SETI, the Search for Extra Terrestrial Intelligence, is an exciting area of research. Currently millions of personal computers running SETI@home are wading through terabytes of data, looking for trademark signals which could be extraterrestrial in source. So isn’t it rather disappointing that they haven’t found anything yet?
It does seem that we are searching the sky exhaustively, but in fact we are not. The SETI@home project only looks at particular frequencies, the emission lines of Hydrogen. Neil Tyson compared this to a drunken man looking for his keys under a lamppost, just because it is light there. If we are to intercept an intergalactic transmission, it could be across several frequencies, to make it robust to interference and noise. Furthermore we have perhaps only surveyed the closest 100 lightyears of space, a miniscule proportion of the galaxy.
The techniques used by SETI projects to detect promising signals are extremely simple. It is hard to find research in the algorithms used, and sometimes they only amount to looking for simple spikes in the signal. Only recently has autocorrelation been employed to look for repetitive noise in SETI@home.
The SETI Challenge is meant to address this problem. It asks the question- how might a SETI signal be encoded? Could we decode such signals? And would we be able detect such a signal with our current techniques? The Challenge makes us think about such issues by posting SETI decoding challenges. A pretend SETI signal is released, and the challenge is to discover what the embedded meaning was. It is practice for the real thing, and it will hopefully cause us to discover new issues in the field of interstellar communications.
Check out the SETI Challenge website. Contribute to the discussion on SETI encodings, and see if you can help to decode any of the signals. Even post your own challenge!