SETI Archives

August 29, 2024August 29, 2024 by Mark Thompson

Giant Low-Frequency Scan Searches for Aliens in 2,800 Galaxies

One of the tiles making up the 32T, a prototype instrument for the Murchison Widefield Array. Natasha Hurley-Walker

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.

August 22, 2024August 22, 2024 by Matt Williams

New Study Proposes how a Black Hole in Orbit Around a Planet Could be a Sign of an Advanced Civilization.

Ray traced shadow of a spinning and charged black hole. Credit: Simon Tyran, CC BY-SA 4.0

In 1971, English mathematical physicist and Nobel-prize winner Roger Penrose proposed how energy could be extracted from a rotating black hole. He argued that this could be done by building a harness around the black hole’s accretion disk, where infalling matter is accelerated to close to the speed of light, triggering the release of energy in multiple wavelengths. Since then, multiple researchers have suggested that advanced civilizations could use this method (the Penrose Process) to power their civilization and that this represents a technosignature we should be on the lookout for.

Examples include John M. Smart’s Transcension Hypothesis, a proposed resolution to the Fermi Paradox where he suggested advanced intelligence may migrate to the region surrounding black holes to take advantage of the energy available. The latest comes from Harvard Professor Avi Loeb, who proposed in a recent paper how advanced civilizations could rely on a “Black Hole Moon” to provide their home planet with power indefinitely. The way this black hole would illuminate the planet it orbits, he argues, would constitute a potential technosignature for future SETI surveys.

August 20, 2024August 20, 2024 by Evan Gough

The Wow! Signal Deciphered. It Was Hydrogen All Along.

The Arecibo Radio Telescope. Though it's decommissioned now, Arecibo Data may explain 1977's mysterious Wow! Signal. Image Credit: UCF

In 1977, astronomers received a powerful, peculiar radio signal from the direction of the constellation Sagittarius. Its frequency was the same as neutral hydrogen, and astronomers had speculated that any ETIs attempting to communicate would naturally use this frequency. Now the signal, named the Wow! Signal has become lore in the SETI world.

But what was it?

August 7, 2024August 9, 2024 by Matt Williams

New Study Suggests that Our Galaxy is Crowded or Empty. Both are Equally Terrifying!

Gaia's all-sky view of our Milky Way Galaxy and neighbouring galaxies, based on measurements of nearly 1.7 billion stars. The map shows the total brightness and colour of stars observed by the ESA satellite in each portion of the sky between July 2014 and May 2016. Brighter regions indicate denser concentrations of especially bright stars, while darker regions correspond to patches of the sky where fewer bright stars are observed. The colour representation is obtained by combining the total amount of light with the amount of blue and red light recorded by Gaia in each patch of the sky. The bright horizontal structure that dominates the image is the Galactic plane, the flattened disc that hosts most of the stars in our home Galaxy. In the middle of the image, the Galactic centre appears vivid and teeming with stars. More information on: http://sci.esa.int/gaia/60169-gaia-s-sky-in-colour/

Is there intelligent life in the Universe? And if so, just how common is it? Or perhaps the question should be, what are the odds that those engaged in the Search for Extraterrestrial Intelligence (SETI) will encounter it someday? For decades, scientists have hotly debated this topic, and no shortage of ink has been spilled on the subject. From the many papers and studies that have been written on the subject, two main camps have emerged: those who believe life is common in our galaxy (aka. SETI Optimists) and those who maintain that extraterrestrial intelligence is either rare or non-existent (SETI Pessimists).

In a recent paper, David Kipping (Prof. “Cool Worlds” himself) and Geraint Lewis examined this debate more closely and offered a fresh take based on a form of probability analysis known as Jayne’s Experiment. By applying this method to astrobiology and the Drake Equation, they concluded that the existence of intelligent life in our galaxy may be an “all or nothing” proposition. To quote the late and great scientist and science fiction author Arthur C. Clarke: “Two possibilities exist: either we are alone in the Universe, or we are not. Both are equally terrifying.”

August 6, 2024August 6, 2024 by Mark Thompson

If Advanced Civilizations Using Quantum Communications, Is That Why We’ve Never Seen Them?

Establishing communication with an alien intelligence is one of the news items I, and I’m sure many others, long to see. Since we have started the search for advanced civilisations we have tried numerous ways to detect their transmissions but to date, unsuccessfully. A new paper suggests quantum communication may be the ideal method for interstellar communication. It has many benefits but the challenge is that it would require a receiver over 100km across to pick up a signal. Alas they know we don’t have that tech yet!

March 29, 2024March 29, 2024 by Andy Tomaswick

Civilizations Could Time Their Communications Based on the Movement of a Single Star

Image of the galactic centre. For the interferometric GRAVITY observations the star IRS 16C was used as a reference star, the actual target was the star S2. The position of the centre, which harbours the (invisible) black hole known as Sgr A*,with 4 million solar masses, is marked by the orange cross.

The Search for Extraterrestrial Intelligence has been ongoing for decades at this point. Despite that, we have yet to find any rock-hard evidence of a signal from an alien civilization. When asked about this, experts point out just how little of the overall signal space we’ve analyzed. A signal could be coming from anywhere in the sky, at any frequency, and might not be continuous. Constraining the “search space” could help us find a signal faster, but what could we use to constrain it? It’s hard to think like an alien intelligence, let alone to mimic them.

March 22, 2024March 23, 2024 by Alan Boyle

Starshot … Not? Get a Reality Check on the Search for Alien Civilizations

Zine Tseng as Chinese radio astronomer, sitting at control panel for antenna — Zine Tseng plays a Chinese radio astronomer in "3 Body Problem." (Credit: Ed Miller / Netflix © 2024)

Fortunately, the real-world search for signs of extraterrestrial civilizations doesn’t have to deal with an alien armada like the one that’s on its way to Earth in “3 Body Problem,” the Netflix streaming series based on Chinese sci-fi author Cixin Liu’s award-winning novels. But the trajectory of the search can have almost as many twists and turns as a curvature-drive trip from the fictional San-Ti star system.

March 7, 2024March 7, 2024 by Andy Tomaswick

How Long Will Advanced Civilizations Try to Communicate With Us?

Technosignature research is heating up, with plenty of papers speculating on the nature, and sometimes the longevity, of signals created by technically advanced extraterrestrial civilizations. While we haven’t found any so far, that isn’t to say that we won’t, and a better understanding of what to look for would undoubtedly help. Enter a new paper by Amedeo Balbi and Claudio Grimaldi, two professors at the Universita di Roma Tor Vergata and the Ecole Polytechnique Federale de Lausanne, respectively. They have taken a statistical model to the problem of understanding how old a technosignature might be before we are likely to find it – and their answer is, surprisingly young.

February 13, 2024February 13, 2024 by Mark Thompson

The SETI Ellipse Tells Us Where to Search for Extraterrestrial Civilizations

The SETI Ellipsoid (Image credit: Zayna Sheikh)

Of all the questions that remain unanswered, the question of life in the Universe is surely the one that captures our attention the most. In a Universe whose observable edge is 46 billion light years away, is it even conceivable that we are alone, the sole planet among the millions and perhaps billions that are out there, where life has evolved, an oasis of life in the cosmic ocean. In the search for alien civilisations, researchers have proposed that it may be possible to use bright galactic events like supernovae to act as a focal point for civilisations to announce their presence!

January 3, 2024January 3, 2024 by Mark Thompson

China’s FAST Observatory is Playing a Key Role in the Search for Aliens

Some years ago I rememeber running the SETI at Home screensaver and would watch it for hours to see if any peaks appeared naively thinking they might be signals from an alien civilisation! There is no doubt that the search for extraterrestrials (ET) has captivated the minds of many people across the years. The search has of course to date, been unsuccesful despite multiple observations that seem to suggest the conditions for life across the cosmos may actually be more common than we first thought. Now Chinese agencies are funding projects to use the Five Hundred Meter Aperture Spherical Telescope (FAST) to conduct searches for alien signals.