Catching a Star’s Helium Flash

Old stellar flashers will be caught in the act in the not-so-distant future, whether they like it or not.

[Smithsonian]

While we have a pretty good idea about how stars like our Sun work, observing all the details that unfold over millions to billions of years of stellar evolution can be difficult, especially if the phenomena occur over short timescales. Take, for example, a particularly explosive and relatively short-lived period our Sun is expected to experience in roughly five billion years.

This event is predicted to happen after our nearest star has burned up all of its hydrogen fuel and starts to burn helium. This is the beginning of the end; the Sun will swell into a vast red giant, ejecting its upper layers of plasma into space via violent solar winds, brightening 1,000 times than it is today. Needless to say, this will be a terribly dramatic time for our solar system (and a definitive apocalypse for anything that remains of our planet’s biosphere), but it will be on the verge of something even more dramatic: a helium flash.

As the solar core starts using helium as fuel, the fusion process will generate carbon and as this begins, a powerful eruption of energy will detonate, as detailed by a UC Santa Barbara statement:

A star like the sun is powered by fusing hydrogen into helium at temperatures around 15 million K. Helium, however, requires a much higher temperature than hydrogen, around 100 million K, to begin fusing into carbon, so it simply accumulates in the core while a shell of hydrogen continues to burn around it. All the while, the star expands to a size comparable to the Earth’s orbit. Eventually, the star’s core reaches the perfect conditions, triggering a violent ignition of the helium: the helium core flash. The core undergoes several flashes over the next 2 million years, and then settles into a more static state where it proceeds to burn all of the helium in the core to carbon and oxygen over the course of around 100 million years.

While the helium flashes of old Sun-like stars have been predicted for 50 years, we have yet to actually observe any kicking off in our galaxy, which isn’t so surprising considering it’s only comparatively recently that we’ve developed the techniques that are capable of precisely measuring the brightness fluctuations of distant stars. This might be about to change, according to a new study published in Nature Astronomy Letters.

“The availability of very sensitive measurements from space has made it possible to observe subtle oscillations in the brightness of a very large number of stars,” said coauthor Jørgen Christensen-Dalsgaard, of the UC Santa Barbara’s Kavli Institute for Theoretical Physics (KITP).

Christensen-Dalsgaard is referring to the growing number of space-based observatories, primed to survey the sky for transiting exoplanets—such as Kepler, CoRoT and TESS—that have extremely sensitive photonics that can detect the slightest changes in stellar brightness. And by virtue of these missions’ wide field of view, taking in the light from many stars at once, the helium flashes and resulting brightness oscillations across the stars’ surfaces could be detected in the near future.

It’s thought that the flash itself should last for no more than two million years, which may sound like a long time to we puny humans, but over cosmic timescales, that’s literally a flash—we need some serious luck to detect them. But with more observatories, longer observation periods, and wider fields of view, luck may be just around the corner.

Interstellar Comet Borisov Looks Weirdly Familiar

The gas cyanogen has been detected in 2I/Borisov’s coma—a historic detection of a gas commonly found in regular comets.

Artist’s impression of a cometary nucleus. [ESA]

It’s official, the solar system is playing host to its second confirmed interstellar visitor only two years after the strangely-shaped `Oumuamua was spotted receding into interstellar expanse. While `Oumuamua was historic in that it was the first confirmed interstellar comet to be discovered, according to a new study (which has yet to be peer reviewed), this newest interstellar vagabond is potentially more significant:

“For the first time we are able to accurately measure what an interstellar visitor is made of, and compare it with our own solar system,” said Alan Fitzsimmons of the Astrophysics Research Center, Queen’s University Belfast, in a statement.

So, why are astronomers so excited about 2I/Borisov?

A (Cometary) Star Is Born

In late August, the comet was discovered by Gennady Borisov, an amateur astronomer in Crimea, and initially designated “C/2019 Q4” because, well, it looked like a regular comet. It was only after repeated observations by Borisov, and confirmed by other amateur and professional astronomers, that the object’s path and speed through the solar system could be realized. It turned out to be traveling fast.

Like, really, really fast.

Clocked at a breakneck pace of 93,000 miles per hour (150,000 kilometers per hour), astronomers realized that C/2019 Q4 was a special kind of comet. While it was found to possess the characteristics of a regular comet (it has a faint coma and tail) there is no way that it’s gravitationally bound to our Sun. Its trajectory is hyperbolic. In other words, it didn’t originate in our solar system—it’s an alien visitor.

This simple animation depicts the comets path through our neighborhood; there’s little ambiguity in the fact that it doesn’t intend to hang around for very long:

With only a slight tug by our Sun’s gravity, the interstellar visit will careen out of the solar system in a few months. [NASA/JPL-Caltech]

Last week, these factors all culminated in the International Astronomical Union (IAU) officially classifying C/2019 Q4 as the second unambiguous interstellar comet discovery to date. It was therefore reclassified as “2I/Borisov” (1I/`Oumuamua being the first, of course). It’s thought interstellar junk passes through our solar system all the time, but only two comets (to date) have been confirmed to have an interstellar origin, suggesting our observational techniques are improving.

Now, the really neat thing about 2I/Borisov is that it’s a lot more active than `Oumuamua; the latter produced very little in the way of a discernible coma or tail after its discovery. Borisov, however, is being far more generous, already allowing astronomers to grab a crude spectroscopic snapshot of the gases being vented into space.

A Mysterious Interstellar Time Capsule

After being thwarted by the glare of the Sun on Sept. 13, an international team of astronomers was able to use the William Herschel Telescope on La Palma in the Canary Islands in the morning of Sept. 20 to measure the light that was being scattered off the gases in its tenuous coma. Follow-up spectral analysis by the TRAPPIST-North telescope in Morocco was also used.

Measuring the spectrum of Borisov allows us to understand the chemical composition of the ices that are fizzing into space as they are slightly heated by our Sun’s radiation via a process known as sublimation. And this is profoundly awesome.

To capture the spectra of any comet reveals the chemicals it contained when it formed billions of years ago. In our solar system, comets are considered to be icy time capsules; they formed from the solar nebula when the Sun was a proto-star and the planets were just starting to accrete from the surrounding protoplanetary disk of ancient debris. To see the chemicals contained within the vapor of these fizzing “dirty snowballs” gives us a five-billion-year-old glimpse of what the solar nebula and its system of baby planets would have contained.

2I/Borisov as imaged by the Gemini North Telescope on Hawaii. [GEMINI OBSERVATORY/NSF/AURA/INTERNATIONAL ASTRONOMICAL UNION]

Borisov wasn’t formed in our solar nebula, however, it was formed from the nebula of a distant, unknown star of unknown age. We have little idea as to where or when it originated (though there’s little doubt that astronomers will use data from the European Gaia space telescope to try to figure out a rough estimate, as they did with `Oumuamua).

Surprisingly Familiar

While previous observations of the comet’s nucleus have revealed a reddish tinge that is similar to the long-period comets that originate from our solar system’s Oort Cloud (such as Hale-Bopp and Hyakutake), the new study has been able to identify another familiar trait: its venting gases contain cyanogen. This chemical is a simple, yet toxic molecule containing one carbon atom and a nitrogen atom (CN). Cyanogen is commonly found in regular comets born in the solar system.

The researchers were also able to make an estimate of the ratio of the dust to gas that is being blasted from the comet’s nucleus and, you guessed it, it is roughly in agreement to what you’d expect a regular comet to generate.

All of these findings point to an unexpected conclusion, as the researchers highlight in their paper: “If it were not for its interstellar nature, our current data shows that 2I/Borisov would appear as a rather unremarkable comet in terms of activity and coma composition.” In other words, if it wasn’t for its extreme speed, 2I/Borisev would look like a regular comet from our solar system.

Does this mean all comets from any star system have similar compositions? That doesn’t seem possible, considering we know other stars and their associated nebulae their comets would have formed from contain different chemicals to our own. It could just mean that Comet Borisov was ejected from a nearby star that formed in the same stellar nursery as our Sun five billion years ago and should therefore contain approximately the same chemicals. But for now, it’s too early to say.

Obviously, more work needs to be done and, fortunately, we have time. The comet will reach perihelion (point of closest approach to the Sun) in early December, and astronomers are predicting maximum nucleus activity in December and January before it starts to recede into the interstellar night.

So, watch this space.

The Sun Is a Beautifully Blank Billiard Ball for Halloween

For the festive season, our nearest star is keeping its choice of costume simple.

I’m not saying the Sun isn’t being creative, it’s just not putting too much effort into this year’s stellar fancy dress party. I mean, look at it:

The Sun right now, as seen by the Helioseismic and Magnetic Imager (HMI) instrument on NASA’s Solar Dynamics Observatory (SDO) [NASA/SDO]

That flawless orange billiard ball is the photosphere of our Sun. Have you ever seen something so smooth and beautifully unremarkable?

Well, you have now, and its blank gaze is actually the reason why it’s causing a bit of a stir. According to our ever watchful solar sentry, Tony Phillips at SpaceWeather.com, the northern summer of 2019 may go down in history as “the summer without sunspots.”

From June 21st until Sept 22nd, the sun was blank more than 89% of the time. During the entire season only 6 tiny sunspots briefly appeared, often fading so quickly that readers would complain to Spaceweather.com, “you’ve labeled a sunspot that doesn’t exist!” (No, it just disappeared.) Not a single significant solar flare was detected during this period of extreme quiet.

Dr. Tony Phillips

So, what does this mean?

Sunspots are the visual cues for magnetic turmoil within our nearest star. Over cycles of approximately 11 years, the Sun’s internal magnetic field becomes stretched and twisted, driving the ebb and flow of space weather.

Starting with our solar billiard ball here, suffice to say that the solar magnetic field is pretty untwisted and, well, chilled. This is the epitome of “solar minimum” — and, as commented on by Phillips, a deep, potentially record-breaking solar minimum at that. It’s very likely that this is as minimum as solar minimum can be, so we could hazard a guess to say that things are going to start getting interesting very soon.

Differential rotation and the formation of coronal loops as demonstrated by my awesome abilities as a Microsoft Word artist [source: my PhD thesis!]

As our Sun is a massive blob of magnetized plasma, it doesn’t rotate uniformly (like the Earth does), it actually rotates a little faster at its equator than at its poles, a phenomenon known as “differential rotation.” Now, if you imagine the solar magnetic field as straight lines running from pole to pole, you can imagine that, over time, the field will start to wrap around the equator like an elastic band being stretched out of shape and wrapped around the middle. At its most extreme, so much rotational tension will be applied to the magnetic field that it becomes contorted. This contortion creates an upward pressure, forcing vast loops of magnetized plasma, known as coronal loops, to pop through the Sun’s photosphere — a.k.a. the solar “surface” — like annoyingly twisted loops of garden hosepipe (see the diagram above).

As its most extreme, in a few years time, we can expect our boring ol’ billiard ball to look something like this:

The Sun in 2014 (during the previous solar maximum), as seen by the SDO’s HMI [NASA/SDO]

About those blotches: those dark spots are sunspots and they are a direct consequence of the magnetic turmoil that rumbles inside the Sun during solar maximum. Remember those coronal loops I was talking about? Well, these huge, beautiful arcs of plasma cause the hotter outer layers of the Sun to be pushed aside, exposing the comparatively cooler (though still thousands of degrees) plasma under the surface — that’s what creates those dark blotches. And by counting sunspots, you can gauge how magnetically active the Sun is.

By viewing the Sun in different wavelengths, we can view the Sun’s atmosphere at different temperatures and, as the Sun’s atmosphere (the corona) is counter-intuitively hotter the higher above the surface you get, let’s take a look at what solar maximum looks like above these sunspots:

Yikes! The Sun’s corona in October 2014 (during the previous solar maximum), as seen by the SDO’s Atmospheric Imaging Assembly (AIA) instrument. And a damn fine effort just in time for Halloween. [NASA/SDO]

As you can see, there’s a lot of coronal loops erupting through the surface, creating huge regions of activity (called active regions, unsurprisingly). And the above observation was captured on Oct. 8, 2014, when the Sun was, apparently, in a terrifyingly festive Halloween mood! These regions can be hothouses for solar flares and coronal mass ejections; explosive phenomena that can have dramatic space weather effects on Earth.

So that was solar maximum; what does the solar corona look like now, at solar minimum?

The Sun’s corona right now, as seen by the SDO’s AIA [NASA/SDO]

Yep, as you guessed, very relaxed. In this state, we can expect very little in the way of explosive space weather events, such as flares and CMEs; there’s simply too little magnetic energy at solar minimum to create many surprises (caveat: even solar minimum can generate flares, they’re just few and far between).

While the Sun may look boring, the effects of space weather are anything but. During these times of solar minimum, the extended solar magnetic field (called the heliosphere), a magnetic bubble that reaches beyond the orbits of all the planets, contracts and weakens, allowing more cosmic rays from energetic events from the rest of the cosmos to reach Earth. Cosmic rays are ionizing particles that can boost the radiation exposure of astronauts and frequent fliers. Also, the solar wind can become a more persistent presence; streams of energized particles that are continuously streaming from the lower corona, so we still get our aurorae at high latitudes.

Recognition that the Sun is now in a deep minimum means the solar vacation is nearing an end. Astronomers have reported that of the handful of sunspots have made an appearance over the last few months with a flip in magnetic polarity, which can mean only one thing: Solar Cycle 25 is coming and the next solar maximum is only four years away.

SCIENCED Podcast: No Tea on Teegarden b

Are you sure it’s THAT habitable? [NASA]

Before zipping off to Hawaii and taking a short writing break, I was invited to appear on the SoCal Science Writing “SCIENCED” podcast with Jessie Hendricks to talk about one of our favorite habitable exoplanets, Teegarden b. So, naturally, we trashed its potential habitability with some science and humor. We also delved into some science communication, how I became a space writer, the search for extraterrestrials, and the meaning of life itself. It’s a fun discussion and Jessie is a fantastic host, check it out.

Are you a science writer/communicator in Southern California? Join the SoCal Science Writing association!

“Solitude” by Enceladus

Today’s digital palette cleanser is bought to you courtesy of Cassini and a small icy moon filled with intrigue.

As we constantly check the news sites for updates on the minutia of our daily lives, refresh our social media feeds, and ponder the existential dread that seems to be flooding our immediate future with increasing volume, it’s nice to find little islands of tranquility that appear out of nowhere. Today, I found that island in a beautiful processed image of Saturn’s moon Enceladus by the incredibly talented Kevin Gill, who works at NASA’s Jet Propulsion Laboratory:

[NASA/JPL-Caltech/SSI/CICLOPS/Kevin M. Gill]

In his tweet, Kevin simply describes this view as “solitude” and that’s pretty damn near perfect. In this image, the beautifully back-lit plumes are visible with the tenuous E-ring of Saturn creating an atmospheric backdrop.

Enceladus is a fascinating moon. During the NASA Cassini mission, which ended its glorious 13-year reign in Saturn orbit in 2017, the spacecraft became intimately familiar with the icy moon and its famous geysers. After flying through the plumes of water vapor, it became clear to mission scientists that not only does this 313 mile wide icy marble have an extensive subsurface liquid water ocean, that ocean contains organic molecules that could hint at astrobiological possibilities.

It’s sometimes nice to escape to Saturn orbit every now and again, so be sure to check out Kevin’s awe-inspiring Flickr album for more.

Nuking a Hurricane Is a Stupid Idea

Why have a hurricane when you could have a radioactive hurricane!

Hurricane Florence as seen from the International Space Station in September 2018 [NASA (edit by Ian O’Neill)]

Now, I don’t like to use the “s” word too often; it’s often misplaced and used to belittle someone’s lack of knowledge. A lack of knowledge doesn’t necessarily mean someone doesn’t want to learn, so to say an idea is stupid suggests someone is willfully ignorant. But this is one occasion where I’ll use “stupid” with a high degree of confidence that this idea is, well, very stupid:

President Trump has suggested multiple times to senior Homeland Security and national security officials that they explore using nuclear bombs to stop hurricanes from hitting the United States, according to sources who have heard the president’s private remarks and been briefed on a National Security Council memorandum that recorded those comments.

Axios

We’re now into year three of this administration’s willful ignorance of climate science, so it may not come as a surprise that the president doesn’t like to surround himself with many scientifically-savvy minds, lest their ideas get in the way of his administration’s damaging policies. So, while his statements may sound a little, shall we say, “extreme,” he’s coming from a place of ignorance and a horrible worldview that obsesses over detonating nuclear weapons to solve problems.

It’s easy for the science community to mock Trump’s comments as he often delivers these half-baked ideas with such bombastic enthusiasm that every day feels like an episode of The Twilight Zone, but it might come as a surprise to hear that he’s not the first to float the idea of nuking hurricanes. In fact, the idea of interrupting the convection currents of hurricanes over the Atlantic Ocean with nuclear blasts dates back to the Eisenhower era. And since then, the National Oceanic and Atmospheric Administration (which is a government body, I might add) regularly receives queries about going all Dr. Strangelove on the Atlantic.

During each hurricane season, there always appear suggestions that one should simply use nuclear weapons to try and destroy the storms. Apart from the fact that this might not even alter the storm, this approach neglects the problem that the released radioactive fallout would fairly quickly move with the tradewinds to affect land areas and cause devastating environmental problems. Needless to say, this is not a good idea.

NOAA

Fears of spreading radioactive fallout far and wide notwithstanding, if a nuke was actually effective at snuffing out a hurricane before it can even form, or at least redirect a powerful one from hitting Florida, say, wouldn’t the ends justify the means? In other words, if a deadly storm (capable of killing thousands) is averted, is a little bit of radiation really that bad? Well, yes, it is really bad, but nuking the ocean would be terribly ineffective hurricane mitigation effort.

As discussed by the NOAA, the amount of energy carried by a fully developed hurricane is huge and to interrupt or redirect a formed hurricane would require a lot of nuclear warheads detonating all the time.

The main difficulty with using explosives to modify hurricanes is the amount of energy required. A fully developed hurricane can release heat energy at a rate of 5 to 20×1013 watts and converts less than 10% of the heat into the mechanical energy of the wind. The heat release is equivalent to a 10-megaton nuclear bomb exploding every 20 minutes. According to the 1993 World Almanac, the entire human race used energy at a rate of 1013 watts in 1990, a rate less than 20% of the power of a hurricane.

NOAA

That’s not all: to concentrate the compression effects of the nuclear blasts on the central region of the cyclone to effectively dampen its sheer power, in a nutshell, simply isn’t possible.

OK then, why not drop a bomb on the weak tropical depressions (i.e. the seeds of hurricanes) to prevent them from growing in the first place? Well, that would be a crap-shoot. According to the NOAA, “[a]bout 80 of these disturbances form every year in the Atlantic basin, but only about 5 become hurricanes in a typical year.” There’s no obvious way of knowing which ones will ripen into that “killer” storm and, besides, we’d still need to dump a lot of nuclear energy into those depressions to stand a chance of stopping them.

Of course, these arguments sound reasonable; there are very few informed people who, after a little research, would doubt that firing nukes at weather systems is a stupid idea. But here we are, talking about the leader of the richest and most powerful nation on the planet wanting to wage a nuclear war on Mother Nature herself, while ignoring the very real science behind global warming (which, by the way, supercharges the ferocity of hurricanes) that is currently causing irreparable damage to our ecosystem.

What a time to be alive.

UPDATE (Aug. 26): Trump denies everything. In a baffling mix of third and first person, which leads me to believe it’s all true:

“Rolling Stones Rock” Is the Coolest Mars Rock That Ever Rolled

The legendary British rock band has been honored by NASA with a rock that the InSight lander rocket-blasted across the Red Planet’s surface last year.

[NASA/JPL-Caltech]

Those of you who frequently read my articles will know that I have a fascination with rolling rocks on celestial bodies. There’s the numerous boulders on the Moon that have been dislodged and rolled down crater sides, leaving their bouncy imprints in the dirt. There’s also the rolling rocks of Ceres. And the theorized rock tracks that are carved into Phobos. Then there’s Mars, the undisputed king of rolling boulders, imaged to beautiful precision by our orbiting armada of spacecraft.

The most famous rolling rock is no boulder, however; it’s barely larger than a golf ball—but it’s now the most famous pebble in the solar system. It’s a little rock that was minding its own business until a car-sized NASA robot rumbled through the Martian skies on Nov. 26, 2018, retro-rockets firing to slow its descent to the ground, that flipped the innocent ruddy bystander three feet (1 meter) from the landing site. It’s sobering to think that that rock probably hasn’t been disturbed for millions of years until that fateful day.

Behold, the “Rolling Stones Rock,” named after rock legends The Rolling Stones and announced tonight by Avengers actor Robert Downey Jr. to tens of thousands of Stones fans at the Rose Bowl Stadium, just before Mick Jagger, Keith Richards, Charlie Watts, Ronnie Wood, and friends rocked Los Angeles to its core. Space exploration doesn’t get much more Hollywood than this:

And a little animated introduction to the rock itself:

“The name Rolling Stones Rock is a perfect fit,” said Lori Glaze, director of NASA’s Planetary Science Division in Washington, in a statement. “Part of NASA’s charter is to share our work with different audiences. When we found out the Stones would be in Pasadena, honoring them seemed like a fun way to reach fans all over the world.”

While, in the grand scheme of things, naming a little rock after The Rolling Stones may not seem like such a big deal (and, besides, it’s an unofficial designation), as my wife and I stood watching the Stones do a blistering performance of “Sympathy For the Devil”, the family next to us were discussing Mars asking what the InSight lander was doing on the Red Planet.

So, mission success, NASA. Mission success.

“Cross-pollinating science and a legendary rock band is always a good thing…”

Robert Downey Jr.

The Rolling Stones and NASA Team Up for Some … Martian Shenanigans?

As the Stones arrive in Los Angeles to continue their No Filter tour, there’s a space-related twist in store at the Rose Bowl Stadium.

It’s been 25 years since the Rolling Stones played at the Rose Bowl Stadium, so SoCal fans of the legendary British rock band are understandably excited. But, for space fans, there’s a little something extra, as actor Robert Downey Jr. teased in a video he posted this morning:

So, what DOES the Rolling Stones, the Rose Bowl, NASA and Robert’s star sign (steady on now) have in common? As he’s an Ares, I’m thinking it’s Mars, a planet that NASA Jet Propulsion Laboratory (which is located near the Rose Bowl) knows more than a thing or two about. And the Stones have a song called “2,000 Light Years From Home”…? OK, I’m reaching a bit on the latter (besides, Mars is much closer to Earth than 2,000 light-years), but there’s definitely something a little Martian going on. Will Curiosity beep a Rolling Stones song from Mount Sharp? Has it got something to do with the upcoming NASA Mars 2020 mission? Will the Mars InSight lander make a cameo? Who knows. But I’m all for melding science with music, so I’m excited.

And I’ll be there to cover the event, so keep an eye on @astroengine on Twitter and Instagram for updates!

Space Telescope Sees a Rocky Exoplanet’s Surface. And It’s Horrible

It’s both too hot and too cold, has no atmosphere, and is no place to take a vacation—but there is an upside.

Artist’s impression of LHS 3844b, which is thought to be covered in dark lava rock with no atmosphere. It’s difficult to see any upside [NASA/JPL-Caltech/R. Hurt (IPAC)]

It’s hard to say anything positive about the exoplanet LHS 3844b. It’s a wretched place; an alien world that orbits its tiny star in less than half a day. As it’s so close to its red dwarf star, it’s tidally-locked—when one side of the planet is always in baking daylight, the other side is in a perpetual frozen night. Oh, and it doesn’t even have an atmosphere.

Why the heck am I even writing about this unfortunate celestial object?

Well, it might not be our idea of an interstellar getaway, but it is remarkable for two profound reasons: It’s a rare look at the surface conditions of a rocky exoplanet orbiting a distant star, and the very fact that astronomers are confident it doesn’t have an atmosphere is a really big deal.

World of Extremes

Discovered in 2018, LHS 3844b is located nearly 49 light-years away. It has a radius 30 percent larger than Earth and orbits a cool M dwarf star. It was detected by NASA’s newest space-based exoplanet hunter, the Transiting Exoplanet Satellite Survey (TESS); every 11 hours, the world drifts in front of the star, blocking a tiny amount of light (and event known as a “transit”) that can be detected by TESS. As it orbits so close to its host star, it’s glowing bright in infrared radiation, giving the researchers of a new study published in Nature an incredible opportunity.

Using observational data from NASA’s Spitzer space telescope, which views the universe in infrared wavelengths, and as the star is comparatively cool and dim, the researchers could discern how much infrared radiation was being emitted from the exoplanet’s “day” side and calculated that it must be cooking at a temperature of 1,410 degrees Fahrenheit (770 degrees Celsius). On measuring the infrared emissions from the exoplanet’s dark side, they realized that the heat from the day side wasn’t being transported to the night side. On Earth, our atmosphere distributes thermal energy around the globe, ensuring that the night and day sides’ temperature difference isn’t so extreme. LHS 3844b, however, isn’t distributing any of its thermal energy creating a sharp drop-off in temperature between both hemispheres. In other words: no atmosphere!

“The temperature contrast on this planet is about as big as it can possibly be,” said Laura Kreidberg, a researcher at the Harvard and Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and lead author of the new study. “That matches beautifully with our model of a bare rock with no atmosphere.

“We’ve got lots of theories about how planetary atmospheres fare around M dwarfs, but we haven’t been able to study them empirically. Now, with LHS 3844b, we have a terrestrial planet outside our solar system where for the first time we can determine observationally that an atmosphere is not present.”

This exoplanet has about as much atmosphere as the planet Mercury or our Moon, and it shares some other traits too. By measuring the amount of starlight the exoplanet reflects (a characteristic known as “albedo”), Kreidberg’s team also took a stab at understanding its composition.

As the world is “quite dark,” they deduced that it’s very likely that it’s covered in basalt (volcanic rock), the same stuff that we find in the crusts of the Moon and Mercury. “We know that the mare of the Moon are formed by ancient volcanism,” said Renyu Hu, an exoplanet scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., “and we postulate that this might be what has happened on this planet.”

An Atmospheric Problem

Red dwarfs are known to play host to entire systems of exoplanets, including many small rocky worlds of similar dimensions as Earth. Many of these worlds have been found within the much-hyped “habitable zone”, where it’s neither too hot or too cold for liquid water to persist. As we probably are all aware, liquid water is super helpful for life (on our planet, at least) to evolve. While LHS 3844b could never be considered “habitable” in any way, shape or form, the fact that it doesn’t have an atmosphere may be very revealing.

It’s simply not good enough to find a habitable zone exoplanet that orbits a red dwarf and say “there’s a good chance that aliens live there!” Even though it has the right temperature, because it’s orbiting a red dwarf and likely tidally-locked could mean these types of worlds are devoid of atmospheres, a serious wrench in the hope that all habitable zone exoplanets have the same likelihood of life. That’s not to say all red dwarf-orbiting exoplanets lack atmospheres, but now at least we are developing techniques that could, one day, help us from the atmospheric potential of more “habitable” candidates.

I, For One, Welcome Our New Tardigrade Overlords

“One small step for (a) water bear, one giant leap for water-dwelling eight-legged segmented micro-animals.” —Teddy Tardigrade

Tardigrades are everywhere. And now they’re on the Moon [Public Domain]

Are you thinking what I’m thinking? Because if you are, you’re thinking that exposing tardigrades to high-energy cosmic rays can only mean one thing: super-tardigrades. From Live Science:

The Israeli spacecraft Beresheet crashed into the moon during a failed landing attempt on April 11. In doing so, it may have strewn the lunar surface with thousands of dehydrated tardigrades, Wired reported yesterday (Aug. 5). Beresheet was a robotic lander. Though it didn’t transport astronauts, it carried human DNA samples, along with the aforementioned tardigrades and 30 million very small digitized pages of information about human society and culture. However, it’s unknown if the archive — and the water bears — survived the explosive impact when Beresheet crashed, according to Wired.

Mindy Weisberger, Senior Writer

Well, OK, as tough as they are, it’s probably unlikely that those microscopic explorers will re-hydrate any time soon before being hit by high-energy particles that will then endow the tiny guys with Marvel-like superpowers, but it’s nice to dream.

But what are tardigrades? Let’s go back to Mindy’s Live Science article, because her explanation is simply too adorable not to reprint:

Tardigrades, also known as moss piglets, are microscopic creatures measuring between 0.002 and 0.05 inches (0.05 to 1.2 millimeters) long. They have endearingly tubby bodies and eight legs tipped with tiny “hands”; but tardigrades are just as well-known for their near-indestructibility as they are for their unbearable cuteness.

Moss piglets! Or should we now say moon piglets?

Light-hearted tardigiggles aside, it’s hard not to feel sorry for the tiny sleeping creatures. In a dehydrated state, they can remain hibernating (I’m not sure if that’s the correct term for being freeze-dried, but let’s go with hibernating) for a decade (!) while they wait for water to appear so they can go about their tardigradey business. They’ve been discovered in just about every environment on Earth, are extremely resilient and can even survive in space without a tiny spacesuit to keep them warm. In short, they’re pretty amazing. And now they’re on the Moon, which may or may not be a good thing (there’s a lot of cosmic rays up there).

Bonus: I’ll close with a short story: