When Nikolai Kardashev looked into the question of where to find advanced extraterrestrial civilizations, he argued that the obvious starting point would be in the vicinity of extreme astrophysics. Active galactic nuclei (AGN) come to mind, or even the centers of comparatively quiet galaxies like our own. Clément Vidal picked up the same point in his The Beginning and the End (Springer, 2014), arguing persuasively that we should consider how black holes could be used, perhaps by manipulating the merger of such objects. And yes, this is astroengineering utterly beyond our skills, but possibly not those of an advanced ETI.
Using black holes for energy is extreme, but Roger Penrose has imagined a super-civilization extracting black hole rotational energy by the injection of matter, and there are a number of other propositions on how such advanced engineering might work. Extracting energy from a black hole’s accretion disk might be the most efficient method, but lower-grade operations could exist around neutron stars. To that idea we might add, as Milan ?irkovi? does in the paper we looked at yesterday, the exploitation of X-ray binaries or quasars like SS433.
The new ?irkovi? paper homes in on gas giants and brown dwarfs, with the possibility of making either into a star. It’s an idea with a popular pedigree, the ignition of Jupiter having gone viral with the film 2010, but the real action is beyond the Solar System entirely. Consider that the number of substellar objects in interstellar space has been estimated to be as high as 105 times greater than the number of main sequence stars (see Island-Hopping to the Stars for more on this estimate and the kind of substellar objects it references).
Image: Artist’s impression of a free-floating gas giant. Credit: NASA/JPL-Caltech.
Could a technologically manipulated gas giant or brown dwarf be a SETI observable? Here we can look at several possibilities. The luminosity of a ‘stellified’ object should be greater than its mass would lead us to expect for natural objects. And, taking the long view, its luminosity should evolve differently from natural stars. Moreover, we might find anomalies in the spectra of such objects, especially early and late in their astronomically-brief lifetimes. And bear in mind that stellified objects would be bright power sources, unlike artificial orbital habitats or other large structures which would only reflect light or become apparent through their thermal emissions.
In other words, if such objects exist, they would be useful targets for Dysonian SETI investigation. ?irkovi? notes that determining the mass of a field star is a tricky proposition, and if we’re considering possible artifacts, we can’t just try to position the object on the Hertzsprung-Russell diagram as if it were a normal main sequence star. An accurate mass determination would require a multiple star system, and even here the measurement is fraught with uncertainties. But where we can determine it, mass is worth pursuing.
From the ?irkovi? paper, referring to Martyn Fogg’s 1989 paper on stellified gas giants:
The outliers from the low-mass stellar luminosity-mass relation deserve our best observational scrutiny, especially if the anomaly is extreme. In Fogg’s model, for instance, luminosity of [a] stellified Jupiter will fairly soon after the beginning of the process be ten orders of magnitude or so above the expected luminosity of such a low-mass free-floating object. If such artefacts are numerous in the Galaxy, their considerably easier detectability could deform and leave an imprint on the substellar mass function.
The evolution of luminosity in such objects would be challenging to gauge because of the timeframes involved — Fogg estimated a 50 million year span of exponentially increasing luminosity in the case of a stellified gas giant like Jupiter. As ?irkovi? notes, we could easily have such artifacts in our stellar catalogs now, for depending on their stage of stellification, they would simply mimic a particular type of star. We seem to be best off in hunting for stellified objects at the beginning and end of their lifetimes, looking for gamma and X-ray flares, for example, during the early stages of a planet’s transformation into a star.
Even so, we still are dealing with relatively transient phenomena compared to main sequence star lifetimes, and advanced technologies about which we can only speculate. Remember that the scenario Martyn Fogg originally came up with assumes using a small black hole, merging it with Jupiter in a carefully controlled orbit that eventually brings it toward the planet’s center. 100 million years of habitability are provided to the Jovian satellite system, but several hundred million years later, runaway accretion would have to be prevented. ?irkovi? comments:
For the initial phase, the period of unstable bursting and flaring can be shortened by sufficiently gently placing the mini-black hole into the substellar objects; for the final phase, duration and properties of instabilities depend on the manner of removing the excess mass from the black hole, as well as on the existing installation/swarm surrounding it. If such anomalies are observed in a planetary system containing at least one planet in the circumstellar habitable zone, this could be further incentive to give it high priority as a SETI target.
My take on all this is that as we are at the beginning of Dysonian SETI, we’re early in the process of developing the necessary parameters. ?irkovi? speaks to this point near the end of this paper, calling for improved quantitative models for the kind of astroengineering projects we can imagine and their possible SETI signatures. The advantage of stellified gas giants is that they are larger and simpler than many of the conjectured astroengineering projects that have been proposed, but we would want to have sound models for a wide range of possibilities.
And there’s the nub of the problem: We’d like to be able to observe an anomaly in our astronomical data and relate it swiftly to a potential technology, using what we believe to be its observables. But Dysonian SETI is built around the concept of abandoning anthropocentrism and simply observing. How does a Kardashev sub-Type I culture like ours envision what a Type II might do? Our conjectures invariably grow out of our preconceptions, and the models we build can only be crude templates. Rather than abandoning the process, we have to keep all this in mind, continually adjusting our assumptions while being alert for data that fit no previous niche.
The ?irkovi? paper is “Stellified Planets and Brown Dwarfs as Novel Dysonian SETI Signals,” in press at JBIS. I also referenced a Nikolai Kardashev paper above; it’s “On the inevitability and possible forms of supercivilizations”, in The Search for Extraterrestrial Life: Recent Developments, ed. M.D. Papagiannis, IAU, Dordrecht, pp.497-504, 1985.
Such stellar engineering makes for magnificent imagery, but is it rational? I find it rather like burning a forest or perhaps inducing an active volcano to create heat for steam engines. It makes far more sense to harvest the energy source in a multitude of smaller scale energy producing devices.
Turn Jupiter into a star? Clarke has a better idea by fusing Phobos as an energy source in “The Sands of Mars”. Better still, fuse Jupiter’s hydrogen in reactors to illuminate the Galilean moons. Sure, the technology must be maintained, but it is far more flexible and less prone to a single point of failure. Similarly with black holes. Again Clarke used a micro black hole as part of the drive in “Imperial Earth”. While the stability of such holes may be in doubt, control of small black holes to create energy on demand, where it is needed, seems to make more sense than extracting energy on a huge scale from stellar-mass holes.
While it is certainly worth looking for such unnatural objects, I tend to think that such engineering solutions suffer from a Victorian mindset on engineering, rather than a rational approach.
If anything, if a civilization wanted a long term energy source, it would be reducing the output of stars. Yellow stars would be turned into red dwarfs, or better still, dismantled back into cold hydrogen clouds to be used later. A K2 civilization would create long term energy stores by putting out stars, or at least make them burn much more slowly, guaranteeing longevity.
Calculations show that even a low rate of economic growth results in a human civilization using up the full output of the sun in just thousands of years. At 3% growth we would transition from a KII to a KIII in less than a millenium, at 1% in just 2500 years. Such growth cannot be sustained. Civilizations must, therefore go with relatively static economies, and harvest energy reserves for the long term, assuming that they plan to do so. Billions of years harvesting the output of the sun might seem like a long time, but a red dwarf might allow a span of 100’s of billions of years. Keeping the hydrogen ready to ignite from other stars would allow time extensions linearly related to hydrogen stores. How that gas would be stored is left to the imagination. If black holes can be broken up at will, they might be useful containers if the hydrogen can be captured without fusing as it crosses the event horizon.
So paradoxically, both this strategy and Dysonian ones will see stars disappear. The latter becoming IR sources, the former perhaps leaving no apparent trace.
Indeed. Paraphrasing Dr. Zubrin, addressing a fourth millennia issue with second millennia thinking might not be instructive.
The issue of continuing growth, though, is very much a current issue. We are living to see the consequences to the planet when every earthling comes to appreciate the lifestyles of Americans and Europeans. At some point, our quaint notions of capitalism and growth will morph, just as did the divine right of kings in the face of social pressure.
I’m not sure there would be much hurry to put out stars; fusion is so inefficient at converting matter to energy that nearly all the mass-energy of the stars will be remaining when it eventually dies, even if stellar husbandry is used to maximise it’s lifespan. Then again, white dwarfs aren’t the easiest of objects to extract matter from…
Dropping mass onto the WD will release energy but only up to the Chandra mass limit and then keep your distance, it gets awfully touchy!
In my view the Kardashev scale itself is deeply anthropocentric. The notion that an “advanced” civilization will be defined by endlessly expanding energy use seems to extrapolate that our pre-21st century values, which were clearly the result of biological baggage that we have not yet fully shed (when you are a pre-technological species on a seemingly infinite planet then expansion at all costs is a good survival strategy) and which are already threatening our well-being (as we confront the reality of the Anthropocene Epoch and realize that endless, mindless expansion is not intelligent behavior) will be shared by supposedly intelligent aliens. In fact, within a couple of centuries we will already have altered this ethos of endless expansion if we are to survive. Moving off Earth does not change this fact, only slightly alters the timescale. Do the math.
Has anyone checked to see whether the M dwarf COMPANION to KIC8462852 may QUALIFY as a POTENTALLY stellified object?
If not, is the telescope to be used Boyajian et al of high enough magnification to get good enough data to determine whegher it is or is NOT a GOOD CANDIDATE?
The professional astronomers are having enough trouble with some of their brethren publicly admitting that Tabby’s Star MIGHT be due to being artificial. A stellified Jupiter is just too big a leap at this time.
Small moves, Ellie. Small moves. :^)
This easily leads to the crackpot idea about a mini-Dyson-Sphere surrounding a tiny artificial star which had had been a (fictional) super-Jupiter orbiting around 10-20 AU from Tabby’s Star, and this mini-Dyson Sphere happened to block a big fraction of the flux coming from the main star.
On the other hand, the event could naturally explained as several swarms of smaller bodies orbiting in some weird horseshoe shape around a (fictional) super-Jupiter’s orbit about 5-10 AU from Tabby’s Star. Adding additional swarms from L1, L4 & L5 the total should have been enough to block enough light too.
I don’t buy it. It surely makes sense to think up interesting ways in which a superior civilization might be detected, but not like this. Consider this silly story.
Ook, the name of one of our hunter and gatherer ancestors happens upon a neatly stacked pile of engineered wood I-beams. At first puzzled, his eyes then alight with an idea. Ook grabs an I-beam and drags it back to the camp and tosses it onto the tribe’s communal cook fire. Everyone was pleased at the effect, and Ook’s ingenuity.
Now then, how is this different from a civilization that can manufacture black holes and can move them around at will, then choosing to toss them into the nearest proto-star and watching it blaze in glory while everyone gathers around to harvest the photon energy.
Silly, isn’t it? Ook doesn’t exist.
What if aliens do it for religious or political reasons? That is certainly a great motivator for the talking monkeys with car keys on this planet. A trillion dollars a month for an unwinable war, no problem. A few billion clams to explore strange new worlds – hey, stop wasting our money!
If there are other intelligent species out there, then I doubt we are the only ones with our numerous flaws and limitations. Remember the ancient Egyptians built massive pyramids that cost a fortune in resources, time, and money, all so that their god-kings could have a really swell afterlife. The trend continues to this day, we just don’t build pyramids or call them pharaohs.
What’s your point? Do you believe this is likely enough a scenario to be the basis of an effective search strategy? That we should expect to find highly advanced civilizations populated by idiots? It’s certainly possible, but likely? I’m not convinced.
I never said they could be idiots. I am saying that unless every other intelligent being in the Universe is a pure and angelic creature, they will be subject to the same emotional and physical imperfections our species has. This includes doing activities and building things that are monuments far more to hubris and sabre-rattling than logic and efficiency.
Project Apollo only happened because the USA and USSR were in a political contest to show everyone else whose ideologies were better. Science was just the cover. Note how we have not sent humans back to the Moon once the main political objective was achieved.
Interstellar missions and beacons are long-term projects in both time and distance. Unless aliens all live in a Star Trek type existence where no one needs money and everyone has a warp-driven starship, they will very likely not be sending messages or vessels across the galaxy out of pure scientific curiosity. Or maybe I have just been a member of a primitive, tribal one-planet species for too long.
You danced around my question. Do you think it’s likely to be as you claim?
In a galaxy of 400 billion suns surrounded by a Universe of 100 billion galaxies, almost anything is possible.
Uh, great. So you bound the probability on the open interval (0, 1). Just realize by avoiding discussion of likelihood there is no basis for allocating resources to a search of this type.
I am not trying to be obtuse, it’s just that with a data point of one (Earth) and no idea where anyone else might be or what they are like, I can only make an educated guess that mortal aliens beings may be as weak, vain, stupid, and violent as humans can be. And there are some odds in such a favor with billions of potentially habitable star systems.
Otherwise I am not certain how you want me put some substance on this. A modification to the Drake Equation can only be so useful at this point.
And here is one reason for building a Dyson Shell/Swarm that doesn’t get brought up very often: They would make incredibly powerful weapons whose planet-level powers of destruction could reach across many light years.
http://www.orionsarm.com/eg-article/48fe49fe47202
Now why build such a megaweapon?
Well, if you are a very advanced, spacefaring ETI with long-term goals and awareness, you might not want any competition down the road as you expand into the galaxy. It’s nothing personal, it’s just business.
Or the galaxy is full of nasty beings at all levels and you want a way to stop them that does not involve an armada of space battle cruisers. We need to stop assuming that advanced intelligence automatically equals nice. They don’t even have to be conventionally evil, they could just be aliens with actually alien mindsets who do things dictated by their own particular rationalizations.
Of course just as we have done with nuclear weapons, you don’t need to use the Nicoll-Dyson phased array beam to destroy everyone else in the galaxy. Just take out a few example targets to let everyone else get the message that you are the top cosmic dog and that messing with you will be a huge mistake. It would not shock me at all if politics as usual exist even on a galactic level with beings who are way above us in terms of technology, knowledge and evolution.
David Grinspoon, exponential growth is a feature of ecosystems entering unoccupied territory , thus arguably not “anthropocentric” at all.
However David Criswell argued years ago, followed by Martin Beech’s astrophysical discussions of “blue stragglers”, that star-lifting and a more conservative approach will see the free mass of the cosmos rearranged by Intelligent Life with the very Long View in mind. Alex is reiterating their conclusions and it’s a scenario to bear in mind.
Dyson’s point was always two-fold – look at the physically possible and from that what’s detectable. It’s more of a physical limit to guide our observations, not a maximum likelihood analysis. Cirkovic & Bradbury’s opinion – that Matrioshka Brains seem more a more intelligent deployment of resources than Stapledon-Dyson Swarms – is fundamentally abiological in outlook, since the assumed goal is maximised computronium not “living room”.
Finally there’s a different, deeper Future view, built on two assumptions – that neutrino heating of iron cores will be the dominant planetary heat-source in the post-Stelliferous Era, and that chemical evolution is tending towards making multitudes of iron-cored planets. Such infra glaciem habitats will last trillions of trillions of years. Ultimately Life might not need the stars.
I posted this in the first stellifying Jupiter article comment thread the other day:
As for lengthening the life of an already existing star, this is a quote from the linked article next, which includes references:
http://www.coseti.org/lemarch1.htm
Reeves (1985) suggested the intervention of the inhabitants that depend on these stars for light and heat. According to Reeves, these inhabitants could have found a way of keeping the stellar cores well-mixed with hydrogen, thus delaying the Main Sequence turn-off and the ultimately destructive, red giant phase.
Beech (1990) made a more detailed analysis of Reeves’ hypothesis and suggested an interesting list of mechanisms for mixing envelope material into the core of the star. Some of them are as follows:
* Creating a “hot spot” between the stellar core and surface through the detonation of a series of hydrogen bombs. This process may alternately be achieved by aiming “a powerful, extremely concentrated laser beam” at the stellar surface.
* Enhanced stellar rotation and/or enhanced magnetic fields. Abt (1985) suggested from his studies of blue stragglers that meridional mixing in rapidly rotating stars may enhance their Main Sequence lifetime.
If some of these processes can be achieved, the Main Sequence lifetime may be greatly extended by factors of ten or more. It is far too early to establish, however, whether all the blue stragglers are the result of astroengineering activities.
Just let the Sun go through its phases and move the Earth out and then back in once it is in the WD stage, got to be easier than changing the Sun. Also once the RG phase is over a huge amount of material is thrown off the Sun including oxygen and carbon, very valuable materials to sustain habitats.
Assuming humanity’s descendants will still be stuck on Earth several billion years from now. And that they do not overbreed and eat up all the resources in the meantime.
Adam – An interesting point. Thank you. I mean to suggest that one definition of true intelligence may involve transcending biological “laws”, so that perhaps ecosystem patterns will not apply to the kind of intelligence capable of persisting for cosmological timescales. Simple application of biological law would suggest that we humans should behave like bacteria, our population following an S shaped curve followed by a precipitous crash. This may be the case, or some self-awareness and foresight may alter the equation. True intelligence will of necessity involve awareness of constraint and perhaps changing values from the primitive unconsciously expansive state will be a given for the immortals. Nobody knows, of course, but I do believe that the Kardashev scale carries implicit assumptions born of the 1960s
“great acceleration” era in which it was born. Interesting to note that both Freeman Dyson and William McNeill, in their personal accounts of Byurakan II (in 1971), observed what wonderful progress the Soviets were making in diverting water from the huge lake near the Byurakan Observatory and irrigating the previously fallow landscape, allowing the small town of Byurakan to grow into a thriving city. Of the dozen largest dams in North America today, more than half of them were built within six years of this gathering. Apollo 8 had just given us our first look in the mirror, and the first Earth Day was held a year and a half before Byurakan II, but the global environmental movement was still only nascent. It is conceivable that an ethos of sustainability is an integral part of what it means to develop an intelligent civilization.
Nobody knows of course and I don’t mean to argue against anyone so much as point out that there seems to me to be an assumption in these discussions that often goes unquestioned and that is countered by some logical (but not ironclad) considerations.
Hi David,
I understand your point, but equally our societal awareness of terrestrial “limits to growth” has caused deep self-questioning of the industrial development ideology that birthed the 60s. We’ve realised Earth is small and there’s an awful lot of dead space around us. Thus we lean towards modest thoughts and ambitions.
I hadn’t heard of “star-lifting” before. Thanks for that lead into some reading last night.
Maybe all those hot/warm Jupiters are just the storage devices for star-lifting civs.
I read your piece in CD (and your website) about neutrino heating of iron cored planets. I’m not convinced by what I read, but I should read the Spivey paper.
Perhaps large mass brown dwarfs are the optimum solution for long-lived energy sources for habitability?
Dyson Spheres Brown Dwarfs
I found a chart the other day that showed mass of objects from dwarf planets to low mass stars. The chart showed a nice progression up the scale except a very odd decrease in numbers that was on the upper end between large Jupiter mass and L or M types stars. From there on it progressed at the same rate as for planetary size objects. At the time I was wondering if this was just being caused by the Brown Dwarf desert or possibly by Dyson spheres around these objects.
http://beyondearthlyskies.blogspot.com/2016/07/dwarf-planets-to-low-mass-stars.html
Nice blog find, thank you. Paul, you should add this to the Centauri Dreams resources list if you have not already.
Good idea, Larry. Have just done so.
http://arxiv.org/pdf/1607.07922v1.pdf
Some more interesting Charts!
Relation between Brown Dwarfs and Exoplanets
Lauren Melissa Flor Torres, Roger Coziol, Klauss-Peter Schröeder, César A. Caretta, Dennis Jack
(Submitted on 27 Jul 2016)
One of the most debated subjects in Astronomy since the discovery of exoplanets is how can we distinguish the most massive of such objects from very-low mass stars like Brown Dwarfs (BDs)? We have been looking for evidences of a difference in physical characteristics that could be related to different formation processes. Using a new diagnostic diagram that compares the baryonic gravitational potential (BGP) with the distances from their host stars, we have classified a sample of 355 well-studied exoplanets according to their possible structures. We have then compared the exoplanets to a sample of 87 confirmed BDs, identifying a range in BGP that could be common to both objects. By analyzing the mass-radius relations (MRR) of the exoplanets and BDs in those different BGP ranges, we were able to distinguish different characteristic behaviors. By comparing with models in the literature, our results suggest that BDs and massive exoplanets might have similar structures dominated by liquid metallic hydrogen (LMH).
Probing giant planets’ dark hydrogen
http://phys.org/news/2016-06-probing-giant-planets-dark-hydrogen.html
Metallic High-temperature Superconductors
Hydrogen-rich compounds consisting of multiple atoms of hydrogen with so-called alkali metals like lithium, potassium or sodium, could provide a new chemical means to alter the compound’s electronic structure.
http://phys.org/news/2016-07-material-advance-superconductivity.html
I think we still have a lot to learn on what is happening in these large gas giants and brown dwarfs!
“Stellified”. I had a related idea many years ago. Let’s imagine that our descendants survive a trillion years into a cooling universe in the future, but only by recreating our original environment by ‘stellificating’ objects. To the ‘natural’ inhabitants of the universe at that time, these events would be unimaginably energetic explosions. Then I thought of gamma-ray bursters, which would seem the same to us. Need I continue?
Talk about feeling like an ant at a construction site.
You don’t have to invoke Kardashev Type 3 civilizations to realize just how small we are in the cosmic scheme of things….
http://www.eamesoffice.com/the-work/powers-of-ten/
Has any scientist or natural philosopher invoked a law previous to this moment stating that the MORE UNIQUE an astronomical object is, the more LIKELY(i.e o.ooooooo1% as opposed to 0%) it is to be NOT OF NATURAL ORIGIN! If NOT, I claim the right to call it “Ray’s Law”. Until now KIC8462852 was the most mysterious star in the galaxy, but NOW it seems to have VERY STIFF COMPETITION: THE FIRST WHITE DWARF PULSAR! Enter AR Scorpii! It is a binary star composed of a white dwarf roughly 3/4 the mass of the sun orbited by an M dwarf companion 1/3 the mass of the sun roughly every 3 hours. The white dwarf is emitting “pulsar beams ” that strike the M dwarf every 1.97 minutes, which brightens the M dwarf fir a few seconds. The 2 minute pulse RATE is FAR SLOWER than the previous record of 8.7 SECONDS for a neutron star. Could an advanced alien civilization CAUSE a White Dwarf star to pulse like this to star lift material off of the M dwarf star. OH, AND BY THE WAY, LIKE neutron star pulsars, the beams emit at RADIO FREQUENCIES as well! ATA should check tis out IMMEDIATELY for a NON- NATURAL signal in the radio noise!
The problem I have with this idea is that it can lead to dysfunctional thinking. The following post on CX550 would suggest, by this criterion, that it might be artificial, simply due to its apparent rarity and unexplained location.
Consider another domain biology. The equivalent is those who this evolution is false and that organisms are designed, bot evolved. What happens is that any unusual organism is then posited as “proof” that it was designed and therefore that evolution is false.
However, we do have the problem in future, when organism design becomes routine. We can imagine a future when the information about this has been lost and scientists have to try to determine which organisms were evolved naturally, and which were designed. At present, the only certain way would be to look for maker’s marks in the DNA.
Such as Synthetic Cloning?
What I REALLY meant about “uniqueness” is that the object STAYS unique over a period of time. Case in point: LGM 1 was “unique for only a few months. KIC 8462852 is STILL unique after a few years. My guess is that CX550 will fall in the “LGM 1” category now that astronomers realize such objects exist and conduct a dedicated search for them. The jury’s still out on AR Scorpii.
ALSO: LGM 1 was PREDICTED PRIOR to its discovery. AR Scorpii ANALOGS WITHOUT radio emission were ALSO predicted, so it is the RADIO pulsing that makes it unique at the moment. What I do NOT know is whether ANYONE EVER predicted a CX550-like object. No one EVER predicted a KIC8462852-like object.
Some did predict Tabby’s Star in their own fashion, but of course they were largely ignored outside of certain circles. And no, they were not science fiction authors. Case in point:
http://www.obs-hp.fr/~larnold/news_0504.html
Good point about Tabby’s Star not being resolved after several years of analysis.
Point well taken. However, the above mentioned “prediction” ALSO stated that astronomers would be able to determine the SHAPES of the transiting objects. The shear shapelessNESS of all of the dips with the POSSIBLE exception of the “Q8” trends toward a NATURAL solution(EITHER comets, as Eniac so STRONGLY advocates, OR, if Schaefer is proven CORRECT, an internal mechanism like the one proposed by Dirk Bontes). According to Jose Solarzano, the “Q8” lightcurve CAN be explained by a Dyson Ring, but whether it WILL BE THE ONLY SOLUTION remains to be seen. I, for one, SERIOUSLY DOUBT IT!
http://arxiv.org/abs/1607.04207
SETI Observations of Exoplanets with the Allen Telescope Array
G. R. Harp, Jon Richards, Jill C. Tarter, John Dreher, Jane Jordan, Seth Shostak, Ken Smolek, Tom Kilsdonk, Bethany R. Wilcox, M. K. R. Wimberly, John Ross, W. C. Barott, R. F. Ackermann, Samantha Blair
(Submitted on 14 Jul 2016 (v1), last revised 29 Jul 2016 (this version, v2))
We report radio SETI observations on a large number of known exoplanets and other nearby star systems using the Allen Telescope Array (ATA). Observations were made over about 19000 hours from May 2009 to Dec 2015. This search focused on narrow-band radio signals from a set totaling 9293 stars, including 2015 exoplanet stars and Kepler objects of interest and an additional 65 whose planets may be close to their Habitable Zone.
The ATA observations were made using multiple synthesized beams and an anticoincidence filter to help identify terrestrial radio interference. Stars were observed over frequencies from 1- 9 GHz in multiple bands that avoid strong terrestrial communication frequencies.
Data were processed in near-real time for narrow-band (0.7- 100 Hz) continuous and pulsed signals, with transmitter/receiver relative accelerations from -0.3 to 0.3 m/s^2. A total of 1.9 x 10^8 unique signals requiring immediate follow-up were detected in observations covering more than 8 x 10^6 star-MHz. We detected no persistent signals from extraterrestrial technology exceeding our frequency-dependent sensitivity threshold of 180 – 310 x 10^-26 W / m^2.
Comments: 225 pages including very long table, 9 figures, 7 tables, resubmitted to Astrophysical Journal
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:1607.04207 [astro-ph.EP]
(or arXiv:1607.04207v2 [astro-ph.EP] for this version)
Submission history
From: Gerald Harp Ph.D. [view email]
[v1] Thu, 14 Jul 2016 16:58:55 GMT (3586kb)
[v2] Fri, 29 Jul 2016 00:55:08 GMT (3577kb)
https://arxiv.org/ftp/arxiv/papers/1607/1607.04207.pdf
‘No deliberate signals to aliens, but they can pick up our TV, radio waves’ – ex-head of SETI
Published time: 5 Aug, 2016 08:00
The search for intelligent life beyond Earth has been ongoing for decades. Electronics scan star after star, planet after planet. But for now, the Universe has remained silent.
What if one day, contact does happen? How will that affect humanity and our outlook on life? Are we even ready for such an event? And if there’s so many stars in our galaxy, why is nobody responding?
We ask prominent astronomer and former Director of the Center for the Search of Extraterrestrial Intelligence Jill Tarter on Sophie&Co today.
Full article here:
https://www.rt.com/shows/sophieco/354700-signals-aliens-radio-waves/
To quote:
SS: Jill, you know, I thought to myself often – what would I ask an alien if I ever encountered it. I’d say, “Do you believe in God?”, because I really want to know if they believe in God. What would you ask an alien if you were to meet him?
JT: Actually, my question would be – how did you manage to grow old? How did you get through the technological adolescence that we find ourselves in at this point on this planet. How did you manage not to do yourselves in? How did you manage not to destroy your environment? How did you do it?
In the time since Fogg wrote his paper, we’ve also learned a lot about black holes and how they work. Though it may sound outlandish and incredibly dangerous, Cirkovic speculates that an advanced posthuman or extraterrestrial civilization will be able to create a mini black hole in the lab, feed it matter in a controlled manner, and then charge it electrically so that it can be maneuvered with strong electric fields.