in 1887 by Albert Michelson and Edward Morley at Case Western Reserve University to detect the motion of Earth through the luminiferous aether

Given that light was an electromagnetic wave, a medium for the wave was postulated: the luminiferous aether.

Watch YouTube video on Michelson-Morley experiment

The Need for Relativity III

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To account for the null results of Michelson and Morley, one proposal was that electricity& magnetism should use a Lorentz transformation rather than a Galilean transformation. Problem is, while Maxwell’s equations are invariant under a Lorentz transformation, Newton’s equations aren’t. Plus, Maxwell’s equations gave a speed of propagation of the electromagnetic force: the speed of light. There was no propagation speed inherent in Newton’s equations.

Galilean Transformations are simple addition and subtraction

This doesn’t work for the electromagnetic force and Maxwell’s Equations. It works fine for

Newtonian mechanics and the gravitational force

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Hints on the homework

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The Need for Relativity IV

The orbit of Mercury wasn’t what it was supposed to be. The perihelion of Mercury's orbit precesses by just over 574 arcseconds per century. Perturbations due to the other planets and the oblateness of the Sun could account 531 arcsecond per century. The other 43 arcseconds per century could not be explained using Newtonian gravity.

Colored Card QuestionThe null results of Michelson and MorleyA) proved there was no luminiferous

aether.B) proved that the Earth dragged the

luminiferous aether with it as it moved through space.

C) proved that, when dealing with light, velocities required a Lorentz transformation rather than a Galilean transformation.

D) didn’t prove anything.

Another Colored Card QuestionThe precession of the perihelion of Mercury was evidence thatA) the planet was dragging the luminiferous

aether with it and thus slowing its motion.B) the force of the Sun’s gravity on Mercury

was stronger than it should be due to its proximity to the Sun.

C) Newton’s law of gravity was wrong and no longer useful anywhere.

D) due to its high orbital speed, a Lorentz transformation for velocity was required to get the correct orbit.

5-Minute EssayMy name is _______.

I am a (sophomore, junior, senior).

My major is ___________.

I am taking Topics in Relativity because I want to learn _______________.

When I graduate I want to __________.