Waiting for the Andromeda galaxy’s stars to twinkle may have extinguished hope for tiny black holes being a significant dark matter candidate
Using the Andromeda galaxy as a huge detector, astronomers have taken a stab at seeing the unseeable — possibly disproving a hypothesis first put forward by the late Stephen Hawking 45 years ago.
According to Hawking’s work, the universe should be filled with black holes that were formed at the beginning of time, when the universe was a chaotic soup of energy just after the Big Bang. Known as “primordial” black holes, these ancient objects are hypothesized to invisibly occupy modern galaxies, including our own, boosting their dark matter mass.
These black holes aren’t the supermassive monsters that lurk in the centers of most galaxies; they’re not even stellar-mass black holes, formed after massive stars go supernova. Primordial black holes are much smaller than that, having leaked most of their mass via Hawking radiation since their formation 13.8 billion years ago. They should, however, still have powerful gravitational effects on the space surrounding them and, in new research published last week in the journal Nature Astronomy, an international team of researchers have leveraged these hypothetical black holes’ space-time-warping powers to reveal their presence.
Or not, as it turns out.
Central to this study is the effect of microlensing. This astronomical method relies on an object passing between us and a distant star. It has been used to great effect when detecting distant exoplanets, or rogue brown dwarfs wandering through interstellar space. Should one of these objects drift directly in front of a star, its gravitational field can create a magnification effect that briefly brightens the star’s light. The gravitational field creates a natural “lens” out of space-time itself, a prediction that arises from Einstein’s general relativity.
It stands to reason that even though primordial black holes don’t generate any light themselves, if you stare at at entire galaxy for long enough, you should see a lot of twinkling stars, or microlensing events caused by the hypothetical swarm of primordial black holes the galaxy should contain. Count the number of events, and you can take a statistical stab the total number of primordial black holes in a galaxy like Andromeda, thereby providing an estimate as to how much of the universe’s missing dark matter mass is made up from these objects.
Using the power of the Subaru telescope in Hawaii, the researchers put this to the test, capturing 190 consecutive images of Andromeda over seven hours during one night with the observatory’s Hyper Suprime-Cam digital camera. If Hawking’s theory held, the telescope should have recorded approximately 1,000 microlensing events caused by primordial black holes with a mass of less than our moon drifting in front of Andromeda’s stars. Alas, only one microlensing event was detected that night. From this observation campaign alone, the researchers estimate that primordial black holes make up no more than 0.1 percent of the total dark matter mass in our universe.
Although this elegant study doesn’t necessarily disprove the existence of primordial black holes — one single event is interesting, but not compelling — it does put a wrench in the idea that they dominate the mass holed up in dark matter. So, the quest to understand the nature of dark matter grinds on and, with the help of this study, astronomers have now narrowed down the search by removing primordial black holes from the dark matter equation.
Gather ’round the campfire kids, it’s time to tell the sad story of a brave bat named Brian.
On March 15, 2009, Twitter was days away from its third birthday, Ashton Kutcher was one month away from becoming the first tweep to reach one million followers, and a community of space enthusiasts habitually live-tweeted the final space shuttle launches from the comfort of their homes. They were simpler times.
One launch, however, became infamous — nay, historic — not for the fact it was one of the last handful of launches of NASA’s shuttle program, but because there was a tiny stowaway attached to the shuttle’s bulbous orange external fuel tank minutes before ignition.
During the countdown to the launch of STS-119, as we watched in anticipation of the successful start of Space Shuttle Discovery’s International Space Station (ISS) servicing mission, something seemed amiss at Discovery’s launch pad. At the time, the assumption was that a fruit bat (a common species in Florida) had mistakenly thought the orange external fuel tank of the shuttle was a tree to latch itself onto. Follow-up investigations identified the bat as a free-tailed bat and, though its intentions were unclear, zoologists posited that the unfortunate critter may have broken its wing. This would explain why it didn’t fly away when the shuttle’s boosters ignited, carrying the bat to the heavens — literally and metaphorically.
No one really knows how long the bat held on for, but some creative-thinkers hypothesized that the bat remained attached for the duration, making it into space. I don’t think I have to explain why this didn’t happen — it was more likely booted from the fuel tank in the first seconds of launch enduring a fiery death via rocket booster exhaust — but it was a poetic thought. Regardless of the bat’s fate, it’s ultimate sacrifice made this routine launch special. What was “just another” live-tweeted shuttle launch, became a spectacle that rapidly evolved into an international news story. That bat was special.
And that bat’s name was Brian.
Why “Brian”? A bit of background: For some personal reason that I cannot fathom, I like to name things “Brian.” I’ve always done it. The squirrel that lives in my backyard? Brian. An interesting and unnamed rock on the surface of Mars? Brian. My first car? Brian. That gopher that demolished my newly-planted garden of impatiens in 2011? Brian. A random free-tailed bat hanging off the shuttle’s external fuel tank? Brian. There’s no reason and no logic behind this, Brian just seems to fit. It’s a personal mystery.
So, when lightheartedly tweeting about the bat on March 15, 2009, I called the bat Brian and the name stuck. I had no idea about its gender, and it didn’t have a nametag, but that bat was a Brian alright. Suddenly, other space enthusiasts following the launch called him Brian and, for reasons I have yet to understand ten years later, in those minutes before launch, “Brian the Bat” went viral and suddenly everyone was personally invested in that “routine” space launch. Yes, there were billions of dollars of hardware on that launchpad with seven brave astronauts on board, but everyone was talking about Brian who was shivering on the side of the vehicle, a place that no living creature should have been.
Was Brian confused? Was he frozen to the cold tank? Would he fly away in the nick of time? No one knew, but the clock was ticking and the commentator on the NASA live video stream seemed confident that, as the boosters began their ignition sequence, the bat would be scared by the vibrations and fly to safety.
For reasons known only to Brian, he remained attached. And as the boosters roared to life, he held tight. As the plume of smoke and steam enveloped Kennedy Space Center Launch Complex 39, I sat with the computer screen nearly pressed to my nose, seeking out the dark pixels of Brian in the place where he was last seen. But the resolution was too low and Brian’s fate was unknown. (Days later, NASA analysts reviewed infrared imagery from the launch, revealing two very sad facts. 1) Brian was warm while attached to the fuel tank, so he hadn’t frozen to death and was alive up to launch, and 2) he remained in place when Discovery lifted off.)
As the adrenaline ebbed and Space Shuttle Discovery soared into the atmosphere, solid rocket boosters separating and tumbling back to Earth, the sad reality crept in. Brian was, in all likelihood, toast.
But his legacy would live on.
Assuming that little space-launch chapter was over, I wrote a summary about Brian’s adventures for Universe Today and on Astroengine with the assumption that Brian would be soon lost to the annals of shuttle-era history. Little did I know, however, that Norwegian journalist Geir Barstein was paying close attention…
Brian also made appearances in The Sun newspaper (but the article has since disappeared) and other smaller publications, and I participated in a number of radio shows devoted to that now-famous shuttle launch.
Not only was the whole event a poignant one, it also made me realize something about the power of social media. In all my years covering space stories, particularly when I was a producer at Discovery News (now called “Seeker”), shuttle launches would receive very little attention. Apart from a few outliers, such as the final shuttle launch, the articles I’d publish about one of NASA’s most significant programs would receive very little readership. The routine nature of these launches meant that, unless you were at Cape Canaveral, interest in seeing shuttles launch into space was lukewarm at best. As a space enthusiast, I was frustrated. Every launch in my eyes was special and certainly not “routine.”
Brian, however, made me realize by accident that you have to seek out the unique thing about that one launch that will hook readers to that story. Granted, not all launches have a “Brian the Bat” moment, but that doesn’t mean they’re not special.
I like to think that the cosmos is doing Brian a solid by commemorating that brave little bat’s ultimate sacrifice.
The event may have been a footnote in humanity’s quest to explore our universe, but I truly believe that the viral social media (and then mainstream media) attention Brian whipped up created a buzz around a launch that may not have otherwise made an impact.
As a science communicator, I’m always on the lookout for interesting hooks to stories that wouldn’t otherwise be of interest, and on March 15, 2009, Brian was that hook — who knows what kind of impact that little free-tailed bat had on viewers who wouldn’t have otherwise been paying attention to one of the biggest endeavors in human exploration history.
So, tomorrow, on March 15, 2019, raise a drink to Brian’s legacy. He will live on in the spirit he inspired when he left our planet attached to the space shuttle’s external fuel tank.
I, for one, welcome our new Mars desert-dwelling overlords.
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.
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.”
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.
The private spaceflight company SpaceX has done it again, and this latest achievement is an important one.
We space writers are very familiar with Elon Musk’s human spaceflight dreams that can be encapsulated in his well-known goal to “make humanity multi-planetary,” starting with a Mars settlement. And today, that goal took another step closer to reality.
I’ve been following Musk’s rocket adventures ever since his early days of exploding single-engine rockets in the South Pacific. Back then, Musk was a “dreamer” and more than a little eccentric. His eccentricities are well documented, but the world’s best known billionaire-entrepreneur is a dreamer no more. The first successful flight of a Falcon 1 happened on Sept. 28, 2008. (You can read my 2008 Space Lifestyle Magazine article on that topic, page 36) A little over a decade later, the Falcon 1 has rapidly evolved into the reusable Falcon 9 workhorse and the Falcon Heavy and, with key partnerships with NASA and companies that need to get stuff into orbit cheaply, SpaceX has developed the human-rated Dragon spacecraft to ultimately get astronauts to the space station, and beyond.
After proving itself in the cargo-delivery arena, the Dragon has now won its human-spaceflight wings: an (uncrewed) Crew Dragon is now attached to the International Space Station’s Harmony module and the outpost’s astronauts have entered the vehicle.
Building a commercially-viable space infrastructure is paramount if humanity is to truly become multi-planetary, and through partnerships between private business and government contracts, today’s achievement is proof that this model can work.
Too often, governments lack the long-term vision for human space exploration, instead plowing money into bloated, politically motivated, and ultimately doomed federally-funded projects. SpaceX may be an exhausting company to work for, but its ultimate mission is crystal clear. It’s not a satellite-launching company, it’s just doing that to build funds to do the Next Big Thing. Dragon’s autonomous berthing with the space station is That Big Thing that will drive more investment into getting stuff beyond Earth orbit.
Musk’s interim target — before getting humans to Mars — is the moon, to create a permanently-crewed lunar base. How that will shape up remains to be seen, but if there’s one thing I’ve learnt from following his dreams of getting into space on a reusable spaceflight infrastructure, it’s don’t bet against SpaceX and Elon Musk’s “eccentricities.”
The question was more of an accusation. The lady asking was sitting across from me at a Christmas dinner a friend of mine was hosting and the previous query was one about my religion. She wasn’t impressed by my response.
Granted, it probably wasn’t the ideal setting to say that I was an atheist, but I wasn’t going to lie either.
“Um, well…” I remember feeling vulnerable when I responded, especially as I’d only just met half the dozen people in the room, including the lady opposite, but I remember thinking: stick with what you know, Ian. So, I continued: “When I’m dead, all the elements from my body will remain on Earth,” — I didn’t want to go into much detail about my real plan of having my remains blended up into a jar and then launched into space (more on that in a future post, possibly) — “and those elements will get cycled through the biosphere through various biological, chemical and physical processes for billions of years. Eventually, however, all good things must come to an end and the sun will run out of fuel, ballooning into a huge red giant star, leaving what is known as a white dwarf in its wake.” (By her glazed look, I could tell she regretted asking, but I continued.) “If, and it’s a big IF, the Earth survives this phase of stellar death, our planet might be hurled out of the solar system. Or, and this is my favorite scenario,” — I’d hit my stride and everyone else seemed to be entertained — “it might careen inward, toward the now tiny white dwarf sun, where Earth will be ripped to sheds under powerful tidal forces, sending all the rocks, dust, and the elements that used to be my body, raining down onto the white dwarf.”
This is an abridged version. I also went into some white dwarf science, why planetary nebulae are cool, and how our sun as a white dwarf would stand as a monument to the once great solar system that will be gone five billion years from now. The recycled elements from my long-gone body could eventually rain down onto the atmosphere of a newborn white dwarf star — pretty cool if you ask me. This might be more of a cautionary tail about inviting an atheist astrophysicist to religious celebrations, but I feel my tabletop TED talk was good value for money. And besides, by turning that inevitable “what religion are you?” question into a scientific one, I hadn’t gotten bogged down with justifying why I’m an atheist — a conversation that, in my experience, never works out well over dinner.
So, why am I remembering that fun evening many years ago? Well, today, there’s some cool white dwarf news. And I love white dwarf news, especially if it’s about dusty white dwarfs. Because dusty white dwarfs are a reminder that nothing lasts forever, not even our beautiful 5-billion-year-old solar system.
One Cool Dwarf
A citizen scientist working on the NASA-led “Backyard Worlds: Planet 9” project has discovered the coldest and oldest white dwarf ever found. The project’s aim is to seek out as-yet-to-be-discovered worlds beyond the orbit of Neptune (re: “Planet Nine” and beyond). Through the analysis of infrared data collected by NASA’s Wide-field Infrared Survey Explorer, or WISE (inspired by data from the European Gaia mission), Melina Thévenot was looking for local brown dwarfs — failed stars that lack the mass to sustain nuclear fusion in their cores, but pump out enough infrared radiation to be detected. In the observations, Thévenot spied what she thought was bad data, but with the help of WISE, she found not a nearby brown dwarf, but a white dwarf that was brighter and further away. After sharing her discovery with the Backyard Worlds team, astronomers at the W. M. Keck Observatory confirmed that not only was that white dwarf lowest temperature specimen yet found, it was also very dusty. In fact, it’s thought that the white dwarf, designated LSPM J0207+3331, has multiple dusty rings. Its discovery, however, is something of a conundrum and the researchers think it may challenge planetary models.
“This white dwarf is so old that whatever process is feeding material into its rings must operate on billion-year timescales,” said astronomer John Debes, at the Space Telescope Science Institute in Baltimore, in a NASA statement. “Most of the models scientists have created to explain rings around white dwarfs only work well up to around 100 million years, so this star is really challenging our assumptions of how planetary systems evolve.”
Interesting side note: It was Debes who first got me excited about dusty white dwarfs when I met him at the 2009 American Astronomical Society (AAS) meeting in Long Beach, Calif. You can read my enthusiastic Universe Today article I wrote on the topic here.
After deducing the tiny Earth-sized star’s cool temperature — 10,500 degrees Fahrenheit (5,800 degrees Celsius) — the researchers estimate that the white dwarf is approximately 3-billion years old. The infrared signal suggests a copious quantity of dust is present, which is a bit weird. As I alluded to in my tabletop TED talk, after a sun-like star runs out of fuel and puffs up into a red giant, it will leave a shiny white dwarf surrounded by a planetary nebula in its wake. Should any mangled planet, asteroid or comet that survived the red giant phase stray too close to that white dwarf, it’ll get shredded. So, it’s poignant when astronomers find dusty white dwarfs; it means those star systems used to have some kind of planetary system, but the white dwarf is in the process of destroying it. That is the inevitable demise of our solar system in 5 billion years time. But to find a 3-billion-year-old specimen with a ring system doesn’t make a whole lot of sense — the white dwarf had plenty of time to consume all that dusty debris by now, a process, according to Debes, that should only take 100 million years to complete.
Debes, who led the study published in The Astrophysical Journal on Feb. 19, and his team, including discoverer and co-author Thévenot, has some idea as to what might be going on, but more research is needed. One hypothesis is that J0207’s dusty ring is composed of multiple rings with two distinct components, one thin ring just at the edge of where the star is breaking up a belt of asteroids and a wider ring closer to the white dwarf. It’s hoped that follow-up observations by the next generation of space telescopes, such as NASA’s James Webb Space Telescope (JWST), will be able to deduce what those rings are made of, thus helping astronomers understand the evolution of these ancient star systems.
Besides being the ultimate way to gain perspective on our tiny existence (and an excellent topic for an awkward dinner conversation), this research underpins a powerful way in which citizen scientists are shaping space science, particularly projects that require many human brains to process vast datasets.
“That is a really motivating aspect of the search,” said Thévenot, who is one of more than 150,000 volunteers who works on Backyard Worlds. “The researchers will move their telescopes to look at worlds you have discovered. What I especially enjoy, though, is the interaction with the awesome research team. Everyone is very kind, and they are always trying to make the best out of our discoveries.”
Now that Opportunity’s mission is complete, many wistfully lament about “bringing our robot home.” There’s just one problem: it’s already home.
I am fascinated with how we anthropomorphize robots, particularly space robots. We call them “brave,” “pioneers” and even give them genders — usually a “she.” We get emotional when they reach the end of their missions, saying they’ve “died” or, as I like to say, “gone to Silicon Heaven.” But these robots are, for all intents and purposes, tools. Sure, they expand the reach of our senses, allowing us to see strange new worlds and parts of the universe where humans fear to tread, but they’re an assembly of electronics, metal, plastic, sensors, transmitters, wheels and solar panels. They don’t have emotions. They don’t breathe. They don’t philosophize about the incredible feats of exploration they are undertaking. They don’t have genders.
Still, we fall in love. When watching Curiosity land on Mars from NASA’s Jet Propulsion Laboratory, I teared up, full of joy that the six-wheeled hulk of a rover — that I’d met personally in JPL’s clean room a couple of years before — had safely landed on the Red Planet. After watching NASA’s InSight lander touch down on Elysium Planitia, again via JPL’s media room last year, there it was again, I was in love. I’m already anthropomorphizing the heck out of that mission, seeing InSight’s landing as another “heartbeat” on Mars. When the European Rosetta mission found Philae lying on its side like a discarded child’s toy on the surface of comet 67P/Churyumov–Gerasimenko, I jumped up from my desk with joy. When Cassini’s mission at Saturn ended in 2017, I was miserable. When the Chinese rover Yutu rolled off its lander in 2014, I realized I was cheering the robot on. When Spirit got stuck in a sand trap in Gusev Crater, I set up a Google alert for any and all news on the recovery efforts.
These emotions aren’t just for the exciting science and engineering strides humanity makes, there’s a certain inspirational character that each robot brings. Undoubtedly, this character naturally emerges from the wonderful scientists and engineers who design and build these amazing machines, and the social media managers who often “speak” for their robots in first person. But if you strip away the science, the technology and the people who build them, we still personalize our beloved robots, giving them their own character and creating a cartoon personality. I believe that’s a beautiful trait in the human condition (except a few flawed cultural and stereotypical missteps) and can be used to great effect to captivate the general public with the science that these robots do.
So there’s no great surprise about the outpouring of emotion for last week’s announcement that NASA called off the communications efforts with Mars Exploration Rover Opportunity. This kick-ass robot traveled 28 miles and lasted nearly 15 years, until a global dust storm in early 2018 starved it of sunlight. It landed on Mars way back in 2004, with its twin, Spirit, beginning its Martian reign with a hole-in-one, literally — after bouncing and rolling across the regolith after its entry and descent, encased inside a genius airbag system, it plopped inside the tiny Eagle crater. We’ve collectively lived through Opportunity’s adventures and the groundbreaking science it has done. There’s a huge number of terrific robot obituaries out there, so I won’t duplicate those efforts here. There is, however, a recurring sentiment that is somewhat misplaced, though entirely innocent.
Opportunity — like Spirit and all the Mars rovers and landers that have come and gone — died at home.
This may sound like an odd statement, but there seems to be this fascination with “returning” our space robots to Earth. I’ve seen cartoons of the Dr Who traveling through time to “rescue” Opportunity. People have argued for the case of future Mars astronauts returning these artifacts to terrestrial museums. There’s that touching XKCD cartoon of Spirit being “stranded” on Mars after NASA declared it lost in 2010, that is being resurfaced for Opportunity. We want our dusty Mars rover back!
It’s understandable, that rover has been continuously exploring Mars for a decade and a half, many of its fans, including myself, could check in on Opportunity’s adventures daily, browsing the latest batch of raw images that were uploaded to the NASA servers. We love that thing. In the tradition of military service members who die abroad, we go to great efforts to bring their bodies home so they can repatriated; we want to repatriate our science service member back to Earth.
But Opportunity is a robot that was designed for Mars. Every single design consideration took the Martian environment into account. The Red Planet’s gravity is roughly 1/3rd that of Earth, so the weight on its actuators and chassis are 2/3rds less than what they’d experience on our planet. Its motors are too under powered to reliably drive the robot forward on Earth. On Mars, they’re perfect. Granted, the mass of the Mars Exploration Rovers (approximately 185 kg) are a lot less than their supersized cousin, Curiosity (899 kg), but if Opportunity and Spirit had a 90-day mission exploring the dunes of the Californian Mojave Desert, I’m betting they wouldn’t get very far; they would be under-powered and grind to a halt. They’d also likely overheat as they were designed to withstand the incredibly low temperatures on the Martian surface.
The robots we send to Mars are undeniably Martian. If we’re going to anthropomorphize these beautiful machines, let’s think about what they’d want. I’m guessing they’d want to stay on that dusty terrain and not return to the alien place where they were constructed. And, in doing so, they become the first generation of archaeological sites on the Red Planet that, one day, the first biological Martians will visit.
“You know what it means? You’re an artist, not a physicist.”
Twenty years later, those words still haunt me.
I was actually a bit surprised to remember this quote, but after a conversation with astrophysicist, science communicator and Twitter buddy Sophia Gad-Nasr, who was commenting on a tweet from @dsxnchezz, I found myself emotionally thinking back to a personal struggle I wanted to share.
A Long Time Ago In a University Far, Far Away
My first semester of studying physics at university was unexpectedly (though, in hindsight, not so surprisingly) rough: I had to confront a demon that I’d spent years running away from. You see, I’m bad at math (or, as we Brits like to call it, “maths”), to the point where I used to be convinced that I wouldn’t progress anywhere in physics. Mental arithmetic is very difficult, calculus is hell, I’m no fan of trig, and I have to spend an extra minute double checking my additions (employing the use of all my available digits). Usually, this would be a minor annoyance, but in the winter of 1999, it became an obvious gaping wound in my abilities as a wannabe astrophysicist. Throw this on top of my history of anxiety, rather than confronting the issue, I’d bury it. If I didn’t think about it, where’s the worry? Unfortunately, I had to think about it.
All the way through my GCSEs and A Levels (the qualifications that you’d take at school before going to university in the late 90’s in the UK) I was a decent student. I was never late with coursework, never skipped class and always tried my best. I was extremely lucky to have very supportive parents and very privileged to live 15 minutes from what I consider to be the best comprehensive (re: state-funded) school in my hometown of Bristol. While not a “straight A” student, I certainly performed well and, during my A Levels I was able to pick up a pleasing A, B and C, for Technology, Physics, and Geography, respectively, nabbing the exact number of UCAS points I needed to secure a place at my first choice university on the beautiful west coast of Wales — The University of Wales, Aberystwyth.
I was riding high and the future was bright. But I always had this baggage buried deep in the back of my brain: I’m bad at math.
If you’ve been through the UK route to university physics, you’ll notice a big, red, flashing neon sign of a problem with my choice of A Levels:
🚨 THERE’S NO MATHEMATICS 🚨
This fact wasn’t lost on the university representatives at the various higher-education fairs I’d attended from 1996 to 1998. A physics rep from one of the more “prestigious” universities had the biggest assholey reaction when I said that, yes! it is true that I’m not studying mathematics at A Level: “You can forget doing physics, then,” he scoffed, before chuckling about it to his buddy. Yep, chuckled. His disdain for the gall a math-anemic student had to approach him to inquire about their astrophysics course was too much for his stupendous brain to bear, it seemed. Fortunately, he was an outlier, the majority of other reps were generally kind, supportive and helpful, but it gave me pause. Was I under-qualified? Was my inability to grasp mathematics going to be a real problem for my dream of studying black holes, galaxies, alien worlds and the Big Bang?
Screw those guys, I thought. Fortunately the detractors at that phase of my education were rare and, though they did nothing to boost my confidence in math, they didn’t dull my excitement for studying physics university. Besides, I’d nailed my grades! Onward to Aberystwyth!
***Aside: Before I continue, I need to emphasize that all my (many) years at university were amazing. To have the wonderful good fortune to live and study in arguably one of the most beautiful places in the world was humbling. As a university town, Aber couldn’t have been a better choice. I made a diverse group of lifelong friends, got a wonderful education, somehow managed to spend a semester in the Arctic studying the aurora, grew as a person, lost an appendix, and developed an appreciation for the Welsh language, all while enjoying the highest density (at the time) of pubs per capita. I only have fond memories of the physics department and all the members of staff and fellow students. The following is more of a conversation about the culture in higher education and how certain assumptions can damage the confidence of students, possibly creating an intellectual barrier for their progression, inspired by the above conversation with Sophia.***
So, with my A Levels behind me, I was ready for university. I was 18 and excited to get the introductory physics courses out of the way so I could dive into the wonders of the cosmos. Ha! Sorry, I couldn’t write that with a straight face; I was excited the meet girls and have a great time playing pub golf and partying until 5am. But once the alcohol haze had lifted after Freshers Week, reality struck. Because I didn’t have a mathematics A Level, I had to take an introductory math course “to get me up to speed” with the mathematical tools I’d need to complete my undergraduate degree. This wasn’t an unfair ask and I had little problem with tackling it. The university had a system in place that made an honest and clear effort to make sure no student was left behind. In some ways, the fact that I had to confront my math angst head-on was reassuring. After all, how the heck could I navigate a career in physics while avoiding math at all costs? Spoiler: I couldn’t and I didn’t want to. It was a fresh start, a ripping of the Band Aid, an anxiety detox. I was ready. Hit me!
To say I enjoyed these early math lectures would be a lie, but I did get a sense of satisfaction from taking them. The lecturers were generally good and delivered a well-organized curriculum. Alongside the intro math, I was doing all the other stuff my colleagues were doing, except for the theoretical classes that left smudges of squiggled chalked integrals and partial differential equations on the blackboard in the lecture theater when my introductory class started. In these early days of my university career, those squiggles may as well have been Egyptian hieroglyphics. But, gradually, like a sapling unfurling from the dirt, I was developing my own way of dealing with math: repetition. I was making progress and I could imagine that, one day, I’d be like my physics friends who could stand up in front of a lecture hall, drawing squiggles with my piece of chalk and explaining why Fourier transforms are so great. Although much of my learning was done parrot fashion, without a lot of comprehension about what I was doing at the time, I was able to, at worst, wing it.
So far, so good, right?
The Pen Game
The whole point of this story is leading to one, singular — nay, pivotal — moment in a cramped office of my first-year supervisor. Every week, small groups of us had meetings with our allocated lecturer-supervisors. My supervisor (who will remain unnamed because he’s not really the point of this story, though he did get under my skin), an older, well-respected professor with thick-rimmed glasses and eccentric humor, really didn’t want to be there. And nor did I. Each week, he’d try to get the most entertainment out of his supervised students, including me and three others who were suffering from the same no-math affliction. These meetings were supposed to be for us to have a space to discuss our math-related struggles and progress, with no fear of embarrassment.
To pass the time, and enforce his own quirky way of teaching, the professor would have this recurring game where he’d drop a bunch of pens on his desk and ask us what number it represents. It was maddening, didn’t make sense and he’d always make us feel shitty for making a blind guess. What’s more, we didn’t get the point, was this a profound lesson in math? Philosophy? Counting the seconds until all the pens had stopped rolling? I took a flier: as the pens landed, some would cross another on the desk, coming to a stop, so I counted the number of crossed pens and shouted “Two!”
Without hesitation, he replied, “No! Wrong! You’re wrong!” And so he’d drop the pens again and ask the same silly question, “What number?”
Obvious eccentricities to one side, the good professor was pissing me off. And I suppose that was the point. So, the following week I went into that office and paid attention to everything. I made a note of the time, the air temperature, the number of other items on his desk… and then I saw it. The four of us sat down and the professor grabbed his usual pens and dropped them on the desk. Without waiting for him to say a word, I blurted “FIVE!”
He looked at my smiling face and nodded. Fireworks erupted in my brain, I’d passed his stupid test. My three colleagues looked at me in astonishment. “Let’s do it again,”—he dropped the pens a second time—”how many?”
“Eight!” I felt like I’d won the professor’s admiration and approval. I might be bad at math, but damn I’m good at this game. He smiled and nodded again. He asked me to tell everyone how I did it. Feeling cocky, I just said, “look at his fingers.” Every time he dropped the pens, he’d lean on the desk, extending a different number of fingers after each drop. All I was doing was counting his goddamn fingers!
And now for the lesson of this stupid game, words that I’ve never forgotten.
“Whenever I’ve played this game,” he started, “it’s always artists who guess it correctly, physicists focus too much on the pens. You know what it means? You’re an artist, not a physicist.” He pointed at me, no longer smiling.
Besides my confusion that it was apparently a bad thing to correctly find a solution to this stupid game, why was I being branded an “artist”? There is nothing wrong with being an artist, or so I thought, but I had chosen a career path to become a physicist. What’s more, I was in a class specifically focused on supporting students who lacked the math qualifications to do physics. It seemed like a teaching self-own. Over the years, I assumed it was his way to motivate me to work harder at math—yes! Reverse psychology! Shame me into doing better! But, nah, the opposite happened.
Impostor syndrome is something, I’ve recently realized, that goes hand-in-hand with my anxiety, so to get verbal confirmation of my personal doubt was like a punch to the gut. I was ready to quit; who was I fooling? I was out of my depth. My excitement for physics fell off a cliff and, with the endorsement of an authority figure who, for whatever reason wanted to make his students feel shitty, had rubber-stamped my self-doubt.
A Better Way
I didn’t quit, but if it wasn’t for the social group that I had, I might have. My challenge with math wasn’t the only mountain I was climbing at the time. Like most undergrad students at university, simply navigating life was hard. But I was lucky, I had a girlfriend and a solid group of friends, a supportive family and a love for the student life. However, drop-out rates in physics are high, or they were 20 years ago, and what was becoming abundantly clear was this arrogant assumption that to be good at physics, I had to be good at math.
After the Pen Game, I became acutely aware of the teaching practices of my lecturers. Lessons would begin with innocuous, throw-away statements like (I paraphrase), “you all know this already,” “you hibernated through school/lived under a rock if you don’t know this,” “let’s skip these steps, if you don’t get it, read a book,” and, my personal favorite, “don’t come crying to me if/when you fail.” Back then, those statements weren’t strange, they were simply educators—many of whom didn’t really want to be teaching, they had research grants to apply for—trying to be witty or, under pressure to deliver their class, they really wanted to make sure they could fit in the entire syllabus in the allotted time. I felt even more precarious when my introductory math courses finished and I should have been “up to speed” with the mathematical tools for a bright physics future. Alas, though I was undoubtedly better at math, my confidence had ebbed to zero.
Fortunately, my want to continue living the university life outweighed my anxieties and I learned to live with it. I didn’t ask for help (in hindsight, I should have), and math just became my dirty secret. It was a specter that followed me around the campus. That said, I was good at physics; I had a great conceptual grasp of all the topics and meandered my way through the math. But the real turning point for me happened when studying the final semester of my Masters year in the high-Arctic, on the Norwegian archipelago of Svalbard. The EU-funded exchange program (Reason 1,324 why I have very strong feelings against Brexit; I took for granted the research and study programs that the UK could seamlessly participate in and I’m devastated that the next generation of students/researchers may not have the same, broad opportunities), that gave me the chance to experience real research on the aurora and other space weather phenomena in this incredible part of the world, made me think of math differently. I’d found my passion—the sun-Earth interaction—and suddenly, I realized math wasn’t the barrier. It was my anxiety and fear. I’d built mathematics up into this impenetrable barrier rather than viewing it as the tool that builds physics theory. Long story short, I had to literally travel to the ends of the Earth (well, the top of the Earth) for me to realize that, ya know, math ain’t that bad.
I went on to do a Ph.D in solar physics—specifically coronal loops, an origin of space weather—and, during a random research trip to Hawaii to work with colleagues who were based in Honolulu, I met my wife. So, I have no regrets and, as I type this from my computer at home in Los Angeles, I remember my struggle with math with fondness, oddly enough. And I have no problems using all my available digits to do basic arithmetic. I even do it in public.
We live at a time where science is regularly overlooked and often derided (re: climate change deniers, anti-vaxxers, flat-earthers etc.) and we need all the most talented critical thinkers to take on careers in science, technology, engineering, art, and mathematics (STEAM) in order to confront some of the biggest challenges facing our planet. So, educators of all levels, never make assumptions of the abilities of your students; just a throwaway comment like “I’m sure you already know this…” can boost needless anxiety in learning.
A tiny rock has been detected in the Kuiper belt, which may not seem like such a big deal, but how it was found is.
We think we have a pretty good handle on how planets form. After the birth of a star, big enough clumps of dust and rock in the disk of leftover debris begin to accrete mass until they turn into spheres under the pull of their own gravity, jostling around, pushing smaller protoplanets out of the way and being shoved aside by, or smashing, into larger ones. Whatever planets survive this messy process end up becoming a solar system. We’ve seen this around other stars and aside from a few interesting twists on this model, we think we know what’s going on pretty well by now.
But there was one piece missing. The math says that to start the planet building process, you need a kind of planetary seed between one and ten kilometers wide. Since we happen to live in a solar system, we should be able to look outwards, towards the Kuiper Belt, which we think is made primarily from the leftovers of planetary formation, and see these protoplanetary fossils drifting across the sky. However, the process has proven to be rather tricky. These rocks are very faint and rather small compared to everything else we can usually see, so looking for them is kind of like trying to spot a grain of dust in a room illuminated only by moonlight, which is why we have so much trouble finding them.
Or at least we did until now, when a 1.3 kilometer Kuiper Belt Object, or KBO was spotted by a simple setup and commercially available cameras as it eclipsed background stars. While that might not sound like much right now, it’s actually an extremely important finding. First, it tells us how to find tiny KBOs so we can take a proper survey of protoplanetary leftovers. Secondly, it shows that we’re correct in our solar system formation model and demonstrated that predicted artifacts of baby planets that never quite made it do exist. The next part will be to try and detect more of these little planet seedlings to figure out how efficient the formation process is, and see what we can learn from that.
As noted, these finds don’t just apply to our own solar system, but to pretty much every planet in the universe. Just consider that mighty gas giants with swirling storms that could swallow Earth whole, exotic icy dwarfs with percolating cryovolcanoes and towering peaks dusted with reddish organic molecules, and tropical worlds with deep oceans teeming with life — which might even be home to an alien civilization living through its heyday — all started out as these little rocks lucky enough to clump together for a few hundred million years, find a stable orbit, and cool down enough to become a cosmic petri dish. They might not be impressive or exciting on their own, but that doesn’t mean they aren’t profoundly important.
Reference: Arimatsu, K., et. al., (2019) A kilometre-sized Kuiper belt object discovered by stellar occultation using amateur telescopes, Nature Astronomy Letters, DOI: 10.1038/s41550-018-0685-8
When our young planet was taking a beating by massive impacts, bits were ejected into space—and some ended up on the moon.
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?
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.
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.
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:
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.
Scientists are closing in on a better understanding about how these magnetic eruptions evolve
For the first time, scientists have created a computer model that can simulate the evolution of a solar flare, from thousands of miles below the photosphere to the eruption itself in the lower corona — the sun’s multimillion degree atmosphere. And the results are not only scientifically impressive, the visualization is gorgeous.
I’ve always had a fascination with the sun — from how our nearest star generates its energy via fusion reactions in its core, to how the tumultuous streams of energetic plasma slams into our planet’s magnetosphere, igniting spectacular aurorae. Much of my interest, however, has focused on the lower corona; a region where the intense magnetic field emerges from the solar interior and reaches into space. With these magnetic fields comes a huge release of hot plasma that is channeled by the magnetism to form beautiful coronal loops. Intense regions of magnetism can accumulate in violently-churning “active regions,” creating sunspots and explosive events — triggered by large-scale magnetic reconnection — such as flares and coronal mass ejections (or CMEs). This is truly a mysterious place and solar physicists have tried to understand its underlying dynamics for decades.
Now, with increasingly-sophisticated solar observatories (such as NASA’s Solar Dynamics Observatory), we are getting an ever more detailed look at what’s going on inside the sun’s deep atmosphere and, with improvements of theoretical models and increases in computer processing power, simulations of the corona are looking more and more like the real thing. And this simulation, detailed in the journal Nature Astronomy, is truly astonishing.
In the research, led by researchers at the National Center for Atmospheric Research (NCAR) and the Lockheed Martin Solar and Astrophysics Laboratory, the evolution of a solar flare has been modeled. This simulation goes beyond previous efforts as it is more realistic and creates a more complete picture of the range of emissions that can be generated when a solar flare is unleashed.
One of the biggest questions hanging over solar (and indeed, stellar) physics is how the sun (and other stars) heat the corona. As we all know, the sun is very hot but its corona is too hot; the photosphere is a few thousand degrees, whereas, only just above it, the coronal plasma skyrockets to millions of degrees, generating powerful radiation beyond what the human eye can see, such as extreme-ultraviolet and X-rays. Basic thermodynamics says that this shouldn’t be possible — this situation is analogous to finding the air surrounding a light bulb is hotter than the bulb’s glass. But what our sun has that a light bulb does not is a powerful magnetic field that dictates the size, shape, temperature and dynamics of the plasma our sun is blasting into space. (If you want some light reading on the subject, you can read my PhD thesis on the topic.)
“This work allows us to provide an explanation for why flares look like the way they do, not just at a single wavelength, but in visible wavelengths, in ultraviolet and extreme ultraviolet wavelengths, and in X-rays. We are explaining the many colors of solar flares.”
Mark Cheung, staff physicist at Lockheed Martin Solar and Astrophysics Laboratory.
The basis of this new simulation, however, investigates another mystery: How and why do solar flares erupt and evolve? It looks like the research team might be on the right track.
Inspired by a powerful flare that was observed in the corona in March 2014, the researchers provided their magnetohydrodynamic model with an approximation of the conditions that were observed at the time. The magnetic conditions surrounding the active region were primed to generate a powerful X-class flare (the most powerful type of solar flare) and several less powerful (but no less significant) M-class flares. So, rather than forcing their simulation to generate flares, they re-enacted the conditions of the sun that were observed and just let their simulation run to create its own flares.
“Our model was able to capture the entire process, from the buildup of energy to emergence at the surface to rising into the corona, energizing the corona, and then getting to the point when the energy is released in a solar flare,” said NCAR scientist Matthias Rempel in a statement. “This was a stand-alone simulation that was inspired by observed data.
“The next step is to directly input observed data into the model and let it drive what’s happening. It’s an important way to validate the model, and the model can also help us better understand what it is we’re observing on the sun.”
Solar flares, CMEs and even the solar wind can have huge impacts on our technological society. The X-rays blasting from the sun’s atmosphere millions of miles away can have dramatic impacts on the Earth’s ionosphere (impacting communications) and can irradiate unprotected astronauts in space, for example. CMEs can be launched from the corona and arrive at Earth orbit in a matter of hours or days, triggering geomagnetic storms that can impact entire power grids. We’re not just talking a few glitches on your cellphone here; satellites can be knocked out, power supplies neutralized and global communications networks interrupted. It’s simulations like these, which aim to get to the bottom of how these solar storms are initiated, that can help us better prepare for our sun’s next big temper tantrum.