12 mins read 08 Sep 2020

WA Telescope finds No Alien Tech in 10 million-star systems

A radio telescope in outback Western Australia has scanned a small portion of the sky, looking across 10-million stars and found no signs of alien technology.

Artist illustration of an Ecumenopolis – a planet-sized city. Credit: Kerbal Space Program.

When we think about the image of aliens in our minds, often we go to little green figures with large black eyes staring at us from their upside-down, teardrop shaped heads, or slithering beings that are able to talk between themselves through telepathic processes. The movies tell us (mostly) that aliens who come to Earth from planets afar, often come with ill-intentions - here to dominate, exterminate or assimilate.

But for Aliens to have even arrived here on Earth, they’d need to have conquered the ability to travel great distances over long periods through the mostly empty voids of space. Even travelling at near the speed of light (a technology challenge of which they must have resolved) the closest star system to Earth is still 4.5 years away – and we are not yet aware of any propulsion system capable of traversing these distances.

Outside of science fiction, it’s thought that if extra-terrestrials existed, they could fall into a number of different categories – microbial sub-surface creatures that crawl, or swim on ocean worlds, much like some of the moons that orbit the giant planets in our own Solar system. Or the more advanced variety, who’ve developed technological solutions (like energy resourcing, propulsion systems, communication structures, and more).

The latter category presents an opportunity for Earth scientists to scan the skies, looking for any tell tale signs that there is another home of beings out there in the dark vastness, broadcasting signals into space (like we do) searching to resolve the very same question that has burned in our bellies for centuries – are we alone?

Native wildflowers growing at the MWA. Credit: MWA Collaboration/Curtin Uni.

Now, a radio telescope located in the central red-Earth plains of Western Australia has scanned a relatively small patch of sky which features at least 10 million stars – and found no evidence of any extra-terrestrial techno-signatures.

The findings, published today in the Publication of the Astronomical Society of Australia were conducted by CSIRO astronomer Dr. Chenoa Tremblay and Prof. Steven Tingay, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR).

To conduct the research, the Murchison Widefield Array (MWA) telescope was used – itself, an array of spider-like antennas grouped together to form a powerful radio telescope, allowing Dr. Tremblay and Prof. Tingay to explore hundreds of times more broadly than any previous search for extra-terrestrial signs of life and technology.

The Vela Supernova Remnant – a massive structure in the constellation Vela from a massive stellar explosion which occurred about 12,000 years ago. Credit: Harel Boren.

Using the MWA, a deep search was conducted around the Vela constellation – which is located in southern skies and covers an area of approximately 500 square-degrees. Interestingly, the Vela constellation features seven star-systems which are known to harbour planets, though these are many times larger in mass than the Earth, and likely to harbour any life (as we know it).

“The Vela constellation is the 32nd largest constellation in the sky and we covered 80% of the constellation with the survey.  The MWA can actually detect the whole of the Vela constellation and some of the Puppis constellation.  However, due to processing constraints we reduced the survey to this size,” said Dr. Tremblay.

“We observed the sky around the constellation of Vela for 17 hours, looking more than 100 times broader and deeper than ever before,” she said.

“The region of the Vela constellation is scientifically interesting as it is the region where a number of large stars have recently (in space terms of a mere million years ago or so) exploded and died.  As the dust and gas gets blown and pushed from the energy of the explosions, they form knots of gas where new stars are forming.  My main science is to study these regions of new star formation and use the molecules to better understand the stars life cycle.”

“With this dataset, we found no techno-signatures—no sign of intelligent life.”

Prof. Tingay said even though this was the broadest search yet, he was not shocked by the result.

“As Douglas Adams noted in The Hitchhikers Guide to the Galaxy, ‘space is big, really big’.”

“And 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,” he said.

Aerial view of the MWA telescope, showcasing the tiles with the 4 x 4 formation the antennas are positioned in. Credit: ICRAR/Curtin University.

Unlike many of the traditional-looking telescopes, the MWA is made up of spider-like antennas, each with 16 dipoles and arranged in a 4 x 4 configuration, sitting atop a 4m x 4m mesh ground plate. It is classed as a radio telescope (technically a low-frequency array instrument) and operates within a frequency range of 70 – 300 MHz.

“The MWA is a unique telescope, with an extraordinarily wide field-of-view that allows us to observe millions of stars simultaneously,” said Dr. Tremblay.

The telescope has been in operation since 2013 and has since achieved some fairly big results, including taking the first radio panorama of the Universe, constraining the limits of the first-ever traceable fast radio burst (FRB), and the creation of a 300,000 galaxy catalogue.

“Although there is a long way to go in the search for extra-terrestrial intelligence, telescopes such as the MWA will continue to push the limits—we have to keep looking,” said Prof. Tingay.

One group of the MWA antenna array – the spider-like dipole antennas in the Western Australian outback. Credit: CSIRO.

The MWA - a world-class radio telescope instrument in it own – is also a precursor instrument for the larger, and more ambitious Square Kilometre Array (SKA) telescope – a mega-science instrument being developed by several nations and hosted in Western Australia and South Africa.

The SKA will feature tens of thousands of antennas, all working together to simulate an enormous eye that can peer deeper, further and faster into the Universe attempting to resolving big science questions such as a better understanding of what Dark Energy is, the evolution of the first galaxies, the nature of time and space in the first few instances after the big bang, and directly related to this latest paper by Dr. Tremblay and Prof. Tingay – are we all alone in our Universe?

The Australian portion of the telescope, the SKA-Low, will be located at the Murchison Radio-astronomy Observatory, a remote and radio quiet astronomical facility established and maintained by CSIRO—Australia’s national science agency. The SKA will be built at the same location but will be 50 times more sensitive and will be able to undertake much deeper Search for Extra-Terrestrial (SETI) experiments.

“There was an experiment done in 1975 with the Arecibo Telescope in Puerto Rico where they emitted a signal at the highest power of the telescope to see how much power it would emit and how we could compare that to signals we could detect.  We are still about three orders of magnitude off in sensitivity for these signals,” said Dr. Tremblay. 

“The SKA will offer the ability to look for these signals at the same frequency but with better spectral resolution and better positional sensitivity.  What this means is that we can look for signals that may have a narrow frequency profile and instead of having a large number of stars grouped together in our image we can better localise individual stellar systems.”

“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,” added Prof. Tingay.

Until the SKA comes online, telescopes the MWA (which itself has been developed and operated by a  consortium of partner institutions from seven countries and led by Curtin University) will continue to be utilised for scanning the skies in the low-frequency radio ranges.

Science Check: TEchno-Signatures

Artist illustration of a Dyson sphere around a star. Credit: Kevin Gill.

Techno-signatures can be described as scientific evidence of a form of technology (past or present) that has been detected through in-situ or remote sensing capabilities. Whilst considering alien technology would mean our likely techno-signature detection is captured through remote-sensing capabilities (i.e. our telescopes see it from Earth, unless, you know – the aliens did arrive), the same terminology could be used if we were to come across an previously undiscovered human society on Earth, and studied the technology of their time.

Extra-terrestrial techno-signatures could certainly be in the form of communication (e.g. broadcast radio waves, or beacons of light simulated in patters like Morse Code), but alternatively, could also be a detection of a powerful propulsion system (to quote Star Trek – the detection of a warp signature generated by a warp-drive), or even leaking radiation from a planet – such as their tv/radio broadcasts.

In fact, Earth has been leaking radiation into space since the birth of long-range radio transmissions in the early 20th century when electrical engineer and inventor Guglielmo Marconi developed the technology. However, due to finite speed at which light travels - for an alien civilisation to come across our own Earthly techno-signatures, they’d need to be within a bubble with a rough diameter of 200 light-years, an incredibly tiny dot in our galaxy, let alone the Universe as a whole. Nobody knows we are here yet.

“We really don’t know where techno-signatures may look like.  Some programs are looking for optical lasers, some are looking for Pulsar-like signals kind of the steady pings of your car alarm when you leave your lights on,” said Dr. Tremblay. 

“However, with the MWA we are looking for signals that are the same frequency as your favourite radio station.  That means we could be sensitive to the leakage of signals and not just purposefully sent signals.”

Lastly, techno-signatures can also take on the form of massively scaled engineering capabilities by alien civilisations, such as harnessing the power of a star by using a Dyson sphere – hypothetical megastructures that encompass a star with energy collecting devices that can fulfill the needs of a civilisation with high-energy demands and ambitions.

The Drake Equation

The Drake Equation. Credit: University of Rochester.

So, if there are no techno-signatures found with the MWA in the Vela Constellation which features 10 million stars, then can we make the assumption that there are no intelligent aliens out there? (we might still get swimming worms in the oceans of Europa!)

In 1961, Dr. Frank Drake wrote an equation (now named after him called The Drake Equation) which started the discussion for scientists (and the SETI program) on the potential quantification of intelligent life in the Milky Way Galaxy. The equation itself is more of an approximation rather than a firm numerical outcome.

The equation states that the number of civilisations in our galaxy with the ability to communicate with us can be determined by looking at several factors, such as the star formation rate of our galaxy, the fraction of those stars with planets that could support life, the fraction of these planets that could have time and the conditions for intelligent life to develop, a further fraction of these planets that have intelligent life with the capability to release detectable signals into space, and the length of release time of these signals.

The Drake Equation has also faced some strong criticism in that the uncertainty of several factors that make up the final result are so ambiguous, that the level of uncertainty derived is almost in every case too large, to even consider it a scientifically justified conclusion.

“For its time, it was a great string of thinking that inspired a generation of ETI searches,” said Dr. Tremblay. 

“Recently, there was a proposed new equation that uses all of the information known regarding our search for ETI, including astrobiology work done on Earth, called the Strong Astro-biological Copernican scenario by Westby & Conselice, with strong meaning intelligent, communicative life.  In this work they determine the estimate in a way that uses terms that make less assumptions and conjecture.”

The future of SETI-like research is still a hot topic for astronomy and science, with major objectives of many Australian facilities like the MWA, SKA and CSIRO Parkes radio telescope currently running dedicated projects searching for any form of techno-signature available.

For Dr. Tremblay, the hunt for interesting things in space using the MWA, doesn’t stop with this study.

“My next major piece of work I am planning is to launch a major campaign on the Galactic Centre using not only the MWA but also with Parkes and ASKAP as well.” 

“The MWA surveys cover such a large amount of the sky, looking at so many objects at once.  The data processing for this field alone has launched five independent papers from myself and others.” 

“So I think this will lead into some really interesting science.  I am excited.”

Maybe the little green aliens don’t know where here as yet and haven’t bothered to look or traverse in our direction of space. Maybe they’ve seen us and simply don’t care, or better still – by reviewing our historical broadcasts, have come to the realisation that we are not the friendly ones (cringe-worthy black and white images of nuclear blasts going off, flash across our minds).

In any case – that we, the humans, can build impressive astronomical infrastructure like the MWA and scan a region of space, assessing 10-million stars to make the determination that no low-frequency techno-signatures exist, is a feat amongst itself.

If someone would have told Marconi 100 years ago what Dr. Tremblay and Prof. Tingay achieved using the MWA today, he’d probably call it one thing.



We acknowledge the Wajarri Yamatji as the traditional owners of the Murchison Radio-astronomy Observatory site.

The paper, A SETI Survey of the Vela Region using the Murchison Widefield Array: Orders of Magnitude Expansion in Search Space, is available on arXiv.org.