Greetings from Louisiana State University. By some odd fluke, I’ve been asked to blog here at the World’s Fair (who says the world is fair?) while the venerable Ben goes emeritus for a while. Don’t worry, you still have Dave!
Anyway, just so you’re not too surprised, here’s the usual kind of posts to expect from me: inappropriate humor, vicious attacks on anti-science conservatives, heart-warming stories about puppies and kittens, celebrity gossip, movie reviews, unauthorized peer review, pharmaceutical industry general disrespect, and lots and lots of art-and-science stuff.
So, let’s start with a post that doesn’t really fit any of those descriptions: a visit to the Louisiana Laser Interferometer Gravitational-Wave Observatory (known to its friends as LA-LIGO, or around here as just LIGO).
LIGO is a gigantic laser based gravity wave detector build in the swamp 40 miles east of Baton Rouge in Louisiana (http://www.ligo-la.caltech.edu/). A friend of mine and I got a personal tour on Friday (it’s also open for public and school visits, see their website for details). There are currently 4 of these in the world: one in Louisiana, two in Washington state, and one in Italy (one scheduled for construction in Australia). They are designed to detect gravity waves — assuming such waves exist. Einstein’s general theory of relativity predicts their existence, but they’ve never been detected. Apparently, according to the space-time warping theory of gravity, when two large objects do something clumsy (like when two stars collide) they make waves of gravity similar to when you throw a rock into a pond and it makes waves. When gravity waves wash over you, they stretch and contract you slightly (only by about 0.000000000000001 meters, so it’s probably not that weird feeling you just had). Anyway, LIGO and it’s sisters all have sets of 4 kilometer long super stable laser beams, whose length and position is constantly being monitored. If (when) a gravity wave washes over these laser beams, they will all stretch and contract by the exact same amount, at the same time, all over the planet — and that will constitute the success of this billions of dollars experiment. Hasn’t happened yet, but prospects look good. One of the biggest technical problems in the experiment is filtering out the non-gravity wave noise: the LIGO in Louisiana can detect vibrations from waves on the shore in the Gulf of Mexico, and of minor earthquakes anywhere on Earth.
Why should we care? Other than proving (or disproving) an Einsteinian prediction, it would apparently be the first detection of a non-electrostatic based energy-wave phenomenon, and could potentially measure the size of the explosion that was the big bang.
Here’s a really nice 20 minute video about LIGO:
We also got a nice tour of their Exploratorium-style outreach center, which has tons of hands-on physics toys to play with out here in the swamp (http://www.ligo-la.caltech.edu/SEC/sechome.html).
Most people in Louisiana don’t even know this giant instrument (4 km by 4 km) is sitting out there in the bayous in their backyard. Makes you wonder what giant experiments are going on in other backyards around the world.