Remember to take notes, SETI kids

Forgan (2016) can be viewed as a discussion of best practices for the documentation of SETI research.

SETI researchers have some unique concerns when it comes to communicating possible positive results. A true positive SETI results would fundamentally change the way humanity views its place in the universe. The results would vary greatly, from riots in the streets to new religions praising the new alien deities.

In response to the many concerns of SETI researchers, the International Academy of Aeronautics (I swear that’s their website) drafted some post-detection protocols to guide researchers in their interactions after the potential discovery was made. But these guidelines are dated and ignore how to communicate results to the public. Hence, this paper.

In this day and age, the internet dominates the spread of information. While traditional sources of news (regular newscasts, newspapers, press conferences, etc.) exist, information reaches most people through tweet, status updates, and YouTube videos. This paper suggests that in addition to the regular procedures of holding a press conference and submitting a paper for publication, potential SETI discoveries should be actively discussed on public online forums. The data should be made available to the public and be checked over by as many people as possible.

The authors believe it is the responsibility of the discoverers (and to a smaller extent the whole SETI community) to ensure that results are interpreted and communicated properly. They also spend a significant portion of time describing how SETI researchers need to be ready for this media craze when conducting any search and should be publicly documenting their research procedures, what they expect to find, and what would constitute a significant result in their experiment, both for people to see later to understand the experiment, and to show that they didn’t look at the data and then decide that it was significant.

What happens when we find them?

This paper by Forgan et al. (2016) talks about the protocol that needs to be followed if  when we find extra terrestrial intelligence. To understand the need for this, one only needs to look at the commotion and media frenzy caused by Tabby’s star and Oumuamua.

The existence and search for ET has always been a favourite of popular media, simply because it catches the eye of the general public. It is a topic that attracts people from all age groups irrespective of their age group. The question of whether we are alone in the Universe is one of the fundamental questions that transcends Astronomy and science, and goes into philosophy and anthropology. It starts delving into the arena of religious beliefs and the anthropocentric view that biases us.

Considering the above, it is important to understand the importance of the search for ET. Any kind of media coverage of this topic is almost guaranteed to get good viewership / readership. Therefore any researcher associated with this field must tread very lightly and be cautious about any kinds of claims made or results published, which even REMOTELY can be interpreted to imply the existence or our successful detection of ET.  This does not mean that one must hide their research or not go public with it, for fear of rebuke. However, as the article discusses, there should be a framework that is followed before a search is conducted and transparency, once it is done and the data has been analyzed, and results obtained.

The article further lays forth a possible path to follow to release the data and clue in the media as to the results and the need for independent verification. Another step that the authors alluded to, is that an international consensus must be built. Currently the only body which has such a mandate is the United Nations. Within the United Nations, perhaps UNESCO? It could get interesting, albeit tricky if the UNESCO is tasked with building up an international opinion and charting a path forward. Namely because the United States of America has decided to withdraw from UNESCO as a member starting 2019.

Going by the past record and partisanship in the UN, it could be problematic for all the nations to reach a consensus. Since, any kind of interaction with an alien civilization could have far reaching consequences for all of humanity today and in the future, it is something that should definitely involve all the stakeholders, or at least their chosen representatives. We still divide the Earth with borders, however Space cannot be (at least not yet). Its contents and inhabitants (?) affect all of humanity. Could the answer be  Asgardia?

 

So you find aliens, then what?

The SETI Protocols were conceived in the 1980s as procedures for individuals or organizations to follow while performing radio searches for extraterrestrial intelligence. A subset of the protocols, the “Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial Intelligence”, provides the guidelines that should be followed after the detection of extraterrestrial intelligence. It was initially adopted in 1989 and revised in 2010 (albeit, the SETI Institute only references the old protocols). As stated in the cover letter, the protocols were adopted by various institutions including:

the Board of Trustees of the Academy and also by the Board of Directors of the International Institute of Space Law […] it was endorsed by the Committee on Space Research, by the International Astronomical Union, by the members of Commission J of the Union Radio Scientifique Internationale, and by the International Astronautical Federation

This marked the first attempt to address the concern of what to do if SETI made an unambiguous detection of extraterrestrial intelligence. Gertz states, in his recent discussion of SETI protocols, the principles from the original protocol can be distilled to three broad tenets:

  1. SETI should be conducted transparently;
  2. a detection should be followed by observations and adhere to rigorous confirmatory procedures; and
  3. all parties must refrain from transmitting a response without authorization from a broadly representative body, such as the Security Council of the United Nations.

The revised protocol states SETI searches should be “conducted transparently, and its practitioners [may] present reports on activities and results in public and professional fora [and] be responsive to news organizations and other public communications media about their work”. This explicitly addresses the prevalence of the internet and social media in sharing information and fomenting misinformation. It is an attempt to mitigate the hijacking of the scientific narrative behind any SETI search. The other addition discusses how to handle evidence and confirm a detection. It makes a direct reference to the Rio Scale (SETI-ists have updated this, paper in preparation). The Rio Scale was developed as a suitable tool for assessing the plausibility of detection signal and gauge the impact such an announcement would have on the public. While the Rio Scale may be under debate (one of the original proponents of the Rio Scale now favors the London Scale and there are other blogs debating its use), it attempts to give scientists a tool to mitigate the subjective nature regarding plausibility. As NASA no longer funds SETI, the primary purpose of this protocol is to ensure the detection is real and mitigate misinformation.

The protocols are not perfect (see Tarter’s take in Movie 1) and have come under criticism. Some have argued social media have made the protocols useless. Others have sensationalized the topic. Gertz has questioned the feasibility of enforcement, noting that while “Western SETI scientists” laws protecting them, it might not be the case elsewhere. Gertz has a nihilistic view on treaties with no legal reparations against individuals or entities who do not adhere to the protocol. He contemplates the need to restrict access to information and would like to see the legal provisions backing future SETI protocols and a complete ban of METI. He is also unaware that publications mentioning restricted access to detections only fuel the conspiracy theorists that the government is trying to cover-up the existence of alien life. Gertz ignores the fact that his view of the protocols appears counterintuitive to his interest in SETI. If one truly does believe SETI/METI pose an imminent danger and warrant militant regulation, then why should anyone do SETI? This blogger views both SETI/METI as benign activities that can improve their scientific standing if the protocols are followed. If not, the age of social media will most likely make a spectacle of any detections and render moot what little credibility SETI/METI. The protocols are still lacking and should be revised to explicitly address the dangers of social media, but the attempt to maximize transparency is important in a field sullied with conspiracies, dubious claims, and distorted facts.

Movie 1. Jill Tarter on Post-detection Protocols
If the SETI Institute detects a signal from extraterrestrial life, what happens next? SETI director Jill Tarter explains the protocol for such a situation. She makes a passing reference to the protocols discussed in this blog.

An effort to keep the press from yelling aliens

In Forgan (2018, submitted), an updated version of the Rio scale is proposed and justified.

The Rio scale is a tool for communicating the significance of a signal to the general public. It works by assigning a score from 0-10 to possible SETI discoveries and attaching qualitative descriptions to each of these scores, ranging from insignificant (R=1) to extraordinary (R=10). The score is based on what the scientific and societal consequences of a signal being true would be and the probability the signal real. The authors feel that this scale could do with a revision to make sure its results are more accurate and transparent, especially to the public.

The new (an old) version is split into terms that are calculated by following a decision tree that is presented in the paper. The first (Q) is concerned with the type, distance, possible contents of a potential signal. This term is directly linked to how societally impactful the signal would be. The second term (δ) is concerned with how investigatable the phenomena is and whether the signal is extraterrestrial in origin. δ is calculated using an intermediate J factor. The context for the Q and J values is presented, similar to the manner of the qualitative descriptions for R. A web-based calculator has been coded up for anyone who wants to toy around with it.

It is suggested that these scores be calculated throughout the process of signal analysis, both by the original group and by other groups so that the public can understand the status of the detection as time goes on.

I don’t know if it is because SETI experiments are inherently harder or if it is just much cheaper to work on these “If I were to work on a SETI experiment, I would do it this way” type papers, but this subfield of astronomy seems to spend an inordinate amount of time on this type of material (see search conduction and post-detection protocol papers by Gertz and Forgan). I understand that if a SETI result is found, it will be incredibly impactful, but it hard for me to see a field with such a dearth of experimentation spend its limited time and resources meticulously documenting the few experiments that are being done. I find it more likely that experimenters would work on producing more analysis results than making sure they have updated Rio scores for each step of their experiment.

Gertz really doesn’t like METI

I feel the need to write about Gertz since I didn’t last time, even though his 2016 paper is still my favourite from this class, due to its excessive amounts of sass.  This paper is (unfortunately) less sassy, but still fairly well written. Gertz is arguing for adding and improving regulations to METI. He goes through the current legislation that technically bans or limits METI, and also motivates his call with current events.

For the most part, I agree with Gertz, especially his line “Actions undertaken post-detection, apart from confirmatory observations, are not science, but matters of vital public policy,” because it is completely true and well worded. I would also go to extend this, as Gertz does, that preemptive communication efforts are also policy. I agree that since there is risk to it, and essentially no risk to SETI, that METI should not be done in general, and certainly should not be done without the consent of everyone who can be affected, which is all of mankind. While it is idealist in thinking that we could get everyone in the UN into agreeing to even talk about METI, it should still be put in place that random groups of people with money shouldn’t just be allowed to spew words into space, especially since these words (unfortunately) represent mankind.

What I don’t agree with about Gertz’s paper is his cited motivation for this paper. He mentions numerous times that China has just entered the field of SETI, and that they might not share any information with the world, but instead keep it secret. He states that Russia or the US, upon receiving a signal, might also mark it as Top Secret and refuse to share it with their nation or other nations. He also numerous times mentions Kim Jong Un and adds in ISIS and “religious groups” as individuals that should not be allowed to represent humanity by sending messages. While I agree with this, I think that these examples are too specific and finger-pointy (for lack of a better phrase). They not only date his paper, but also make it seem fairly whiny, conspiratorial, and just yellow the legitimacy of his claims and this call for action. He could have made the same points by saying “countries,” “groups,” or “leaders,” that would have made the paper still relevant in a few years time.

Is the 9 dimensional haystack enough?

In this post I shall build upon some of the discussion from  Paul Davies (2013).  The article describes a search effort which uses data from the Lunar Reconnaissance Orbiter. They attempt to use data from this satellite with a resolution of about 50 cm/pixel, to find artifacts of ET on the Moon.

An important consideration in this search is the size of the data set that needs to be sifted through. The complete data set is expected to contain about a million frames of 500 Megabytes each, which translates to about 500 Terabytes in all. The search is for something left behind accidentally or on purpose by alien civilizations, a la  Transformers: Dark of the Moon (but mostly smaller?).

The challenge over here is that it is simply to numerous for a human or groups of humans to go over the entire data set manually, and the computer algorithms being used are not necessarily primed to look for signatures or anomalies highlighting the artificial origin. Another example of this is the Kepler mission. It has looked at more than 100,000 stars. A great search technique to find Dyson swarms, or other hallmarks of advanced ET civilization in orbit around a star. The periodic dip if caused not by a planet, but a irregular (non spherical structure) would encode information about its structure, in the residuals.  As has been discussed in Wright et al. (2016), there are a number of anomalies in exoplanet science which might be from astrophysical phenomenon or possibly from an advanced ET civilization. If we find more than one such anomaly in a system, it would be difficult to attribute it to natural sources.

Therefore, from a SETI point of view there is a LOT of information in these giant data sets from missions like Kepler, TESS, LSST, among others. Citizen Science initiatives do help in this by using human cognitive abilities in pattern recognition to pick out these anomalies and outliers; arguably better than any computer can do.  However, when it comes to automated pipelines, we should quantify their efficacy.

The point I would like to make here, is that in the era where we are transcending the radio region of the electromagnetic spectrum into the optical and infrared, we must make use of these existing big astrophysical missions and include them in our quantification of the search volume probed for ET.  However, I propose that we must add a 10th dimension to this haystack which quantifies the ability of our data pipeline to retrieve these signals IF we were to receive them. By this I mean, if there is a pipeline which is analyzing an existing database to find anomalies, the completeness fraction of that pipeline should also be quantified. By inserting artificial signals into the data, and counting the ones we retrieve, this can be done. However, that is an overtly simplistic view of this problem. This is not an easy task since we do not know the nature of these signals and can hence only hypothesize and to a certain extent – guess.

This way we could include Kepler, and other such missions in our search volume (volume searched by all SETI projects so far) using their actual efficiency and not a mere theoretical one.  This 10th dimension fraction should ideally be close to unity for most searches, however as mentioned in the paragraph above, in the absence of knowledge about the nature of the signal we can only hypothesize using our current understanding of Physics.

 

Addendum: 2018 – 04 – 30

After further research and work on the 9-dimensional haystack , I realize that in the original Haystack proposed by Jill Tarter in 2010, this ability to retrieve potential signals from the data is exactly what she meant in the modulation axis.

9 suffices. Phew!

SETI can be cheap; let’s do it

This post won’t really include much about Davies & Wagner 2013, expect for one line:

“[T]he criteria for searching a database should be primarily tied to cost rather than plausibility. If it costs little to scan data for signs of intelligent manipulation, little is lost in doing so, even though the probability of detecting alien technology at work may be exceedingly low.”

This is remarkably well said, and I completely agree. A huge argument against SETI is that nothing has been found yet, so it’s a waste to keep looking. While this argument is fallacious in itself, it can quite easily be rebutted with the above statement. If searching requires little time/money/effort, than there is no waste.

One great thing about SETI is that it (normally) does not require its own dataset. Astronomers are already observing interesting targets with different instruments at different wavelengths, either to catalog them or to look for anomalies. Any anomalies discovered will probably be scrutinized, so why not borrow the data and look at it from a SETI point of view? There are currently many algorithms searching datasets now (a solution to our big data problems), so altering these algorithms just slightly to look for expected ETI alterations or just anomalies takes minimal effort and, if the algorithm is light, has minimal computation costs. Such searches could even just piggyback off of current searches (flag anomalies) such that there is no additional computational costs.

Davies and Wagner specifically motivate looking through all of the wonderful data we have on the Moon, noting that because the resolution is so great, many artifacts/trash would be visible (assuming they aren’t buried in regolith). Personally I think that looking at these by eye is not the way to go, and that the search should be automated. It would also be neat if some machine learning were applied to find such artifacts, but this would require some kind of training set and therefore not only more work/time/money but also some kind of assumptions about the sizes and shapes of alien artifacts.

I think it would be really neat if someone were to dedicate some time (probably unpaid =/) to developing algorithms for finding anomalies in all of the (mostly planetary) datasets we have (images, transits, gravity anomalies, all-sky surveys in every wavelength). This would not take much, and the algorithms could just run in the background. Follow-ups for any flagged anomalies would include compilation of all possible data and either human or artificial analysis to somehow rank how anomalous the data are. This would simply be really awesome.

 

Interstellar Semaphores?

This article by Luc Arnold (2005) explores light curves from aspherical transiting objects – namely a triangle, two screen, and a six screen. By analyzing the resultant light curve and its deviation from a standard light curve (due to a spherical object), it argues  that these can be potential signatures of Extra Terrestrial Intelligence (ETI) and even as a means of interstellar communication .

Louver like six screen object

Arnold first establishes the premise for the detectability by space based telescopes of such irregular shaped objects (shown above), and then the ability to distinguish these asymmetric shapes from spherical planets. He then considers not one such object, but a series of objects of different sizes and spacing (gaps). These objects could encode a pattern (say prime numbers) to be used as a means of transmitting information. This is reminiscent of late 18th century communication during the Anglo – Franco wars using optical telegraphs and semaphores (as shown below).

Here, they used various ON and OFF positions of the shutter to transfer 6 bits of information – 2^6 – 1 = 63.

 

Murray’s 6 shutter telegraph 

 

A similar concept is hypothesized by Arnold, as a means of interstellar information transfer. The variations in the light curve will be akin to the shutters in the telegraph changing state. He then compares the data transfer rate per steradian of this method with that of laser beacons. Though they have a higher transfer rate if focussed on one star due to their small cone angle, if one aims to transmit over a greater area, then the interstellar semaphores are faster.

I think it is a very novel method for communication that has parallels with techniques used by humanity a few centuries ago. Further, using this technique we may communicate with civilizations which are not in the Earth Transit Zone by giant sails and solar panels in polar orbits of the Sun, perhaps a viable alternative to energy intensive beamed transmission?

 

 

Kardashev 1964

In his 1964 Nikolai Kardashev (1932 – ) reviews and articulates the basic requirements for interstellar communication using radio waves. Further, it considers the noise sources in the radio and attempts to establish the ideal wavelength range for space communication. Not only this, calculating the energy requirements for such communication he classifies the three types of civilizations (now known as Kardashev civilizations) based on their energy harnessing capacities.

He starts off by stating that the 1 GHz – 100 GHz frequency space should be ideal for interstellar communication since the absorption due to the interstellar medium is minimum at these frequencies. The limiting factor for communication within the galaxy is the background from the galactic disk. However for intergalactic communication we also need to start worrying about radiation from the halo of the galaxy. Considering both these cases for communication, Kardashev again states that the 1 – 10 cm  wavelength range (~ 1 GHz) would be the optimum band since the noise background reduces.

He then talks about the information content of the signal and the minimum power that would be required to establish a signal of appreciable statistical significance over the noise.  To consider the maximum power of which a signal a civilization can transfer, he classifies levels of civilization and technological advancement.

As shown in the Figure below, a Type I civilization can garner all the energy incident on a planet from its host star.

Type II civilizations can utilize all of the energy of the star. As discussed in Dyson (1960), a potential way to do this by using a (now called) Dyson sphere or Dyson swarm, an artificial cloud of material to enshroud the star and absorb all of its energy output.  There are also hypothetical scenarios proposed by Roger Penrose (1931 – ) where the the civilization can feed its star into a black hole and utilize the waste heat produced by the accretion disk.

Type III civilizations are those which can harness the entire energy output of their galaxy, potentially the supermassive black holes at the center and even quasars.

Humanity in its current era, is more of a 0.7 on this scale. Michio Kaku posits that it would take humanity another century or two to reach a type I stage.

 Kardashev civilizations

It is interesting to note that one of the potential extraterrestrial sources he mentions in this paper (CTA-102) was later discovered to be a quasar.

Also the fact that he posits the development of radio telescopes 100,000 m^2 in area, the same year that the construction for Arecibo began. Arecibo has an area of about 70,000 m^2.

I think this paper is of historical significance as the first mention of the Types of civilizations which are now famous as Kardashev civilizations. Not only that, but also the fact that it takes the idea of the Dyson sphere and provides it with a much broader framework  as to its significance for an advancing civilization.

I believe it is also important in the context of Science Fiction, the possibility of a realm where a single civilization can harness the energy of the entire galaxy. The concept seems to be too far fetched to humanity in the present, but it provides fodder for the imagination of authors and Sci-Fi creators to run wild with possible technologies of the future which can achieve this. Technologies and achievements which could potentially be realized in the future.

 

 

The Case for Artifact SETI

Olaf Stapledon’s 1937 science-fiction novel, Star Maker, pushed the imagination by featuring an advanced civilization that built a spherical shell around its host star to capture the radiation and meet its energy requirements. This spherical shell would later become known as a Dyson sphere (see Figure 1), after the astrophysicist who contemplated the mid-IR excess such an object would release. While the concept originated in fiction, it has since gained a niche as a potential alien mega-structure that could be observed. It also emphasizes that the search for extraterrestrial intelligence (SETI) is difficult due to the limitations of our imagination. While SETI is fundamentally a search for a society capable and willing to communicate, there exist other approaches that make the SETI more feasible and draw on the concept of waste-heat from alien activities, such as the Dyson sphere. Jason Wright and fellow scientists recently published a four-part series to motivate and present the Glimpsing Heat from Alien Technologies (G-HAT or Ĝ) survey. Wright et. al. argue the sensitivity of a waste-heat search would be greatest for a civilization which satisfies a physicist’s definition of intelligent life. This defined ETI as a species that (i) “processes resources and energy to produce more of itself” and (ii) “overcome[s] local resource limitations through the application of energy”. They surmise that “if a species is spacefaring, then its level of intelligence is such that there is no practical resource limitation that it cannot overcome, except that of energy”. The authors note there may be other intelligent life excluded by this definition of intelligent life, but argue such a society would not be easily detected through the Ĝ survey.

Dyson (not the vacuum)!
Figure 1: An artists depiction of a Dyson sphere. It can be considered a swarm of steerable energy collectors. Most cases assume it is at roughly 1 AU around a Sun-like star. The Ĝ survey aims to discover the excess IR radiation from such a structure (if it exists). Source: New Scientist, Mark Garlick/Science Photo Library

The first paper introduces the philosophies of SETI, with particular emphasis on the Hart argument that the dearth of ETI encounters implies we must be the first intelligent species in our galaxy. Hart stated there were four categories of solutions to this problem: (i) physical, (ii) sociological, (iii) temporal, and (iv) ETI has visited, but he denounced each solution and conclude we were alone in our galaxy. Wright et. al. review each of the categories with insights from our current understanding of astrophysics and reinforce the temporal and sociological reasons presented by Hart. An order-of-magnitude calculation show a colony of ships traveling at 10-4 c (comparable to the velocity of Voyager 2 or Pioneer) in a rotating disk (i.e. our galaxy) should populate the Milky Way in at most a billion years. With regards to the extinction theories, the authors aptly note this must hold for all colonies of a civilization that has spread throughout its galaxy. A species confined to one planet can go extinct but as long as there is a self-sufficient colony somewhere away from a gamma ray burst or interstellar war (anything lethal), the species can always repopulate the galaxy. The authors state that sustainability arguments do not hold because, before all stars are colonized, there is no limit in the relevant resource (stars) and there is no reason galactic hegemony must be explicitly driven by a lack of resources.

While Hart’s argument was pessimistic, it only considered one galaxy. Therefore, if each galaxy is considered to be an “independent realization” of his experiment, there could exist galaxy-spanning ETIs. Wright et. al. then describe the previous searches for Dyson spheres and discuss the promise of NASA’s Wide-Field Infrared Explorer (WISE). Wright has stated that “WISE was launched by NASA for pure, natural astrophysics; it just happened to be perfect Dyson sphere finder.” In the case of a Dyson sphere, if a star were perfectly encased by a shell at roughly 1 AU, the resulting spectrum could be approximated with a few-hundred-Kelvin blackbody. The results of searching for this heat-waste, this artifact of ETI activity, would at worst put an upper limit on alien activity.

The Ĝ survey strives to address some of the issues inherent in typical SETI, namely the assumption that ETI is emitting a signal amenable to radio detection. Instead of forcing ETI to behave this way, artifact SETI seeks to detect the thermodynamic consequences of galactic-scale colonization. In this first paper, the Wright et. al. briefly note something like the Ĝ survey will be “hard pressed to prove that an unusual source is artificial”. IR observations are prone to contamination from dust and must be disentangled form other, astrophysical processes. The survey analyzed roughly 100,000 galaxies to determine the reddest sources and concluded “no galaxies resolved by WISE contain galaxy-spanning supercivilizations with energy supplies greater than 85% of the starlight in the galaxy”. Others have introduced possible corrections to the treatment of data, but nothing so far suggests galaxy-spanning civilizations exist.

Movie 1: Above is a video showing KIC 8462852 and a possible alien mega-structure (around the 1:00 mark) explaining the decrease in flux. Source: The Washington Post

While the Ĝ survey is more scientific and data driven than conventional SETI, it is important to carefully vet candidates and, at the very least, apply the law of parsimony. One such example of artifact SETI gone awry is KIC 8462852 (see Movie 1). Perhaps to Wright’s chagrin, he has been “credited” with fomenting the idea that an alien mega-structure is to blame for the dips in KIC 8462852 (see here and especially here). Additional observations suggest optically thin dust may cause the dips. The biggest damage is to the credibility of SETI, as it degrades the science behind these papers to nothing more than a form of sensational pseudoscience. The support from the Templeton Foundation, often criticized as having a history of supporting controversial and speculative research (see here for physicist’s opinion), is another issue that may affect the credibility of the Ĝ survey. Regardless of one’s prior on SETI, Dyson provides some keen insight:

“If there are any real aliens, they are likely to behave in ways that we never imagined. The WISE result shows that the aliens did not follow one particular path. That is good to know. But it still leaves a huge variety of other paths open. The failure of one guess does not mean that we should stop looking for aliens.”

This blogger, while having concerns with SETI as a whole, firmly believes more research should be done with both conventional SETI and artifact SETI. Until there is more data, it is unscientific to completely reject the premise of SETI, however flawed its premise may be.