The search for extraterrestrial intelligence (SETI) has fascinated us for decades. Now a team of researchers have used the Murchison Widefield Array in Australia to scan great swathes of sky for alien signals. Unusually for a SETI project, this one focussed attention on 2,800 galaxies instead of stars within our own. They have been on the lookout for advanced civilisations that are broadcasting their existence using the power of an entire star. Alas they weren’t successful but its an exciting new way to search for alien intelligence.
Our first attempts to search for alien intelligence began back in 1960 with Project Ozma. It was led by astronomer Frank Drake and used the 85 foot radio telescope at Green Bank in West Virginia. The aim was to try and detect alien radio signals from Epsilon Eridani and Tau Ceti, should they have existed. Alas they found nothing but it marked the first step in a scientific approach to search for extraterrestrial intelligence. Typically SETI tends to focus on electromagnetic signals such as radio waves an in particular unusual patterns that could suggest intentional communication.
Radio telescopes monitor the sky at the Allen Telescope Array in California. Finding a signal from a distant civilization is one way we could experience first contact with ET. (SETI Institute Photo)This recent attempt to try out a new approach was led by Dr Chenoa Tremblay of the SETI Institute and Prof. Steven Tingay from the Curtin University. The approach was to utilise the magnificent field of view of the Murchison Widefield Array (MWA) which allows one observation to cover 2,800 galaxies. Among them, there are 1,300 galaxies that we know the distance too. The MWA in Western Australia utilises low frequencies (100MHz) to probe the distant galaxies.
By searching these galaxies for signs of alien signals we are actually looking for advanced civilisations. It’s one thing to be able to send radio signals across interstellar space, indeed we have been doing that for decades since the advent of radio communication. As radio signals propagate across space, they weaken and certainly could not traverse the immense distances between the galaxies. It’s just possible that advanced civilisations might have the technology to harness the power of their Sun and perhaps other stars in their galaxy to send signals powerful enough to travel the millions of light years between galaxies.
I quite love the idea of advanced civilisations that may have developed the technology to transmit ‘technosignatures’ or signs of alien technology across the Universe but alas the study did not find any. Queue sad emoji It did however provide valuable insight into just how we may be able to widen our search for alien intelligence beyond the Milky Way.
The MWA uses thousands of dipole antennae that are spread across several kilometres giving it a wide 30 degree field of view. It has been designed to operate between 70 and 300 MHz allowing it to participate in studies of the early universe, mapping the cosmos, and detecting solar activity. It helped advance radio and interferometry technology facilitating the development of the Square Kilometre Array.
The Murchison Widefield Array radio telescope in remote Western Australia. Brown University.Using MWA and other radio installations to study the properties of stars and galaxies also allows for the search for technosignatures. It’s a new approach and it highlights the importance of continuing the development of new technology to open up new ways to search for ET.
Source : First low frequency search for alien technology in distant galaxies
