This is LIGO (Laser Interferometer Gravitational-Wave Observatory), a giant Michelson interferometer designed to detect gravitational waves. What is a gravitational wave? Remember that charges attract with a 1/r2 force, and if you wiggle one, it emits electromagnetic waves, according to Maxwell's equations. Likewise, masses attract with a1/r2 force, and the complete theory of gravity (Einstein's General Relativity) predicts that when masses wiggle they send out gravitational waves. Gravitational waves are VERY hard to detect, and only the most violent astrophysical events make enough for there to be any chance. LIGO uses the interference pattern between two laser beams to sense tiny motions caused by gravitational waves.
Lectures this week on Chapter 37, Interference and Diffraction.
The last CAPA (#15) is due Monday Dec. 10 at 9 pm. The last recitation/homework problem is due on Tuesday, Dec. 11.
The Final will be on Dec. 18, 4:30-7:00 pm. Click on Exams for details.
Home page from weeks 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
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