In February 1995, a small research organisation known as the SETI Institute launched what was then the most comprehensive search for an answer to a centuries-old question: are we alone in the universe?

This February marks the 30th anniversary of the first astronomical observations conducted for the search, named Project Phoenix. These observations were done at the Parkes Observatory on Wiradjuri country in the central west of New South Wales, Australia – home to one of the world’s largest radio telescopes.

While Project Phoenix planned to use several large telescopes around the world, these facilities were undergoing major upgrades. So it was at Parkes that the observing program started. On February 2 1995, Murriyang pointed towards a carefully chosen star 49 light-years from Earth in the constellation of, naturally, Phoenix. This was the first observation conducted as part of the project. Over 16 weeks, the Project Phoenix team observed 209 stars using Murriyang at frequencies between 1,200 and 3,000 MHz. They searched for both continuous and pulsing signals to maximise the chance of finding genuine signals of alien life.

Radio telescopes are able to detect the faint radio emissions from distant celestial objects. But they are also sensitive to radio waves produced in modern society (our own techno-signatures) by mobile phones, Bluetooth connections, aircraft radar and GPS satellites. These kinds of local interference can mimic the kinds of signal SETI searches are looking for. So distinguishing between the two is crucial. To do this, Project Phoenix decided to use a second radio telescope some distance away for an independent check of any signals detected. CSIRO provided access to its 22 metre Mopra radio telescope, about 200 kilometres north of Parkes, to follow up signal candidates in real time.

Over the 16 weeks, the team detected a total of 148,949 signals at Parkes – roughly 80% of which could be easily dismissed as local signals. The team checked a little over 18,000 signals at both Parkes and Mopra. Only 39 passed all tests and looked like strong SETI candidates. But on closer inspection the team identified them as coming from satellites.

When Project Phoenix ended in 2004, project manager Peter Backus concluded “we live in a quiet neighbourhood”. But efforts are continuing to search for alien life with greater sensitivity, over a wider frequency range, and for more targets. Breakthough Listen, another privately funded project, commenced in 2015, again making use of the Parkes telescope among others. Breakthrough Listen aims to examine one million of the closest stars and 100 closest galaxies.

The next generation of radio telescopes will provide a leap in sensitivity compared to facilities today – benefitting from greater collecting area, improved resolution and superior processing capabilities.

To learn more about the history of the famous observatory and the first telescopes that searched for ETI, read the article.

Source: CSIRO