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SETI (Search For Extraterrestrial Intelligence): Compendium / Miscellaneous

Our Efforts to Find Alien Life Have Gone Nowhere. This New Strategy Could Change That.​


For more than 60 years, scientists have been pointing radio antennas at the sky, hoping to overhear a broadcast from an alien civilization—proof that we’re not alone in the universe.

But the search for extraterrestrial intelligence, or SETI, is like listening for a whisper in a hurricane. Space is incomprehensibly big. There’s noise sputtering from every direction, especially from the countless number of stars dying and being born. A signal from E.T. might be faint. We’ve got only so many instruments and so much time, money and manpower for our intergalactic eavesdropping.

Worse, we might not even recognize an alien broadcast when we hear it. After all, who knows how E.T. would actually communicate?

Ross Davis, a specialist in information and communication sciences at Indiana University, is willing to venture a guess at what aliens sound like from afar. He hopes that could be enough to help SETI scientists cut through the noise and narrow their search. “All of this to help us arrive closer to the answer of one of humanity’s most important questions—is there life elsewhere in the universe?” Davis told The Daily Beast.

In a new study that has not yet been peer-reviewed, Davis described how a high-tech alien civilization might use long-range microwave radio to relay messages from planet to planet—and also help navigate between them.

With this dual-purpose “technosignature” as a guide, SETI practitioners could direct their attention to the spots in space where possible alien broadcasts make the most sense, thereby eliminating huge chunks of the galaxy from the SETI search pattern.

It’s a potentially elegant solution to an old problem in radio-based SETI.

https://www.yahoo.com/entertainment/efforts-alien-life-gone-nowhere-032719124.html

maximus otter
 
maximus otter said:

Our Efforts to Find Alien Life Have Gone Nowhere. This New Strategy Could Change That.​


For more than 60 years, scientists have been pointing radio antennas at the sky, hoping to overhear a broadcast from an alien civilization—proof that we’re not alone in the universe.

But the search for extraterrestrial intelligence, or SETI, is like listening for a whisper in a hurricane. Space is incomprehensibly big. There’s noise sputtering from every direction, especially from the countless number of stars dying and being born. A signal from E.T. might be faint. We’ve got only so many instruments and so much time, money and manpower for our intergalactic eavesdropping.

Worse, we might not even recognize an alien broadcast when we hear it. After all, who knows how E.T. would actually communicate?

Ross Davis, a specialist in information and communication sciences at Indiana University, is willing to venture a guess at what aliens sound like from afar. He hopes that could be enough to help SETI scientists cut through the noise and narrow their search. “All of this to help us arrive closer to the answer of one of humanity’s most important questions—is there life elsewhere in the universe?” Davis told The Daily Beast.

In a new study that has not yet been peer-reviewed, Davis described how a high-tech alien civilization might use long-range microwave radio to relay messages from planet to planet—and also help navigate between them.

With this dual-purpose “technosignature” as a guide, SETI practitioners could direct their attention to the spots in space where possible alien broadcasts make the most sense, thereby eliminating huge chunks of the galaxy from the SETI search pattern.

It’s a potentially elegant solution to an old problem in radio-based SETI.

https://www.yahoo.com/entertainment/efforts-alien-life-gone-nowhere-032719124.html

maximus otter
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... and of course there may be civilisations out there in a pre-industrial state who are, say, fifty years away from inventing radio transmitters. This wouldn't make them any less fascinating than a civilisation that has microwave transmitters.
 

Do you speak extra-terrestrial? Research hub considers response to life beyond Earth​


What does humanity do when we discover we are not alone in the cosmos? A new international research hub at the University of St Andrews will coordinate global expertise to prepare humanity for such an event and how we should respond.

The new SETI Post-Detection Hub, hosted by the Centre for Exoplanet Science and the Centre for Global Law and Governance of the University of St Andrews, will act as a coordinating centre for an international effort bringing together diverse expertise across both the sciences and the humanities for setting out impact assessments, protocols, procedures, and treaties designed to enable a responsible response.

There are now procedures and entities established with the United Nations for dealing with the threat posed by impacts of asteroids on Earth, but there is nothing similar in place for picking up a radio signal from E.T.

Currently, the only existing agreed ‘contact’ protocols are those drawn up by the SETI community itself in 1989, which were last revised in 2010. Focusing entirely on general scientific conduct, they constitute non-enforceable aspirations and fall short of being useful for managing in practice the full process of searching, handling candidate evidence, confirmation of detections, post-detection analysis and interpretation, and potential response.

The SETI Post-Detection Hub for the first time provides a permanent ‘home’ for coordinating the development of a fully comprehensive framework.

https://news.st-andrews.ac.uk/archi...-hub-considers-response-to-life-beyond-earth/

maximus otter
 
Re the 'Wow!" signal, this is both disappointing and encouraging:

"Since that time, the signal has been discussed at great length in the astronomy community, but nobody has been able to explain its origin. And until now, no one has taken a detailed survey of the part of the sky where the signal originated."

https://phys.org/news/2022-11-telescope-zone-wow.html

Two telescopes didn't find anything but that was just one of over 80 candidate stars
 
I've always wondered whether the Wow! Signal could have originated in space, either from a moving ship of some description or something in orbit that was broadcasting as it was being manoeuvred to point at some other target.
 
The star they have singled out as a likely candidate for the origin of the Wow! signal is 2MASS 19281982-2640123, a Sun-like star about 1800 light years away.

Note that the signal was sent when our own world was still host to the Roman Empire, an empire in China and one in India, as well as the start of the Mayan empire. If the aliens had telescopes big enough to observe the Earth at the time the signal was sent, they would be observing our planet in 1600 BC, when none of these empires even existed.

Attempting to communicate over such vast distances is more-or-less pointless.
 
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eburacum said:
The star they have singled out as a likely candidate for the origin of the Wow! signal is 2MASS 19281982-2640123, a Sun-like star about 1800 light years away.

Note that the signal was sent when our own world was still host to the Roman Empire, as well as an empire in China and one in India, as well as the start of the Mayan empire. If the aliens had telescopes big enough to observe the Earth at the time the signal was sent, they would be observing our planet in 1600 BC, when none of these empires even existed.

Attempting to communicate over such vast distances is more-ore-less pointless.
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Which makes me think that if the signal was intended it wasn't intended for us. Was there anything that was a likely target between Sol and 2MASS 19281982-2640123 (and considerably nearer the latter) that we know about 1800 years ago? Or could they have been trying to target an Oumuamua type object in or near their system?

Or maybe they were worried about contacting another species but wanted to send a signal to prove they could do it (Rather as we did to IIRC a globular custer) and picked an area with nothing in it for a good distance?
 
Some other possibilities;
a/ The signal originated near a non-Sunlike star, probably a red dwarf, of which there are several much closer candidates in the search region. We may be committing stellar chauvinism by expecting all intelligent life to be found near Sunlike stars. If humans ever colonise the galaxy, we would probably inhabit red dwarfs as well as all the other types of star - especially since red dwarfs are very-long-lived objects, and could support a civilisation for trillions of years.
b/ The signal came from an object within our own solar system - perhaps an alien spacecraft or probe, or a colony on a distant Oort cloud object. Maybe we'll discover something eventually which has an orbit that intersects the search area. Why would this alien probe send a message towards Earth, instead of (say) communicating with its home world far away? Perhaps there are probes nearer Earth that need to be contacted occasionally. It's no good looking in the search area for a transmitting probe, if it is within our system - its orbit will have taken it out of that region long ago.
 
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eburacum said:
Some other possibilities;
a/ The signal originated near a non-Sunlike star, probably a red dwarf, of which there are several much closer candidates in the search region. We may be committing stellar chauvinism by expecting all intelligent life to be found near Sunlike stars. If humans ever colonise the galaxy, we would probably inhabit red dwarfs as well as all the other types of star - especially since red dwarfs are very-long-lived objects, and could support a civilisation for trillions of years.
b/ The signal came from an object within our own solar system - perhaps an alien spacecraft or probe, or a colony on a distant Oort cloud object. Maybe we'll discover something eventually which has an orbit that intersects the search area. Why would this alien probe send a message towards Earth, instead of (say) communicating with its home world far away? Perhaps there are probes nearer Earth that need to be contacted occasionally. It's no good looking in the search area for a transmitting probe, if it is within our system - its orbit will have taken it out of that region long ago.
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a/ Didn't realise that they hadn't considered red dwarfs - they do seem likely candidates.
b/ Perhaps Earth was in the way of the signal being sent to the home world from somewhere in the outer solar system and maybe it never has been since? A colony/probe in the Oort cloud could as it orbits the sun now be further away from its home world and now need to transmit through the inner system.
 
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Twitter comment (not mine):
Richard Easther @REasther
Actually, I'd comment that it is predicated on a speculative technology that is not only far in advance of anything we do but is very likely unbuildable even in principle. So fun but not about to put the radio peeps and their "airport radar at 100 light years" out of business.
 
If they were aiming beyond the Earth, the target might have been 37 Geminorum - a relatively nearby sunlike star- or Wasat, a subgiant star. Both these stars are about the same distance from Sol (60 ly) but (roughly) in the opposite direction to the Wow! event.
 
I don’t want to be the bad guy, but after 37 years SETI has not find anything that I am aware of.

Some suggestions over the years is that SETI should be looking for laser beams instead of waves.
 
Although astronomers have not made many deliberate searches for laser messages, I note that the same methods that can detect extrasolar planets in transit should be able to detect powerful laser emissions as well. Instead of a miniscule decrease in the luminosity as seen from Earth, a star with a laser transmitter nearby would show a small increase in brightness.
 
eburacum said:
Although astronomers have not made many deliberate searches for laser messages, I note that the same methods that can detect extrasolar planets in transit should be able to detect powerful laser emissions as well. Instead of a miniscule decrease in the luminosity as seen from Earth, a star with a laser transmitter nearby would show a small increase in brightness.
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Wouldn't laser transmitters be highly directional though? If we're not along the line of transmission to the intended target, we won't see anything?
 
Exactly. Here are two reasons we might be in the cone of a highly-directional laser message (laser beams spread out into very thin cones because of diffraction):
1/ If the transmitting civilisation is attempting to contact spacecraft or probes in the vicinity of Sol. Even an autonomous probe might be capable of receiving updates and instructions from the culture which sent it; whether it accepts those instructions is another matter.
2/ If the transmitting civilisation wants to actively contact other potential civilisations and start a dialogue. This is one of the starting assumptions of SETI; that other civilisations are communicative, and hopefully friendly and not deliberately deceptive. None of these assumptions need to be correct. The same assumptions and caveats apply to Optical SETI (which may involve laser beams).
 
Talking about Laser SETI, here's a recent search of Alpha Centauri A+B
https://astrobiology.com/2022/11/a-search-for-optical-laser-emission-from-alpha-centauri-ab.html

A search for laser light from the directions of Alpha Centauri A and B was performed by examining 15362 optical, high-resolution spectra obtained between 2004 and 2018. None of the spectra exhibit laser emission lines.
The threshold was 10% of the continuum intensity of the spectra of both stars at all wavelengths between 3850 and 6900 Å. This search would have revealed optical laser light from the directions of Alpha Cen B if the laser had a power at least 1.4 to 5.4 MW (depending on wavelength) and was positioned within the 1 arcsecond field of view (projecting to 1.3 AU), for a benchmark 10-meter laser launcher.
For Alpha Cen A, the laser power must be 3 times greater for detection. Lasers of smaller aperture would also have been detected but would require more power. Considering all optical surveys, a growing desert is emerging in the search for extraterrestrial technology.
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charliebrown said:
I don’t want to be the bad guy, but after 37 years SETI has not find anything that I am aware of.

Some suggestions over the years is that SETI should be looking for laser beams instead of waves.
Click to expand...

We all watched the film 'Contact' and wondered how long until SETI is successful, unfortunately it is truly needle in a haystack stuff:

"Of that immense volume, weve searched a mere 2.4 1098 m5 Hz2 s W-1, which amounts to a fraction of 3.8 10-19. This is equivalent to a small swimming pools worth of water compared to the volume of Earths oceans!"

https://ui.adsabs.harvard.edu/abs/2018nova.pres.4304H/abstract


Then you have the possibility of planets where radio has yet to be invented etc. The future, in my opinion, is looking for biospheres on exoplanets:

"Oxygen in Earth's atmosphere is due to photosynthesis by microbes and plants. To the extent that exoplanets resemble Earth, oxygen in their atmospheres may also be a sign of life."

https://phys.org/news/2020-05-exoplanets-life.html
 
The detection of oxygen might indicate life, but there are a number of possible ways in which an exoplanet might acquire an oxygen-rich atmosphere without the presence of photosynthesis. Ocean planets could form high levels of O2 by photolysis of water by sunlight, and this could also occur on a planet near a red dwarf due to the effects of stellar flares. As we start to investigate exoplanet atmospheres, we need to beware of false positives.

We also need to beware of false negatives; our own planet had a biosphere for at least two billion years before the atmosphere contained significant levels of oxygen. Some exoplanets might have complex life that uses different metabolic pathways and could appear lifeless to our telescopes.
 
Tunn11 said:
a/ Didn't realise that they hadn't considered red dwarfs - they do seem likely candidates.
b/ Perhaps Earth was in the way of the signal being sent to the home world from somewhere in the outer solar system and maybe it never has been since? A colony/probe in the Oort cloud could as it orbits the sun now be further away from its home world and now need to transmit through the inner system.
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Absolutely, it does seem that the human ego assumes it was for our benefit whereas we may simply have gatecrashed someone else's conversation
 
SET utilising AI and some interesting initial results:

"Now, research published in Nature Astronomy and led by an undergraduate student at the University of Toronto, Peter Ma, along with researchers from the SETI Institute, Breakthrough Listen and scientific research institutions around the world, has applied a deep learning technique to a previously studied dataset of nearby stars and uncovered eight previously unidentified signals of interest."

https://www.seti.org/press-release/will-machine-learning-help-us-find-extraterrestrial-life

See also:

"AI is now used in virtually all areas of science to help researchers with routine classification tasks. It’s also helping our team of radio astronomers broaden the search for extraterrestrial life, and results so far have been promising."

https://theconversation.com/ai-is-h...e-and-weve-found-8-strange-new-signals-198754
 

"How scientists decide if they’ve actually found signals of alien life​

When searching for extraterrestrial intelligence, being certain can be tricky business"

https://www.popsci.com/science/extraterrestrial-life-seti-protocols/

...and:

"The truth is out there—and researchers at University of California, Berkeley are determined to find it with a new method announced in a scientific journal Tuesday for finding possible extraterrestrial life through radio signals from space."

https://www.cbsnews.com/sanfrancisc...serchers-develop-new-technique-radio-signals/
 
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