Looking for signs of life on Kepler 186-F

[ 9 ] Comments

Consider this post, which firmly states that proto-Earth Kepler 186-f has a 50% chance of harboring technologically equipped intelligent life:


Although about science, this blog is primarily lacking in real science. By my reckoning, even the most optimistic assumptions indicate a probability of << 1/1000. But that is the topic of another blog.


A few of the 42 radio dishes of he Allen Telescope Array at the time of its dedication in October 2007. Photo courtesy of the SETI Institute.

Here I’m exposing greater detail about a secret experiment conducted at the SETI Institute in March and April of 2014.

On 18-April-2014, Elisa Quintana and several co-authors made the cover of Science magazine with the discovery of the most Earth-like planet ever observed, anywhere. Impressively named, planet “f” orbits the 186th star in the Kepler catalog. Imaginatively nicknamed, Kepler 186-f is about 500 light years from the sun.

To our good fortune, Dr. Quintana made this discovery in her capacity as principal investigator at the SETI Institute, and those of us doing radio SETI with the Allen Telescope Array were favored with early knowledge of the discovery. You see, Quintana et al. hold themselves to the highest standard of scientific ethics and did not announce their discovery until their paper had received full peer-review. That is, unbiased and anonymous experts in the field were confidentially consulted by Science magazine, and those experts agreed that Quintana’s paper was both valid and suitable for publication. While this was the right thing to do, there were several nervous weeks between the time the paper was submitted and when the paper was finally published. During this period, public discussion of Kepler 186-f was “embargoed,” a technical term for “secret.” Only employees at the SETI Institute, who are bound by contract to keep company secrets, knew about the discovery.

This was an exciting time. We pointed the Allen Telescope Array (ATA) in the direction of Kepler 186-f and listened for signs of technology embedded in radio signals between 1-9 GHz. As far as I know, besides Quintana herself only a handful of people knew what we were doing with the telescope as we hunted in the same direction over and over again. This was our big chance, we had a head-start on every other observatory in the world, and 186-f was a very good candidate for finding technology.

In case you haven’t heard, the ATA is a radio interferometer telescope designed especially for the search for extraterrestrial intelligence (SETI) and running SETI algorithms for 12 hours every day. For a ground-based telescope observing frequencies below visible, the optimal range is called the terrestrial microwave window (TMW, 1-10 GHz). The ATA is especially suited for SETI searches since it has an instantaneous coverage from 1-9 GHz, and we’re not afraid to use it! Most previous SETI searches have been constrained to observe only in lower frequencies (1-3 GHz) or in narrow slices of the TMW. The ATA leads the field in recognizing that the entire TMW is fair game for interstellar communications, and we made near-continuous coverage of 90% of the TMW.

We completed 2-3 scans over this range, with a sensitivity of ~100 Jy in 1 Hz (that is, a very good sensitivity). Multiple scans are important at frequencies >4 GHz, because signals sent continuously may still fade in and out over time due to scattering from interstellar gas on the way to Earth. Multiple observations increase the likelihood that our telescope will detect the signal.

Simply put, if about 500 years ago, 186-f were transmitting a tuning-fork like radio beacon, then we would have seen it.  Provided their transmitter were at least 8x as powerful as the most powerful transmitter on Earth, the Arecibo planetary radar. Considering that ET probably has better technology than humans do (since we are a very young technological civilization), this is far from impossible.

Each day, the signal reports came in, but there was no evidence of alien signals. We celebrated on the day that we finished the first complete scan 1-9 GHz of the planet. Even though we didn’t find ET, we knew that we could support Quintana’s discovery by helping to answer the obvious question, “So you’ve discovered an Earth-like planet, do you think it bears life?” By the time Kepler 186-f was published by Science, and the embargo was lifted, we had a very good sample including 2-3 scans over the planet. Whew! That was fun!

It is important to note that our SETI measurements do not prove there is no intelligent life on Kepler 186-f. If 186-f has intelligent life, then they might be sending signals weaker than we can detect, or they might be sending signals in the visible (optical) domain, or perhaps not at all in the direction of Earth. Future research may find signals we missed.

Kepler 186-f is just the first of uncountable planets that could harbor life “as we know it.” Extrapolations of Kepler results suggest that Earth-like planets are abundant. Still, life as we know continues to be evasive. As Fermi put it, “Where are they?”

About gharp

Trained in condensed matter physics at U.W.-Milwaukee; was once Assoc. Prof. of Physics at Ohio University, Athens, OH. Switched to Astrophysics in 2000 and joined SETI Institute in Mountain View, CA . Presently Harp is the director for SETI research and works with the radio telescope. Allen Telescope Array (ATA), to perform SETI and astrophysics observations.

9 Responses to Looking for signs of life on Kepler 186-F

  1. With all due respect:

    Open my article and scroll down to the waterfall image, taken by the ATA, revealed on April 12th to those of us who are part of the SETI Live project. (This is the screen shot of the waterfall with all it’s context, note the date stamp and the Kepler 8120608 identifier. This corresponds to Kepler 186 as the open exoplanet catalog confirms.

    Those of us who look at these waterfalls for SETI live often see data, in real time, as it is coming off the ATA. The site actually tells us when the dishes are rotating to a new target and makes us wait for the data to process into a waterfall. Did you know that people like me actually see your data at the same time as, if not before, you do? It’s understandable if this is news to you as your position is very high up the ladder and my not make contact with facts on the ground so much.

    We get to look at it, but we don’t get to really keep it. It would be nice to be able to obtain a .fits file of the data for our own personal analyses. A screen shot .png or .jpg is all SETI live volunteers like me get to keep. Meanwhile, if I wanted to download a .fits of say the CMB data from Planck, or the Glimpse catalog from Spitzer, I could. So why not a publicly accessible catalog of all the data taken by the ATA? Others may find things you didn’t think of. If not evidence of life perhaps other interesting phenomena. There are numerous benefits to having open access to data. The more eyes that look the better chance someone will see.

    Why not share your data like everyone else? Why do “secret experiments”? A block of data appearing in an online database would not by itself alert the public.

    With the type of data available to me, I could use noise filtering techniques used for image processing which were most appropriate. The waterfall from SETI Live was removed from it’s frame and subjected to five Weiner filters. I even posted the code for carrying out this noise filtering so others could scrutinize it. You see after five Weiner noise filtering’s this is the result.

    Certain line segments stand out on the filtered waterfall. They form sets of parallel dashed lines. Though not in perfect unison like some natural phenomena would be. IF of intelligent origin they would be some sort of radar made to scan space ( like our air forces PAVE PAWS / BMEWS early warning radar) or perhaps a system designed for deep space communication within their own solar system. That is IF they existed 500 years ago and are intelligent.

    Bear in mind a red dwarf lives longer than a sun like star so any life there will have had much longer to evolve. That raises the probabilities considerably. Even on a planet that is likely very cold, and very weird. Especially if we allow for the real chance it is tidally locked to it’s star. A planet with either day or night, never both. Sci-fi has yet to imagine a place so strange and potentially so familiar in other ways.

    There is a scientific logic to my claim. A hypothesis which can be tested as I explained in my article. It’s like making a stool. Finding a Earth-mass habitable zone planet is one leg, a marginal radio signal is just another leg, even a “tuning fork like signal” alone would prove nothing certain to me without the third leg. We need to somehow, someway, get more detailed observations of Kepler-186f. We need to find a way to examine Kepler-186f’s spectrum and look for the chemical markers of life, and possible technology. Only then will we have a stool that can stand, and only then could we claim to have certainly found life let alone technology.

    Even if we have to invent a telescope of a scale and type never dreamed of before. I am ready and willing to let my signals be shown to be as illusory as Percival Lowell’s Martian canals.

    Proposing a hypothesis, and a way to test it is science. Even or especially if that test would be a technical challenge.

    Falling back on institutional clout, personal titles (i.e. Dr. so and so or even Professor Some such person MS), having the money to afford the publication fees journals ask for, having the institutional backing to just work on one thing for months to get it through peer review, is not science.

    Science is not the process of publishing in a journal. Science is the process of inquiry guided by a method that can’t be bought and paid for. Journals are a curated communications channel with boundaries both scientific and monetary. With all respect to the publishers they are businesses. Tell us how much it cost to publish in Science, Nature, etc. The blog where I have covered the news for 7 years cost me nothing and even pays me a very little money. Don’t make the common mistake of thinking that money and those trappings of a career in science, and institutions of science == the only legitimate sources of science.

    An enhanced and extended form of this reply with figures can be found at

    One more friendly question. Which is proper, Kepler-186f, Kepler 186f, Kepler 186-f? I have seen all of those used by various sources? Is there a standard for that?

    • gharp says:

      To Hontas F. Farmer,
      Your message is very appropo. I do not criticize any of your points.
      In my limited knowledge, I can tell you some info that you may not be aware of. I am very sorry to report that the SETI Live project was never brought to full fruition.
      As you may know, the “SonATA” (SETI on ATA) campaign had, as a first priority, a near-real time followup of candidate signals that did not initially appear to be man-made interference right off the bat. The SonATA system keeps an up-t0-date database of man-made interference (that is, signals that are obviously coming from near Earth) and uses this database of man-made signals to reject those signals that are Earth-bourne.
      The SETI Live data that you were exposed to did not reject such obviously man-made signals.

      This was not a mistake. It was our intention to filter SETI Live signals through our ordinary SonATA tests to exclude “radio frequency interference” signals through our database and then identify non-RFI signals and follow them up according to our standard algorithms.

      Unfortunately, our partners at Galaxy Zoo did not succeed in their attempts to send SETI Live results back in time to permit our algorithms to be applied. The SETI live results were sent back too late (time restriction was 90 seconds) for our automated systems to analyze them properly.

      This is a very sad situation, and I apologize on behalf of the entire SETI team. At this time, our collaborators at Galaxy zoo have given up on the project and I regret to say that SETI Live is now an incomplete project with no clear future.

      You (and others) may have discovered interesting signals. But without the necessary followup that we insist upon for discovery of ET signals, we cannot make heads or tails of the signals you have seen. It isn’t anyone’s fault; it was just that the technology enabling SETI Live was not up to the task. SETI Live was an attempt to leapfrog current capabilities and as an experimental program.

      SETI Live had a goal to look in “congested bands” where there is a lot of human-generated artificial signals. The hope was that we could discover ETI signals within these congested bands. It is not at all surprising that you found copious signals with artifical charateristics. This was known at the beginning of the project. But without the artificial intelligence processing built into SonATA, to weed out the man-made signals, it is very difficult to interpret the many signals you may have found in observations of Gliese or other sources. I regret to tell you that the many interesting signals you and others have discovered cannot, at this time, be verified as ETI or not.

      With all best wishes,

      Gerry Harp

      ps. I do not actually know the standardized appelation for Kepler – 186f. But I believe your suggestions are all acceptable. G.

  2. I see I needed to add some HTML paragraph tags to this:/

  3. gharp says:

    Dear Hontas Farmer


    Thanks for your thoughtful response. I welcome the conversation.

    Without much detail, I assure you that I was no silver-spoon baby. I’m the first in my family tree to get a college degree of any kind. Also, I don’t believe science can be done only by people with Ph.D.s. Michael Faraday is a hero of mine. To do useful science you need be only clever and very well informed. In the 21st century, the scientific method is deeply engrained, and to paraphrase Picasso, all children are scientists.

    In my piece, I chose your blog (from many poorer quality and less well reasoned alternatives) because that particular posting didn’t provide much support for the estimate of a 50-50% chance of life on Kepler-186f. I did not mean to imply anything about your Blog wholististically. Sorry if there was a misunderstanding there.

    On reflection, I am sometimes guilty of the same — making statements without backup. Sometimes to tell a story well, you have to keep things simple. In a scientific venue there is greater responsibility to provide logic or citations for what seem to be surprising conclusions. A blog posting is in a gray area. On to other questions.

    Why are not all the SETILive data available? The primary, ultimate, super, number one reason is that we can’t afford to pay someone to put them online (almost trivial) and manage the resulting archive (unimaginably time consuming). Seriously, even a willing volunteer working full time for free still requires a few hours of feedback/oversight per week from a paid employee who understands the system. Our observation budget is that tight. If there were a philanthropist interested in supporting such an archive, then we have all the data (and much more!) on disk from 10 years of observations. We would be happy to develop a modest proposal (~$100K) to create and care for an archive (with yearly maintenance, improvements and customer support budget) say, hosted on Amazon. We’ve tried something like this before on a shoestring budget and the project failed b/c no one here is a real librarian (archivist) and we had no maintence/customer support funding. Someday, we to put all of our data out.


    A selected waterfall plot as it comes out of our SETI detector. Most waterfalls look like white noise with no particular features. This one is more interesting with two signals, nearly sine wave (tuning fork) signals. Unfortunately, those signal were generated by Earth technology.

    I apologize in advance that with my current workload I won’t be able to maintain prolonged technical discussions about things like SETILive or our hoped-for archival results. Given a choice between an educational role and a role of actually using the telescope in a constant search for new signals, I am forced to make a choice about how I spend my time. If I can’t always respond in detail, please don’t hate me. Besides, I’m better at science than at blogging and by Ricardo’s principle, I should be spending all of my time on science.

    But this once, please accept my observations of your SETILive image analysis. To begin, you have observed a real anomaly in the provided data. Your instincts and follow-up noise-suppression processing are commendable. Unfortunately, the artifact you identify is generated by our waterfall imaging algorithms. I believe most SETILive waterfalls will show vertical streaks similar to those you have discovered. This is our fault.

    Waterfall above

    Noise speckles are observed here as in all waterfalls.
    The waterfalls are intentionally oversampled, especially in the vertical direction. Thus a single
    spot in the waterfall always extends across 3 adjacent horizontal rasters. No matter how short the spot really is.
    As a result, even the original waterfall is prone to exhibit vertical dashes in place of simple, round spots.

    Coming straight out of the SETI detector (SonATA, short for SETI on ATA)
    the images dimensions are 769 x 259 pixels (aspect ratio = 3:1).
    For reasons of convenience, the folks at “***Zoo” who designed the website insisted on
    resizing the images to 1412 x 708 (aspect ratio = 2:1, magnification 2x)
    Hence, each vertical raster in the SETILive waterfall has been stretched by a factor of 1.5 in the vertical direction.
    Even the shortest blip in time is now stretched from 3 to ~5 pixels in the vertical direction.
    By sheer statistical chance, it occasionally happens that 3 or more pixels line up by accident in original image. This could lead to a vertical streak >8 pixels in length before magnification. Since SETILive images are magnified 2x, the resultant streak is 16 pixels in length.
    Choosing one of the longer streaks in your SETILive waterfall capture, we find it is just 16 pixels in vertical length.
    This was done honestly! I didn’t look at the length until after computing my estimate. Hypothesis -> Test and real science (^_^).

    Selected stripe from SETILive image as it appeared in Farmer’s post.

    I hope this clarifies some things. Good luck to everyone, lets hope we _do_ find evidence of technology around Kepler 186.

  4. “…Considering that ET probably has better technology than humans do (since we are a very young technological civilization), this is far from impossible.”

    BZZZT! Bad science alert.

    Everyone is allowed to make assumptions but you’re trying to argue with other points of view on the basis of your assumptions. We know of precisely 1 technological civilization in the universe so far: our own. There is absolutely NO scientific basis for any statements about probabilities with respect to ET civilizations.

    We don’t even know if another civilization would have to discover and use radio waves. Until we can grow our database of empirical examples for evolved, intelligent life in the universe (on a per-planet basis), all speculations are just that: speculations.

    Nobody knows better than anyone else in these matters. Not yet.

    • gharp says:

      Thanks. Yes, with only one civilization at hand, we cannot make provable (or statistically-based) assumptions about the next-door civilization.

      Yet, if the civilization next door is more than 100 years behind us (on human timeline) then we know that they will not have the technology to communicate in a way that we can detect them with our pitiful telescopes on Earth. Only a civilization more advanced than us, in terms of technology, will be able to produce a strong enough (or focused enough) beacon that can be detected by Earth receivers. Indeed, even the Earth’s most powerful transmitters would not be detectable by Earth’s most powerful telescopes at 100 LY.

      In other words, it is not unreasonable to say that the transmitting civilization must be more advanced than our own, if we are to detect them at 100 LY radius. This is simply the limits of Earth technology.

      It is NOT the limits of what is physically possible. With the square kilometer array (SKA), which has better technology, we may find SETI transmitters that are no more powerful than our own. But at the present time, we are limited by the abilities of our current technology.

      Thank you for the comment and the criticism. All we can do now is the best we can do. If I’m missing something, then I certainly will welcome corrections. I do not claim to know everything, and my blog is a reflection of imperfect knowledge.



  5. […] generalizations, it’s best to make them about matters outside your own field of study. In another blog post Dr. Harp writes the following: Simply put, if about 500 years ago, 186-f were transmitting a tuning-fork […]

    • gharp says:


      Unfortunately, I cannot find a way of replying to to this anonymous poster directly. Too bad the poster did not provide info; it might have been an interesting conversation.

      I am slightly affronted (how dare you!, ha ha!) by the characterization of my post as “bad science.” But then again, I’m open to criticism.

      While I hesitate to re-enter the “God” discussion, I have been told repeatedly by many people that God set up the universe s.t. there is no way to prove/disprove God’s existence. It requires faith to believe in God, or at least a religious experience. I cannot personally imagine a scientific test for God’s existence, which may show a lack of imagination on my part. I’d be eager to learn of any suggestions for how to prove/disprove God! Until I hear of such an experiment, I will stick to my guns and say that the existence of God is not a question that can be answered through the scientific method. And for the record, my posts are not intended to be vitriolic, and such characterization is a remarkable misreading.

      Giving the author due credit, she is quite right in many respects. Yes, my blog speaks of technology as known to humans. For example, I’m often told that we should be looking for signals carried by neutrinos. Unfortunately, human technology can barely detect even a small handful of neutrinos emanating from humongous astronomical events. And to the extent possible, people are combing these data for evidence of ETI. And for the most part, humans know enough about electromagnetic radiation to conclude that ETI signals can be communicated between stars using radio waves or light.

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