Waiting on the Wave

Nov 30, 2015

I’m a couple of months into postgraduate research, and I’ve decided early on that I should probably write a blog about what I’m doing.

My research is centred around attempting to detect gravitational waves. These are tiny ripples in spacetime which are made when black holes (and other exotic cosmic animals) crash into each other, when stars explode, and when the most spherical objects in the universe grow mountains. The current efforts to do this are currently centred around two large detectors in the USA, one in Italy (and soon on in Japan). I’m now part of a collaboration of hundreds of astronomers, physicists, and engineers who built these detectors, and now operate them, which is a pretty humbling experience (and attempting to read the flow of highly technical emails which come through on mailing lists from the collaboration every day has been a pretty efficient way of telling me how little I know about my subject!) Science is probably safe for the moment though; I’m thousands of miles from the detectors, and they don’t let me into the labs where they make the bits in Glasgow. They do let me have a computer, and lots of paper though.

Somebody clearly things it's pretty hard for me to inadvertently blind someone with a computer at least.

As an astronomer my job is to look at the data which comes out of the detectors, and try and make sense of it, and to try and tell if there’s actually any evidence of astronomical events in it. This is a harder job than it perhaps sounds, because the signals coming from the universe are drowned out by signals produced by objects moving around on the Earth (and by the Earth moving: gravitational wave detectors are also very sensitive to earthquakes, and people put a lot of time into trying to isolate them from tremors.) Right now I’m working on improving the process which we use to detect collisions between black holes, using a technique known as machine learning.

We’ve still not detected gravitational waves (astronomers have been looking for them for a while now). The idea that they might even exist is pretty new (in astronomical terms, anyway): they were theorised in 1916 as a prediction of Einstein’s General Theory of Relativity (which turned 100 last week), but Einstein himself concluded that they’d be impossible to detect because of the tiny effect they would have on the universe. Fortunately there are now quite a lot of people who think Einstein was wrong, and some of them have decided that it’s a sound investment to pay me to do science (these are clearly betting people). So here I am, waiting for these detectors to pick up the hints of a wave in spacetime, produced by two black holes, locked in some hazy cosmic jive.

I’m fairly sure I didn’t expect to be teaching computers how to detect crashing black holes a decade ago, when I was really getting interested in astronomy, but I’m not complaining.