Lecture 3
Oh, ouch! Ouch! Ouch! Acid tummy, trouble sleeping, cranky colleagues and proposals due. It must be September!
This year starts unusually badly: our DOE guy visits tomorrow, my NSF proposal is due next week, my daughter’s birthday is next week too and EVERYONE is cranky and one edge.
Tali is back and I guess everything came out alright (pun intended). 8.033 is launching into relativity with the Michelson-Morley experiment. Historically, it is not clear how much Einstein knew about M-M. He certainly had the idea c is the same in all interial frames, but I’ve never really been clear how much Einstein was up on the scientific literature. Certainly, MM has a large impact on Lorentz, Fitzgerald, Poincare, etc. who did a great deal to develop the theory prior to Einstein’s great synthesis.
The MM experiment itself is quite amazing. Their limit on the shift from aether drift in 1887 was 0.0005 of a fringe. This corresponds to a a change of travel distance of 0.2 nm (200 trillionths of a meter). This in the era when experimental apparatus was made from wood, leather, candles, glass mirrors, and, of course, mercury. These days, Michelson interferometers like LIGO (Laser Interferometer Gravity wave Observatory, http://www.ligo.caltech.edu/) look for distance shifts a million times smaller from passing gravity waves. MIT has a big group working on LIGO and its a great place to do a UROP (talk to Nergis Mavalvala (nergis@ligo.mit.edu) or Erik Katsavounidis (kats@mit.edu)).
Next year in 8.13 or 8.14 (Junior Lab), you may have a chance to use a Michelson interferometer yourselves in the Moessbauer experiment (http://web.mit.edu/8.13/www/13.shtml) where it is used to calibrate an apparatus capable of measuring energies to a part in a trillion. Inventing this technique got my pal Rudolf Moessbauer a quick Nobel when he was, like, 25 years old.
