ET, call Lexington

If you needed more evidence that we're living in surreal times, some scientists have collaborated with the Tourism Board of Lexington, Kentucky to send a message to aliens inviting them to come to the city for a visit.

The message was sent via infrared laser toward TRAPPIST-1, a multi-planet system about forty light years from Earth.  Astonishingly, they actually got permission from the Federal Aviation Administration -- not a government office known either for its flexibility or its sense of humor -- to beam the message out.  The message, in coded bitmap form, contained information regarding the intent of the transmission, some photographs of the Lexington area, and an audio recording of blues musician Tee Dee Young.

"The bitmap image is the key to it all," said Andrew Byrd, a linguistics expert at the University of Kentucky, who was one of the scholars involved in the project.  "We included imagery representing the elements of life, our iconic Lexington rolling hills, and the molecular structure for water, bourbon, and even dopamine because Lexington is fun."

It also contained the message, "Come to Lexington!  We have horses and bourbon.  Just don't eat us."

I feel obliged to interject here that I'm not making any of this up.

The Lexington Tourism Board's promo art for the project, which I also did not make up

Regular readers of Skeptophilia know that the possibility of alien life -- perhaps intelligent life -- is a near-obsession with me, but I'm not sure this is really the way to go about trying to contact it.  While TRAPPIST-1 isn't a bad choice given the fact that it's fairly close and we know it has seven planets, there's no indication any of them host life.  Four of the planets appear to orbit within the star's "Goldilocks Zone," where the temperatures are "just right" for water to exist in liquid form, but that doesn't mean the planets have liquid water, or even atmospheres.  The fact that the planets have such tight orbits -- the farthest one only has an orbital radius six percent of Earth's, and orbits its star in nineteen days -- suggests they're probably tidally locked, meaning the same side of the planet always faces the star.  (I wrote about the difficulty of life evolving on a tidally-locked planet a year ago, if you're curious to read more about it.)

Then there's the problem of waving hello at aliens who might be vastly more powerful than we are and would respond by squashing us.  Stephen Hawking addressed this in stark terms back in 2010, saying, "We don't know much about aliens, but we know about humans.  If you look at history, contact between humans and less intelligent organisms have often been disastrous from their point of view, and encounters between civilizations with advanced versus primitive technologies have gone badly for the less advanced.  A civilization reading one of our messages could be billions of years ahead of us.  If so, they will be vastly more powerful, and may not see us as any more valuable than we see bacteria."

Of course, if there are intelligent aliens out there, they probably already know about us.  At least the ones under 104 light years away do, because there's an expanding bubble of radio and television transmissions sweeping outward from us at the speed of light that began with the first commercial radio broadcast in 1920.  Assuming any aliens on the receiving end are at least as smart and technologically capable as we are, they're probably already decoding those transmissions and listening to Fibber McGee and Molly and watching Lost in Space, after which they will definitely think we're no more valuable than bacteria.

The last issue -- and this may be the good news, here, if you buy what Hawking said -- is that because TRAPPIST-1 is forty light years away, any aliens who might live there won't receive the message until 2064, and the earliest we could get a response is 2104.  Even if they have some kind of superluminal means of travel and jumped into their spaceships as soon as they got the message, it wouldn't be until the 2060s that they could even potentially get here.  

At least the Lexington Tourism Board has a good window of time to get their hotels ready for the influx of alien tourists.  And if they turn out to be hostile, at that point (if I'm still alive) I'll be over a hundred years old, and I figure that an alien laser pistol blast to the face is about as dramatic a way to check out as I could ask for, so I suspect I'll be fine with the Earth being invaded regardless which way it goes.

So the Lexington Tourism Board's efforts fall squarely into the "No Harm If It Amuses You" department.  And I guess the more time people spend focusing on this sort of thing, the less they'll spend dreaming up new and different ways to be awful to each other.  So as far as that goes, I'm all for sending messages to the stars.

Even if the best things you can think of to talk about are horses, bourbon, and dopamine.

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Room for exploration

As a followup to yesterday's post, about my generally dubious take on the claim of a Mexican scientist that he'd discovered fossilized alien bodies, today we're going to look at why we haven't run across aliens yet.  As big as the universe is, it seems like we should have heard from someone by now.  What are we, a bad neighborhood, or something?  Do the aliens go zooming by the Earth, making sure their windows are rolled up and their doors are locked?

I mean, Elon Musk alone would be justification for their doing so, but it's still kind of disappointing.

I've discussed the Fermi Paradox here at Skeptophilia before -- and the cheerful idea of the Great Filter as the reason why we haven't heard from alien life.  As I explained in a post a while back, the explanation boils down to three possibilities, nicknamed the "Three Fs."

We're first, we're fortunate, or we're fucked.

Being an aficionado of all things extraterrestrial, that has never sat well with me.  The idea that we might be all alone in the universe -- for any of the three Fs -- is just not a happy answer.  

Yes, I know, I always say that the universe is under no obligation to act in such a way as to make me happy.  But still.  C'mon... Vulcans?  Time Lords?  Ewoks?  G'gugvuntts and Vl'hurgs?  There's got to be something cool out there.  With luck, lots of cool things.  The Dentrassi, the Ood, Quantum Weather Butterflies, the Skithra, Andorians, the Vashta Nerada...

Okay, maybe not the Vashta Nerada.  But my point stands.

The Andromeda Galaxy [Image licensed under the Creative Commons Adam Evans, Andromeda Galaxy (with h-alpha), CC BY 2.0]

So I was considerably cheered yesterday when I ran into a study out of Pennsylvania State University that attempted to estimate what fraction of the universe we actually have surveyed in any kind of thorough fashion.  The authors, Jason Wright, Shubham Kanodia, and Emily G. Lubar, write:

Many articulations of the Fermi Paradox have as a premise, implicitly or explicitly, that humanity has searched for signs of extraterrestrial radio transmissions and concluded that there are few or no obvious ones to be found.  Tarter et al. (2010) and others have argued strongly to the contrary: bright and obvious radio beacons might be quite common in the sky, but we would not know it yet because our search completeness to date is so low, akin to having searched a drinking glass's worth of seawater for evidence of fish in all of Earth's oceans.  Here, we develop the metaphor of the multidimensional "Cosmic Haystack" through which SETI hunts for alien "needles" into a quantitative, eight-dimensional model and perform an analytic integral to compute the fraction of this haystack that several large radio SETI programs have collectively examined.  Although this model haystack has many qualitative differences from the Tarter et al. (2010) haystack, we conclude that the fraction of it searched to date is also very small: similar to the ratio of the volume of a large hot tub or small swimming pool to that of the Earth's oceans.  With this article we provide a Python script to calculate haystack volumes for future searches and for similar haystacks with different boundaries.  We hope this formalism will aid in the development of a common parameter space for the computation of upper limits and completeness fractions of search programs for radio and other technosignatures.

The actual analogy Wright and his colleagues used is that saying our current surveys show there's no intelligent life in the universe (except for here, which itself seems debatable some days) is comparable to surveying 7,700 liters of seawater out of the total 1.335 billion trillion liters in the world's oceans.

So basing a firm conclusion on this amount of data is kind of ridiculous.  There could be intelligent alien species out there yelling, "Hey! Earthlings!  Over here!  We're over here!", and all we would have to do is have our radio telescopes pointed a couple of degrees off, or tuned to a different wavelength, and we'd never know it.

Which is pretty cool.  Given the fact that my all-time favorite movie is Contact, I'm hoping like hell that people don't read Wright et al.'s paper and conclude we should give up SETI because it's hopeless to make a thorough survey.  When I think about what poor Ellie Arroway went through trying to convince her fellow scientists that her research was valid and deserved funding... yecch.  And if anything, the current attitudes of the government toward pure research are, if anything, worse than those depicted in the movie.

But despite all that, it's awe-inspiring to know we've got so much room to explore.  Basically... the entire universe.  So my dream when I was a kid, sitting out in my parents' yard with my little telescope, that as I looked at the stars there was some little alien boy in his parents' yard looking back at me through his telescope, may one day prove to be within hailing distance of reality.

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Patterns out of noise

We all have intuition and common sense about how the world works, and it is fascinating how often that intuition is wrong.

Not that I like having my worldview called into question, mind you; but I have to admit there's a certain thrill in discovering that there are subtleties I had never considered.  Take, for example, Benford's Law, that I first heard about a while back while listening to the radio program Freakonomics.  In any reasonably unrestricted data set, what should be the relative frequencies of the first digit?  Put another way, if I was to take a set of numbers (like the populations of all of the incorporated villages, towns, and cities in the United States) and look only at the first digits, how many of them would be 1s, 2s, 3s, and so on?

On first glance, I saw no reason that the distribution shouldn't be anything but equal.  That's what a set of random numbers means, right?  And how are the populations of municipalities ranging from ten people all the way up to several million anything other than a collection of random numbers?

Well, you've probably already guessed this isn't right.  Lining up the frequencies of 1s through 9s in order, you get a perfect inverse relationship.  About 30% of the first digits are 1s, all the way down to only 5% being 9s.

Why is this?  Well, the simple answer is that the statisticians are still arguing about it.  But it does give a way to catch when a supposedly real data set has been altered or fudged; the real data set will conform to Benford's Law, and (very likely) the altered one won't.

Another interesting one, and in fact the reason why I was thinking about this topic, is Zipf's Law, named after American linguist George Kingsley Zipf, who first attempted a mathematical explanation of why it works.  Zipf's Law looks at the frequencies of different words in long passages of text, and finds that there's an inverse relationship, similar to what we saw with Benford's Law.  In English, the most commonly used word is "the."  The next most common ("of") has half that frequency.  The third ("and") has one-third the frequency.  And on down the line; the tenth most frequent word occurs at one-tenth the frequency of the most common one, and so forth.

Zipf's Law has been tested in dozens of different languages, including conlangs like Esperanto, and it always holds.  So does the related pattern called the Brevity Law (there's an inverse relationship between the length of a word and how commonly it's used), and -- to me the most fascinating -- the Law of Hapax Legomenon, which states that in long passages of text, about half of the words will only occur once (the name comes from the Greek ἅπαξ λεγόμενον, meaning "being said once").

Where things get really interesting is that these three laws -- Zipf's Law, the Brevity Law, and the Law of Hapax Legomenon -- may have relevance to the search for extraterrestrial intelligence.  Say we pick up what seems like radio-wave-encoded language from another star system.  The difficulty is obvious; translating a passage from another language when we don't know the sound-to-meaning correspondence is mind-bogglingly difficult (although it has been accomplished, most famously Alice Kober's and Michael Ventris's decipherment of the Linear B script of Crete).  

The task seems even more hopeless for an alien language, that shares no genetic roots with any human language, and thus the most useful tool we have -- noting similarities with known related languages -- is a non-starter.  Just like Dr. Ellie Arroway in Contact, we'd be faced first with the seemingly insurmountable problem of figuring out if it is an actual alien language, and not just noise or gibberish.

The three laws I mentioned may solve at least that much of the problem.  The fact that they've been shown to govern the frequency distribution of every language tested, including completely unrelated ones like Japanese and Swahili, suggests that they might represent a universal tendency.  Just as Benford's Law can help statisticians identify falsified data sets, the three laws of word frequency distribution might help us tell if what we've picked up is truly language.

It still leaves the linguists with the daunting task of figuring out what it all means, but at least they won't be working fruitlessly on something that turns out to be mere noise.

I find the whole thing fascinating, not only from the alien angle (which you'd probably predict I'd love) but because it once again demonstrates that our intuition about things can lead us astray.  Who would have guessed, for example, that half of the words in a long passage of text would occur only once?  I love the way science, and scientific analysis, can correct our fallible "common sense" about how things work.

And, as with Zipf, Brevity, and Hapax Legomenon, open up doors to understanding things we never dreamed of.

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Ever get frustrated by scientists making statements like "It's not possible to emulate a human mind inside a computer" or "faster-than-light travel is fundamentally impossible" or "time travel into the past will never be achieved?"

Take a look at physicist Chiara Marletto's The Science of Can and Can't: A Physicist's Journey Through the Land of Counterfactuals.  In this ambitious, far-reaching new book, Marletto looks at the phrase "this isn't possible" as a challenge -- and perhaps, a way of opening up new realms of scientific endeavor.

Each chapter looks at a different open problem in physics, and considers what we currently know about it -- and, more importantly, what we don't know.  With each one, she looks into the future, speculating about how each might be resolved, and what those resolutions would imply for human knowledge.

It's a challenging, fascinating, often mind-boggling book, well worth a read for anyone interested in the edges of scientific knowledge.  Find out why eminent physicist Lee Smolin calls it "Hugely ambitious... essential reading for anyone concerned with the future of physics."

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

 

Requiem for an old friend

My fascination for astronomy started a long time ago.  I started learning the constellations when I was about six, and received a telescope as a Christmas present from my grandmother when I was eight.  Just about any clear night it was a good bet I'd be out in my front yard looking up at the stars, wondering what it was like out there, thinking about what other planets might host life -- and if somewhere there was a little alien boy looking back my way and wondering the same thing.

It was about that time that I found out about the Arecibo Observatory in Puerto Rico.  One of the many astronomy books I had called the three-hundred-meter radio dish "our eye on the sky" -- it was my first introduction both to the idea that not all telescopes looked like the little tube with lenses on a stand that I owned, and that it was possible to "see" the sky using wavelengths of light that were invisible to human eyes.  Also, if you were to view the sky with a radio telescope (or in microwaves, or x-rays, or ultraviolet light, or whatever) you would see a very different set of features than the familiar twinkling points of light set against a black background.

In the microwave region, for example, you'd see light coming from basically all directions at once -- the "three degree microwave background radiation" which Arno Penzias and Robert Wilson discovered -- and which is one of our most persuasive pieces of evidence of the Big Bang.  (This discovery was made not at Arecibo but at the Holmdel Horn Antenna in New Jersey.)  X-ray astronomy is how black holes were discovered, and we know about the terrifyingly powerful Wolf-Rayet stars because of telescopes sensitive to the ultraviolet region of the spectrum.

Arecibo, though, was particularly evocative, not only for its function but because of its site, in a limestone sinkhole in the jungles of northern Puerto Rico.  Add to this its role in searching for signs of extraterrestrial life, and you have a combination sure to capture the imagination.  Because of this it made a number of appearances in science fiction, such as the 1994 episode of The X Files called "Little Green Men," and most notably, the amazing 1997 movie Contact, which remains my number-one favorite movie ever, not only for the story but because of a tour de force performance by Jodie Foster as the indomitable astronomer Ellie Arroway.

[Image is licensed under the Creative Commons Mariordo (Mario Roberto Durán Ortiz), Arecibo radio telescope SJU 06 2019 6144, CC BY-SA 4.0]

So it was with considerable sadness that I found out a couple of weeks ago that Arecibo was being permanently dismantled.  Earlier this year, a pair of cable breaks ripped gashes in the dish, and it seemed like the venerable telescope was unrepairable.  As if to confirm that, just two days ago the nine-hundred-ton equipment platform collapsed, falling almost two hundred meters and destroying the entire center of the telescope.

"When we looked outside the control room, we started to see the eventual downfall of the observatory," observatory director Ángel Vázquez said.  "After the breakage of two cables earlier this year, strands of the remaining three cables had been unraveling in recent days, increasing the strain.  And because two of the support towers maintained tension as the collapse occurred, some of the falling equipment was yanked across the side of the dish rather than falling straight down through its focal point...  This whole process took thirty seconds, and an icon in radio astronomy was done."

Vázquez isn't the only one to feel its loss deeply.  "While life will continue, something powerful and profoundly wonderful is gone," said astronomer Seth Shostak, whose work with SETI (the Search for Extraterrestrial Intelligence) was a good part of the inspiration for Contact.

I understand the sentiment.  The whole thing makes me feel something like grief.  Arecibo has been an inspiration to me since I was a child, and its destruction is like losing an old friend.  I know there are other, and more powerful, telescopes out there, but this one seemed to me to be a symbol of our search for something beyond ourselves, for unraveling the secrets of the universe while still right here, looking up into the skies from our home planet.

So farewell to Arecibo.  There will always be something unique and marvelous about the image of that huge telescopic eye in the Puerto Rican jungle.  As Seth Shostak pointed out, its loss won't stop our yearning for knowledge, but it's hard to imagine finding something as grand and iconic to take its place in our imaginations.

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One of the most compellingly weird objects in the universe is the black hole -- a stellar remnant so dense that it warps space into a closed surface.  Once the edge of that sphere -- the event horizon -- is passed, there's no getting out.  Even light can't escape, which is where they get their name.

Black holes have been a staple of science fiction for years, not only for their potential to destroy whatever comes near them, but because their effects on space-time result in a relativistic slowdown of time (depicted brilliantly in the movie Interstellar).  In this week's Skeptophilia book-of-the-week, The Black Hole Survival Guide, astrophysicist Janna Levin describes for us what it would be like to have a close encounter with one of these things -- using the latest knowledge from science to explain in layperson's terms the experience of an unfortunate astronaut who strayed too close.

It's a fascinating, and often mind-blowing, topic, handled deftly by Levin, where the science itself is so strange that it seems as if it must be fiction.  But no, these things are real, and common; there's a huge one at the center of our own galaxy, and an unknown number of them elsewhere in the Milky Way.  Levin's book will give you a good picture of one of the scariest naturally-occurring objects -- all from the safety of your own home.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]