Tag: Extraterrestrial life

Never Say Never: Life on Ancient Venus

~ J.S. Pailly ~ 9 Comments

Hello, friends!  Today’s post is about the planet Venus, but the real lesson today is this: never say never.

Could Venus have supported life at some point in the past?  Yes.  In theory, yes.  Despite being closer to the Sun than Earth, Venus still orbits within the so-called habitable zone of our Solar System (this depends a little on whom you ask; some sources say Venus is inside the habitable zone while others will tell you she’s skirting the habitable zone’s edge).  So it is plausible that, at some point in the distant past, Venus could have had more Earth-like temperatures and more Earth-like surface conditions.

But then something went catastrophically wrong.  Carbon dioxide gas somehow started accumulating in Venus’s atmosphere.  Carbon dioxide is naturally good at trapping heat, so rising CO2 levels caused the temperature to also rise.  Rising temperatures caused more CO2 to outgas from the planet’s crust.  The outgassing of more CO2 caused the temperature to rise further, which caused more outgassing of CO2, which caused temperatures to rise further, which caused more outgassing of CO2, which caused… you get the idea.  This process is known as a runaway greenhouse effect.

Cartoon of Venus, looking eager, and Earth, looking shocked, as Venus says, "Oh, Earth! I used to have 'organisms' crawling on me, too. But then I filled my atmosphere with CO2, triggering a runaway greenhouse effect. That killed everything!"

I don’t think anyone knows for certain what started the runaway greenhouse effect on Venus (or at least, I’ve read many different ideas about what the initial cause might have been).  All we know for certain is what Venus is like today: hell.  Insane heat.  Insane atmospheric pressure.  Insane levels of CO2 plus insane weather, most notoriously sulfuric acid rain.  I think it’s safe to say that no planet in the Solar System is more hostile to life as we know it than modern day Venus.

But the runaway greenhouse effect was not the only catastrophe to befall Venus.  Venus also experienced something called a global resurfacing event.  Resurfacing may sound like something you’d do to a parking lot, but when we’re talking about planets, resurfacing means spreading fresh lava over a planet’s surface, essentially paving over whatever surface features might have been there before.

So could Venus have supported life at some point in the past?  Sure.  It’s possible.  But this always seemed like an untestable hypothesis to me.  The runaway greenhouse effect would have killed everything (well, almost everything… see my post script), and the global resurfacing event would have paved over any fossils or other evidence of past Venusian life.  So if there ever was life on Venus, we’d never know about it.  Never.

We now come to the “never say never” part of today’s post.  On Venus, there are patches of rough terrain called tesserae (singular, tessera).  As longtime readers of this blog know, Venus is my favorite planet, so naturally I have heard about the tesserae on Venus before; however, I was previously led to believe tesserae were formed by thrust faults, volcanic eruptions, or some other relatively modern geological activity.  But recently, I read a research paper that mentioned, rather casually, that tesserae might also be the remnants of ancient continental crust jutting up above the otherwise smooth, resurfaced landscape.

So the tesserae we see today could be ancient Venus’s version of the Rocky Mountains, the Alps, or the Himalayas.  They are (or were) the highest of high elevation regions on ancient Venus—regions high enough to survive the global resurfacing event.  If true, then the tesserae of Venus may preserve some hard evidence of what Venus used to be like before the runaway greenhouse effect and the global resurfacing event wrecked the place.

So was there ever life on Venus?  It’s possible, but we don’t know for sure.  I once resigned myself to the belief that we could never know, but you should never say never.  Signs of ancient water and ancient life may be preserved on Venus after all, just waiting for us to discover.

P.S.: Some scientists believe there may be life on Venus today.  There is some very circumstantial evidence of microorganisms floating around in Venus’s upper atmosphere.  I do have some thoughts about that, but I’ll save that for another blog post.

Want to Learn More?

Here is the research paper I mentioned that casually mentions tesserae might be the remnants of ancient continental crust.

And here is a paper I found describing possible signs of water erosion on Venus’s tesserae.  Water erosion could not possibly happen on Venus today, so this would be further evidence that tesserae have preserved something of Venus’s ancient history.

And lastly, just because this “tesserae equals continental crust” idea is new to me, that doesn’t mean it’s new to science.  Here’s a paper from 1990 discussing the possibility.  Even if some of the information in this paper is out of date, I think it’s still worth a look, if only to see how much history this idea has.

Carbon Dating Alien Life

~ J.S. Pailly ~ 12 Comments

Hello, friends!

A little over a week ago, the bodies of two dead extraterrestrials were presented to Mexico’s Congress as evidence that Earth has, in fact, been visited by aliens.  My initial reaction, upon first hearing about this, was: Is this it?  Is this the proof we’ve all been waiting for?  I used to believe in U.F.O.s, and there’s a part of me that still wants to believe.  But wanting to believe something doesn’t make it true.

The very first news article I read about this—the very first paragraph of that article, in fact—threw up one of the biggest red flags I’ve ever seen in all my years of researching space and science stuff.  I don’t remember who published that article.  CNN, Reuters, the Associated Press… it was one of those news sources, I think.  Anyway, the article stated in the very first paragraph that scientists used carbon dating to determine the age of these supposed extraterrestrial bodies.  Which… come on, seriously?

For anyone who doesn’t know how carbon dating works, I’ll provide a link in the “want to learn more” section below.  The important thing is this: carbon dating only works because we know how much carbon-14 (a radioisotope of carbon) is present in Earth’s atmosphere.  So if we ever discover a dead organism on Mars, and if we decide to try carbon dating that dead Martian organism, we would first need to know the carbon-14 content of Mars’s atmosphere.

As for these purported extraterrestrials, we don’t even know what planet they (supposedly) came from.  We have no way of knowing how much carbon-14 would be in their home planet’s atmosphere, or how much was in the atmosphere aboard their spaceship, or how much would’ve been in the atmospheres of any other worlds they may have visited before they happened to die here on Earth.  So why would you even bother carbon dating these alien bodies?  What purpose could that possibly serve?

If the people presenting these “extraterrestrials” to Mexico’s Congress were serious scientists doing serious science, they would know all that.  They’d know carbon dating is pointless in this situation.  The only reason carbon dating was mentioned at all (I presume) is because it sounds very sciency to the general public.  It adds an air of scientific legitimacy.  “We carbon dated these things, which means they must be what we say they are.”

After turning to some less gullible science news sources, like Live Science and Smithsonian Magazine, I learned that the people behind these alien corpses have a history of “discovering” alien bodies.  In previous cases, these “discoveries” have turned out to be the disfigured remains of a child and indigenous Peruvian mummies that were mutilated to appear extraterrestrial.  The story gets super gross, and if the allegations are true, then I hope the people who did this are prosecuted to the full extent of the law.

Look, I want to believe in U.F.O.s.  I want to believe that Earth has been visited by extraterrestrials.  That would be—well, it would be terrifying, in one sense, but it would also be kind of a relief.  The notion that we are alone in the universe bothers me on a deep, existential level.  But when you really want to believe something like that, it’s important to be extra skeptical of people telling you exactly what you want to hear (or in this case, showing you exactly what you want to see).

The real lesson here is not that Earth has been visited by aliens.  The real lesson, I think, is that we should all be on guard against our own wishful thinking.  Or maybe the lesson is that if you’re going to talk a big game about carbon dating, make sure you know how carbon dating actually works.

WANT TO LEARN MORE?

As promised, here’s a link to an article from How Stuff Works explaining how carbon dating works.

And here’s an article from Live Science about those extraterrestrial bodies that were shown to Mexico’s Congress and the credibility of the people who showed that.

And here’s a similar article from Smithsonian Magazine.

That Time NASA Discovered Life on Earth

~ J.S. Pailly ~ 10 Comments

Hello, friends!

As some of you may already know, there is life on Earth.  NASA discovered that fact in 1990.  Let me explain.

In the decades prior to the Space Age, certain astronomers had claimed to observe vegetation growing on the Moon, artificial canals on the face of Mars, and some scientists even speculated that beneath the clouds of Venus (which were surely H2O clouds), we might find a world dense with jungle.  Writers and philosophers had long speculated about how other worlds might be populated by other people, and at least a few theologians argued that there must be life on other planets (for why would God create all these planets and then leave them empty?).

And yet, as both the Soviet and American space programs ventured farther and farther out into space, they found nothing.  No vegetation on the Moon (not even on the far side of the Moon).  No canals on Mars.  Definitely no jungles on Venus (and as for Venus’s clouds, it turns out they’re not made of H2O—they’re not made of H2O at all!!!).

I don’t want to make it sound like everybody expected to find life on the Moon, Mars, or elsewhere, but a lot of people were expecting to find life.  So what happened?  Why couldn’t our space probes find life on any of the other worlds of the Solar System?  There were two possible explanations.  Either there was no life out there to find, OR something was wrong with our space probes.  Maybe they weren’t carrying the right equipment to detect life, or maybe they weren’t performing their experiments properly, or maybe they weren’t sending the correct data back to Earth.

Which brings us to 1990.  NASA’s Galileo spacecraft was heading out to Jupiter, but for navigational reasons it needed to do a quick flyby of Earth first.  A certain scientist named Carl Sagan saw this Earth flyby as an opportunity.  What would happen if Galileo did a thorough scan of our home planet?  Could this fairly standard NASA space probe, equipped with a fairly standard suite of scientific instruments, detect life on a planet where we already knew life existed?

The results were published a few years later in a paper entitled “A search for life on Earth from the Galileo spacecraft.”  This “search for life on Earth” paper is my all time favorite scientific research paper.  First of all, for a scientific paper, it’s a surprisingly easy read.  Turns out Carl Sagan was a good writer with a knack for explaining science in a clear and accessible manner.  Who knew?  Secondly, the experiment itself is really cool.  And third, the results of the experiment are a little more ambiguous than you might expect.

Among other things, Galileo detected both oxygen and methane in Earth’s atmosphere.  If you didn’t already know there was life on Earth, it would be difficult to explain how those two chemicals could both be present.  Oxygen and methane should react with each other.  They should not exist together in the same planet’s atmosphere for very long—not unless something unusual (like biological activity) continuously pumps more oxygen and more methane into the atmosphere.

Additionally, Galileo noticed a strange “red-absorbing” substance widely distributed across Earth’s landmasses.  This mystery substance could not be matched with any known rock or mineral, suggesting a possible biological origin.  This red-absorbing mystery substance was, in fact, chlorophyll—the chemical that allows plants to perform photosynthesis.

And lastly, Galileo picked up radio transmissions.  Galileo couldn’t determine the content of these transmissions, but the transmissions were clearly artificial—an indication that there is not only life but intelligent life on Earth.

I’ve read this “search for life on Earth” paper several times over the years.  Like The Lord of the Rings or Ender’s Game, it’s one of those things I love to read again and again, and each time I feel like I get a little more out of it.  The main take away, I have come to believe, is that if there were anything similar—anything even remotely similar—to Earth’s biosphere on the Moon or Mars or anywhere else in the Solar System, we would know about it.  Our space probes would absolutely be able to detect something like that.

However, there’s still a lot of stuff here on Earth that the Galileo probe missed.  Some little details, for example: chlorophyll absorbs both red and blue light, but Galileo apparently didn’t notice the blue absorption.  Only the red.  And Galileo overlooked some big things, too.  Cities, roadways, the Great Wall of China?  Maybe a follow-up mission to Earth would find those things, but Galileo didn’t see any of that stuff.  And then there’s Earth’s oceans.  Galileo couldn’t detect anything beneath the surface of the water.  Water very effectively blocked all of Galileo’s sensors.

So our space probes are not fundamentally flawed, but they do have a few blind spots.  Today, no one expects to find jungles on Venus or canals on Mars.  Our space probes say those things aren’t there, and we can be confident that our space probes are working properly.  But there are a few niche environments out there were alien life might still be hiding.

WANT TO LEARN MORE?

Science communicators (myself included) dumb things down for their readers, which is why reading actual scientific papers has become an important part of my research process.  Dumbed down science is fine, provided it still says what the actual scientific research says.  But reading these sorts of papers is a skill, and it takes some time and practice to do it.  If you’ve ever wanted to start reading scientific papers for yourself, “A search for life on Earth from the Galileo spacecraft” by Carl Sagan et al. is a good starter paper.

Are We Alone in the Universe?

~ J.S. Pailly ~ 16 Comments

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?

Sciency Words: Flora and Fauna

~ J.S. Pailly ~ 11 Comments

Hello, friends!  Welcome to another episode of Sciency Words, a special series here on Planet Pailly where we talk about the definitions and etymologies of science or science related terms.  In today’s post, we’re talking about two words:

FLORA AND FAUNA

So this weekend, I was thinking about alien life, as I often do, and it occurred to me that the words “plant” and “animal” are woefully inappropriate words to apply to extraterrestrial organisms.  That got me wondering if maybe the words “flora” and “fauna” would be better.

This is hardly a revolutionary insight.  Arik Kershenbaum talks about this in his book The Zoologist’s Guide to the Galaxy.  You see, in the cosmic sense, when we’re considering life across the entire universe, the words “plant” and “animal” are highly Earth-specific terms.  Strictly speaking, plants are organisms belonging to the kingdom Plantae, and animals are organisms belonging to the kingdom Animalia.  These kingdoms are two branches of the tree of life—Earth’s tree of life.  Not Mars’s tree of life.  Not Proxima b’s tree of life.  Earth’s.

Extraterrestrial life forms would belong to the kingdom… who the heck knows?  I guess astro-taxonomists will have to figure that out if/when extraterrestrial life is discovered.  In the meantime, would it make sense to use the words “flora” and “fauna” as generic terms for plant-like and animal-like aliens?  Initially I thought it would, but after doing some research, I’m not so sure.

Definitions of flora and fauna: In ecology, the words flora and fauna refer to all the plants and animals, respectively, found within a particular ecological region.

Etymologies of flora and fauna: The word “flora” traces back to the Latin word for flower.  Fauna comes from the name of an ancient Roman goddess of fertility.

So the words flora and fauna are not exactly synonyms for plants and animals; however, they do include the words “plants” and “animals” in their definitions.  And extraterrestrials, no matter how plant-like or animal-like they may be, would still have to be categorized as something else.

I still feel like referring to alien life forms as flora and fauna is better than calling them plants and animals.  Or at least it’s less wrong.  But it’s still not perfect.  In a distant, Sci-Fi future, new terminology may need to be invented.

WANT TO LEARN MORE?

I highly recommend reading The Zoologist’s Guide to the Galaxy by Arik Kershenbaum.  Obviously we do not know at this point what alien life might be like, but, as Kershenbaum argues, we can make some educated guesses based on the way life on Earth does (or does not) work.

Arguing with Myself: The Search for Alien Life

~ J.S. Pailly ~ 24 Comments

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!

October Is Europa Month Here on Planet Pailly!

~ J.S. Pailly ~ 6 Comments

Hello, friends!  Let’s talk about aliens!

If we want to find alien life, where should we look?  Well, if money were no object, I’d say we should look anywhere and everywhere we can.  Phosphorous on Venus?  Could be aliens.  Let’s check it out.  Melty zones beneath the surface of Pluto?  Let’s check that out too.  Ariel?  Dione?  Ceres?  Let’s check them all for signs of alien life!

But money is an object.  We simply don’t have the resources to explore all of these places.  Space exploration is expensive.  Space exploration will always be expensive so long as we’re stuck using rocket-based propulsion.  The Tsiolkovsky rocket equation makes it so.

Whenever you’re working within a restrictive budget, you need to think strategically.  With that in mind, astrobiologists (scientists who specialize in the search for alien organisms) have focused their efforts on four worlds within our Solar System.  Their names are Mars, Europa (moon of Jupiter), Enceladus (moon of Saturn), and Titan (another moon of Saturn).

This month, I’m going to take you on a deep dive (no pun intended) into Europa.  In my opinion, of the four worlds I just listed, Europa is the #1 most likely place for alien life to be found.  I don’t mean to denigrate Mars, Enceladus, or Titan.  There are good reasons to think we might find life in those places, too.  But there are also good reasons to think we might not.

  • Mars: Life may have existed on Mars once, long ago.  But then the Martian oceans dried up.  We’re unlikely to find anything there now except, perhaps, fossils.
  • Enceladus: Enceladus’s age is disputed.  She may be only a few hundred million years old, in which case she may be too young to have developed life.
  • Titan: If you want to believe in life on Titan, you have to get a little imaginative about how Titanian biochemistry would work.

Europa doesn’t have those issues.  Unlike Mars, Europa has an ocean of liquid water right now, in modern times.  Unlike Enceladus, Europa’s age is not disputed; she’s definitely old enough for life.  And unlike Titan, Europa doesn’t require us to get imaginative about biochemistry.  The same carbon-based/water-based biochemistry we use here on Earth would work just as well for the Europans.

There are still good reasons to search for aliens on Mars, Enceladus, and Titan.  Finding fossils on Mars would be super exciting!  Enceladus’s age is, as I said, in dispute, with some estimates suggesting she’s very young, but others telling us she’s plenty old.  And while life on Titan would be very different than life on Earth, scientists don’t have to imagine too hard to find plausible ways for Titanian biochemistry to work.

But if I were a gambler, I’d put my money on Europa.  And if I were in charge of NASA’s budget, I’d invest heavily in Europa research and Europa missions.  Europa just seems like the safest bet to me, if we want to find alien life. And in the coming month, I plan to go into more detail about why I feel that way.

WANT TO LEARN MORE?

If you’re interested in learning more about the Tsiolkovsky Rocket Equation, you may enjoy this article from NASA called “The Tyranny of the Rocket Equation” (because NASA is the American space agency, and anything Americans don’t like is tyranny).

As for astrobiology, I highly recommend All These Worlds Are Yours: The Scientific Search for Alien Life, by Jon Willis.  Willis frames the search for alien life just as I did in this post: alien life could be anywhere, but you only have a limited budget to use to find it.  So how would you spend that money?