Given our decades-long lack of success in finding hard evidence for an extraterrestrial civilization, it hardly comes as a surprise that a recent campaign studying the seven-planet TRAPPIST-1 system came up without a detection. 28 hours of scanning with the Allen Telescope Array by scientists at the SETI Institute and Penn State University produced about 11,000 candidate signals for further analysis, subsequently narrowed down to 2,264 of higher interest. None proved to be evidence for non-human intelligence, but the campaign is interesting in its own right. Let’s dig into it.
The unique configuration of the TRAPPIST-1 planets allowed the scientists involved to use planet-planet occultations (PPOs). A cool M-dwarf star, TRAPPIST-1 brings with it the features that make such stars optimal for detecting exoplanets. The relative mass and size of the planets and star mean that if we’re looking for rocky terrestrial-class worlds, we’re more likely to find and characterize them than around other kinds of star. True, they’re also orbiting a class of star that is dim, but another beauty of TRAPPIST-1 is that it’s only 40 light years out, and we see its seven planets virtually edge-on.
Planets e, f and g can be squeezed into the star’s habitable zone (liquid water on the surface) if we tweak our numbers for possible atmospheres. The edge-on vantage means that planets can pass in front of each other from our viewpoint, with the additional advantage that this well-studied system has planetary orbits that are sharply defined. This raises intriguing possibilities when you consider our own space activities. The Deep Space Network sends powerful signals to communicate with distant craft like the Voyagers, signals wide enough to propagate beyond them and into deep space. The right kind of receiver, if by chance aligned with them, might make a detection, producing evidence for a technology by the nature of its signal.
At TRAPPIST-1, there are seven planet-planet occultations, with two of them involving a potential transmission-source planet within the star’s habitable zone. But we have to consider that transmissions between planets might not be this limited, for radio traffic could move through relays placed for communications purposes on worlds that are uninhabitable. This would obviously be traffic never intended for interstellar reception, the kind of ongoing activity that marks a society communicating with itself, but perhaps leaving a technosignature that would reach the Earth through the width of its beam.
Image: A look from above at the communications line of sight between two worlds in the TRAPPIST-1 system, illustrating the PPO method used in this study. Credit: SETI Institute/Zayna Sheikh.
The possibilities of a detection using this PPO technique vary, of course, with the orbital parameters of the planets in any given system. We must also account for the drift rates produced by orbital motion. The paper explains the recent search’s technique this way:
…it is assumed that the TRAPPIST-1 planets are tidally locked due to their proximity to their host star and will have a negligible rotational contribution to the drift rate of a transmitter on their surfaces. Additionally, their orbital parameters are well constrained, making it possible to calculate the drift rate contributions from their orbital motion. Satellite transmitters in circular orbit around each planet could produce much higher drift rates, up to an additional ∼45 nHz on top of the contribution from the planet’s orbit around the star. However, we have chosen to limit our scope to analogues of our deep space communications, the strongest of which are surface transmitters to deep space probes.
The seven planet-planet occultations studied during the 28 hours of observation ranged from 8.6 minutes to 99.4 minutes. And it turns out that widening that window of observation through simulations produces numerous PPOs with a similarly large range of duration, making this strategy still more interesting. The animation below shows the TRAPPIST-1 system in motion and the possible communications opportunities. Credit: Tusay et al., citation below.
Animation: This is Figure 10 from the paper, the caption of which reads: Simulated potential PPO events during our observations. Online viewers will see a concatenated video of the orbital configuration of the system during each of the observations, including any potential PPO events that we found to occur during those windows. A still image of a PPO event during the observation on Oct 29, 2022 is included where the animation is not accessible. The top panel shows a bird’s-eye view of the system with planet radii scaled up for better viewing. The distances and beam sizes are to scale, assuming a beam created with a 3.4m dish at 3.3 GHz (the maximum frequency observed during this particular session) from the surface of planet g aimed at planet e. The bottom panel shows the edge-on view with planet sizes scaled with distance, showing how much of the beam spills over the planet toward the direction of Earth in the negative z-direction. The red dashed lines in the illustrated beam is the inner angle blocked by the occulting planet, e. The blue dashed lines show the outer angle of the beam that would spill over the planet. The window for this event lasted roughly 95 minutes. Credit: Tusay et al.
Is this method the longest of longshots? SETI itself might be described that way, depending on your views of life in the cosmos. But our steadily growing capabilities at signal detection can’t be ruled out when we consider the possibilities. From the paper:
The analysis of the observations presented here demonstrates that precise characterization of ideal systems, like TRAPPIST-1, enabling orbital dynamical modeling and prediction of PPO events offer practical application for leaked emission searches. This provides SETI a powerful new observational tool and search strategy. As signal detection and RFI mitigation pipelines improve, the inclusion of PPOs to provide narrow search windows may make it more feasible to increase time resolution and sensitivity at higher drift rates.
What beckons most strongly about technosignatures is that they assume no intent (which in any case would be unguessable) on the part of a hypothetical alien civilization. We would essentially be eavesdropping on their activities. Grad student Nick Tusay (Pennsylvania State), lead author of the paper on this work, adds this: “[W]ith better equipment, like the upcoming Square Kilometer Array (SKA), we might soon be able to detect signals from an alien civilization communicating with its spacecraft.” And that would be a SETI detection for the ages.
The paper is Tusay et al., “A Radio Technosignature Search of TRAPPIST-1 with the Allen Telescope Array,” currently available as a preprint.
Unless all the Trappit-1 planets in the HZ have purely non-biological life (a robot civilization), then we should expect this method would only provide a signal if a biosignature was also detected. Unless the civilization was extremely old, then the probability of a technosignature is far lower than the probability of a biosignature. I think it is also likely that the older the civilization, the more technologically developed it will be, and that communicating with spacecraft with low bandwidth radio is unlikely compared with, e.g. lasers, something that NASA is already testing.
IOW, “longshot” is an understatement.
Now if we did get a signal from Trappist-1 (or any other star) and the signal originated on a planet that did not have a biosignature, this might indicate that the planet was colonized (like Mars) or that it had life but became sterilized leaving behind a non-biological intelligence.
While I appreciate the logic that radio is a low-power means of communication and perhaps the best low-tech means of signaling across interstellar distances, for any other purpose it seems like the equivalent of looking for the funnel smoke of steam engines – a technology that is transient in technological development. Our own communication systems are increasingly eclipsing high-power radio waves for low-power radio and optical fiber. Radar may be the last high-power radio emissions we still use. Unless ETI detected our radio and tv broadcasts during the first century of use, they would now find that Earth seems to have gone rather quiet. If ETI worries about the “Dark Forest”, then they would likely minimize any broadcasts, relying on tight beam communications (e.g. to spacecraft) that would have a low probability of being detected, at least by the technologies we are aware of.
Maybe we are looking in the wrong frequency band. Gamma rays would have the highest data transmission of all electromagnetic radiation so our radio transmission may be like smoke signals to a Kardashev Type 2 civilizations. Gamma ray lasers would be the ultimate frequency to use for high data transmissions at interstellar distances.
Just this morning thinking about Kardashev Type 2 civilizations around red dwarfs and how they would have a much easier time using the power of the red dwarf then our giant sun. They may have figured out how to manipulate the flares for interstellar communication and possibly use the huge amount of energy
from them to form a soliton that would act like a “warp bubble’”, contracting space in front of it and expanding space behind. Could this be why many flying disks have a burnt bottom due to hard radiation and show their ability to create huge magnetic fields in some vehicle close encounters?
Looking around on the internet I came across this:
Serendipitous discovery of likely alien distress call: an SOS signal from the direction of TRAPPIST-1.
https://www.mpi-hd.mpg.de/HESS/pages/home/som/2017/04/
The left side are in degrees south. Here is a constellation chart showing Trappist 1 position:
https://www.eso.org/public/images/eso1615d/
The problem with Gamma ray telescopes is their resolution, which is about 6 minutes of an arc. The moon at that resolution would be about 20 total pixels at 5×5 pixel length and width.
How would we be able to decipher a gamma ray transmission? That is a very good question, anyone have a clue?
What else could Kardashev Type 2 civilizations around red dwarfs do with these huge and very powerful energy machines?
Here is a start involving gamma-ray communications:
https://i4is.org/wp-content/uploads/2023/11/IRG-23-X-ray-and-%CE%B3-ray-Beam-Interstellar-Communication-and-Implications-for-SETI-Principium43-2311270915opt.pdf
IRG 23: X-ray and γ-ray Beam Interstellar Communication and
Implications for SETI
Recent decades have seen the development of both X-ray and gamma-ray (γ-ray) beam sources [2]. These
have been used for scientific purposes, but they raise the possibility that such devices could also be used for
communications. Plasma based x-ray lasers were first demonstrated in 1980 and have been shown to lase in
wavelengths as short as 0.15 nm (8.27 keV photon energy), while being developed for applications as wide
ranging as materials science and national defence. Free electron x-ray lasers are now operating at >12 keV
of x-ray photon energy (<0.1 nm wavelength) and with watts of X-ray power available in a widely tunable
(250 eV – 20 keV) and high pulse rate (120 Hz – 929 kHz) source. Future designs seek to combine these
two X-ray laser technologies and achieve even higher laser powers. The use of X-ray optics already allows
for keV class X-rays to be focused to near diffraction limited [3] spots and may allow for X-ray recycling
cavities in the near future to further increase total laser power and efficiency.
Gamma ray sources are more
difficult to develop, but many decades of work have left firm theoretical ground for potential gamma ray
lasers using either antimatter or excited nuclear states as the source material.
Since the diffraction limited beam spread is proportional to wavelength, a gamma-ray or x-ray laser
generating a beam at even modest power could be detectable at enormous distances, and with potentially
enormous bandwidth. This implies that any civilisation needing to communicate across interstellar distances
may choose X-ray or gamma-ray beams due to low background noise, high efficiency, and high bandwidth.
Searching for these signals would have the same issues as trying to detect incidental broadcasts, ie, the
presumed low probability of having a detector looking in the right place at the right time.
However, if there
are many interstellar civilizations, they may be using an efficient communications scheme like this, making
the odds of catching a beam passing the Earth more likely. It’s also possible that such signals may have been
detected already without being recognized, since X-ray and gamma-ray telescopes don’t collect data on
short time scales (milliseconds) unlike X-ray/gamma ray spectrometers used for radioactive material assay.
OOK (On-Off-Keying) modulation was assumed for this study, but similar conclusions could be reached
for other forms of modulation.
Various file types were analysed, spanning a wide range of signal sizes and
compression types (where information might be obscured by the compression). There was no discernable
difference between the artificial signals and a random signal when considering only Shannon Entropy.
Entropy refers to a measurement of vagueness and randomness in a system and the concept of entropy was
used by Shannon in information theory for the data communication of computer sciences.
At the IRG 23 Symposium in July 2023 Gerrit Bruhaug[1] presented work
by Lucas Beveridge, X-ray and γ-ray Beam Interstellar Communication and
Implications for SETI. In this report Peter Milne summarises the associated
draft paper kindly provided by Dr Beveridge, due for publication in Acta
Astronautica in the near future.
[1] Video of the presentation at –
http://www.youtube.com/watch?v=AZfGnmA3GfY&list=PLaEYPgNFlkhb2emnGXzC7Noy2JkqOGabh&index=32&pp=iAQB
Irrespective of the beam frequency used, any compression algorithm will show a signal as having high entropy. The current means of detecting possible signals it to check for beam frequency spread – i.e. high signal-to-noise at specific frequencies. Natural sources will have a wide spectrum whilst an artificial beam will have very narrow, tuned frequencies, possibly several separated frequencies with frequency noise. At least that is our assumption based on terrestrial communications to date.
The problem for us receiving these beams by chance is likely to be vanishingly low unless they are very common and we can constantly watch much of the sky from space to be lucky to catch these transients.
However, these ever more fancy search ideas, like the preceding post, strike me as grasping for anything that might possibly indicate technological ETI. Radio SETI was an idea based on “low hanging fruit” for ease and hoped for [expected?] success. Lack of success is blamed on the small size of the possible search space – frequencies, transients, sources, etc. I would hope that exoplanet life is fairly common, and if so, those exoplanets should be targets for more careful exploration, although I suspect that any technosignature or evidence of intelligence may be absent on all these worlds.
If so, then just perhaps we should discard the prime directive and try uplifting the most intelligent species to drive evolution and eventual cultural and technological advance. A goal for the far future assuming we achieve that capability and a civilization that has proved very stable and capable of maintaining such long-term goals, even if the result will not be achieved for millions of years. Less monolith and more genetic manipulation coupled with discoverable caches of technology from the wheel upwards.
Thanks LJK, a lot of good information!
What if red dwarf flares are actually launches of soliton spaceships at faster then light speed. What would be the observed spill over in radiation from such an occurrence if pointed in earths direction?
Red dwarfs as sources of cosmic rays and detection of TeV gamma-rays from these stars.
The long-term observations of red dwarfs show that these stars are sources of the variable TeV Gamma-ray flux up to 10 TeV. This flux is detected mostly during the flares on active dwarf stars. The observed light curves of V388 Cas, V780 Tau, V962 Tau, V1589 Cyg and GL 851.1 at TeV energies.
https://www.sciencedirect.com/science/article/abs/pii/S0273117719306076
How do you correlate between red dwarf flares and FTL soliton spacecraft launches? I am going to assume only so many flares might be artificial. Why red dwarf flares and not other type of solar flares, since I am asking here?
What exactly is a soliton spacecraft?
1. Flares are flares, regardless of the type of stars they originate from; they form due to magnetic reconnection. However, we were unaware of their existence until the 1859 Carrington Event. On Trappist-1e, you would be 46 times closer to these flares, which is about 2 million miles away. As a result, Trappisit 1 would appear four times larger than our Sun. Anyone living in or colonizing on these systems would be acutely aware of the immense energy released by these flares.
https://scx2.b-cdn.net/gfx/news/hires/2024/the-evolution-of-the-t-1.jpg
2. We have no way of producing the energy that is required to produce a soliton warp drive but maybe flares could. Perhaps the most intriguing aspect of the Lentz Soliton Drive is its connection to a conducting electromagnetic plasma. The stress-energy of a plasma and classical electromagnetic fields can provide the source for producing Lentz’s space-time soliton. Lentz indicates in his paper that much theoretical work remains to be done to take advantage of this.
I can’t think of a more stressful plasma environment than during magnetic reconnection events in solar flares or those of red dwarf stars. There are articles discussing simulations of such conditions, but it’s possible that superluminal particles are produced naturally during these flares. We should be able to observe indications of what is produced, similar to the effects from a soliton warp drive, albeit on a much smaller scale.
If I’m interpreting table 1 in the paper correctly, the minimum transmission power detectable by this observation was 18 MW emitted by a dish antenna, or multiple GW with an omnidirectional antenna.
As a point of reference, the Deep Space Network works in the 20 kW range when sending data to Voyager or New Horizon[1]. The most powerful broadcast radio transmitters on Earth are about 2 MW[2].
Given how closely spaced the planets of TRAPPIST-1 are, it makes little sense for an ETI to use more than the above for interplanetary communication.
So even if there is radio communication between the planets, it seems very unlikely to be at power levels that can be detected with our current instruments.
[1] https://space.stackexchange.com/questions/9824/how-much-rf-transmit-power-does-dsn-need-to-send-commands-to-voyager
[2] https://en.wikipedia.org/wiki/Transmitter_Solt
Not if they had a cold war, the US BMEWS put out an extremely powerful beam. Now they would have a IMWS or Interplanetary Missile Warning System for nuclear missile launches between planets…
According to this article[1], BMEWS had two 4 MW beams. Still falling short, but at least getting into the right order of magnitude.
Speaking of radar, Arecibo was capable of 2.5 MW pulses[2].
Looks like radar pulses rather than communications may be the first radio techno signature we will detect. Imagine the excitement and subsequent frustration of just hearing a ping or chirp with no encoded data. Could make for an interesting SciFi plot :)
[1] https://radomes.org/museum/BMEWS.php
[2] https://www.sciencedirect.com/science/article/pii/S0094576523002643
A spacefaring society in their own solar system would need to conduct radar pings throughout its interplanetary space to check for roaming planetoids and comets. We already do that when investigating NEOs.
So while such “signals” would be random in terms of where the beams go, if there were enough of them in enough exosystems with advanced ETI, then there is a chance we might come across a few. They would carry no information, but their artificial nature should be evident.
One notable type of microwave signature is associated with Air Traffic Control (ATC) and the North American Aerospace Defense Command (NORAD). Both organizations utilize the same radar systems; however, ATC predominantly relies on transponder signals, while NORAD uses raw radar data. This radar emits a narrow beam horizontally towards the Earth, which flashes as the radar beam rotates and as the Earth rotates. These systems operate 24 hours a day, every day, covering all of the USA and many other countries around the world.
Early research in the Search for Extraterrestrial Intelligence (SETI) has indicated the influence of the Earth’s rotation on the microwave energy emitted. The microwave signals from these radars are significantly stronger than those from radio or television stations, as they feature a pulsing beam combined with antennas similar to those used in radio telescopes.
During my time working with NORAD, I saw these antennas while stationed in Alaska and also heard them when listening to the pipe in radio music.
I’m just wondering about gamma rays and pair production? You have negative energy and time from the positron so could this be put in a Soliton Hyperwave or maybe be used as a gamma wave receiver? Virtual particles jumping from one place to another and electron/positrons communicating their state instantly over huge distances… Hmm
https://thedebrief.org/government-funded-study-explores-warp-drives-as-means-of-faster-than-light-communication-through-hyperwaves/
https://www.fanaticalfuturist.com/2022/02/worlds-first-real-warp-bubble-created-by-accident-as-scientists-mull-future-warp-drive/
Additionally, it’s interesting to note that solar flares produce flux tubes, which may create solitons within them. This raises the question of whether we might be overlooking natural locations where superluminal conditions arise. Flux tubes and waveguides share similar characteristics, and the high-stress plasma polarization during magnetic reconnections creates conditions that could allow for the formation of superluminal solitons.
There’s also a compelling connection to UFOs: Vehicle interference caused by these spacecraft might be a result of their own use of magnetic reconnection.
“Looking around on the internet I came across this:
Serendipitous discovery of likely alien distress call: an SOS signal from the direction of TRAPPIST-1.
https://www.mpi-hd.mpg.de/HESS/pages/home/som/2017/04/”
The article literally states it’s an April Fool’s Day Edition…
And if that was not enough the statement of a confidence level of sigma 9.7 had me smile broadly.
Else from that, it was a clever observation strategy they had come up with. Since our current instruments generally are unable to pick up any transmissions intended for communication within any planetary system.
With this exception for if and when we end up in the path of one narrow directed and powerful transmitter.
That kilometer array mentioned might indeed get the sensitivity for a first actual survey for possible regular data, TV or radar signals in the neighbourhood. I still doubt there will be any, but keep looking, also negative data is important here. And nobody knows, even though I expect very few civs to exist at the same as ourselves – there might be something automatic left by any precursor civ that repeatedly calls ‘Where did you guys go?’
I have been thinking some of this through and realized that the five Lagrange points around Trappist 1 planet b and c would be good locations to put power and possibly soliton generation sites. This would make 12 different points for capture the extreme power generated by red dwarfs solar flares.
https://upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Lagrange_points_simple.svg/1920px-Lagrange_points_simple.svg.png
Now looking at 5 other planets Lagrange points would also make a perfect network for interplanetary internet. X-ray and Gamma ray relays would have the highest bandwidth for holographic games and advance AI. Has anyone figured out what particles or electromagnetic radiation would be created by a Soliton Hyperwave real-time internet network?
Maybe this should be what we are looking for instead of radio smoke signals…
Exoplanet solar systems like TRAPPIST-1 could be ideal candidates for colonization.
The seven planets in this compact system offer numerous advantages. With thirty-five Lagrange points available, they can serve as low-energy highways for travel, significantly reducing transit times between planets from years to just a few days for cargo ships. Additionally, several of these potentially habitable planets may require minimal effort to terraform. As a result, these systems could resemble bustling cities rather than isolated outposts in space.
Not only that, but great SF story material in a concept like this.
Rocky planets orbiting small stars could have stable atmospheres needed to support life.
New research shows that while TRAPPIST-1b, second from the left, has no atmosphere, TRAPPIST-1e, third from the right, could have a long-term stable atmosphere.
https://www.nature.com/articles/s41467-024-52642-6