Sciency Words: Flying Saucer

Hello, friends!  Welcome back to Sciency Words, a special series here on Planet Pailly where we talk about science or science-related terms.  Today’s Sciency Word is:


Okay, first question: does this really count as a scientific term?  Probably not, but the origin of the term “flying saucer” is pretty interesting nonetheless.  I’m going to go ahead and say this one’s sciency enough for Sciency Words!

So, on June 25, 1947, an article appeared in The East Oregonian reporting on the sighting of “nine saucer-like aircraft flying in formation.”  American businessman and aviator Kenneth Arnold had been flying his airplane near Mount Rainier, in Washington State, when he saw something he could not explain: nine flashes of light, like sunlight glinting off metal.

By all accounts, Arnold was legitimately confused by these strange lights.  But he did not jump to any conclusions.  He did not immediately assume he was looking at a squadron of extraterrestrial spaceships.  In other words, Kenneth Arnold was not this guy:

Instead, Arnold tried to observe and record as much information as he could, in an objective and unbiased manner, paying attention to any details that might help solve the mystery.  Based on what it says in this article (an interview with the newspaper reporter who initially interviewed Arnold), it sounds like Arnold went to the press in the hope that someone out there might read the story and come forward with a plausible explanation for what those weird light really were.

But some details of Arnold’s story were not reported accurately.  Most notably, Arnold never said the flying objects he saw looked saucer-like.  In this article from The Atlantic, Arnold is quoted trying to clear up the confusion:

These objects more or less fluttered like they were, oh, I’d say, boats on very rough water or very rough air of some type, and when I described how they flew, I said that they flew like they take a saucer and throw it across the water.  Most of the newspapers misunderstood and misquoted that too.  They said that I said that they were saucer-like; I said that they flew in a saucer-like fashion.

According to that same article from The Atlantic, this may have been “one of the most significant reporter misquotes in history.”

It’s not entirely clear when “saucer-like aircraft” got simplified into “flying saucer,” but it seems to have happened in a matter of weeks, if not days.  The original news article was published on June 25, 1947; according to the Oxford English Dictionary, the earliest known usage of “flying saucer” is from July 8th of the same year, and the quotation cited by the O.E.D. makes it sound like this “nickname” was already in widespread usage.

And thus, flying saucers became part of the popular lexicon, not because Kenneth Arnold said that’s what he saw but because Arnold was misquoted by a newspaper reporter.

A Breath of Fresh Hydrogen

Hello, friends!

So let’s imagine that extraterrestrials don’t breathe oxygen.  Oxygen is a pretty dangerous chemical, after all, so there’s good reason why alien organisms might want to avoid it.  But what would these aliens breathe instead?

A few years back, I came across an interesting “fact” on a conspiracy theory website.  The government doesn’t want you to know this, but apparently a lot of alien species breathe hydrogen.  That conspiracy theory website said a lot of weird and wacky things, but this hydrogen-breathing alien idea… based on what I know about chemistry, that idea kind of made sense to me.

You see we Earthlings use oxygen to oxidize our food.  This oxidation reaction generates the energy we need to stay alive.  But oxidation reactions are sort of equal-and-opposite to reduction reactions.  Oxygen is a powerful oxidizing agent, obviously, but hydrogen?  Hydrogen is a pretty effective reducing agent.

A paper published earlier this year examined the possibility of Earth-like planets with hydrogen-rich atmospheres.  Such planets could, in theory, exist, but they’d have to meet one or more of the following criteria:

  • The planet would have to be much colder than Earth (think Titan or Pluto-like temperatures).
  • The planet would have to have much higher surface gravity than Earth.
  • The planet would have to continuously outgas hydrogen from some underground source (subsurface reservoirs of water ice mixed with methane ice might do the trick).

If one or more of these conditions are not met, then a hydrogen-rich atmosphere would quickly fizzle out into space through a process called Jeans escape.

Now, could life exist in that sort of hydrogen-rich environment?  The answer is yes.  Absolutely yes.  Even here on Earth, there are organisms that “breathe” hydrogen and use it to generate energy through reduction reactions.  These organisms can be found deep underground, or clustered around deep-sea hydrothermal vents, or in other exotic niche environments where hydrogen is plentiful and oxygen is rare.

The real question is: could hydrogen-breathers evolve into complex, multicellular life forms?  Earth’s hydrogen-breathers are mere microorganisms.  Their version of respiration is nowhere near as efficient as the oxygen-based system we humans and our animal friends use.  The inefficiency of hydrogen-based respiration has stunted the evolutionary development of Earthly hydrogen-breathers.

But maybe on another planet—a planet with a hydrogen-rich atmosphere unlike anything Earth has ever seen—maybe complex multicellular life could evolve on a planet like that.  Maybe.

It’s plausible enough for science fiction, at least.

Galactic Census Report: How Many Civilizations Are in Our Galaxy?

Hello, friends!  Have you heard the news?  Scientists have determined that there should be at least thirty-six alien civilizations in our galaxy right now.

Here’s the actual research paper from The Astrophysical Journal (warning: paywall).  As you might imagine, this research is based on some key assumptions.  And the authors do make it clear that they are making assumptions.  Reasonable assumptions, they argue, but still… ASSUMPTIONS!!!

The first major assumption is this: any Earth-like planet with an Earth-like chemical composition that happens to have an Earth-like orbit (i.e.: habitable zone) and has been around for an Earth-like period of time (approximately 4.5 billion years) has a reasonably good chance of developing Earth-like intelligent life.

The second major assumption is this: once a civilization advances to the point that it can start broadcasting its presence to the rest of the universe, that civilization will also have advanced to the point of being able to destroy itself.  Earth-like intelligent life has a tendency, the authors argue, for self-destruction.  Maybe it’ll be nuclear weapons, or maybe a climate catastrophe of some kind.  Or, I don’t know, maybe an increasingly globalized society will make itself more vulnerable to some sort of global pandemic.

Obviously the authors make other assumptions as well, but those two are the big ones.  When plugging numbers into a modified version of the Drake Equation, the most pessimistic assumptions yield an estimate of 36 civilizations in our galaxy (with a margin of error that could push that number all the way down to 4).  The most optimistic assumptions yield an estimate of 928 civilizations (with a margin of error that could push the number all the way up to 2908).

As I’ve said before, scientific papers should never be taken as proclamations of absolute fact.  That’s especially true for papers like this one.  Scientific papers are part of an ongoing back-and-forth conversation in the scientific community.  What do we currently know?  How much do we still have to learn, and what should our expectations realistically be?  That’s what this paper from The Astrophysical Journal is really about: setting expectations for SETI research.

So what should our expectations be, based on those two key assumptions the authors made?  Well, even under the most optimistic scenarios, our nearest neighbors are predicted to be hundreds (if not thousands) of lightyears away—far enough away that they’d be very, very, very difficult to find using our current technology, and establishing two way communications would be virtually impossible.

So maybe we’re not alone in the universe, but we may as well be.

Sciency Words: CETI vs. SETI

Hello, friends!  Welcome back to Sciency Words, a special series here on Planet Pailly where we take a closer look at the definitions and etymologies of scientific terms.  Today on Sciency Words, we’re talking about:


On October 10, 1966, scientists from the International Academy of Astronautics met in Madrid, Spain, to discuss CETI: Communications with ExtraTerrestrial Intelligence.  This was surely not the first time the term CETI was ever used, but based on my research, that 1966 meeting seems to be the earliest official usage of the term by the scientific community.

CETI refers to the act of sending signals or messages out into space for the express purpose of making contact with intelligent alien life.  It’s the human race shouting into the void, asking if anybody’s out there.  The most famous example of this is the Arecibo message, which was broadcast from the Arecibo radio telescope in Puerto Rico in 1974.

The idea of deliberately trying to attract the attention of extraterrestrials has always been controversial.  What if an alien intelligence does hear us?  What if that alien intelligence is not friendly?  But for the purposes of a Sciency Words post, I’m going to skip over that controversy and focus on the controversy about the word CETI itself.

CETI is far too easily confused with SETI (the Search for ExtraTerrestrial Intelligence).  CETI and SETI are closely related fields, but there’s one very important distinction between them.  It’s the difference between talking and listening.  CETI is about trying to talk to the rest of the civilized universe (assuming other civilizations exist, of course).  SETI is about listening patiently to see if anyone out there is trying to talk to us.

According to Google ngrams, the term CETI peaked in the late 1970’s/early 1980’s.  Since then, the term METI (Messaging ExtraTerrestrial Intelligence) has far surpassed CETI.  And in 2018, a special committee on SETI nomenclature recommended that CETI be dropped from scientific discourse in favor of METI.

And yet CETI still appears, from time to time, in scientific research.  For example, this paper from June of 2020 uses the term CETI extensively.  But we’ll talk about that paper more on Monday.  It makes some rather bold predictions about how many CETI-capable civilizations should exist in our galaxy at this very moment.

P.S.: The authors of that 2020 paper offer another solution to the CETI vs. SETI problem.  They suggest CETI should be pronounced as “chetee.”  I’m not sure how I feel about that.

P.P.S.: Actually, I am sure how I feel about that.  I’d rather use the term METI instead.

Orbiting the Blogosphere: Aliens, NASA Missions, and Flat Earthers

Hello, friends!

Today, I thought we’d take a quick look around the blogosphere and see what other space/science enthusiasts have been writing about.

First up, why is science fiction so obsessed with alien life?  Steven Lyle Jordan explores that question in an article for Medium.  Click here to check out that article, or click here to visit Steven’s blog.

Next, NASA has announced the finalists for the next Discovery-class mission, and one of those finalists involves a return to Neptune (frickin’ finally, am I right?).  Specifically, this would be a mission to explore Triton, Neptune’s largest moon.  Jay Cole from Digestible Space can tell you more.  Click here!

Meanwhile, NASA’s InSight mission has been gathering a surprising amount of data about earthquakes on Mars (a.k.a. marsquakes).  Maybe Mars isn’t as geologically dead as we thought?  Blaine Henry from Gimme Space can tell you more.  Click here for that!

And lastly, but not leastly, Fran from My Hubble Abode pays tribute to a prominent Flat Earther who recently passed away.  Fran has done many great posts debunking Flat Earth nonsense and other conspiracy theories.  But still, everyone deserves some compassion and respect.  Fran has set a wonderful example of how to disagree with someone without being disrespectful.  Click here.

That’s all for now.  If you read and enjoyed any of these posts, please be sure to let the author know with a comment.  It’s important that we all keep sharing and spreading our love for space and for science!

Next time on Planet Pailly: this might sound like an odd question, but which way is time going?

Where Are the Earthlings?

Have you ever looked up at the night sky and wondered if maybe, somewhere out there, someone might be looking back at you?  Well, I’m here to tell you the answer to that question is yes.  Or at least there are aliens out there who are trying very hard to find us.  I even have video evidence to prove it!

For us Earthlings, it’s pretty obvious that there’s life on this planet.  How could you possibly miss it?  But for aliens observing Earth from a distance—perhaps a very great distance—the most obvious biosignatures are frustratingly difficult to detect.

In the early 1990’s, Carl Sagan wrote a famous paper about this problem.  One of NASA’s own space probes, which was heading out to Jupiter, briefly turned all its instruments back on Earth.  Based on that data alone, without any prior knowledge about this planet, you could probably figure out there’s life on Earth. Probably.

This more recent paper published in The Astrophysical Journal follows up on Sagan’s work.  Assuming the aliens are smart (a big assumption, based on what the video evidence shows us), they should be looking for a planet with both an oxidizing gas AND a reducing gas in its atmosphere.

Oxidizing and reducing agents should react with each other relatively quickly, removing each other from the planet’s atmosphere.  So in order to have those two things coexisting long term, some exotic process (like biological activity) must be constantly replenishing them.

A spectroscopic analysis of Earth’s atmosphere would reveal a whole lot of the chemicals in our air, but not all of them. Apparently some spectral signatures are so strong they cover up others, which I think is an important thing to know.  But oxygen (an oxidizing gas) should still be detectable in the visible light part of the spectrum, and methane (a reducing gas) should show up in visible and infrared.

But still, it sounds like difficult work, teasing the signatures of oxygen and methane out of all the other spectral signatures you’d get from Earth’s atmosphere.  This could be why the aliens are having such a hard time finding us, and also why we are having such a hard time finding them.