In 1992, the US National Aeronautics and Space Administration, NASA, set up a program, the Microwave Observing Program, MOP. MOP was designed to be a part of and a complement to the various programs then ongoing in the United States and elsewhere that were involved in the search for extraterrestrial intelligence (SETI). This was not NASA’s first involvement in this search; indeed, given the agency’s mandate, it would have been inexplicable if they had not been concerned with probable, possible or inevitable extraterrestrial civilizations/intelligences.
MOP was designed to address a major issue that had faced SETI investigators ever since SETI had taken off in 1960 i.e. the trade off between range and sensitivity. Simply put, the question was whether the investigators should design/calibrate their equipment to be sensitive enough to gather potential information from a limited section of the sky, which section might have no information worth gathering in SETI terms, or cover a wider expanse of the sky in the hope of getting information which, even if it were there for the taking, might be missed because of the (relative) lack of sensitivity of the information gathering process.
In seeking to tackle these issues, MOP was designed as a two phase stream, both running simultaneously. The first phase was to tackle the issue of sensitivity by a targeted search of some 800 or so of the nearest Sol (that’s our local star, the sun) like stars, whilst the second phase was a general and indiscriminate search of the entire sky, which would tackle the issue of range. The survey was to be done using NASA’s own deep space network in conjunction with the 43 metre dish at the National Radio Astronomy Observatory at Green Banks, West Virginia, and the giant 300+metre dish at the Arecibo Observatory, Puerto Rico. In addition, a series of 15 million channel spectrum analysers were to be deployed to analyse the information; and these analysers could be used in tandem to get even better results if circumstances required. The analysers used for the targeted search were set at 1 hertz per channel, whilst those for the general search were set at 30 hertz per channel.
Unfortunately, but, perhaps, not surprisingly, the idea failed. Not for technical or scientific reasons, but for political ones. The US Congress derided the project and funding was stopped just a year after the project took off. But SETI advocates and enthusiasts were not to be put down; the failure of Congress to fund the program galvanised people to come up and fund it.
In 1995, the SETI Institute, a non-profit organisation situated in California, took up part of the challenge and set up Project Phoenix. Like the legendary bird, Phoenix was set to rise from the ashes and carry on the targeted search which Congress had prevented NASA from doing.
Phoenix took off in February 1995, using the Parkes radio telescope located in New South Wales, Australia, which is the largest such facility located in the southern hemisphere. Subsequently, between September 1996 and April 1998, Phoenix utilised the facilities of the National Radio Astronomy Observatory, Green Bank, West Virginia, US.
As indicated above, Phoenix did not try to replicate the entire MOP program of NASA. Phoenix is directly concerned with the targeted approach to stellar systems similar to Sol’s, which are nearby (within 200 or so light years), and which seem likely to have planets which are able to support life: in fact, roughly the same 800 or so suns that the NASA’s MOP program had targeted. The radio signals for which Phoenix searches are also roughly in the range set by the designers of the MOP program, which is also not surprising, since quite a number of the folk involved in MOP moved over to Phoenix after MOP was axed. Since 1998, observations for the Phoenix project are made from the big dish at Arecibo, Puerto Rico.
In March 2004 the project announced that after checking out the 800 stars on its list, it had failed to find any evidence of extraterrestrial signals. In the words of the project leader, Peter Backus, it is possible that we live in a quiet area, which should not surprise anyone. Sol, and its daughters, Earth inclusive, inhabit a particularly deserted area of the galaxy. In any event, it is well to keep in mind that radio is a fairly new phenomenon for us; less than 150 years. If there were a civilization roughly at the same stage with ours, which started radio broadcasting just 200 years or so ago, and which was at the limit of the search (200 light years), we’d have a few more years to wait before any of their radio emissions get to us. After all, the broadcast (the Arecibo broadcast) we (Earth, that is) sent out a few years back isn’t expected to get anywhere near any possible recipient for the next 25,000 years, give or take a few!
Phoenix, as we can see is concerned only with the targeted segment of the MOP program, but, for SETI enthusiasts, there is no cause for alarm. The general sky search has survived Congress’ axe. The SETI League, Inc, a membership supported non-profit organization is carrying out that portion of the job with more than 100 radio telescopes in more than 20 countries.
