Teegarden Party: Don’t Pack Your Interstellar Travel Bags … Yet

While it’s an exciting discovery, the nearby star system is a very alien place with its own unique array of challenges.

The universe is stranger than we can imagine, so when a star system is discovered with some familiar traits to ours, it can be hard not to imagine extraterrestrial lifeforms and interstellar getaways. But before you dream of bathing on the exotic shores of Teegarden b, breathing in the moist and salty air, while sipping on a Teegarden Tequila Sunrise, keep in mind that the reality will likely be, well, much stranger than we can imagine.

This is how the star Teegarden might look at sunset on its two “habitable” exoplanets, Teegarden b and c [PHL @ UPR Arecibo]

So, what is all the fuss about Teegarden’s Star?

This week, astronomers announced the discovery of two “habitable zone” exoplanets orbiting the tiny red dwarf star, which is located a mere interstellar stone’s throw away. While 12.5 light-years may sound like quite the trek, in galactic distances, that’s no distance at all. The two exoplanets, Teegarden b and c, are now in a very exclusive club, being the joint fourth-nearest habitable zone exoplanets to Earth (after Proxima Centauri b, Tau Ceti b and GJ 273 b). On the Earth Similarity Index (ESI), however, we have a new champion: Teegarden b—after considering its mass and derived surface temperature—this fascinating world is 95% “Earth-similar,” according to Abel Mendez’s analysis at the Planetary Habitability Laboratory (PHL). And like TRAPPIST-1, there’s some optimism that there should be more small exoplanets, some that may also be habitable, that have yet to be discovered around Teegarden.

All of these facts are cause for celebration, no? They are, but a heavy dose of reality needs to be applied when it comes to any world that has been discovered beyond our solar system.

More Exoplanets, More Possibilities

As alien planet-hunting missions continue to add more worlds to the vast menagerie of known exoplanets that exist in our galaxy, an increasing number of them are falling inside the “habitable zone” category.

Top 19 potentially habitable exoplanets, sorted by similar size and insolation to Earth [PHL @ UPR Arecibo]

The habitable zone around any star is the distance at which a rocky planet can orbit where it’s neither too hot or too cold for liquid water to exist on its surface (if it has water, that is). Liquid water is the stuff that Earth-like biology has an affinity to; without it, life on Earth wouldn’t have evolved. So, even before we have any clue about its H2O-ness, if an exoplanet is seen to have an orbit around its star that is deemed habitable, that’s +1 point for habitability.

Now, the next point can only be won if that world is also of approximate Earth-like size and/or mass. There would be little reason in getting too excited for a Jupiter-sized exoplanet sitting in the habitable zone possessing liquid water on its “surface” (because it won’t have a surface). That’s not to say there can’t be some gas giant-dwelling balloon-like alien living in there, but we’re looking for Earth-like qualities, not awesome alien qualities we read in science fiction. (I’d also argue that these kinds of exoplanets might have habitable Earth-sized moons—like Avatar‘s Pandora—but that’s for another article…)

The two key methods for exoplanet detection is the “radial velocity” method and the “transit” method. The former—which precisely measures a star’s light to detect tiny stellar wobbles as an exoplanet gravitationally “tugs” at it as it orbits—can deduce the exoplanet’s mass, thereby revealing whether or not it has an Earth-like mass (Teegarden’s two worlds were discovered using this method). The latter—which was employed by NASA’s Kepler space telescope (and now NASA’s Transiting Exoplanet Survey Explorer, among others) to look for the slight dips in brightness as an exoplanet passes in front of its star—can deduce the exoplanet’s physical size, thereby revealing whether or not it has an Earth-like size. Should a habitable zone exoplanet possess either one of these Earth-like qualities, or both (if both methods are used on a target star), that’s another +1 point for its habitability.

The orbital characteristics of Teegarden b and c, both falling well within the star’s habitable zone [PHL @ UPR Arecibo]

There’s a few other measurements that astronomers can make that may add to a hypothetical world’s habitability (such as observations of the host star’s flaring activity, age, or some other derived measurement), but until we develop more powerful observatories on Earth and in space, there are several factors that quickly cause our hypothetical exoplanet to diminish in habitable potential.

The Unhabitability of “Habitable” Worlds

So far in our burgeoning age of exoplanetary studies, we’ve only been able to measure (and derive) a handful of characteristics—such as mass, orbital period, physical size, density—but we have very little idea about these habitable zone exoplanets’ atmospheres. Apart from measurements of a few massive and extreme exoplanets—such as “hot-Jupiters” and exoplanets getting blow-torched by their star when they venture too close—astronomers haven’t been able to directly measure the existence of any of these “habitable” exoplanet’s hypothetical atmospheres. Do they even possess atmospheres? Or are they the opposite, with hellish Venus-like pressure-cooker atmospheres? Who knows. Even if they do have atmospheres that are more Earth-like, are the gases they contain toxic to life as we know it?

Recently, theoretical models of exoplanetary atmospheres brought carbon dioxide and carbon monoxide into the discussion. CO2 is a powerful greenhouse gas that helps maintain a balance in our atmosphere, regulating a temperate world (until industrialized humans came along, that is). But too much can be a very bad thing. For exoplanets existing on the outer edge of their habitable zone to remain habitable, they’d need massive concentrations of CO2 to remain temperate—concentrations that would render the atmosphere toxic (to complex lifeforms, at least). In the case of carbon monoxide (the terrible gas that asphyxiates anything with a cardiovascular system), as our star is so hot and bright, its ultraviolet radiation destroys large accumulations of CO in Earth’s atmosphere. But for habitable zone exoplanets that orbit cool red dwarf stars (like Teegarden), huge concentrations of CO may accumulate and snuff-out life before it has the opportunity to evolve beyond a germ. These two factors are a big negative against life as we know it, shrinking the effective habitable zone around certain stars and certain exoplanetary orbits.

Artist impression of a transiting exoplanet [ESO]

Most habitable zone exoplanets have been found orbiting red dwarfs, primarily because our observations have been biased in favor of these little stars—they’re small and cool, meaning that any planet orbiting within their habitable zones need to get up-close and personal, so its an easier task to detect the periodic star wobbles or exoplanetary transits to confirm their existence.

While this may sound cute, orbiting so close to a red dwarf is a blessing (for astronomers) and a curse (for any unfortunate aliens). Many red dwarf stars generate powerful stellar flares that would regularly bombard nearby worlds with radiation that terrestrial biology would not be able to tolerate. Unless those planets have incredibly powerful global magnetic fields to, a) protect their inhabitants from being irradiated and, b) prevent the savage stellar winds from stripping away their protective atmospheres, there’s limited hope for the evolution of life.

Interestingly, however, according to the Teegarden study published in the journal Astronomy & Astrophysics, this particular red dwarf is relatively quiet on the life-killing flare front, so that’s something. Another tentative +1 for Teegarden’s actual habitability! (Pass the tequila.)

Known habitable zone exoplanets plotted against the type of star they orbit and distance from star. Note: all temperate worlds discovered so far orbit stars far cooler (and smaller) than the Sun [C. Harman]

As you can tell, there’s lots of exciting implications balanced by plenty of sobering reality checks. There is, however, one factor that is often missed from big announcements about worlds orbiting small stars that, whether they are habitable or not, is truly beyond our experience.

Eyeballing Temperate Red Dwarf Systems

Teegarden is an eight-billion-year-old star system, approximately twice the age of our solar system. If life has found a way, it will have come and gone, or be in an evolved state (though this is anyone’s guess, we have little idea about the hows and whys of the emergence of life on Earth, let alone on a different planet). But the worlds themselves, if either possess liquid water (Teegarden b, being the one that should be the most temperate of the pair, so will have the higher odds), they certainly wouldn’t look like Earth, even if they have Earth-like qualities.

Having settled billions of years ago, any orbital instabilities would have ebbed, and the planetary orbits would be clearly defined and likely in some kind of resonance with the other bodies in the star system. In addition, both Teegarden b and c will, in all likelihood, be tidally locked with their star.

To understand what this means, we need only look up. When we see our moon, we only see one hemisphere—the “near side”; the lunar “far side” is never in view. Except for the Apollo astronauts, no human has ever seen the moon’s far side with their own eyes. That’s because the moon’s rotation period (28 days) exactly matches its orbital period (28 days) around the Earth. Other examples of tidally-locked systems in the solar system are Pluto and its largest moon Charon, Mars and both its moons Phobos and Diemos, plus a whole host of moons orbiting Jupiter, Saturn, Uranus and Neptune.

The same tidal physics applies to red dwarf stars and their closely-orbiting worlds. And Teegarden b and c have very close orbits, zipping around the star once every five and eleven days, respectively, so they are very likely tidally locked, too.

So what does a habitable zone exoplanet orbiting a red dwarf star look like? Enter the “Eyeball Earth” exoplanet:

Earth-like, right? [source: Rare Earth Wiki]

I’ve written about this hypothetical world before and it fascinates me. As temperate exoplanets orbit red dwarfs so snugly, and if they have an atmosphere, they may too look like the above artistic rendering.

Looking like an eyeball, the star-facing hemisphere of the planet will be perpetually in daylight, whereas the opposite side will be in perpetual night. The near-side will likely be an arid desert, but the far side will be frozen. Computer simulations of the atmospheric dynamics of such a world are fascinating and well worth the read. The upshot, however, is that these worlds may have dynamic atmospheres where habitability is regulated by powerful winds that blast from the star-facing hemisphere to the night-side, transporting water vapor in a surprisingly complex manner. These worlds will never be fully-habitable, but they may host in interesting array of biological opportunities nonetheless.

For example, there may be a “ring ocean” that separates the desert from the ice, where, on one side, tributaries flow into the hot hemisphere only to be evaporated by the incessant solar heating. The vapor is then transported anti-star-ward, only to be deposited as it freezes on the night-side. One could imagine this massive buildup of ice on the planets night-side as an hemisphere-wide glacier that slowly creeps sun-ward, where it melts and pools into a temperate ring ocean where the process starts all over again.

Like Earth, the atmospheric dynamics would need to be balanced perfectly and if an alien ecosystem manages to get a foothold, perhaps such a planet-wide “water cycle” could be sustained while maintaining the life that thrives within.

“Hypothetically Habitable”

So, whenever we hear about the latest exoplanetary discovery, and take note that these strange new worlds are “Earth-like” or “habitable,” it’s worth remembering that neither may be accurate. Sure, finding an Earth-sized world in orbit around their star in the habitable zone is a great place to start, but it’s just that, a start. What about its atmosphere? Does it have the right blend of atmospheric gases? Is it toxic? Does it even have an atmosphere? Whether or not an alien world has a global magnetic field could make or break its habitable potential. Does its star have sporadic temper tantrums, dousing any local planets with a terrible radiation storm?

These challenges are no stranger to the astronomers who find these worlds and speculate on their astrobiological potential, but in the excitement that proceeds the discovery of “Earth-like” and “habitable” exoplanets, the headlines are often blind to the mechanics of what really makes a world habitable. The next step will be to directly observe the atmospheres of habitable exoplanets, a feat that may be within reach when NASA’s James Webb Space Telescope (JWST) and the ESO’s Extremely Large Telescope (ELT) go online.

The fact is, we know of only ONE habitable world, all the others are hypothetically habitable—so let’s look after this one while it can still sustain the rich and diverse ecosystem we all too often take for granted.

Toxic “Habitable” Worlds Could Be Havens for Alien Microbes

Don’t forget your spacesuit: Complex lifeforms, such as humans, would not survive on many of the worlds we thought would be interstellar tropical getaways

[Pixabay]

Worlds like Earth may be even rarer than we thought.

We live on a planet that provides the perfect balance of ingredients to support a vast ecosystem. This amazing world orbits the Sun at just the right distance where water can exist in a liquid state—a substance that, as we all know, is an essential component for our biology to function. Earth is also an oddball in our solar system, being the only planet where these vast oceans of liquid water persist on its surface, all enshrouded in a thick atmosphere that provides the stage for a complex global interplay of chemical and biological cycles that, before we industrialized humans came along, has supported billions of years of uninterrupted evolution and biological diversity.

Humans, being the proud intelligent beings that we profess to be, are stress-testing this delicate balance by pumping an unending supply of carbon dioxide into the atmosphere. Being a potent greenhouse gas, we’re currently living through a new epoch in our planet’s biological history where an exponential increase in CO2 is being closely followed by an increase in global average temperatures. We are, in effect, altering Earth’s habitability. Well done, humans!

While this trend is a clear threat to the sustainability of our biosphere, spare a thought for other “habitable” worlds that may appear to have all the right stuff for complex lifeforms to evolve, but toxic levels of the very chemicals that keep these worlds habitable has curtailed the possibility of complex life from gaining a foothold.

Welcome to the Not-So-Habitable Zone

Habitable zone exoplanets are the Gold Standard for exoplanet-hunters and astrobiologists alike. Finding a distant alien world within this zone—a region surrounding any star where it’s not too hot and not too cold for water to exist on its surface, a region also known as the “Goldilocks Zone” for obvious reasons—spawns a host of questions that our most advanced telescopes in space and on the ground try to answer: Is that exoplanet Earth-sized? Does it have an atmosphere? What kind of star is it orbiting? Does its system possess a Jupiter-like gas giant? These questions are all trying to help us understand whether that world has the Earthly qualities that could support hypothetical extraterrestrial life.

(Of course, there’s the debate as to whether all life in the universe is Earth-life-like, but as we’re the only biological examples that we know of in the entire galaxy, it’s the best place to start when pondering what biological similarities extraterrestrial life may have to us.)

The habitable zone for exoplanets is a little more complicated than simply the distance at which they orbit their host stars, however. Greenhouse gases, such as carbon dioxide, can extend the area of a star’s habitable zone. For example: If an atmosphere-less planet orbits beyond the outermost edge of its habitable zone, the water it has on its surface will remain in a solid, frozen state. Now, give that planet an atmosphere laced with greenhouse gases and its surface may become warm enough to maintain the water in a liquid state, thereby boosting its habitable potential.

But how much is too much of a good thing? And how might this determination impact our hunt for truly habitable worlds beyond our own?

In a new study published in the Astrophysical Journal, researchers have taken another look at the much-coveted habitable zone exoplanets to find that, while some of the atmospheric gases are essential to maintain a temperature balance, should there be too much of the stuff keeping some of those worlds at a habitable temperature, their toxicity could curtail any lifeforms more complex than a single-celled microbe from evolving.

“This is the first time the physiological limits of life on Earth have been considered to predict the distribution of complex life elsewhere in the universe,” said Timothy Lyons, of the University of California, Riverside, and director of the Alternative Earths Astrobiology Center.

“Imagine a ‘habitable zone for complex life’ defined as a safe zone where it would be plausible to support rich ecosystems like we find on Earth today,” he said in a statement. “Our results indicate that complex ecosystems like ours cannot exist in most regions of the habitable zone as traditionally defined.”

Toxic Limits

Carbon dioxide is an essential component of our ecosystem, particularly as it’s a greenhouse gas. Acting like an insulator, CO2 absorbs energy from the Sun and heats our atmosphere. When in balance, it stops too much energy from being radiated back out into space, thereby preventing our planet from being turned into a snowball. Levels of CO2 have ebbed and flowed throughout the biological history of our planet and it has always been a minor component of atmospheric gases, but its greenhouse effect (i.e. the atmospheric heating effect) is extremely potent and the human-driven 400+ppm levels are causing dramatic climate changes that modern biological systems haven’t experienced for millions of years. That said, the CO2 levels required to keep some “habitable” exoplanets in a warm enough state would need to be a lot more concentrated than the current terrestrial levels, potentially making their atmospheres toxic.

“To sustain liquid water at the outer edge of the conventional habitable zone, a planet would need tens of thousands of times more carbon dioxide than Earth has today,” said lead author Edward Schwieterman, of the NASA Astrobiology Institute. “That’s far beyond the levels known to be toxic to human and animal life on Earth.”

In the blue zone: some of the known exoplanets that fall within the habitable zones of their stars may have an overabundance of CO (yellow/brown), at a level that is toxic to human life. Likewise, the more CO2 (from blue to white) will become toxic at a certain point. The sweet-spot is where Earth sits, with Kepler 442b (if it has a habitable atmosphere) coming in second [Schwieterman et al., 2019. Link to paper]

From their computer simulations, to keep CO2 at acceptable non-toxic levels, while maintaining planetary habitability, the researchers realized that for simple animal life to survive, the habitable zone will shrink to no more than half of the traditional habitable zone. For more complex lifeforms—like humans—to survive, that zone will shrink even more, to less than one third. In other words, to strike the right balance between keeping a hypothetical planet warm enough, but not succumbing to CO2 toxicity, the more complex the lifeform, the more compact the habitable zone.

This issue doesn’t stop with CO2. Carbon monoxide (CO) doesn’t exist at toxic levels in Earth’s atmosphere as our hot and bright Sun drives chemical reactions that remove dangerous levels of the molecule. But for exoplanets orbiting cooler stars that emit lower levels of ultraviolet radiation, such as those that orbit red dwarf stars (re: Proxima Centauri and TRAPPIST-1), dangerous levels of this gas can accumulate. Interestingly, though CO is a very well-known toxic gas that prevents animal blood from carrying oxygen around the body, it is harmless to microbes on Earth. So it may be that habitable zone exoplanets orbiting red dwarfs could be a microbial heaven, but an asphyxiation hell for more complex lifeforms that have cardiovascular systems.

While it could be argued that life finds a way—extraterrestrial organisms may have evolved into more complex states after adapting to their environments, thereby circumventing the problems complex terrestrial life has with CO2 and CO—if we are to find a truly “Earth-like” habitable world that could support human biology, these factors need to be considered before declaring an exoplanet habitable. And, besides, we might want to make the interstellar journey to one of these alien destinations in the distant future; it would be nice to chill on an extraterrestrial beach without having to wear a spacesuit.

“Our discoveries provide one way to decide which of these myriad planets we should observe in more detail,” said Christopher Reinhard, of the Georgia Institute of Technology and co-leader of the Alternative Earths team. “We could identify otherwise habitable planets with carbon dioxide or carbon monoxide levels that are likely too high to support complex life.”

Earth: Unique, Precious

Like many astronomical and astrobiological studies, our ongoing quest to explore strange, new (and habitable) worlds has inevitably led back to our home and the relationship we have with our delicate ecosystem.

“I think showing how rare and special our planet is only enhances the case for protecting it,” Schwieterman said. “As far as we know, Earth is the only planet in the universe that can sustain human life.”

So, before we test the breaking point of our atmosphere’s sustainability, perhaps we should consider our own existential habitability before its too late to repair the damage of carbon dioxide emissions. That’s the only way that we, as complex (and allegedly intelligent) lifeforms, can continue to ask the biggest questions of our rich and mysterious universe.

What Might We Name the First Mars Microbes?

I, for one, welcome our new Mars desert-dwelling overlords.

Just some random (terrestrial) microbes doing microbial things [MSU]

It’s a question I’ve been pondering for some time: if we discover microbes eking out an existence on Mars, what might they be called? At first, I presumed it would be a variation on how we designate microbial names on Earth. Something like Staphylococcus aureus but swap out the “aureus” for “ares” (Greek for “Mars”, the god of war) or … something.

As you can see, biology isn’t my strong suit and butchering Latin and Greek is all in a day’s work. So, feeling out of my depth, I decided to leave that thought alone and file the idea under “Interesting, But Needs More Research.” That’s where the topic stayed for a while; I wanted to wait for a related piece of science to appear in a journal that could be a catalyst for my question. And last week, that research surfaced. I saw my opportunity.

Searching for Martians on Earth

The Atacama Desert is an amazing place. Having visited the ESO’s Paranal Observatory and the Atacama Large Millimeter/submillimeter Array in 2016 as a lucky member of the #MeetESO team, I have first-hand experience of that extreme and breathtaking region. While driving between sites, we’d often go for hours without seeing any vegetation or life of any kind. Atacama is the driest place on Earth; its salty, parched soil is bombarded by ultraviolet radiation, and the core of the desert doesn’t receive rain for decades. But just because life isn’t obvious in the arid ‘scapes, that doesn’t mean it’s not there.

The flora and fauna that does call Atacama their home are very specialized in finding ways to thrive. On the smallest life scales, for some microbes that means living underground, which makes them very interesting organisms indeed.

In a new study, published in Frontiers in Microbiology, the results of a mock-Mars-life-hunting rover campaign in the Atacama Desert’s core have been revealed.

The research was driven, in part, to develop techniques for robotic missions to the Red Planet that will seek out alien bacteria that may be holed up in an underground colony. Remember, Mars has the same land area as Earth, so there’s a lot of real estate to search for microscopic lifeforms. Sure, scientists are smart and can narrow down potentially-habitable regions that they can drop a life-seeking robot on, but once landed on that toxic soil, what kind of methodology should they use to look for these hypothetical bacteria? The Atacama Desert makes for a decent analog of Mars; it’s very dry and its soil is laced with toxic perchlorate salts, so if microbes on Mars bear any resemblance to the nature of microbes in the Atacama, scientists can take a stab at predicting their behavior and guide their Mars rovers to the most likely places where they might be hiding.

Researchers already know that bacterial life occupies even the harshest Atacama regions, but according to team leader Stephen Pointing, a professor at Yale-NUS College in Singapore, the microbes we are familiar with are common species that live on the surface, using sunlight for energy. But Pointing isn’t so interested in what’s on the surface; his rover is fitted with a drill and extraction system that can take samples of soil from underground. During the campaign, Pointing’s team made some compelling discoveries.

“We saw that with increasing depth the bacterial community became dominated by bacteria that can thrive in the extremely salty and alkaline soils,” he told me. “They in turn were replaced at depths down to 80 centimeters by a single specific group of bacteria that survive by metabolizing methane.”

Methane. Huh. That’s interesting.

These subsurface microbes are known to science — they have been found in deep mine shafts and other subterranean environments — but they’ve never been found living under the surface of the world’s most arid region. They’ve also fine-tuned their evolution to specifically adapt to this harsh environment. “The communities of bacteria that we discovered were remarkably lacking in complexity, and this likely reflects the extreme stress under which they develop,” said Pointing.

The biggest discovery made during this research was that the subsurface colonies of bacteria were very patchy, said Pointing, a factor that will have ramifications for the search for their Martian cousins. “The patchy nature of the colonization suggest that a rover would be faced with a ‘needle in a haystack’ scenario in the search for Martian bacteria,” he said.

Desert Planet Survivor

This research is a fascinating glimpse into how Earth-based environments are being used to better understand how alien bacteria may evolve in their native environments. But the desert-thriving, methane-munching bacteria of the Atacama may also inspire their name — should they be discovered one day.

Pointing explained: “The way we assign Latin names to bacteria is based on their evolutionary relationship to each other and we measure this using their genetic code. The naming of Martian bacteria would require a completely new set of Latin names at the highest level if Martian bacteria were a completely separate evolutionary lineage — that is they evolved from a different common ancestor to Earth bacteria in a “second genesis” event [and not related to Earth life via panspermia]. If we find truly “native” Martian bacteria I would love to name one, and call it Planeta-desertum superstes, which translates in Latin to ‘survivor on the desert planet.'”

So there we have it, an answer to my question about what our Martian neighbors might be called, if we find them: Planeta-desertum superstes, the desert planet survivor.

Read more about Pointing’s research in my HowStuffWorks article “Hunting for Martians in the Most Extreme Desert on Earth

Our Universe Is a Cosmic Mixologist Looking for the Recipe of Life

Creating the conditions of interstellar space in the lab has led to a sweet discovery

The Egg Nebula, as imaged by Hubble, is a protoplanetary nebula with a young star in its core [NASA/ESA]

What do you get if you combine water with methanol and then bombard the mix with radiation? It turns out that the resulting cocktail is where the building blocks for life are found. But these chemicals aren’t bubbling out of the puddles of primordial goo pooling on some alien planet; the cocktail shaker is the frigid depths of interstellar space and the mixologist is the universe.

As described in a new study published on Tuesday in Nature Communications, a team of NASA scientists took what they knew of interstellar space and recreated it in a laboratory experiment. Interstellar space may not seem like a place where the chemistry of life could gain a foothold, but given enough time and the right ingredients, chemical reactions do happen — albeit very slowly. And if there’s one thing the universe has it’s time, and we’re beginning to understand that the cosmos we reside in could be a vast organic experiment.

“The universe is an organic chemist,” said Scott Sandford, a senior scientist in the NASA Ames Astrophysics and Astrochemistry Laboratory and co-investigator of the study. “It has big beakers and lots of time — and the result is a lot of organic material, some of which is useful to life.” 

To see what chemistry might be going on in the void between the stars, the researchers simulated this extreme environment inside a vacuum chamber at Ames that was cooled to near-absolute zero. Inside, they placed an aluminum substance and then added the gaseous mixture of water vapor and methanol, a very common carbon-based molecule that is known to exist throughout our galaxy. Holding the aluminum at such low temperatures caused a frosty layer to form upon it. Then, they irradiated the substance with ultraviolet light — a form of radiation that is abundant in stellar nurseries, for example — and found that some interesting chemical reactions had occurred.

They discovered that a variety of sugar derivatives had formed on the substance — and one of those sugars was 2-deoxyribose. Yes, the same stuff you’d find in deoxyribonucleic acid. That’s the “D” in our DNA.

But this isn’t the first time an essential ingredient for life has been created in the lab while simulating the conditions of interstellar space. In 2009, the same team announced the discovery of uracil in their laboratory experiments — a key component of ribonucleic acid (RNA), which is central to protein synthesis in living systems. Also, in 2016, a French group discovered the formation of ribose, the sugar found in RNA.

“For more than two decades we’ve asked ourselves if the chemistry we find in space can make the kinds of compounds essential to life. So far, we haven’t picked a single broad set of molecules that can’t be produced,” said Sandford in a NASA statement. 

Although these are significant discoveries that provide new insights to how and where the most basic ingredients for life may form, it’s a long way from helping us understand whether or not life is common throughout the universe. But it turns out that some of the coldest spaces in the cosmos could also be the most fertile environments for the formation of a range of chemicals that are essential for life on Earth. It’s not such a reach, then, to realize that the protoplanetary disks surrounding young stars will also contain these chemicals and, as planets form, these chemicals become an intrinsic ingredient in young planets, asteroids and comets. Over four billion years ago, when the planets condensed from our baby Sun’s nebulous surroundings, Earth may have formed with just the right abundance of molecules that form the backbone of DNA and RNA to kick-start the genesis of life on our planet. Or those ingredients were delivered here later in the frozen cores of ancient comets and asteroids.

The building blocks of life are probably everywhere, but what “spark” binds these chemicals in such a way that allows life to evolve? This question is probably well beyond our understanding for now, but it seems that if you give our Cosmic Mixologist enough time to concoct all the chemicals for life, life will eventually emerge from the cocktail.

If Aliens Pilot Interstellar Object ‘Oumuamua, They Snubbed Us

The Seti Institute has monitored the object for radio transmissions, just in case it isn’t natural

We humans are a sensitive bunch. We keep pondering the question: “are we alone?” If we consider the answer is a “yes,” we then start having an existential crisis over our place in the universe. But if the answer is a “no,” a can of worms open and we start asking even more questions. “If they’re out there, where are they?” “Isn’t it a bit weird we haven’t heard from our extraterrestrial neighbors?” “Are they just too far away for us to communicate?” and my personal favorite: “Have they consciously decided not to communicate with us because we’re considered not worth communicating with?!” The Fermi Paradox is certainly as paradoxical as they come.

Cue a random object that cruised through our solar system last year. The interstellar visitor zoomed right into our interplanetary neighborhood, used the Sun’s gravity for a cheeky course correction, and then slingshotted itself back out into deep space. The whole thing happened so quickly that astronomers only noticed when the thing was speeding away from us at high speed.

Naturally, we took a hint from science fiction, remembering Arthur C. Clarke’s classic novel “Rendezvous With Rama” — when a huge artificial object appears from interstellar space and a brave team of astronauts are sent to intercept it. Might this interstellar object also be artificial? After all, it has an odd, tumbling shape (like a spinning cigar) and the precision at which it flew past us with the trajectory it did (using the Sun to change its direction and speed of travel) just feels artificial.

So, with the help of the SETI Institute’s Allen Telescope Array (ATA) in California, astronomers decided to take aim at the departing object from 
Nov. 23 and Dec. 5, 2017, when it was 170 million miles from Earth. The objective was to listen out for artificial radio transmissions that might reveal any kind of extraterrestrial intelligence. By monitoring frequencies from 1 to 10 GHz (at 100 MHz intervals), the ATA would be able to detect a very low powered onmidirectional transmitter, with a transmitting power as low as 10 Watts — the approximate equivalent to a citizen band radio.

According to the SETI study to be published in the February 2019 issue of Acta Astronautica, no signals were detected. Though this is obviously a blow for working out whether this thing was being actively piloted by some kind of intelligence, it does narrow down the true nature of the object, that has since been named ‘Oumuamua — which, in Hawaiian, roughly means “scout,” or “messenger.”

“We were looking for a signal that would prove that this object incorporates some technology — that it was of artificial origin,” said Gerry Harp, lead author of the study, in a SETI Institute statement. “We didn’t find any such emissions, despite a quite sensitive search. While our observations don’t conclusively rule out a non-natural origin for ‘Oumuamua, they constitute important data in assessing its likely makeup.”

Although this doesn’t prove ‘Oumuamua isn’t an alien spacecraft, it does put limits on the frequencies it could be transmitting on, if it is transmitting. And even if it isn’t transmitting, it doesn’t mean it’s not artificial. Could it be an ancient spacecraft that’s been sailing the interstellar seas for millions or billions of years, long after its intelligent occupants have died? Or long after its artificial intelligence has run out of energy? 

Or — and this is the big one — did it zoom through our solar system, aware of our presence, and not bother communicating with us? If that scenario played out, we need to re-open that can o’ worms and try to understand where we stand in the universal ecosystem of competing intelligences. Perhaps we are the cosmic equivalent of an ant colony; our intelligence just isn’t worth the time when compared with the unimaginable alien intelligences that have the technology to send ‘Oumuamuas to probe distant star systems for life.

Alas, it’s probably a case of Occam’s razor, where the simplest explanation is most likely the correct one: ‘Oumuamua is probably a strange-looking asteroid or ancient comet that was randomly shot at us by some distant star system and astronomers were lucky to detect it. But, we still need to ponder the least likely explanations, you just never know…

It’s a Trap: Extraterrestrial Ozone May be Hidden at Exoplanets’ Equators

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ESO/M. KORNMESSER

Fortunately for life on Earth, our planet has an ozone layer. This high-altitude gas performs an invaluable service to biology, acting as a kind of global “sunscreen” that blocks the most damaging forms of ultraviolet radiation. Early in the evolution of terrestrial life, if there were no ozone layer, life would have found it difficult to gain a foothold.

So, in our effort to seek out exoplanets that are suitable for life, future telescopes will seek out so-called “biosignatures” in the atmospheres of alien worlds. Astrobiologists would be excited to find ozone in particular — not only for its biology-friendly, UV-blocking abilities, but also because the molecule’s building blocks (three oxygen atoms) can originate from biological activity on the planet’s surface.

But in a new study published Wednesday (Nov. 29) in the journal Monthly Notices of the Royal Astronomical Society, researchers modeling atmospheric dynamics on tidally-locked “habitable zone” exoplanets have concluded that finding ozone in these exo-atmospheres may be a lot more challenging than we thought.

Red Dwarf Hellholes

Recently, two exoplanets have taken the science news cycle by storm. The first, Proxima b, is touted as the closest temperate exoplanet beyond our solar system. Located a mere 4.22 light-years from Earth, this (presumably) rocky world orbits its star, Proxima Centauri, at just the right distance within the habitable zone. Should this world possess an atmosphere, it would receive just the right amount of energy for any water on its surface to exist in a liquid state. As liquid water is essential for life on Earth, logic dictates that life may be possible there too.

Whether or not Proxima b has the right orbit about its star is academic; there are many other factors to consider before calling it “Earth-like.” For starters, habitable zone exoplanets around red dwarfs will be “tidally locked.” Tidal locking occurs because red dwarf habitable zones are very close to the cool star; so to receive the same amount of heating as our (obviously) habitable Earth, habitable exoplanets around red dwarfs need to cuddle up close. And because they are so close, the same hemisphere will always face the star, while the other hemisphere will always face away. These strange worlds are anything but “Earth-like.”

Also, Proxima Centauri is an angry little star, blasting its locale with regular flares, irradiating its interplanetary space with X-rays, UV and high-energy particles — things that will strip atmospheres from planets and drench planetary surfaces with biology-wrecking radiation. As I’ve previously written, Proxima b is likely a hellhole. And things don’t bode well for that other “habitable” exoplanet TRAPPIST-1d, either.

It’s a Trap

But let’s just say, for astrobiology-sake, that a tidally-locked world orbiting a red dwarf does host an atmosphere and an alien biosphere has managed to evolve despite these stellar challenges. This biosphere is also pretty Earth-like in that oxygen-producing lifeforms are there and the planetary atmosphere has its own ozone layer. As previously mentioned, ozone would be a pretty awesome molecule to find (in conjunction with other biosignatures). But what if no ozone is detected? Well, according to Ludmila Carone, of the Max Planck Institute for Astronomy in Germany, and her team, not finding detecting ozone doesn’t necessarily mean it’s not there, it’s just that the atmospheric dynamics of tidally-locked worlds are very different to Earth’s.

“Absence of traces of ozone in future observations does not have to mean there is no oxygen at all,” said Carone in a statement. “It might be found in different places than on Earth, or it might be very well hidden.”

Earth’s ozone is predominantly produced at the equator where sun-driven chemical reactions occur high in the atmosphere. Atmospheric flows then transport chemicals like ozone toward the poles, giving our planet a global distribution. When carrying out simulations of tidally-locked worlds, however, Carone’s team found that atmospheric flows may operate in reverse, where atmospheric flows travel from the poles to the equator. Therefore, any ozone produced at the equator will become trapped there, greatly reducing our ability to detect it.

“In principle, an exoplanet with an ozone layer that covers only the equatorial region may still be habitable,” added Carone. “Proxima b and TRAPPIST-1d orbit red dwarfs, reddish stars that emit very little harmful UV light to begin with. On the other hand, these stars can be very temperamental, and prone to violent outbursts of harmful radiation including UV.”

So the upshot is, until we have observatories powerful enough to study these hypothetical exoplanetary atmospheres — such as NASA’s James Webb Space Telescope (JWST) or the ESO’s Extremely Large Telescope (ELT) — we won’t know. But modelling the hypothetical atmospheres of these very alien worlds will help us understand what we will, or won’t, see in the not-so-distant future.

“We all knew from the beginning that the hunt for alien life will be a challenge,” said Carone. “As it turns out, we are only just scratching the surface of how difficult it really will be.”

Repeating “Fast Radio Bursts” Detected in Another Galaxy — Probably Not Aliens, Interesting Anyway

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The Green Bank Radio Telescope (NRAO)

A radio astronomy project intended to find signals from intelligent aliens has announced the intriguing detections of “repeating” fast radio bursts (FRBs) from a single source in a galaxy three billion light-years distant. This is definitely an exciting development, but probably not for the reasons you think.

The ambitious $100 million Breakthrough Listen project aims to scan a million stars in our galaxy and dozens of nearby galaxies across radio frequencies and visible light in hopes of discovering a bona fide artificial signal that could be attributed to an advanced alien civilization. But in its quest, Breakthrough Listen has studied the signals emanating from FRB 121102 — and recorded 15 bursts — to better understand what might be causing it.

FRBs remain a mystery. First detected by the Parkes Radio Telescope in Australia, these very brief bursts of radio emissions seemed to erupt from random locations in the sky. But the same location never produced another FRB, making these bizarre events very difficult to understand and impossible to track.

Hypotheses ranged from powerful bursts of energy from supernovae to active galactic nuclei to (you guessed it) aliens, but until FRB 121102 repeated itself in 2015, several of these hypotheses could be ruled out. Supernovae, after all, only have to happen once — this FRB source is repeating, possibly hinting at a periodic energetic phenomenon we don’t yet understand. Also, because FRB 121102 is a repeater, in 2016 astronomers could trace back the location of its source to a dwarf galaxy 3 billion light-years from Earth.

Now we ponder the question: What in the universe generates powerful short bursts of radio emissions from inside a dwarf galaxy, repeatedly?

Using the Green Bank Telescope in the West Virginia, scientists of Breakthrough Listen recorded 400 TB of data over a five hour period on Aug. 26. In these data, 15 FRBs were recorded across the 4 to 8 GHz radio frequency band. The researchers noted the characteristic frequency dispersion of these FRBs, caused by the signal traveling through gas between us and the source.

Now that we have dedicated and extremely detailed measurements of this set of FRBs, astrophysicists can get to work trying to understand what natural phenomenon is generating these bursts. This is the story so far, but as we’re talking radio emissions, mysteries and a SETI project, aliens are never far away…

Probably Not Aliens

It may be exciting to talk about the possibility of aliens generating this signal — as a means of communication or, possibly, transportation via beamed energy — but that avenue of speculation is just that: speculation. But to speculate is understandable. FRBs are very mysterious and, so far, astrophysicists don’t have a solid answer.

But this mystery isn’t without precedent.

In 1967, astronomers Jocelyn Bell Burnell and Antony Hewish detected strange radio pulses emanating from a point in the sky during a quasar survey to study interplanetary scintillation (IPS). The mysterious pulses had an unnaturally precise period of 1.33 seconds. At the time, nothing like it had been recorded and the researchers were having a hard time explaining the observations. But in the back of their minds, they speculated that, however unlikely, the signal might be produced by an alien intelligence.

During a dinner speech in 1977, Bell Burnell recalled the conundrum they faced:

“We did not really believe that we had picked up signals from another civilization, but obviously the idea had crossed our minds and we had no proof that it was an entirely natural radio emission. It is an interesting problem – if one thinks one may have detected life elsewhere in the universe how does one announce the results responsibly? Who does one tell first? We did not solve the problem that afternoon, and I went home that evening very cross here was I trying to get a Ph.D. out of a new technique, and some silly lot of little green men had to choose my aerial and my frequency to communicate with us.”

This first source was nicknamed “LGM-1” (as in “Little Green Men-1”), but far from being an artificial source, the duo had actually identified the first pulsar — a rapidly-spinning, highly magnetized neutron star that generates powerful emissions from its precessing magnetic poles as it rotates.

This is how science works: An interesting signal is detected and theories are formulated as to how that signal could have been generated.

In the case of LGM-1, it was caused by an as-yet-to-be understood phenomenon involving a rapidly-spinning stellar corpse. In the case of FRB 121102, it is most likely an equally as compelling phenomenon, only vastly more powerful.

The least likely explanation of FRB 121102 makes a LOT of assumptions, namely: aliens that have become so incredibly technologically advanced (think type II or even type III on the Kardashev Scale) that they can fire a (presumably) narrow beam directly at us through intergalactic space over and over again (to explain the repeated FRB detections) — the odds of which would be vanishingly low — unless the signal is omnidirectional, so they’d need to access way more energy to make this happen. Another assumption could be that intelligent, technologically advanced civilizations are common, so it was only a matter of time before we saw a signal like FRB 121102.

Or it could be a supermassive black hole (say) doing something very energetic that science can’t yet explain.

Occam’s razor suggests the latter might be more reasonable.

This isn’t to say aliens don’t exist or that intelligent aliens aren’t transmitting radio signals, it just means the real cause of this particular FRB repeater is being generated by a known phenomenon doing something unexpected, or a new (and potentially more exciting) phenomenon that’s doing something exotic and new. It doesn’t always have to be aliens.

h/t:

TRAPPIST-1: The ‘Habitable’ Star System That’s Probably a Hellhole

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Red dwarfs can be angry little stars (NASA/GSFC/S. Wiessinger)

There are few places that elicit such vivid thoughts of exotic habitable exoplanets than TRAPPIST-1 — a star system located less than 40 light-years from Earth. Alas, according to two recent studies, the planetary system surrounding the tiny red dwarf star may actually be horrible.

For anyone who knows a thing or two about red dwarfs, this may not come as a surprise. Although they are much smaller than our sun, red dwarfs can pack a powerful space weather punch for any world that orbits too close. And, by their nature, any habitable zone surrounding a red dwarf would have to be really compact, a small detail that would bury any “habitable” exoplanet in a terrible onslaught of ultraviolet radiation and a blowtorch of stellar winds. These factors would make the space weather environment around TRAPPIST-1 extreme to say the least.

“The concept of a habitable zone is based on planets being in orbits where liquid water could exist,” said Manasvi Lingam, a Harvard University researcher who led a Center for Astrophysics (CfA) study, published in the International Journal of Astrobiology. “This is only one factor, however, in determining whether a planet is hospitable for life.”

The habitable zone around any star is the distance at which a small rocky world can orbit and receive just the right amount of heating to maintain liquid water on its hypothetical surface. Orbit too close and the water vaporizes; too far and it freezes. As life needs liquid water to evolve, seeking out exoplanets in their star’s habitable zone is a good place to start.

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The peaceful surface of a TRAPPIST-1 habitable zone exoplanet as imagined in this artist’s rendering (NASA/JPL-Caltech)

For the sun-Earth system, we live in the middle of the habitable zone, at a distance of one astronomical unit (1 AU). For a world orbiting a red dwarf like TRAPPIST-1, its orbital distance would be a fraction of that — i.e. three worlds orbit TRAPPIST-1 in the star’s habitable zone at between 2.8% and 4.5% the distance the Earth orbits the sun. This is because red dwarfs are very dim and produce meager heating — for a world to receive the same degree of heating that our planet enjoys, a red dwarf world would need to snuggle up really close to its star.

But just because TRAPPIST-1 is dim, it doesn’t mean it holds back on ultraviolet radiation. And, according to this study, the three “habitable” exoplanets in the TRAPPIST-1 system are likely anything but — they would receive disproportionate quantities of damaging ultraviolet radiation.

“Because of the onslaught by the star’s radiation, our results suggest the atmosphere on planets in the TRAPPIST-1 system would largely be destroyed,” said co-author Avi Loeb, who also works at Harvard. “This would hurt the chances of life forming or persisting.”

Life as we know it needs an atmosphere, so the erosion by UV radiation seems like a significant downer for the possible evolution of complex life.

That’s not the only bad news for our extraterrestrial life dreams around TRAPPIST-1, however. Another study carried out by the CfA and the University of Massachusetts in Lowell (and published in The Astrophysical Journal Letters) found more problems. Like the sun, TRAPPIST-1 generates stellar winds that blast energetic particles into space. As these worlds orbit the star so close, they would be sitting right next to the proverbial nozzle of a stellar blowtorch — models suggest they experience 1,000 to 100,000 times stellar wind pressure than the solar wind exerts on Earth.

And, again, that’s not good news if a planet wants to hold onto its atmosphere.

“The Earth’s magnetic field acts like a shield against the potentially damaging effects of the solar wind,” said Cecilia Garraffo of the CfA and study lead. “If Earth were much closer to the sun and subjected to the onslaught of particles like the TRAPPIST-1 star delivers, our planetary shield would fail pretty quickly.”

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The TRAPPIST-1 exoplanet family. TRAPPIST-1 e, f and g are located in the system’s habitable zone (NASA/JPL-Caltech)

So it looks like TRAPPIST-1 e, f and g really take a pounding from their angry little star, but the researchers point out that it doesn’t mean we should forget red dwarfs as potential life-giving places. It’s just that life would have many more challenges to endure than we do on our comparatively peaceful place in the galaxy.

“We’re definitely not saying people should give up searching for life around red dwarf stars,” said co-author Jeremy Drake, also from CfA. “But our work and the work of our colleagues shows we should also target as many stars as possible that are more like the sun.”

The ‘Alien Megastructure’ Star Is Doing Weird Things Again

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NASA (edit by Ian O’Neill)

In our quest to understand what the heck is going on with Tabby’s Star, astronomers have been given a cosmic gift — a dimming event is happening right now and they’re collecting data in real time.

Early Friday morning, the star — officially designated KIC 8462852 — dipped in brightness inextricably and bulletins started to fly around the internet. Astronomers involved in the original discovery took to Twitter to announce the awesomeness and rally the world’s observatories to point their telescopes at the action 1,300 light-years away:

But why all the excitement? Well, this is the same star that, last year, hogged the headlines with speculation that a super advanced alien civilization was building some kind of “megastructure” around the star. (You can read my article on it here.) But why would the world’s media, let alone professional scientists, be okay with even hinting at the “alien” thing?

Well, as part of the Planet Hunters project, Tabby’s Star is wonderfully weird. After analyzing observations from NASA’s exoplanet-hunting Kepler Space Telescope, the citizen scientists noticed something peculiar.

Usually, Kepler’s ultra-sensitive optics detect the slight dimming of stars when any planets in orbit drift in front — an event known as a “transit.” These transits are typically very slight, but the signals detected at KIC 8462852 were mind-boggling. Between 2011 and 2013, Tabby’s Star exhibited a series of dips, dimming the brightness of the star by over 20 percent. Tabby’s Star was so-named after astronomer Tabetha Boyajian who led this research. Further studies of the star has also revealed a longer period of dimming.

And on Friday morning, it started happening again.

“At about 4 a.m. this morning, I got a phone call from Tabby [Boyajian] saying that Fairborn [Observatory] in Arizona had confirmed that the star was 3 percent dimmer than it normally is and that is enough that we are absolutely confident that this is no statistical fluke,” said Jason Wright, an associate professor of astronomy at Pennsylvania State University, during a live webcast. “We’ve now got it confirmed at multiple observatories I think.”

Now that astronomers are able to observe the star while the dimming is happening live (rather than studying past observations, which as been the case up until now), spectra of the star can be recorded and compared to previous data. This spectral information might reveal what material is causing the weird transit signals, potentially ruling some hypotheses out. But it might also create new questions.

Many hypotheses have been put forward for these unprecedented events before Friday. The most popular natural explanation has been the possibility that a giant “swarm” of comets drifted between the star and us, blocking the starlight. But this explanation falls short and doesn’t really explain why the brightness dips are so dramatic.

The most popular unnatural explanation is — you guessed italiens and astronomers are having a really hard job disproving this hypothesis. This idea is based around the possibility that a super advanced alien civilization (that’s well on its way to becoming a type II Kardashev civilization) is building a star-spanning solar array, akin to a Dyson swarm. In this scenario, the dimming in brightness would be caused by vast solar arrays blocking the light from view.

Now that the dimming is happening again, it will be interesting to see how the megastructure idea evolves.

Although imagining super-advanced aliens building stuff around a nearby star is fun, this episode so early in our hunt for extrasolar worlds is giving us a glimpse of just how strange our galaxy can be. In all likelihood, it probably isn’t an alien megastructure and more likely something astronomers have completely overlooked. But it could also be that these Kepler data are being caused by a natural stellar phenomenon that we’ve never seen before — a possibility that could be revealed very soon.

Enceladus Could Be a Cosmic Shaker for the Cocktail of Life

NASA/JPL-Caltech/Space Science Institute

A little frozen Saturn moon, with a diameter that could easily fit inside the state of New Mexico, holds some big promises for the possibility of finding basic alien life in our solar system.

Enceladus is often overshadowed by its larger distant cousin, Europa, which orbits Jupiter and the Jovian moon’s awesome potential has been widely publicized. But Enceladus has one thing Europa doesn’t — it has been visited very closely by a robotic space probe that could take a sniff of its famous water vapor plumes. And this week, there was much excitement about another facet of the moon’s complex subsurface chemistry, thanks to analysis carried out on data gathered by NASA’s Cassini mission.

But before we get into why this new discovery is so cool, let’s take a very quick look at the other signs of Enceladus’ life-giving potential.

The Cocktail Of Life

Being living, breathing creatures on a habitable planet, it may not come as a surprise to you that for biology to evolve, it needs a few basic ingredients. Liquid water is a definite requirement, of course. Heat also helps. Throw some organic chemistry into the mix and we have a party.

Enceladus, however, is a tiny icy globe, there’s no sign of liquid water on its surface. But when Cassini arrived at Saturn in 2004, Enceladus revealed some of its best-kept secrets. Firstly, it may be a smooth ice ball, but the moon has a large quantity of water under its surface. This water even escapes as geysers, through fissures in its icy crust, producing stunning plumes that eject material hundreds of miles high and into Saturn’s rings.

Before Cassini was launched to Saturn, we had little clue about Enceladus’ watery potential — though this finding explained why Enceladus appeared so bright and how it contributes material to Saturn’s E-ring. Fortunately, the spacecraft has an instrument on board — a mass spectrometer — that could be used to “taste” the watery goodness of these plumes. During its Enceladus flybys, Cassini was able to fly through the plumes, revealing a surprisingly rich chemical cocktail — including a high concentration of organic chemistry.

It’s as if all the building blocks of life have been thrown into a small icy cocoon, shaken up and gently heated from within.

Now, another fascinating discovery has been made. Further analysis of Cassini data from its last 2015 plume fly-through, molecular hydrogen has been detected and planetary scientists are more than a little excited to add this to Enceladus’ habitable repertoire.

Deep In The Enceladus Abyss

“Hydrogen is a source of chemical energy for microbes that live in the Earth’s oceans near hydrothermal vents,” said Hunter Waite, principal investigator of Cassini’s Ion Neutral Mass Spectrometer (INMS) at the Southwest Research Institute (SwRI), in a statement on Thursday (April 13). “Our results indicate the same chemical energy source is present in the ocean of Enceladus.”

This hydrogen could be a byproduct of chemical reactions going on between the moon’s rocky core and the warm water surrounding it. And there’s a lot of hydrogen gas being vented, probably enough to sustain basic lifeforms deep in the Enceladus abyss.

“The amount of molecular hydrogen we detected is high enough to support microbes similar to those that live near hydrothermal vents on Earth,” added co-author Christopher Glein, who specializes in extraterrestrial chemical oceanography, also of SwRI. “If similar organisms are present in Enceladus, they could ‘burn’ the hydrogen to obtain energy for chemosynthesis, which could conceivably serve as a foundation for a larger ecosystem.”

Yes, we’re talking alien microbes. (Also, “extraterrestrial chemical oceanography” — oceans on other worlds! — is one hell of a mind-blowing topic to specialize in, just sayin’.) And did he mention “larger ecosystem”? Why yes! Yes he did.

So, in short, we know Enceladus has a liquid water ocean. We know that it has an internal heat source (hence the liquid oceans). We also know there’s organic chemistry. And now there’s solid hints that there’s water-rock interactions going on that terrestrial microbes living at Earth’s ocean vents like to munch on. If that’s not a huge, blinking neon sign pointing at Enceladus, saying: “We need a surface mission here!” I don’t know what is.

Although the researchers are keen to emphasize that alien microbes have not been found (because Cassini isn’t capable of looking for life), the universe has given us a moon-sized Petri dish where an “ecosystem” may have taken hold. All the ingredients are there, wouldn’t it be cool to find out if Enceladus could be another place in the solar system where life may be hanging out?

There was also some great news about Europa’s habitable potential this week, but you can go here for that piece of cosmic awesomeness.

Want to know more about Cassini’s final months at Saturn, check out my recent Space.com article on the commencement of the veteran mission’s Grand Finale.