Are We Alone in the Universe?

Hello, friends!

I have only recently returned to regular blogging, and in several recent posts I’ve alluded to the fact that I’m planning to take my Sci-Fi writing in a new creative direction.  A lot of things are changing for me right now.  A lot of the things I’m doing (or trying to do) are new.  With that in mind, I feel like this is a good time to restate some of my views and beliefs about science and the universe, starting with my views and beliefs about extraterrestrial life.

When people ask “Do you think we’re alone in the universe?” I get slightly annoyed by that question.  It’s too big a topic to reduce to a simple yes or no question.  In Humanity’s search for extraterrestrial life, there are really three kinds of life we might find out there:

Microbial Life: Almost as soon as Earth existed, terrestrial microorganisms existed, too.  Microbes developed so swiftly and so easily on this planet that the same thing must have happened elsewhere.  For this reason, I believe extraterrestrial microorganisms are plentiful across the cosmos.

Multicellular Life: Complex multicellular organisms—fish, plants, bugs, etc—exist on Earth due to a happy accident.  About 2.4 billion years ago, some of Earth’s microbes started burping up oxygen.  To those microbes, oxygen was a waste product, but that waste product could also be used in biochemical reactions to create energy.  Lots of energy.  Enough energy to make complex multicellular life possible.  If multicellular life requires this sort of happy accident in order to exist, then I suspect multicellular life must be rare across the universe.

Intelligent Life: I’m going to define intelligence as the ability of a species to make and use tools, to communicate complex ideas, and to generally improve upon its knowledge and technology over time.  As far as we can tell, life like that only evolved one time on our planet.  Given the vastness of the entire universe, I think intelligent life must exist elsewhere, but I also think it must be extremely rare.

Some time around 1950, nuclear physicist Enrico Fermi famously asked “Where is everybody?” in reference to alien life.  As Fermi saw it, advanced alien civilizations should be out there, and their activities in space should be obvious to us.  And yet when we look out into the universe, we see nothing.  This apparent contradiction—aliens should be everywhere, and yet they seem to be nowhere—is today known as the Fermi Paradox.

So I guess my answer to questions like “Where is everybody?” or “Are we alone in the universe?” depends on what kind of alien life we’re talking about.  If we’re talking about alien microorganisms, I think they’re plentiful, and I think it’s only a matter of time before we find evidence of alien microbes on Mars or on one of the icy moons of the outer Solar System.  If we’re talking about multicellular life, that sort of life is rare.  And intelligent life must be rarer still—so rare, in fact, that our nearest intelligent neighbors may be hundreds, thousands, or even millions of lightyears away.

But these are just my opinions.  My opinions about this topic have changed over time, and as I keep learning, my opinions and expectations will, no doubt, change again.

So, friends, what are your opinions and expectations concerning extraterrestrial life?  Do you think I’m on the right track, or is there something I’ve missed that you think I should learn more about?

Our Place in Space: An Immature Technosphere

Hello, friends!  Welcome to Our Place in Space: A to Z!  For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space.  If you don’t know what the A to Z Challenge is, click here to learn more.  In today’s post, I is for…


In a previous post, I told you about the DART Mission, our first real experiment to see if we can defend our planet from incoming asteroids.  I believe humanity has a tremendous responsibility to protect our planet, not only for our own benefit but for the benefit of the entire Earthly biosphere.  Incoming asteroids can do serious harm to Earth’s biosphere (just ask the dinosaurs).  But, of course, there are other threats to the biosphere that should concern us—more immediate and urgent threats, too.

The term “immature technosphere” is mainly associated with SETI research.  Imagine, if you will, a planet that is home to alien life.  Over cosmic timescales, we might expect this hypothetical alien planet to go through several phases of development.

Phase One: The Immature Biosphere
Life has begun!  The first microorganisms are swimming around in the planet’s water (or whatever liquid this planet has instead of water).  But biological activity produces biological waste, in one form or another, so as these early organisms multiply and spread, they may end up poisoning their own environment with their own waste products.

Phase Two: The Mature Biosphere
Life has found a way.  A variety of organism have now evolved, and the waste produced by one organism serves as fertilizer, food, or fuel for others.  A natural balance has been achieved.  Natural cycles have emerged.  Life not only survives but thrives!

Phase Three: The Immature Technosphere
Intelligent life has emerged, by which I mean life capable of creating and using technology.  But as these intelligent life forms begin using technology on a grander and grander scale, they may inadvertently disrupt the natural cycles and the natural balance of their world.  Life is threatened once again, this time by technological waste.

Phase Four: The Mature Technosphere
If intelligent life is truly intelligent, it will recognize the harm it is doing to its own environment and start inventing ways to undo that damage, or at least to keep the damage in check.  In time, perhaps a new balance will be achieved, with nature and technology working together in harmony.

Turning our attention back to Earth, I think it’s fair to say our planet is in the “immature technosphere” phase of development.  But an immature technosphere today implies that a mature technosphere may develop later on, and that gives me hope.

I keep saying that this “Our Place in Space” series is a highly optimistic view of humanity’s future.  Part of what I mean by that is that we will not leave Earth behind.  We will not make a new home for ourselves on the Moon or Mars or elsewhere after destroying our first home here on Earth.  I doubt that that would work anyway; any off-world colony we might establish would still be dependent on Earth for a long, long time to come.

I know a lot of people who see the state of the world and despair.  Things are bad right now, and some of the damage we are doing to our planet and to each other cannot be undone.  But a better future is still possible.  Humanity just needs a bit more time to mature.

Want to Learn More?

Earth in Human Hands by David Grinspoon is one of my all time favorite books.  It’s certainly my #1 favorite non-fiction book.  As an astrobiologist, Grinspoon has more knowledge and authority on scientific matters than I do, but his view of the future is much like the view I’ve been presenting in these A to Z Challenge posts.

So if you’re worried about the state of the world and you want to believe that a better and brighter future is still possible, I highly recommend picking up Grinspoon’s book.

Our Place in Space: The Far Side of the Moon

Hello, friends!  Welcome to Our Place in Space: A to Z!  For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space.  If you don’t know what the A to Z Challenge is, click here to learn more.  In today’s post, F is for…


The James Webb Space Telescope has been getting a lot of press lately.  It’s the biggest and best telescope we humans have ever put into space.  But today, we’re going to imagine an even bigger and (potentially) an even better telescope.  We’re not going to put this telescope in space, though.  We’re going to build it on the surface of the Moon.

The far side of the Moon is the perfect location to build a radio telescope.  We’ve certainly built radio telescopes here on Earth, but those Earth-based radio telescopes keep running into the same two problems.  First, Earth’s atmosphere (especially the ionosphere) blocks certain cosmic radio wave frequencies from reaching us here on the ground.  And second, there’s a whole lot of terrestrial radio chatter happening here on the ground.  That chatter can interfere with any radio signals that do make it through from outer space.

But on the far side of the Moon, those problems don’t exist.  There’s no atmosphere, and certainly no ionosphere.  And since this is the far side of the Moon we’re talking about—i.e., the side of the Moon that always faces away from the Earth—all that terrestrial radio noise is gone.  The Moon itself would block those signals from ever interfering with our radio telescope.

The telescope itself would be absolutely enormous.  It would be built inside of a crater, with a dish approximately one kilometer wide.  NASA has already approved funding to research this idea; please note, they have not approved funding to build it yet!  Only to research the idea, to see if it’s actually feasible using current technology.  If it turns out that it is feasible, though, building a radio telescope on the far side of the Moon might end up being part of NASA’s new Artemis Program.

What would we do with our new lunar telescope?  Well for one thing, we could “look back in time” to see what the ancient universe was like.  Specifically, we could study a period of time known as the “cosmic Dark Ages.”  This would have been a time after the Big Bang but before the formation of the first stars—literally, the cosmic Dark Ages, like I said.  The hydrogen gas permeating the universe in that era would have emitted some amount of electromagnetic radiation, which we can still detect today in certain radio wave frequencies (or we could detect it, if Earth’s stupid atmosphere would stop getting in the way!).

In addition to looking for these naturally-occurring radio signals, our lunar radio telescope could also watch for radio signals that do not appear to be natural in origin.  Radio transmissions from aliens, in other words.

Searching for aliens would definitely not be the main reason to build a radio telescope on the Moon.  The stuff I said about the cosmic Dark Ages—that’s the main reason to do this.  The aliens thing would just be a side benefit.

For this “Our Place in Space” series, I’ve mostly focused on projects that I think could happen in the distant future.  But this lunar radio telescope project is something that probably needs to happen sooner rather than later.  The far side of the Moon is the perfect location for a radio telescope right now, but as humans start spreading out across the Solar System, things may change.  The far side of the Moon may get a whole lot noisier, in terms of radio chatter.

So in the distant future, rather than building a radio telescope on the Moon, we might prefer to build our radio telescopes farther out.  Places like Pluto, Orcus, Eris, or Quaoar—all those little dwarf planets beyond the orbit of Neptune—may end up being super useful for future radio astronomers.

Want to Learn More?

Check out this article from NASA’s Jet Propulsion Laboratory: “Lunar Crater Radio Telescope: Illuminating the Cosmic Dark Ages.”

Also, here’s an article from Universe Today: “The Moon is the Perfect Spot for SETI.”

Arguing with Myself: The Search for Alien Life

Hello, friends!

So a certain argument has been playing out in the back of my mind for a long, long time now.  Whenever I write, there are really two different versions of me who do my writing.  On the one hand, there’s science enthusiast me.  On the other, there’s Sci-Fi author me.  And these two versions of me view science, space exploration, and the universe at large in dramatically different ways.  One of the biggest ongoing disagreements I have with myself involves alien life.

Science enthusiast me believes that extraterrestrial microorganisms are pretty common in the universe.  Science enthusiast me thinks we will find evidence of extraterrestrial microbes in the very near future, perhaps hiding under the ice on Mars or swimming around in the oceans of Europa, Enceladus, or even Titan.  (I almost wrote unambiguous evidence there, but science enthusiast me also expects that confirming the discovery of extraterrestrial microbes will be tricky—just ask the researchers who found (or thought they found) microfossils inside a Martian meteorite back in 1996).

As for complex multicellular life—plants and animals, or whatever the extraterrestrial equivalent of plants and animals might be—science enthusiast me is far less optimistic.  While microorganisms have proven again and again that they can survive almost anything, even direct exposure to the vacuum of space, multicellular organisms seem to be far more fragile, far less resilient.  Earth may be one of the very few worlds where complex, multicellular organisms like us are able to survive and thrive over cosmic timescales.

And intelligent life?  Science enthusiast me believes intelligent life must exist elsewhere in the universe—surely it must!  But the universe is an awfully big place.  Our nearest intelligent and communicative neighbors could be many galaxies away.  Humanity is not alone in the universe, according to science enthusiast me, but we may as well be.

Sci-Fi author me, however, sees things from a different perspective.

Sci-Fi author me wants to write stories where encounters with alien life are commonplace, almost routine—stories where the aliens are sometimes friendly and sometimes not so friendly—stories where all sorts of weird and wacky interspecies adventures are possible!  And Sci-Fi author me takes a particular and peculiar pleasure in handwaving away all the concerns and objections science enthusiast me might have, not just regarding alien life but also in relation to faster-than-light travel, time machines, cybernetics, et cetera, et cetera.  Part of the fun, for Sci-Fi author me, is thinking up clever excuses for why impossible things are now possible (in the context of the story world, at least).

So there is this ongoing argument happening in the back of my mind.  This argument is never going to end, and I’ve decided that that’s okay.  Not every argument needs to have a winner and a loser, nor do arguments necessarily need to end in compromises.  Sometimes a house divided can stand after all.  Science enthusiast me believes the universe is like this; Sci-Fi author me would prefer (for story reasons) if the universe were more like that.  And the tension between these two different versions of myself drives my creativity, both as a science blogger and a science fiction writer.

P.S.: For those of you who might be interested, both the “I Heart Science” and “I Heart Sci-Fi” designs in this post are available in my RedBubble store.  Click here if you heart science, or click here if you heart Sci-Fi.  And remember: nobody’s stopping you from clicking both if you heart both!

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.

Sciency Words: Colony

Hello, friends!  Welcome to another episode of Sciency Words.  Normally on Sciency Words, we talk about those strange words scientists use, but today we’re going to talk about a word scientists—or at least some scientists—would prefer to stop using.  And that word is:


Mars is so eager for humans to come visit and maybe even stay permanently.  And plenty of humans are eager to do just that!  We’ll bring life to Mars.  Not only that, we’ll bring civilization and culture.  One might say it is humanity’s destiny to colonize Mars.

But is this language of “colonization” and “destiny” too evocative of European imperialism?  Some think so, and they would ask that we stop using such colonialist language when we talk about space exploration.

Now I want to be clear about where I’m coming from on this: I try my best to call people by the names and terms they prefer to be called, and if I find out that the language I use offends somebody, I’ll do may best to change.  Some would accuse me of being too P.C., but I think it’s just good manners.

And I have found that if you make an effort to be respectful and accommodating to others, others will make an effort to be respectful and accommodating to you, and in general they’ll be more willing to forgive you if/when you do slip up and say something unintentionally hurtful.

So a few years back, when I came across this article from National Geographic, I started reading it with an open mind and a willingness to change.  But by the end of the article, even I felt like this was an example of political correctness run amok.  The word “colony” is offensive.  So are the words “settlement” and “frontier.”  Okay.  What words should I use instead?  Even that National Geographic article seems to concede at one point that we don’t have many workable alternatives to these terms.

But this concern does seem to be coming up more and more.  Plenty of people in the scientific community are shying away from words like colony and colonization.  Bill Nye (the Science Guy) says he avoids the word colony, and this official glossary of SETI terminology warns that “settle” and “colonize” may have certain negative connotations for some people.

So at this point, I’m not sure what to think.  What about you?  Do you think this is much ado about nothing, or should we really start looking for alternatives to words like “colony” or “settlement” in our space exploration vocabularies?

Next time on Planet Pailly… I actually don’t have anything planned yet for my next blog post.  We’ll probably just talk about more space stuff.

Sciency Words: Dial Tone

Sciency Words: (proper noun) a special series here on Planet Pailly focusing on the definitions and etymologies of science or science-related terms.  Today’s Sciency Word is:


Some of you may be too young to know what a dial tone is, so here’s an instructional video explaining the concept.

According to this article from Teletech Services, it was German engineer August Kruckow who invented the dial tone back in 1908.  A dial tone is a buzzing or humming sound that landline telephones make to let you know they’re connected and working.

It’s hard to say when “dial tone” became a SETI term, but the earliest usage I was able to find is this 1995 paper by Steven Dick entitled “Consequences of Success in SETI: Lessons from the History of Science.”

In that paper, Dick draws a distinction between extraterrestrial signals that communicate information vs. extraterrestrial signals that serve essentially the same function as a dial tone.  The general public, Dick argues, would react quite differently if we picked up some sort of intergalactic dial tone instead of a “Greetings, Earthlings, would you like to learn more about calculus?” type of message.

Later papers (like this one or this one) continue to use this dial tone metaphor, and in 2018 a special committee on SETI nomenclature adopted the following as the official definition for the term: “A content-free beacon, i.e. one that communicates only the existence of technological life.”

That same committee goes on to note some concern that the conventional meaning of “dial tone” may soon become obsolete; if so, the committee worries, then the continued use of “dial tone” as a SETI term might become problematic.  I’m not sure I agree with that concern, though.  Lots of terms and phrases have stuck around even after their original meanings have faded into history.

In the near future, maybe it won’t be obvious to everyone that “dial tone” originally had something to do with telephones, but if SETI scientists keep using the term, I don’t think it’s that hard for people to understand what the term means… is it?

Sciency Words: The Rio Scale

Sciency Words: (proper noun) a special series here on Planet Pailly focusing on the definitions and etymologies of science or science-related terms.  Today’s Sciency Word is:


The Rio Scale is a classification system used by SETI scientists.  Let’s say someone’s detected possible evidence of an alien intelligence.  How significant is this discovery?  How seriously should we take that news?  The Rio Scale is a tool to help answer those questions.

The Rio Scale was created in the year 2000 at the International Astronomical Congress, which was held that year in Rio de Janerio. Mathematically speaking, the Rio Scale is expressed as:

(Q1 + Q2 + Q3) * ∂

You have to look through a chart in order to plug numbers into those variables.  I’m not going to reproduce that whole chart here, but if you’re interested here’s a Rio Scale calculator where you can learn more.

The quick version is that Q1 is the “what” of what we’ve discovered.  Q2 represents how we discovered it, and Q3 represents how far away from Earth it is.  So as an example, let’s say aliens are transmitting a message straight at Earth.  Let’s say the message was detected by a radio telescope and confirmed by subsequent SETI observations.  And let’s say the message is coming from Proxima Centauri, the star nearest to our own Sun.  This scenario would score very well on the Rio Scale.

As another example, let’s say we find some anomalous infrared radiation, the possible heat signature of an alien megastructure. Let’s say this was found in archival data from the 1970’s.  And let’s say this anomalous radiation came from the Triangulum Galaxy. This scenario would score rather poorly on the Rio Scale.

Lastly, before I forget, let’s talk about ∂.  That variable is a credibility factor. If information about a possible extraterrestrial signal is presented in a peer-reviewed scientific journal, ∂ will be a fairly high number.  If it’s just a press release, ∂ will be lower.  And if the information is coming from some weirdo on the Internet, ∂ equals zero.

Given the chance, I’m sure SETI scientists would like to follow up on every possible detection of extraterrestrial intelligence.  But SETI research does not have infinite resources.

In my opinion, the Rio Scale doesn’t sound like the most scientifically objective system; however, I imagine it does help when comparing and contrasting different possible discoveries.  That way, given the limited resources available to them, SETI scientists can better judge which detections are worth further investigation and which can probably be ignored.

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?