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

Oldest Earth Rock Found In Lunar Exile

When our young planet was taking a beating by massive impacts, bits were ejected into space—and some ended up on the moon.


An artist’s impression of what our planet probably looked like over 4 billion years ago, during the violent Hadean epoch [Simone Marchi (SwRI), SSERVI, NASA]

This is an interesting thought: When Apollo astronauts were busy exploring the lunar surface, it wasn’t just moon rocks that were crunching beneath their moon boots—bits of Earth were there too. But how did Earth stuff get mixed-in with moon stuff?

According to a new study published in the journal Earth and Planetary Science Letters, this question may be a controversial one, but it’s not without some compelling evidence.

During the Apollo 14 moon landing in February 1971, when NASA astronauts Alan Shepard and Ed Mitchell were exploring the Fra Mauro Highlands, they scooped up some moon rocks and returned them to Earth for study. Fast-forward 48 years and an international group of researchers think that a 2 gram shard of rock in one of their scoops has terrestrial origins. That is a cool find in itself, but this particular sample is ancient, and possibly the oldest sample of Earth rock ever found, heralding from a time when the Earth was a very different place.

Between 4 and 4.6 billion years ago, our planet was a mess. Still in the process of forming, it was getting pummeled by an incessant barrage of asteroids and comets. Many parts of the Earth’s surface would have been molten, all of it would have been cratered, and none of the continents or oceans that we are familiar with today would have been present (see the image at the top of this page for an imagining of what it may have looked like). This was the Hadean epoch — named after the Greek god of the underworld, Hades — and it would have been a hellish time.

Apollo 14’s Ed Mitchell using a map during an EVA [NASA]

With all these impacts, large and small, it seems logical to think that a few of these impacts would have been large enough to launch a sizable quantity of debris into space. Back then, the moon orbited Earth much closer than it does now — four times closer in fact (which is a cool thought; the moon would have loomed four times larger in Hadean skies than it does now). As the moon was closer, there would have been higher odds of the terrestrial collision debris to come crashing down on the lunar surface. And this was the beginning of the epic journey of the 2 gram shard of rock that was returned to Earth and now lives in a lab.

The international team of researchers are associated with the Center for Lunar Science and Exploration, a part of NASA’s Solar System Exploration Research Virtual Institute, and they carried out a new analysis technique to search for Earth rocks in the Apollo moon samples. In one of the samples was a piece that is composed of quartz, feldspar, and zircon. These minerals are all common on Earth, but not on the lunar surface. Their interest was piqued. Further chemical analysis of the sample revealed how the rock formed: it crystallized in an oxidized atmosphere at temperatures more akin to Earth’s at the time. Moon rock typically crystallized at much higher temperatures devoid of an oxygen-rich atmosphere. The implication is clear: this particular sample didn’t form on the moon, it formed on Hadean Earth. But its journey from the Earth to the moon and into an Apollo astronaut’s sample scoop is quite the epic story.

A sample of moon rock collected by Apollo 14 astronauts [NASA]

Through the chemical analysis on the sample, a surprising amount of detail about the hows and whens could be deduced. First, after considering the mineral components of the sample, the rock must have formed around 20 kilometers under the surface, in young Earth’s crust, approximately 4.1 billion years ago. At the time, it wasn’t uncommon for massive impacts to excavate craters thousands of kilometers wide. These impact events would have easily have reached 20 kilometers deep, blasting some Earth stuff into space. The 2-gram sample was likely part of a bigger chunk that eventually collided with the moon, creating its own lunar crater, where it remained, in relative peace for a couple of hundred million years. Then, around 3.9 billion years ago, another lunar impact pummeled the sample, partially melting it, burying it deeper under the moon’s surface.

This sample holds this incredible record of geological history of a time when massive impacts were very common, when planets were accreting mass and life was just beginning to emerge on an embryonic Earth. After that lunar impact, the sample remained buried in moon rock for a few billion years.

Then, 26 million years ago, a comparatively small meteoroid slammed into the moon to create the 340-meter wide Cone Crater. The 2-gram sample was once again kicked onto the moon’s surface where it was randomly scooped by Shepard or Mitchell in 1971. The photograph below shows the boulders at the rim of Cone Crater where the sample was collected:


A photo taken on the Apollo 14 mission in the Fra Mauro highlands of the moon showing a cluster of boulders on the rim of Cone Crater during EVA-2 [NASA]

Although it may be logical to assume that ancient rocky debris from Earth likely ended up on the moon’s surface, it’s phenomenal that a tiny piece of Hadean Earth was discovered in an Apollo 14 sample. This could be an indicator as to how common it is; Earth rock preserved for billions of years on a world with no weather or tectonic processes continually erasing signs of the geological past, helping us better understand how our planet evolved.

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.

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

eso1736a-rotated (1)
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.”

Heavy Stellar Traffic Sends Dangerous Comets Our Way

New image of comet ISON
Comet C/2012 S1 (ISON) as imaged by TRAPPIST–South national telescope at ESO’s La Silla Observatory in 2013 (TRAPPIST/E. Jehin/ESO)

Sixty-six million years ago Earth underwent a cataclysmic change. Back then, our planet was dominated by dinosaurs, but a mass extinction event hastened the demise of these huge reptiles and paved the way for the mammalian takeover. Though there is some debate as to whether the extinction of the dinosaurs was triggered by an isolated disaster or a series of disasters, one event is clear — Earth was hit by a massive comet or asteroid and its impact had global ramifications.

The leading theory is that a massive comet slammed into our planet, creating the vast Chicxulub Crater buried under the Yucatán Peninsula in Mexico, enshrouding the atmosphere in fine debris, blotting out the sun for years.

Although there is strong evidence of comet impacts on Earth, these deep space vagabonds are notoriously hard to track, let alone predict when or how often they may appear. All we know is that they are out there, there are more than we thought, they are known to hit planets in the solar system and they can wreak damage of apocalyptic proportions.

Now, using fresh observations from the European Space Agency’s Gaia mission, astronomer Coryn Bailer-Jones, who works at the Max Planck Institute for Astronomy in Munich, Germany, has added an interesting component to our understanding of cometary behavior.

Stellar Traffic

Long-period comets are the most mysterious — and troubling — class of comet. They will often appear from nowhere, after falling from their distant gravitational perches, zoom through the inner solar system and disappear once more — often to be never seen again. Or they hit something on their way through. These icy bodies are the pristine left-overs of our solar system’s formation five billion years ago, hurled far beyond the orbits of the planets and into a region called the Oort Cloud.

In the Oort Cloud these ancient masses have remained in relative calm far from the gravitational instabilities close to the sun. But over the eons, countless close approaches by other stars in our galactic neighborhood have occurred, causing very slight gravitational nudges to the Oort Cloud. Astronomers believe that such stellar encounters are responsible for knocking comets from this region, sending them on a roller-coaster ride to the inner solar system.

The Gaia mission is a space telescope tasked with precisely mapping the distribution and motion of stars in our galaxy, so Bailer-Jones has investigated the rate of stellar encounters with our solar system. Using information in Gaia’s first data release (DR1), Bailer-Jones has published the first systematic estimate of stellar encounters — in other words, he’s estimated the flow of stellar traffic in the solar system’s neighborhood. And the traffic was found to be surprisingly heavy.

In his study, to be published in the journal Astronomy & Astrophysics, Bailer-Jones estimates that, on average, between 490 and 600 stars will come within 16.3 light-years (5 parsecs) of our sun and 19-24 of them will come within 3.26 light-years (1 parsec) every million years.

According to a press release, all of these stars will have some gravitational effect on the solar system’s Oort Cloud, though the closest encounters will have a greater influence.

This first Gaia data release is valid for five million years into the past and into the future, but astronomers hope the next data release (DR2) will be able to estimate stellar traffic up to 25 million years into the past and future. To begin studying the stellar traffic that may have been responsible for destabilizing the dinosaur-killing comet that hit Earth 66 million years ago will require a better understanding of the mass distribution of our galaxy (and how it influences the motion of stars) — a long-term goal of the Gaia project.

An Early Warning?

Spinning this idea into the future, could this project be used to act as an early warning system? Or could it be used to predict when and where a long-period comet may appear in the sky?

In short: “No,” Bailer-Jones told Astroengine via email. “Some close stellar encounters will for sure shake up the Oort cloud and fling comets into the inner solar system, but which comets on which orbits get flung in we cannot observe.”

He argues that the probability of comets being gravitationally nudged can be modeled statistically, but this would require a lot of assumptions to be made about the Oort Cloud, a region of space that we know very little about.

Also, the Oort Cloud is located well beyond the sun’s heliosphere and is thought to be between 50,000 and 200,000 AU (astronomical units, where 1 AU is the average distance between the sun and the Earth) away, so it would take a long time for comets to travel from this region, creating a long lag-time between stellar close approach and the comet making an appearance.

“Typically it takes a few million years for a comet to reach the inner solar system,” he added, also pointing out that other factors can complicate calculations, such as Jupiter’s enormous gravity that can deflect the passage of comets, or even fling them back out of the solar system again.

This is a fascinating study that goes to show that gravitational perturbations in the Oort Cloud are far from being rare events. A surprisingly strong flow of stellar traffic will constantly rattle otherwise inert comets, but how many are dislodged and sent on the long journey to the solar system’s core remains a matter for statistics and probability.

The Solar Eclipse Is Going to Cost the U.S. $700 Million? Good.

annular
A photo of the 2012 annular eclipse from Malibu, Calif., using an old digital camera and solar filter (Ian O’Neill)

The U.S. media is currently saturated with hot takes, histories, weird facts, “how to’s” and weather reports around the Great American Eclipse that will glide across the continent on Monday (yes, THIS Monday, it’s finally here). But, today, one news report stood out from the crowd:

Inevitably, Twitter had an opinion about this.

On reading the NBC News report (that was penned by an unknown Reuters writer), it is as tone deaf as the headline.

“American employers will see at least $694 million in missing output for the roughly 20 minutes that outplacement firm Challenger, Gray & Christmas estimates workers will take out of their workday on Monday to stretch their legs, head outside the office and gaze at the nearly two-and-a-half minute eclipse,” they write.

“Stretch their legs” for a “two-and-a-half minute eclipse,” — wow, what a waste of time. Worse than that, “[m]any people may take even longer to set up their telescopes or special viewing glasses, or simply take off for the day.” Unbelievable. Those skiving freeloaders.

How dare they take some time to step away from their computer screens to take a little time to gaze in awe at the most beautiful and rare natural celestial event to occur on our planet.

How dare they put pressure on the U.S. economy by bleeding hundreds of millions of dollars in lost revenue from the monstrous multi-trillion dollar consumerist machine.

How dare they be moved to tears as the moon completely blocks the sun, an event that has caused fear, suspicion, omen, wonderment, joy, inspiration, excitement and unadulterated passion throughout the history of our species.

How dare th— oh wait a minute. The lede appears to be buried:

“Compared to the amount of wages being paid to an employee over a course of a year, it is very small,” Challenger said. “It’s not going to show up in any type of macroeconomic data.”

So what you’re staying is, $700 million won’t even show up as a blip in economic analyses? Tell me more.

“It also pales when compared with the myriad other distractions in the modern workplace, such as March Madness, Cyber Monday, and the Monday after the Super Bowl,” they write. Well, whatdoyouknow, the Super Bowl is a distraction too? Those monsters.

So what you’re saying is, this isn’t really news. As a science news producer, I completely understand the pressures to keep up with the news cycle and finding fresh takes on tired stories (and let’s face it, 2017 has seen its fair share of eclipse articles). But for this particular angle, I think I would have most likely relegated the “lost” revenue to a footnote in a more informative and less clickbaity piece.

Monday’s eclipse will do untold good to this nation. The U.S. is going through a tumultuous stage in its young history, to put it mildly. This nation needs perspective to overcome the ineptitude, anti-science rhetoric and messages of segregation coming from its government; it needs an event that will be enjoyed by everyone, not just a fortunate subsection of society or the elite. The eclipse will inspire millions of people to look up (safely!) and ponder why is it that our planet’s only natural satellite can exactly fit into the disk of the sun.

Astronomy is an accessible gateway to the sciences and the eclipse will inspire, catalyzing many young minds to consider a future in STEM fields of study. This will enrich society in a myriad of ways and the economic gains from events such as Monday’s eclipse will make “$700 million” look like a piss in a swimming pool.

So, you know what? I’m glad this eclipse will “cost” the U.S. $700 million — I see it as an accidental investment in the future of this nation, a healthy nation that will hopefully put the antiscience stance of its current leaders behind it.

Want more eclipse stuff? Here’s a couple of my favorite angles:
How Eclipses Reveal Information About Alien Worlds, Light-Years Away
How a Total Solar Eclipse Helped Prove Einstein Right About Relativity

Also, be sure to view the eclipse safely:
Total Solar Eclipse 2017: When, Where and How to See It (Safely)

Sorry, Proxima Centauri Is Probably a Hellhole, Too

proximab
The surface of Proxima b as imagined in this artist’s impression. Sadly, the reality probably doesn’t include an atmosphere (ESO/M. Kornmesser)

The funny thing about habitable zones is that they’re not necessarily habitable. In fact, depending on the star, some of them are likely downright horrible.

Take, for example, the “habitable zone exoplanet” orbiting our neighboring star Proxima Centauri. When the discovery of Proxima b was announced last year, the world erupted with excitement. After all, astronomers had detected an Earth-sized world right on our galactic doorstep, a mere four light-years away.

Immediately there was discussion about Proxima b’s habitable potential (could there be aliens?) and the possibility of the world becoming an interstellar target (might we one day go there on vacation?).

Alas, for the moment, these exo-dreams are pure fantasy as the only things we know about this world are its mass and its orbital period around the star. We have no clue about the composition of this exoplanet’s atmosphere — or even if it has an atmosphere at all. And, according to new research published in The Astrophysical Journal Letters, Proxima b would probably be a very unlikely place to find extraterrestrial life and you’d be ill advised to invest in a vacation home there.

Like TRAPPIST-1 — that other star system that contains “habitable, but probably not so habitable” exoplanets — Proxima Centauri is a red dwarf star. By their nature, red dwarfs are small and cooler than our sun. Their habitable zones are therefore very compact; to receive enough heating energy to keep water in a liquid state on their surfaces, any “habitable” red dwarf exoplanets would need to snuggle up really close to their star. Liquid water (as we all know) is essential for life. So, if you want to find life as we know it (not that weird Titan life), studying habitable zone planets would be a good place to start. And as red dwarfs are abundant in our galaxy, seeking out habitable zone planets in red dwarf star systems would, at first, seem like an even better place to start.

Except, probably not.

Red dwarfs are angry. They erupt with powerful flares, have powerful stellar winds and their habitable zones are awash with intense ultraviolet radiation. And, like TRAPPIST-1, Proxima Centauri probably wouldn’t be a great place to live.

But the researchers decided to test this hypothesis by throwing Earth in at the deep end.

“We decided to take the only habitable planet we know of so far — Earth — and put it where Proxima b is,” said Katherine Garcia-Sage, a space scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md., and lead author of the study.

The big advantage for Earth is that it possesses a powerful global magnetic field that can deflect our sun’s solar wind and coronal mass ejections with a minimum of effort. But put Earth in a habitable zone orbit around Proxima Centauri and bad stuff starts to happen, fast.

At this location, the intensity of extreme ultraviolet radiation becomes a problem. Using data from NASA’s Chandra X-ray Observatory, the researchers could gauge the star’s activity and how much radiation would hit Proxima b. According to their calculations, the exoplanet receives hundreds of times more extreme ultraviolet radiation than Earth receives from our sun and, even if we assume Proxima b has an “Earth-like” magnetosphere, it will lose its atmosphere very quickly.

As ultraviolet radiation will ionize the exoplanet’s atmosphere, electrons (that are negatively charged) will be readily stripped from light atoms (hydrogen) and eventually the heavier atoms too (like oxygen and nitrogen). As the electrons are lost to space, a powerful “charge separation” is created and the positively charged ions that are left behind in the atmosphere will be dragged with the electrons, causing them to also be lost to space. Granted, the global magnetic field will have an effect on the rate of atmosphere loss, but the researchers estimate that this process will drain an atmosphere from Proxima b 10,000 times faster than what happens on Earth.

“This was a simple calculation based on average activity from the host star,” added Garcia-Sage. “It doesn’t consider variations like extreme heating in the star’s atmosphere or violent stellar disturbances to the exoplanet’s magnetic field — things we’d expect provide even more ionizing radiation and atmospheric escape.”

In the worst-case scenario, where the outer atmospheric temperatures are highest and the planet exhibits an “open” field line configuration, Proxima b would lose the equivalent of the whole of Earth’s atmosphere in just 100 million years. If the atmospheric temperatures are cool and a “closed” magnetic field line configuration is assumed, it will take 2 billion years for the atmosphere to be completely lost to space. Either way you look at it, unless the atmosphere is being continuously replaced (perhaps by very active volcanism), Proxima b will have very little chance to see life evolve.

“Things can get interesting if an exoplanet holds on to its atmosphere, but Proxima b’s atmospheric loss rates here are so high that habitability is implausible,” said Jeremy Drake, of the Harvard-Smithsonian Center for Astrophysics and study co-author. “This questions the habitability of planets around such red dwarfs in general.”

The Sun Just Unleashed a Massive Explosion — at Mars

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NASA/ESA/SOHO

The Earth and Mars are currently on exact opposite sides of the sun — a celestial situation known as “Mars solar conjunction” — a time when we have no way of directly communicating with satellites and rovers at the Red Planet. So, when the Solar and Heliospheric Observatory (SoHO) spotted a huge (and I mean HUGE) bubble of superheated plasma expand from the solar disk earlier today (July 23), it either meant our nearest star had launched a vast coronal mass ejection directly at Earth or it had sent a CME in the exact opposite direction.

As another solar observatory — the STEREO-A spacecraft — currently has a partial view of the other side of the sun (it orbits ahead of Earth’s orbit, so it can see regions of the sun that are out of view from our perspective), we know that this CME didn’t emanate from the sun’s near side, it was actually launched away from us and Mars will be in for some choppy space weather very soon.

It appears the CME emanated from active region (AR) 2665, a region of intense magnetic activity exhibiting a large sunspot.

“If this explosion had occurred 2 weeks ago when the huge sunspot was facing Earth, we would be predicting strong geomagnetic storms in the days ahead,” writes Tony Phillips of Spaceweather.com.

CMEs are magnetic bubbles of solar plasma that are ejected at high speed into interplanetary space following a magnetic eruption in the lower corona (the sun’s lower atmosphere). From STEREO-A’s unique vantage point, it appears the CME detected by SoHO was triggered by a powerful solar flare that generated a flash of extreme-ultraviolet radiation (possibly even generating X-rays):

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Observation by STEREO-A of the flaring event that likely triggered today’s CME (NASA/STEREO)

When CMEs encounter Earth’s global magnetic field, the radiation environment surrounding our planet increases, posing a hazard for satellites and unprotected astronauts. In addition, if the conditions are right, geomagnetic storms may commence, creating bright aurorae at high latitudes. These storms can overload power grids on the ground, triggering mass blackouts. Predicting when these storms will occur is of paramount importance, so spacecraft such as SoHO, STEREO and others are constantly monitoring our star’s magnetic activity deep inside the corona and throughout the heliosphere.

Mars, however, is a very different beast to Earth in that it doesn’t have a strong global magnetosphere to shield against incoming energetic particles from the sun, which the incoming CME will be delivering very soon. As it lacks a magnetic field, this CME will continue to erode the planet’s thin atmosphere, stripping some of the gases into space. Eons of space weather erosion has removed most of the Martian atmosphere, whereas Earth’s magnetism keeps our atmospheric gases nicely contained.

When NASA and other space agencies check in with their Mars robots after Mars solar conjunction, it will be interesting to see if any recorded the space weather impacts of this particular CME.

h/t Spaceweather.com

Great Balls of ‘Space Mud’ May Have Built Earth and Delivered Life’s Ingredients

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Artist’s impression of the molten surface of early Earth (NASA)

When imagining how our planet formed 4.6 billion years ago from the protoplanetary disk surrounding our sun, images of large pieces of marauding space rock slamming into the molten surface of our proto-Earth likely come to mind.

But this conventional model of planetary creation may be missing a small, yet significant, detail. Those massive space rocks may not have been the conventional solid asteroids — they might have been massive balls of space mud.

This strange detail of planetary evolution is described in a new study published in the American Association for the Advancement of Science (AAAS) journal Science Advances and it kinda makes logical sense.

Using the wonderfully-named Mars and Asteroids Global Hydrology Numerical Model (or “MAGHNUM”), planetary scientists Phil Bland (Cornell University) and Bryan Travis (Planetary Science Institute) simulated the movement of material inside primordial carbonaceous chondrite asteroids — i.e. the earliest asteroids that formed from the sun’s protoplanetary disk that eventually went on to become the building blocks for Earth.

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A simulated cross section of a 200-meter wide asteroid showing its internal temperature profile and convection currents (temperatures in Celsius). Credit: PSI

It turns out that these first asteroids weren’t cold and solid lumps of rock at all. By simulating the distribution of rock grains inside these asteroids, the researchers realized that the internal heat of the objects would have melted the icy volatiles inside, which then mixed with the fine dust particles. Convection would have then dominated a large portion of these asteroids, causing continuous mixing of water and dust. Like a child squishing a puddle of dirt to create sloppy “mud pies,” this convection would have formed a ball of, you guessed it, space mud.

Travis points out that “these bodies would have accreted as a high-porosity aggregate of igneous clasts and fine-grained primordial dust, with ice filling much of the pore space. Mud would have formed when the ice melted from heat released from decay of radioactive isotopes, and the resulting water mixed with fine-grained dust.”

In other words: balls of mud held together by mutual gravity, gently convected by the heat produced by the natural decay of radioactive materials.

Should this model hold up to further scrutiny, it has obvious implications for the genesis of life on Earth and could impact the study of exoplanets and their habitable potential. The ingredients for life on Earth originated in the primordial protoplanetary soup, but until now the assumption has been that the space rocks carrying water and other chemicals were solid and frozen. If they were in fact churning away in space as dynamic mud asteroids, they could have been the “pressure cookers” that delivered those ingredients to Earth’s surface.

So the next question would be: how did these exotic asteroids shape life on Earth?

Cassini Sees Earth and Moon Through Saturn’s Rings

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NASA/JPL-Caltech/Space Science Institute

NASA’s Cassini mission sure has a knack for putting stuff into perspective — and this most recent view from Saturn orbit is no different. That dot in the center of the image isn’t a dud pixel in Cassini’s camera CCD. That’s us. All of us. Everyone.

To quote Carl Sagan:

“Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives…”

Sagan wrote that passage in his book “Pale Blue Dot: A Vision of the Human Future in Space” when reflecting on the famous “Pale Blue Dot” image that was beamed back to Earth by NASA’s Voyager 1 spacecraft in 1990. That’s when the mission returned a profound view of our planet from a distance of 3.7 billion miles (or 40.5AU) as it was traveling through the solar system’s hinterlands, on its way to interstellar space. Since then, there’s been many versions of pale blue dots snapped by the armada of robotic missions around the solar system and Cassini has looked back at us on several occasions from its orbital perch.

Now, just before Cassini begins the final leg of its Saturnian odyssey, it has again spied Earth through a gap between the gas giant’s A ring (top) and F ring (bottom). In a cropped and enhanced version, our moon is even visible! The image is composed of many observations captured on April 12, stitched together as a mosaic when Saturn was 870 million miles (roughly 9.4AU) from Earth.

On April 20 (Friday), Cassini will make its final flyby of Titan, Saturn’s largest moon, using its gravity to fling itself through Saturn’s ring plane (on April 26) between the innermost ring and the planet’s cloudy upper atmosphere, revealing a view that we’ve never before seen. For 22 orbits, Cassini will dive into this uncharted region, possibly revealing new things about Saturn’s evolution, what material its rings contain and incredibly intimate views of its atmosphere.

This daring maneuver will signal the beginning of the end for this historic mission, however. On Sept. 15, Cassini will be intentionally steered into Saturn’s atmosphere to burn up as a human-made meteor. It is low in fuel, so NASA wants to avoid the spacecraft from crashing into and contaminating one of Saturn’s potentially life-giving moons — Titan or Enceladus.

So, appreciate every image that is captured by Cassini over the coming weeks. The pictures will be like nothing we’ve seen before of the ringed gas giant, creating a very bittersweet phase of the spacecraft’s profound mission to Saturn.