Howdy Y'all. Did anybody else just feel that gravity wave?

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 ( 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 (

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.

More like this

First, what is a gravitational wave? I find it interesting that some people are expressing difficulty in understanding what a gravitational wave is, as though everybody (who is not a physicist) has a perfectly good understanding of what any kind of wave is. We don't need to go too deeply beneath…
One of the things that I always have to explain toward the end of my laser cooling spiel is that the technique only works well for particular atoms. Somewhere on the high side of twenty different elements have been laser cooled and trapped, but the standard techniques don't generalize well to even…
There are, as far as the layman is concerned, two kinds of scientific truth. At one end of the spectrum -- the gamma ray end, if we use the electromagnetic spectrum as a model -- there are the kinds of concepts we associate with science's grand design, the truths which permeate the dark depths of…
What's the application? LIGO stands for Laser Interferometer Graviitational Wave Observatory, because (astro)physicists feel free to drop inconvenient words when making up cute acronyms. This is an experiment to look for disturbances in space-time caused by massive objects, which would manifest as…


Glad to see you here on ScienceBlogs, finally. Hope all is well in the lab!

I miss the Christmas plays.

Best Regards,

Your headline was a pretty cheap trick. I clicked on it thinking that I was going to read about the first detection of a gravity wave, and instead I get a verbal tour of the Louisiana Laser Interferometer Gravitational-Wave Observatory. Do you also go around calling "wolf! wolf!"?

By oscar zoalaster (not verified) on 10 Jan 2010 #permalink

I'd like to make a comment here with a slight correction to your blog. You'll notice that LIGO is called the "Gravitational"-Wave Observatory... that is because a gravity wave is a well-known atmospheric phenomena. You should be clear what you are talking about! So "did anyone feel that gravity wave" would be incorrect as to the actual topic of your blog - you should have put "Did anyone feel that gravitational wave?"

Hello Oscar Z. Wow, harsh. Sorry I tricked you. But I guess that racks up my very first point on the "inappropriate humor" scoreboard. I'll be excited to hear about the first gravitational wave too, but I'm guessing that when the first one is detected, that this blog will not be the first place you'll hear about it. Seems like they are predicting they might see one around 2014 or 2015, so we'll all have to hold on a while longer. According to crb's comment, you might be mis-using the words "gravity wave" too? Didn't know this before. Would love more feedback on your interest in the waves -- I only know a little about them (I actually work with the other end of the scale - microgravity and its effects on biological systems). Thanks for reading!

Hello crb. That's neat. Looks like "gravity wave" is even far more general than atmospheric, and covers ocean waves and all kinds of fluid dynamic phenomena too. Sounds like they are called "gravity waves" because gravity helps restore equilibrium after some sort of disturbance within a fluid or between two "fluids". Is this essentially correct? So maybe I did feel a gravity wave. Interesting. Thanks!

Okay, I'm a bit more than fashionably late! Almost a month. However, GRAVITATIONAL (for brevity let's just say "G") waves are a topic of interest to me. Does anyone know the frequency of G waves? I mean length of duration, not how often they happen. What if the duration of one wave is so long that devices like ligo simply aren't big enough to detect them with the limitations of current measurement technology? Example: Let's say the duration of a G wave is a month from the leading edge to the trailing edge. With anything of that duration the detection equipment in current use isn't anywhere near large enough to capture the entire event, only a small part of the wave. Is the detection equipment in use sensitive enough? At some point length of duration and amplitude of the wave will quite simply put it beyond our technical ability to detect! The fact that ligo type facilities have been around for a while and haven't detected even a single wave supports this theory. What do you think?