How to look for something that isn’t there

A common artifact searched for in looking for ETI is Dyson spheres, or some other megastructure whose purpose is to collect energy from the star. This structure was first suggested by Dyson 1961, but later expanded on by Kardashev 1964. Kardashev suggested that civilizations could be categorized into three different types, depending on the quantity of resources collected: a type I civilization would gather resources from their planet, type II from their star, and type III from their galaxy. Kardashev 1964, and later Annis 1999, and even later (sort of) Villaroel et al. 2016 argued that these different stages of civilizations could potentially be discovered! If a civilization were to harvest all of the energy from their star, then we would no longer see them (in the visible; the heat would dissipate as IR, leading to searches for this waste heat).

Villaroel et al. looked for disappearing stars. They compared data from Sloan and from archived data, looking for sources that were present in the latter but no longer there for the former. In essence, looking for disappearing stars. In the end, they found one potential candidate.

I said earlier that they sort of argued that this was a method for detecting other civilizations. I say “sort of” because they didn’t directly mention it. The thought is there, that this is a way to look for ETI, but the reasoning behind why ETI would cause a star to disappear is not mentioned. I’m sure there are a number of explanations that sci-fi fanatics could list, and maybe the authors did not want to potentially embarrass themselves by playing sci-fi author? Nonetheless, I’m not really sure, short of a Dyson swarm, what would cause a star to vanish. Feeding it to a BH?

That being said, I am becoming a fan of “parasitic” SETI searches. There is something about only needing to pay for time (not receivers or data) that really seems great to me! The data are already there, so why not go for it?

Finding life from spectra, but not your typical way

Lin et al. (2104) identify pollutants such as chlorofluorocarbons in the Earth’s atmosphere that would be detectable using JWST on other planets. In particular, they find that the time dedicated to an atmosphere with other potential biosignatures would be sufficient to constrain the levels of these CFCs, so the search can be parasitic, in a sense.

I think this is a great idea! As I come across ideas for artefact SETI, especially parasitic ones, I get more excited about the prospects for the field. Two major issues facing SETI are the lifetime of a technological civilization and funding. Both of these are, if not solved, greatly minimized by artefact SETI.

With that being said, I fear such a search for CFCs will flop. Even though the timescales of CFCs and excess carbon are large (especially compared to the age of human technology), I don’t have much faith in atmospheric measurements. I know that JWST will improve all of our current measurements, but from what I remember it will only be useful for large or close planets. All of the studies on exoplanet atmospheres have returned one result: clouds. I don’t expect this to change by much, but hopefully we’ll get a spectrum that isn’t flat! I do agree with the authors that since this data will already be gathered and analyzed for biosignatures, it might as well be analyzed for CFC absorption. The worst that happens if we find such absorption is that chemists/geologists/biologists publish ways that CFCs can be produced in the absence of intelligent life, which will further our understanding (and maybe will lead us to ways of removing the CFCs in our atmosphere!).

The one issue I have with this paper is the white dwarf thing. In the beginning, the authors say that they will only look at planets around white dwarfs, but say that their results “are generalizable to other telescopes and planetary systems.” I understand their arguments for a white dwarf, in that they provide better contrast, they could be the same temperature as the Sun, and they have very long lifetimes, but as of now (2018), we have yet to find a single planet around a white dwarf. I just feel they should have expanded their discussion to include all stars, and if they wanted the low contrast, then just M dwarfs. I personally don’t have enough background to state whether the absorption features from CFCs in an atmosphere around an Earth-like planet around an FGKM star would be visible. I wish this information had been provided by the authors in this paper.

As one of the youngest fields, SETI is now old

Only in truly engaging astrobiological, AI, transhumanist, global risk, and philosophical communities in fruitful interdisciplinary worldview can SETI truly achieve the respect and dignity that pioneers like Carl Sagan justifiably aspired to.

Amen! Preaching to the choir here. During my long experience with SETI (as of writing this, it has been almost eight whole weeks), I have slowly shifted my thoughts towards those beautifully reflected in this paper. Bradbury and co. point out that SETI used to be considered imaginative and maybe even daring, the field but has not continued to develop with the times. Many searches continue to be what the authors call “orthodox SETI” which is looking for signals at a particular frequency (usually radio), and this is what many think of when they think of SETI (aside from crackpots looking for little green men). The authors suggest expanding SETI to include artifact searches, or traces of a civilization that could remain past the civilizations lifetime. These searches also remove the assumption that the ET civilization is trying to contact us or otherwise alert us of their existence, an assumption that, while required to be able to search for beacons, might not be true.

This paper slightly amuses me in that it’s sort of a shaming of the field. The authors realized that the field had become stagnant, and this was apparently a good way to get it moving again? I’m not sure if this paper brought about any change, but as an idealist, I’d like to believe that it did. Since this paper, there seems to have been an emergence of artefact SETI (that the authors refer to as Dysonian SETI), but this might be a trend that I have only noticed through the diverse papers selected for this class. I will say that I have not noticed much on an increase in the interdisciplinary interactions of SETI, but I feel a lot of that is academics too embarrassed to join the field (or they think it BS). This is something that I really wish would change, as I’m sure many in the field wish also. Bringing SETI up-to-date with current technologies (oh, the irony), knowledge, and collaboration could really improve where the field is going, as well as improve its funding.

Literally my first SETI paper

My opinion of this paper is completely biased by the fact that I’ve actually met David Kipping and that I read this paper back when it first went on the arxiv. This was my first exposure to SETI (beyond science fiction, if that counts) and I think it went well!

Kipping and Teachey postulate that a civilization (even the Earth) could use lasers in some interesting ways. They first suggest that a planet’s transit could be clocked, monochromatically, against a Kepler-like survey, without the need for much power (~30MW). Due to the Earth’s rotation, this would require multiple laser stations, but in the end, it would be doable. They then continue on to talk about clocking the signal at all wavelengths. This would be a bit more challenging, since many lasers at many different lasers would be required, and again these lasers would need to be placed around the planet, and the power requirement would increase by an order of magnitude, but a committed civilization could manage it. Both of these cloaking processes can be argued against since the planet would still be detectable via other detection methods (namely RV).

The last bit of cloaking they suggest involves the cloaking of biosignatures. A disequilibrium in an atmosphere (normally of oxygen) is a decent indication of life on a planet. These and other related absorption features are referred to as biosignatures. If lasers were emitted at these absorption features, then the planet would still be detected and noticed, but it would just not be studied much since it would be presumed uninhabitable. This is all, of course, under the assumption that other life out there is Earth-like, and that this Earth-like life would be looking for signatures similar to their life (Earth-like). Because of this Earth-like assumption, it is possibly that another civilization is already doing this for *their* biosignatures, we just don’t notice it though because we are looking for our biosignatures (also clouds are apparently all that we can see right now).

Lastly, the authors bring up the point that this laser method can be used not just to cloak, but also to signal existence. They briefly mention that the easiest way to get someone’s attention with this would be to cloak the transit’s ingress and egress, making the transit appear boxy and all around wrong.

Although this is a neat idea, it seems a little far fetched and specific to me. Sure, we have tons of data, so someone might as well look through for boxy transits (I think someone has already done this with Kepler data), but this seems so absurdly unlikely to happen. However, my thoughts on the likelihood of this completely come from the way I view humanity and our goals and motivations, so it’s just as possible that my thoughts of this being a waste are a minority in the galaxy.

Spin ‘er up, and call it alien!

Harwit describes a characteristic of photons that most, including this blog writer, did not know actually existed: orbital angular momentum. On top of this description, he also explains that we are able to incite large values of this momentum on photons ourselves and that we can (sort of) measure this value. Since nature doesn’t make photons with such high orbital angular momentum, such a detection would be an indication of artificial origin.

I happened to read this entire paper before realizing that the important bits were in Section 4.3, but oh well. The authors bring up interesting astrophysical applications aside from SETI, including probing a turbulent medium for inhomogeneities and studying different characteristics of black holes. According to the authors “radiation with high values of photon orbital angular momentum might have [significant advantages] for communication and quantum computing.” Apparently, taking this additional spin into considerations, one is able to encode more bits of information than previously (which makes sense given the additional degree of freedom). I think this paper is fantastic! It’s a good idea that is now

I must confess, this paper basically goes completely over my head, which I suppose could be formed as a sort of critique. I think it is important in science in general, but also in something as interdisciplinary as SETI to be clear in one’s writing and to lead the reading through all of your arguments, even if this means sometimes being repetitive or dumbing down your work. Although fields such as astronomy are marked by academics making things excessively convoluted to make them seem above the populace, I’d like to believe those days were over, and should have been over by 2003. Someone with a degree in physics or astronomy should be able to understand this paper, and although it could be my lack of coffee, Harwit should have written his paper at a more comprehendible level.

Given my lack of complete understanding of this paper and the fact that this paper is now 15 years old, most of my musing might not be all that interesting. For instance, how far have we actually progressed in this? Can we now readily inflict orbital spin on a photon and then detect it? Can we, with our current technology, encode messages in these photons, send them, and then later detect them?

A quick Google search has showed me that Wikipedia is, once again, a bro. Preliminary tests of radio and microwave photons showed that we are able to transmit 32 gigabits per second over the air, and 2.5 terabits of data per second through optical fibers. This is fantastic and amazing; this would revolutionize the telecommunications industry around the world! It reminds me of Artemis by Andy Weir, but with less mafia. Unfortunately, we have apparently not yet figured out how to reliably measure the orbital angular momentum. Since orbital angular momentum can have as many states as it wants, there is no device that can separate out more than two modes. A diffractive holographic filter is promising, but this idea is still being investigated.

MASERS, LASERS, ETI, and other fun initialisms

A reoccurring thought while I read this paper was “What the hell are masers?” I just kind of assumed they would be defined *somewhere.* Well, they’re not. So here’s what masers are: “microwave amplification by stimulated emission of radiation.” So lasers, but specifically in the microwave. The acronym was coined in 1953 when the first maser (I think) was successfully operational. Later, an “optical maser” was successfully created in 1960. The optical maser was first envisioned in 1957, and the term LASER (*light* amplification by stimulated emission of radiation) was coined that same year. Apparently Charles H Townes made the first ammonia maser:

Given this information, it makes sense that Townes would look into additional uses for his optical maser (from now on, just laser). At the time, SETI was new and exciting (well new-ish; the idea of contacting ET species had existed for centuries), and was not weighed down by the “giggle factor” that it experiences today. An inventor could write a paper like this, and receive mostly positive support for the idea without anyone calling BS or science-fiction on the idea. This paper, I believe, marks the first discussion of contacting ET species with lasers and possibly detecting such signals. These ideas have now been integrated, and other papers written on them, but the first to propose it is always the coolest (right?). Townes computes that with modern (from 1961) technology, we could already detect specific laser signals, and postulates that with only a bit more time (and narrow-band optical receivers) other laser signals would have high enough signal-to-noise to be detected.

One last note is I enjoy how Schwartz and Townes end their paper. The paper is fairly technical and a nice proof of concept, but they end the paper with a quick SETI discussion, saying that searches should go beyond the waterhole, that UCE and IR are absorbed by most atmospheres (so not to really bother with those), but also that a civilization more advanced than our own could have technology that we currently rule out as unfeasible. I do appreciate this throw-in, since we only ever look for traces that could have potentially been left by humans, since we need to set restrictions to actually make a search, but it is nice to acknowledge that other civilizations could be unlike us, and therefore could be communicating in ways unimaginable to us.

Optimal Frequency According to Hippke

Although this seems like unfair criticism, I found this paper to be dense, boring, and unnecessarily long. Given that, this post will be drier and terser than my other posts (apologies to my big fans).

The authors try to find the optimal frequency for an ET civilization (or I suppose possibly even Earth) to communicate with for long distances. In particular, they look to maximize the data rate. While this is all well and good, and is an interesting thing to think about, I’m not going to bother going into their analysis or even their conclusions because I frankly find them to be useless. All of the analysis assumes Earth technology and Earth knowledge and Earth communication. It irks me. While these assumptions are fair to a degree for when you are designing a search (with current technology we could produce this signal and detect this signal, etc), I feel that expanding them into such a deep analysis is not fruitful. I feel there is merit into looking into most wavelengths, and since a lot of SETI will turn into parasite searches or hopefully get its own funding to do its thing, most wavelengths will be analyzed, especially if time stretches on for a while without a detection. So I don’t think this paper is very useful for SETI.

That being said, there is merit to this for mankind and our possibly inevitable expansion in the solar system and maybe beyond. If there is a specific wavelength that, with our knowledge and technology, works best for long distance travel in terms of data rate, then maybe we should keep this in mind as an alternative to radio (if it’s better). I’m not sure our technology is currently advanced enough to communicate with x-rays, but in the near future I wouldn’t be surprise if it becomes feasible.

Updates to the Prime Directive, I mean the First Protocol

In 1989 then later in 2010, a group of SETI-ists agreed to a list of protocols for how a detection should be handled. The list is nicely summarized by Gertz 2017 as:

(a) SETI shall be conducted transparently; (b) a detection should be followed by rigorous confirmatory procedues and follow up observations; and (c) everyone must refrain from transmitting a response without authorization from a broadly representative body

Forgan & Schulz 2016 found this document a bit lacking, and made suggestions for updates. Their main complaint was that this document did not really take into consideration the current methods for spreading information, mainly social media. Before ~2008, news spread via word of mouth, newspapers, magazines, radio, and television. There were a few chain emails going around, but these channels were basically all there was. Then came the launching of facebook, twitter, instagram. The world now communicates in a different way and at a faster pace than it did ten years ago. Forgan & Schulz were correct to suggest updates to the document. Although the First Protocol isn’t outdated per se, it is missing information that is now critical.

The authors keep to the original protocols summarized above, but expand to include social media and microblogging. In actuality, they suggest that scientists keep the public updated via whatever medium is popular at the time. For example, they suggest that scientists maintain an online account of news and updates in the form or a blog, tweets, and video blogging. They continue with the thought of transparency by saying that these updates should be detailed and include everything about the experiment and any criteria for detections. To avoid looking like fools, scientists should develop and maintain communication and media skills and establish “competence and trustworthiness” before any detection is announced. They should also be leery of their online footprint to keep themselves safe from any backlash.

If scientists believe they have found a detection, it should be published in a peer-review journal, and their data should be hosted online somewhere easy to find. The publication should be clearly worded, transparent, as to the authors’ confidence in their signal, and “an acknowledgement that until proved otherwise, the tentative signal should be assumed to be caused by natural or human-made phenomena.” (although Tabby’s star showed us that even such statements can simply be ignored when aliens are involved). The authors should then become and remain active in a global conversation regarding this potential discovery that goes beyond their colleagues and includes multiple disciplines.

Forgan & Schulz close their paper by saying that, if the detection is confirmed, the scientists should be committed to talk about this detection for the rest of their lives. Before they discuss this, though, they mention that, if the detection cannot be confirmed, the test “must publish a statement clearly stating that the signal cannot be confirmed to be of ETI origin.” While I generally agree with all of the statements the authors make, I completely and whole-heartedly agree with this one. I feel a lot of people are scared of losing face, and some might not want to give the world this update, that the signal cannot be confirmed. But it is a very important part of science, to acknowledge any short-comings of a discovery, and should be pursued even if there is potential backlash.

Before reading this paper (and then Gertz’s paper and then the First Protocol), I had never thought about what protocol SETI scientists or scientists in general should follow, and any thoughts I might have had probably would not have included such a public online footprint. But I agree with the authors that transparency (which requires being public and clear about everything) is key to any announcement related to SETI, a field that has been disregarded as psuedo-science for the last few decades but a field in which any positive discovery would change the world.

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.

Buzzfeed, fake news, and how it could be aliens

Back in 2015, Stephen Colbert hosted Neil DeGrasse Tyson and Seth MacFarlane on his show. Stephen brought up Tabby’s star, explaining that one of the explanations for the drastic dips, although improbable, was that an alien megastructure could be orbiting the star. Although I would have preferred he listed the other possible explanations, I suppose I’m okay with how he introduced the topic because he mentioned that the likelihood of it being aliens was low.

It’s the next statement that bothers me. Seth MacFarlane chimes in with “Ya, I read that on Buzzfeed, so it must be true” (sarcastically), but this annoys me! Since the 2000’s with Wikipedia, there has been this sarcastic statement going around of “well I read it on the internet, so it must be true.” In extension to this, outlets such as Buzzfeed have started developing reputations as only there for their fans, publishing anything their fans might like, regardless of whether it was true or not (I’m saying this is becoming their reputation, not that they don’t fact check because honestly I don’t know). With all this, if Buzzfeed posts something about an alien megastructure found by astronomers, it will either reflect poorly on them or on astronomers.

Unfortunately, there is no way to get around the fact that the general population automatically calls BS to anything about aliens. As shown in this clip from Late Night, it is near impossible to have a legitimate discussion about SETI without astronomers rolling their eyes and everyone else just thinking it “fake news” (another popular statement these days). Neil responds to this statement with an exasperated expression and the statement “Just because you don’t understand something, doesn’t mean it’s aliens.” Well you know what, Neil?? No one said it *was* aliens! It was proposed as a solution, along with a ton of other things, but it *is* a solution to this anomalous data. The media picked up on that one little thing, and went crazy with it. Neil is right, in general, but I think it is important to remember that aliens are an explanation to different things we don’t understand, and while all other explanations should always be explored first (and with more fervor), aliens should not be removed as a solution just because sci-fi has trained us all to believe this silly and impractical.