SETI@Home emailed me:
We’d like to invite you to reconnect with SETI@home. Our records show that you’ve been with SETI@home since 18 May 1999, but it’s been 265 days since you last returned a work unit. We want you back…
SETI@Home sends out radio transmission data to computers around the world, which do data analysis, checking for evidence of extraterrestrial intelligence. From the wiki entry:
SETI@home searches for possible evidence of radio transmissions from extraterrestrial intelligence using observational data from the Arecibo radio telescope. The data are taken ‘piggyback’ or ‘passively’ while the telescope is used for other scientific programs. The data are digitized, stored, and sent to the SETI@home facility. The data are then parsed into small chunks in frequency and time, and analyzed, using software, to search for any signals–that is, variations which cannot be ascribed to noise, and contain information. The crux of SETI@home is to have each chunk of data, from the millions of chunks resulting, analyzed off-site by home computers, and then have the software results reported back. Thus what appears an onerous problem in data analysis is reduced to a reasonable one by aid from a large, Internet-based community.
I think I’ll install the client and start looking for aliens again.