LIGO (Laser Interferometer Gravitational-Wave Observatory)

Have they seen anything yet? Should they have?

Every so often, I wonder if LIGO has seen anything yet, but whenever I check, no detection of anything yet. Is this to be expected at this point?

They’ve detected plenty of things: Earthquakes, loggers, passing traffic, tumbleweeds blowing by, etc. The LIGO noise stream is a wealth of data, for anyone who can use it. But no, they haven’t yet detected any gravitational waves. Nor is this a surprise: At current levels of sensitivity, and with current models of astronomical sources, we expect to get about one detection every 30 years or so. All of the science runs up until now have basically been done just in case there’s some louder source out there that we didn’t expect, or that we get lucky and happen to pick up one of those few per century that we do expect. The next round of upgrades, though (which I think are in progress right now), will bring the sensitivity levels up to where we expect about one event per year, so stay tuned.

Indeed, the Advanced LIGO upgrades are in progress. One thing to note is that the detection rate scales as the cube of the sensitivity gain. So, a factor of 10 in sensitivity means a factor of 1000 in volume probed (and thus objects accessible).

Thanks. I was wondering what the current expected observation rate was.

The expected event rate for Advanced LIGO (the upgrade currently being installed) is closer to 40/year than 1/year. The upgrade will take a few years, however, so you won’t hear anything until then.

Ah, right, I think I was thinking of Enhanced LIGO. I’d forgotten that they were skipping right over that and going straight for Advanced.