Tag: Breakthrough Listen

The Evolving Science of Technosignatures

Optical SETI searches for distant laser bursts as possible signs of technologial socieites in very far away solar systems. (SETI)

The Search for Extraterrestrial Intelligence (SETI) began decades ago as an effort to pick up radio signals from distant civilizations.  The effort was centered at the Green Bank Observatory in West Virginia and was by today’s standards quite rudimentary.

A much broader search for distant radio signals remains very much at the core of SETI but the effort has also expanded to be an increasingly rigorous search for “technosignatures.”

These include radio signals,  laser beams, the presence of chemical pollutants, unusual planetary heating and even the construction of massive structures around distant planets.  All could potentially be signs of intelligent beings living and trying to communicate.

Laser SETI is one of the fastest growing branches of this search of technosignatures and a recent paper that will appear in The Astronomical Journal describes an intriguing technosignature collaboration.

It is a joint effort by The Breakthrough Listen effort, a very large and privately-fund search for evolved extraterrestrial life, and the operators of VERITAS, a ground-based gamma-ray instrument operating at the Fred Lawrence Whipple Observatory (FLWO) in southern Arizona.

The paper does not report any unexpected laser pulses.  But as a proof of concept it shows that searching for laser pulses from many light years away is both possible and plausible.

“I would describe our current results as a very promising start,” Gregory Foote,  a doctoral student at the University of Delaware and a co-author of the paper, said in an email. “The analysis and observation pipeline is built, so now we can scale up both within VERITAS and with any next generation telescopes which show interest in performing such searches.”

One of the four 12-meter telescopes comprising the VERITAS gamma-ray observatory. VERITAS (Very Energetic Radiation Imaging Telescope Array System) is located at the Fred Lawrence Whipple Observatory in southern Arizona. (CfA/Rick Peterson)

Optical SETI is the name of the overall search for optical technosignatures; signals based on optical light emitters such as lasers.  There are two types of laser-based signals that astronomers are currently looking for — a continuous laser beam at a specific wavelength, and nanosecond time-scale pulse lasers. The VERITAS telescope can detect the nanosecond burst of lasers.

“Overall, if one wants to build an interstellar communication system, using pulsed lasers is a power-efficient way to do it,” Foote said. “The technology for both transmitting and receiving doesn’t require any sci-fi infrastructure: it exists today.… Read more

Breakthrough Listen Searches The Crowded Center of the Milky Way for Possible Signals From Intelligent Beings

The Galactic Center from radio to X-ray frequencies.  ( X-Ray: NASA, CXC, UMass, D. Wang et al.; Radio: NRF, SARAO, MeerKAT)

Searching for technologically advanced civilizations inhabiting distant exoplanets is the astrobiological equivalent of swinging for the fences.

While much of the search of extraterrestrial life is now focused on microbes and chemical biosignatures in exoplanet atmospheres that would likely be byproducts of life, the search for extraterrestrial intelligence (or SETI) takes a very different approach.

SETI practitioners scan the skies for radio signals, and now laser signals, that are irregular and different from what is naturally produced.  Were such a signal to be detected, then it would be studied as the potential work of extraterrestrial life that is highly advanced — perhaps far more so than we Earthlings.

This search has been going on since Cornell University astronomer Frank Drake began it 1960 and has advanced (in steps large and small) ever since.  The biggest financial boost to the search took place five years ago when techno-billionaire Yuri Milner, in partnership with Stephen Hawking and other prominent scientists,  set up the Breakthrough Listen project with $100 million to buy telescope time and to greatly expand the SETI search.

And as part of that expanded search, radio telescopes focused on the crowded galactic center of the Milky Way for 600 observing hours.  The thinking was that stars and likely exoplanets are most plentiful in that central region — some 60 million  stars in the line of sight into the galactic center at low astronomical frequencies; 500,000 at higher frequencies  — and so the chances of finding a signal were perhaps higher.

Some preliminary and partial results of that effort were recently released and, unfortunately, no signals were found.  That has been the fate of all SETI searches so far.

But as SETI scientists explain, the night sky is huge and the percentage of stars (and their exoplanets) that have been sampled remains quite small.

The Green Bank Radio Observatory in West Virginia is one of the two main sites for the Breakthrough Listen galactic center campaign.  The other is the Parkes Telescope in Australia . (NRAO)

This latest effort was unique in that it was the “most sensitive and deepest targeted SETI” survey ever done of the galactic center, as the SETI scientists write in a study set to be published in the Astronomical Journal (a preprint is currently available on the arXiv).… Read more

Big News for SETI Enthusiasts

The CHIME telescope has detected a mysterious repeating radio signal far away in the cosmos – only the second ever identified of its kind.  CHIME is the Canadian Hydrogen Intensity Mapping Experiment (CHIME) is an interferometric radio telescope at the Dominion Radio Astrophysical Observatory in British Columbia, (Danielle Futselaar)

It has been almost 60 years now that scientists — a first a few intrepid souls and now many more — have been searching the skies for radio signals that just might be coming from other advanced, technological civilizations.  There have been some intriguing anomalies that created great interest, but nothing has to date survived further study.

But two recent developments in the this Search for Extraterrestrial Intelligence (SETI) make clear that the lack of alien signals so far has not diminished interest in the field and in the science and technology behind it.  Rather, SETI is alive and doing quite well.

A first sign is scientific and involves what are called “fast radio blasts” or FRBs — high energy pulses that are extremely short lived and, until recently, determined to be sporadic and random.  But a paper last week from a Canadian team reported a series fast radio blast from a galaxy a 500 million light-years away that appeared to be repeating about every 16 days.

The authors put forward a number of astrophysical explanations for this most unusual pattern and shied away from any kind of SETI hypothesis.  More on this later.

But the detection is the kind of radio signal anomaly that SETI scientists and enthusiasts are looking for.  And now they will also have the opportunity to search a vast new trove of data provided by Breakthrough Listen, part of the privately-funded Breakthrough Initiatives.

A sequence of 14 of the 15 fast radio bursts from FRB 121102, the first repeating fast radio burst to be identified, in 2018. The streaks across the colored energy plot are the bursts appearing at different times and different energies because of dispersion caused by 3 billion years of travel through intergalactic space. The bursts were captured in a broad bandwidth via the Breakthrough Listen backend instrument at the Green Bank Telescope. It does not repeat in patterns like the one just discovered by the Canadian team. (Berkeley News.)

At the close of a meeting of the American Association for the Advance of Science (AAAS) on Friday, the Breakthrough team announced the release nearly 2 petabytes (2 million gigabytes) of data, the second massive data dump from the four-year old Breakthrough Listen search for extraterrestrial intelligence

The data, most of it fresh from the telescope prior to detailed study by astronomers, comes from a survey of the radio spectrum between 1 and 12 gigahertz (GHz).… Read more

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