Australian astronomers say they’ve found no technological signs of alien life in a study of more than 10 million star systems.
Perth-based researchers used the Murchison Widefield Array (MWA) radio telescope in the Western Australian outback, in a project dubbed ‘looking for ET’.
The MWA searches for powerful radio emissions at low frequencies, similar to FM radio frequencies on Earth that allow radio broadcasts.
These emissions from space, known as ‘technosignatures’, could possibly indicate the presence of an intelligent aliens with technological innovations similar to our own.
The team completed the ‘deepest and broadest search’ of a patch of sky known to include at least 10 million stars, in the southern constellation of Vela.
But the researchers concluded that, in this part of the universe, other civilisations are ‘elusive, if they exist’ at all.
Scroll down for video
A 20-second exposure showing the Milky Way overhead the Murchison Widefield Array (MWA) radio telescope in Western Australia
‘The MWA is a unique telescope, with an extraordinarily wide field-of-view that allows us to observe millions of stars simultaneously,’ said Dr Chenoa Tremblay at Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia.
‘We observed the sky around the constellation of Vela for 17 hours, looking more than 100 times broader and deeper than ever before.
‘With this dataset, we found no technosignatures – no sign of intelligent life.’
The team stressed that the area searched was still a comparatively tiny portion of outer space.
‘As Douglas Adams noted in The Hitchhikers Guide to the Galaxy, “space is big, really big,”‘ said Professor Steven Tingay from the International Centre for Radio Astronomy Research (ICRAR) in Perth.
‘Even though this was a really big study, the amount of space we looked at was the equivalent of trying to find something in the Earth’s oceans but only searching a volume of water equivalent to a large backyard swimming pool.
‘Although there is a long way to go in the search for extraterrestrial intelligence, telescopes such as the MWA will continue to push the limits – we have to keep looking.’
The team observed the sky in a supernova remnant in the Southern constellation of Vela, where there are around six known exoplanets.
However, it is likely that a vast number of exoplanets remain unknown in this system.
Using the MWA in the frequency range 98-128 MHz over a 17-hour period, the Vela Supernova Remnant was observed with a frequency resolution of 10 kHz.
The northern portion of the Vela Supernova Remnant. The team observed Vela which the team observed with a frequency resolution of 10 kHz. Within the field of study there are six known exoplanets
At the positions of the six exoplanets, the astronomers found no narrow band signals consistent with radio transmissions from intelligent civilisations.
In total, combined with two previous surveys, the researchers have now examined 75 known exoplanets at low frequencies without finding a trace of civilisations.
‘Our results clearly continue to demonstrate that searches for extraterrestrial intelligence (SETI) has a long way to go,’ the authors say in their research paper, published in Publications of the Astronomical Society of Australia.
Earlier this year, MWA was responsible for detecting the ‘biggest explosion since the Big Bang’ from a supermassive black hole in a galaxy 390 million light years away.
The extremely powerful eruption occurred hundreds of millions of years ago in the Ophiuchus galaxy cluster, and was five times as powerful as the previous ‘largest explosion’ record holder.
It was so powerful it punched a cavity in the cluster plasma – super-hot gas surrounding the black hole – big enough to fit 15 Milky Way galaxies inside it.
The MWA is a precursor for the Square Kilometre Array (SKA), a £1.5 billion observatory with telescopes in Western Australia and South Africa.
The Murchison Widefield Array (MWA) is a low frequency radio telescope and is the first of four Square Kilometre Array (SKA) precursors to be completed. It allowed the team to dive deeper into the distance galaxy to uncover the secret
Dipole antennas of the Murchison Widefield Array (MWA) radio telescope in Mid West Western Australia
It’s is one of four official SKA precursor telescopes – instruments that provide information to help guide the SKA.
The SKA precursor telescopes were designed primarily as engineering testbeds for the future SKA.
‘When building something the size of the SKA, it’s important to try on a smaller scale first to test and refine technologies and anticipate potential challenges on a larger scale,’ said Richard Schilizzi, former director of the SKA project.
With the SKA, scientists will be able to survey billions of star systems and seek technosignatures ‘in an astronomical ocean of other worlds’, according to Professor Tingay.
‘Due to the increased sensitivity, the SKA low-frequency telescope to be built in Western Australia will be capable of detecting Earth-like radio signals from relatively nearby planetary systems,’ he said .
THE MWA AND THE SKA
The Murchison Widefield Array (MWA) is a low-frequency radio telescope.
It’s located at the Murchison Radio-astronomy Observatory, a remote and radio quiet astronomical facility established and maintained by CSIRO – Australia’s national science agency.
A consortium of partner institutions from seven countries (Australia, USA, India, New Zealand, Canada, Japan, and China) financed the development.
It has been designed to look for ‘neutral atomic hydrogen emissions’ from the earliest days of the universe.
It will also study the Sun’s heliosphere, the Earth’s ionosphere and map the extragalactic radio sky.
The upcoming Square Kilometre Array (SKA) will be built at the same location but will be 50 times more sensitive and will be able to undertake much deeper SETI experiments.
The SKA project is an international effort to build the world’s largest radio telescope, with eventually over a square kilometre (one million square metres) of collecting area.
SKA will eventually use thousands of dishes and up to a million low-frequency antennas that will enable astronomers to monitor the sky in unprecedented detail and survey the entire sky much faster than any system currently in existence.
Both South Africa’s Karoo region and Western Australia’s Murchison Shire were chosen as co-hosting locations for the SKA.