Sciency Words A to Z: Wow! Signal

Welcome to a special A to Z Challenge edition of Sciency Words!  Sciency Words is an ongoing series here on Planet Pailly about the definitions and etymologies of science or science-related terms.  In today’s post, W is for:


There’s a ton of radio noise in space, coming from stars and nebulae and black holes and so forth.  There’s so much radio noise that it can easily drown out the relatively weak radio and television broadcasts that might be coming from a planet like Earth.

So if aliens want to talk to us, they’re going to have to send a much stronger transmission, something that will come through loud and clear over all that other space noise.  And in 1977, astronomers at Ohio State University picked up exactly that kind of signal.

As the story goes, Ohio State was conducting a SETI search with their “Big Ear” radio telescope.  The telescope recorded electromagnetic emissions coming from space, reporting the strength of those emissions on a scale from 0 to 9. If Big Ear happened to pick up anything stronger than a 9, it represented that with a letter—A represented a 10, B represented 11, and so forth.

On the morning of August 18, 1977, astronomer Jerry Ehman was reviewing Big Ear’s latest data when he saw a bunch of large numbers, and even a few letters.  Famously, Ehman circled those letters and numbers and wrote one word next to them: Wow!

Image courtesy of Wikipedia

Appropriately, this is now known as “the Wow! Signal” (the exclamation point is usually included in the name).

In one sense, the Wow! Signal is exactly what SETI scientists were hoping to find.  Even the radio frequency—approximately 1420 megahertz—was consistent with expectations.  In this 1959 paper, physicists Giuseppi Cocconi and Philip Morrison singled out 1420 MHz as the frequency extraterrestrials were most likely to use.

But in another sense, the Wow! Signal was not what we wanted it to be, because it only happened one time, and it has never repeated since. Despite many follow-up searches of the constellation Sagittarius (like this one or this one), where the Wow! Signal originated from, we’ve never picked up a signal like it again.

As I’ve said several times this month, in our search for alien life, we have to hold ourselves to the same standards as a court of law: proof beyond a reasonable doubt.  The Wow! Signal very well might have been aliens… it might have been anything… and that’s the problem.  Unless and until we pick up the Wow! Signal again, we can’t prove one way of another what it was.

Next time on Sciency Words A to Z, you can’t have life without water.  Or can you?

Sciency Words A to Z: SETI

Welcome to a special A to Z Challenge edition of Sciency Words!  Sciency Words is an ongoing series here on Planet Pailly about the definitions and etymologies of science or science-related terms.  In today’s post, S is for:


In September of 1959, Italian physicist Giuseppi Cocconi and American physicist Philip Morrison published this paper, titled “Searching for Interstellar Communications.”  That paper is essentially the founding document for SETI, the search for extraterrestrial intelligence, which is now considered a subfield of astrobiology.

The SETI Institute, on the other hand, was established in 1984 by Thomas Pierson and Jill Tarter.  As stated in this report on the proper use of SETI nomenclature:

SETI should not be used as a shorthand for the SETI Institute, which is an independent entity and should be referred to by its full name to avoid confusion.

And let me tell you, this SETI vs. SETI Institute distinction… that really can cause a lot of confusion.

A few years back, I saw a report on the news.  SETI (the Institute, I presumed) had picked up a signal form outer space, from a star located 94 light years away.  According to the news lady on TV, a SETI spokesperson had this to say, and that to say, and some more stuff to say about this amazing discovery.  “Oh cool,” I thought, and I quickly went to the SETI Institute’s webpage to learn more.

There was nothing—absolutely nothing—about it.

Another day or two went by, and then this article was posted on the SETI Institute’s website.  Some Russian radio astronomers had picked up what they thought was a SETI signal (it eventually turned out to be a satellite).  Somehow the media picked up on this story and ran with it, apparently without contacting the SETI Institute—or speaking with any actual SETI Institute spokesperson—to find out if any of this were true.

I should probably mention that in my day job, I work in the T.V. news business.  This sort of sloppy journalism infuriates me, but I’ve found that it’s quite typical of how the popular press handles science news.

However, to be fair, prior to that misleading news report, I didn’t know to make a clear distinction between SETI and the SETI Institute myself. But I’ve tried to be more careful about this ever since.  Language can be a messy way to communicate, so it’s important to try to be clear about what we mean.  Otherwise, someone (perhaps even someone from the media) will get the wrong idea and run with it.

Next time on Sciency Words A to Z, the first astronauts on Titan may find themselves in a very sticky situation.

Sciency Words A to Z: Intelligence

Welcome to a special A to Z Challenge edition of Sciency Words!  Sciency Words is an ongoing series here on Planet Pailly about the definitions and etymologies of science or science-related terms.  In today’s post, I is for:


In 1959, this paper by Giuseppi Cocconi and Philip Morrison appeared in the journal Nature.  The ideas Cocconi and Morrison laid out in that paper were bold, and maybe a little presumptuous, but they became the foundation for a very important subfield of astrobiology: the search for extraterrestrial intelligence, or SETI for short.

The A to Z Challenge being what it is, it’s too early for us to start digging in to the subject of SETI research.  But we can talk about part of it.  Specifically the I part—“intelligence.”  It’s fairly obvious what “search” means, and “extraterrestrial” simply refers to something that’s not from Earth. But what is the definition of “intelligence”?

What does it mean to be intelligent? How would we recognize an extraterrestrial intelligence if and when we find one?  Are we sure we humans are a good example of what an intelligent life form is like?  (No, wait, maybe don’t answer that last one!)

In this article from, the famous SETI scientist Jill Tarter is quoted as saying:

SETI is not the search for extraterrestrial intelligence.  We can’t define intelligence, and we sure as hell don’t know how to detect it remotely.  [SETI]… is searching for evidence of someone else’s technology.  We use technology as a proxy for intelligence.

This reminds me of a joke from the Hitchhiker’s Guide to the Galaxy, that humans think we are the most intelligent creatures on Earth because we built cities and nuclear weapons and things like that, while dolphins believe they are more intelligent than us because they chose not to do those things.

So it is time we change SETI to SETT—the search for extraterrestrial technology?  It sounds like Tarter would support that change.  She calls the SETI acronym “problematic” and suggests that we “talk about a search for technosignatures” instead.  But as regular readers of Sciency Words should know by now, once a word gets embedded in the scientific lexicon, it’s really, really, really hard to change it, no matter how problematic it might seem. Don’t believe me?  Click here or here or here or here or here.

And I suspect that Jill Tarter knows this.  In this report on SETI nomenclature, which is co-authored by Tarter, it says, “Definitions of intelligence are slippery […]” however, “[the word’s] use in the acronym SETI is sufficiently entrenched that we recommend against a more precise rebranding of the field.”

So what does it mean to be intelligent?  For the purposes of SETI, no one knows.  The term is vague to the point of being unusable for official scientific discourse.  But scientists have been talking about and writing about this for decades—remember, that Cocconi-Morrison paper came out in 1959—so at this point we’re sort of stuck with the I in SETI.

Next time on Sciency Words A to Z, we’ll get the latest juicy gossip from the moons of Jupiter.