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.
New models trying to infer the geology of potentially habitable moons orbiting Jupiter and Saturn hint at surprisingly cool, geologically inactive worlds, the opposite of what a diverse alien ecosystem would need
Imagine a spaceship finally landing on Europa and slowly drilling into the ice. After weeks of very careful progress, it pierces the moon’s frozen shell and releases a small semi-autonomous submarine connected to the probe with an umbilical to ensure constant communication and a human taking over in case of an emergency. Much of the time, it will chart a course of its own since piloting it with an hour long delay between command and response would be less than ideal. It navigates through the salty ocean, shining its light on structures never before seen by a human eye, making its way deeper and further into the alien environment to find absolutely… nothing at all.
That’s the sad scenario proposed by a team of geologists who crunched the numbers on the four leading contenders to host alien life in our outer solar system: Europa, Ganymede, Titan, and Enceladus. According to their models, looking at gravity, the weight of water and ice on the rocks underneath, and the hardness of the rocks themselves, these moons would be more or less geologically dead. Without volcanoes or sulfur vents, there would be very little in terms of nutrient exchange and therefore, very little food and fuel for an alien ecosystem more complex than microbe colonies.
Of course, these results are a pretty serious departure from the hypotheses commonly held by planetary scientists that the gravity of gas giants cause tidal kneading inside their moons, citing Io as an example. According to the researchers’ model, only Enceladus would be a promising world to look for life, as evidenced by the plumes breaking through its icy crust, spraying organic material into space. The reason why the numbers are different, they say, is because its core is likely to be porous, meaning its ocean would be heated deep inside the moon, fueling geysers and churning organic matter while effectively making the little world a ball of soggy slush.
Since these findings are so different from what’s implied by observations, the researchers aren’t in a rush to publish them are are soliciting other scientists’ opinions to make sure they have a complete picture, and lead investigator Paul Byrne grumbled about his disappointment with what the models indicate. That said, while he’s hoping to be proven wrong, we shouldn’t forget that these are alien worlds and while we’ve spent decades studying them, our knowledge came in bursts. Simply put, we might know a fair bit but far from everything and disappointing surprises may lurk under their icy surfaces and subterranean oceans.
The binary system observed by ALMA isn’t wonky, it’s the first example of a polar protoplanetary disk
Some star systems simply don’t like conforming to cosmic norms. Take HD 98000, for example: It’s a binary system consisting of two sun-like stars and it also sports a beautiful protoplanetary disk of gas and dust. So far, so good; sounds pretty “normal” to me. But that’s only part of the story.
When a star is born, it will form a disk of dust and gas — basically the leftovers of the molecular cloud the star itself formed in — creating an environment in which planets can accrete and evolve. Around a single star (like our solar system) the protoplanetary disk is fairly well behaved and will create a relatively flat disk around the star’s spin axis. For the solar system, this flat disk would have formed close to the plane of the ecliptic, an imaginary flat surface that projects out from the sun’s equator where all the planets, more or less, occupy. There are “wonky” exceptions to this rule (as, let’s face it, cosmic rules are there to be broken), but the textbook descriptions of a star system in its infancy will usually include a single star and a flat, boring disk of swirling material primed to build planets.
Cue HD 98000, a star system that has flipped this textbook description on its head, literally. As a binary, this is very different to what we’re used to with our single, lonely star. Binary stars are very common throughout the galaxy, but HD 98000 has a little something extra that made astronomers take special note. As observed by the Atacama Large Millimeter/sub-millimeter Array (ALMA), its protoplanetary disk doesn’t occupy the same plane as the binary orbit; it’s been flipped by 90 degrees over the orbital plane of the binary pair. Although such systems have been long believed to be theoretically possible, this is the first example that has been found.
“Discs rich in gas and dust are seen around nearly all young stars, and we know that at least a third of the ones orbiting single stars form planets,” said Grant M. Kennedy, of the University of Warwick and lead author of the study published today in the journal Nature Astronomy, in a statement. “Some of these planets end up being misaligned with the spin of the star, so we’ve been wondering whether a similar thing might be possible for circumbinary planets. A quirk of the dynamics means that a so-called polar misalignment should be possible, but until now we had no evidence of misaligned discs in which these planets might form.”
This star system makes for some rather interesting visuals, as shown in the artist’s impression at the top of the page. Should there be a planetary body orbiting the stars on the inner edge of the disk, an observer would be met with a dramatic pillar of gas and dust towering into space with the two stars either side of it in the distance. As they orbit one another, the planetary observer would see them switch positions to either side of the pillar. It goes without saying that any planet orbiting two stars would have very different seasons than Earth. It will even have two different shadows cast across the surface.
“We used to think other solar systems would form just like ours, with the planets all orbiting in the same direction around a single sun,” added co-author Daniel Price of Monash University. “But with the new images we see a swirling disc of gas and dust orbiting around two stars. It was quite surprising to also find that that disc orbits at right angles to the orbit of the two stars.”
Interestingly, the researchers note that there are another two stars orbiting beyond the disk, meaning that our hypothetical observer would have four suns of different brightnesses in the sky.
The most exciting thing to come out of this study, however, is that ALMA has detected signatures that hint at dust growth in the disk, meaning that material is in the process of clumping together. Planetary formation theories suggest that accreting dust will go on to form small asteroids and planetoids, creating a fertile enviornment in which planets can evolve.
“We take this to mean planet formation can at least get started in these polar circumbinary discs,” said Kennedy. “If the rest of the planet formation process can happen, there might be a whole population of misaligned circumbinary planets that we have yet to discover, and things like weird seasonal variations to consider.”
What was that I was saying about “cosmic norms”? When it comes to star system formation, there doesn’t appear to be any.
I worked on TRIUMF’s Five-Year Plan (2020-2025) last year, so Astroengine is featuring a few physicsy articles that were included in the document to tell the center’s story
Last year, I had the honor to help write TRIUMF’s Five-Year Plan for 2020-2025. TRIUMF is Canada’s particle accelerator center, located next to the University of British Columbia’s campus in Vancouver, and it tackles some of the biggest problems facing physics today.
Every five years, research facilities in Canada prepare comprehensive documents outlining their strategies for the next five. In this case, TRIUMF asked me to join their writer team and I was specifically tasked with collaborating with TRIUMF’s management to develop and write the Implementation Plan (PDF) — basically an expanded version of the Strategic Plan (PDF) — detailing the key initiatives the center will carry out between 2020 and 2025.
As the location of the world’s largest and oldest operational cyclotron, the center is a multi-faceted physics lab with hundreds of scientists and engineers working on everything from understanding the origins of matter to developing radiopharmaceuticals to treat late-stage cancers. I only had a vague understanding about the scope of TRIUMF’s work before last year, but, as the months progressed after visiting the center in April 2018, I was treated to an unparalleled learning experience that was as dizzying as it was rewarding.
As a science communicator, I wanted to understand what makes TRIUMF “tick,” so I decided to speak to as many TRIUMF scientists, engineers, collaborators, and managers as possible. During my interviews, I was excited and humbled to hear stories of science breakthroughs, personal achievements and mind-bending physics concepts, so I included a series of miniature articles to complement the Implementation Plan’s text. As the Five-Year Plan is a public document (you can download the whole Plan here, in English and French), I’ve been given permission by TRIUMF to re-publish these articles on Astroengine.
“Beyond Multimessenger Astronomy”
Background: To kick off the series, we’ll begin with nuclear science. Specifically, how astrophysical processes create heavy elements and how TRIUMF studies the formation of radioisotopes in the wake of neutron star collisions.
After the 2017 LIGO detection of gravitational waves caused by the collision of two neutron stars (get the details here), and the near-simultaneous detection of a gamma-ray burst from the same location, scientists heralded a new era for astronomy — nicknamed “multimessenger astronomy,” where gravitational wave and electromagnetic signals measured at the same time from the same event can create a new understanding of astrophysical processes. In this case, as it was confirmed to be a neutron star merger — an event that is theorized to generate r-process elements — spectroscopic analysis of the GRB’s afterglow confirmed that, yes, neutron star collisions do indeed create the neutron-rich breeding ground for heavy elements (like gold and platinum). Although multimessenger astronomy may be a new thing, TRIUMF has been testing these theories in the laboratory environment for years, using rare isotope beams colliding into targets that mimic the nuclear processes that produce the heavy elements in our universe. This process is known as nucleogenesis, and it’s how our cosmos forges the elements that underpin stardust, the stuff that makes the planets, stars, and the building blocks of life.
For this mini-article, I had a fascinating chat with Dr. Iris Dillmann, a nuclear physics research scientist at TRIUMF. I’ve lightly edited the text for context and clarity. The original article can be found on page 22 of the Implementation Plan (PDF).
The article: TRIUMF’s investigations into neutron-rich isotopes were well-established before the advent of multi-messenger astronomy. “It was a cherry on top of the cake to get this confirmation, but the experimental program was already going on,” said Dillmann.
“What we do is multi-messenger nuclear physics; we are not looking directly into stars. TRIUMF is doing experiments here on Earth.”
Whereas the combination of gravitational waves and electromagnetic radiation from astrophysical events gives rise to a new era of multi-messenger astronomy, TRIUMF’s Isotope Separator and Accelerator (ISAC) facilitates the investigation of heavy isotopes through an array of nuclear physics experiments all under one roof that can illuminate the characteristics of isotopes that have been identified in neutron star mergers.
“For example, astronomers can identify one interesting isotope and realize that they need more experimental information on that one isotope,” she said. “We then have the capability to go through the different setups and, say, measure the mass of the isotope with the TRIUMF Ion Trap for Atomic and Nuclear Science (TITAN) experiment’s Penning trap.”
With ISAC, all these measurements are carried out in one place, where teams from each experiment work side by side to solve problems quickly and collaborate effectively. “We have the setups in the hall to investigate an isotope from different perspectives to try to get a complete picture just from one department — the nuclear physics department,” said Dillmann.
A nearby baby star has been discovered with a warped protoplanetary disk — a feature that may reveal the true nature of the solar system’s planetary misalignments
Textbook descriptions of our solar system often give the impression that all the planets orbit the sun in well-behaved near-circular orbits. Sure, there’s a few anomalies, but, in general, we’re led to believe that everything in our interplanetary neighborhood travels around the sun around a flat orbital plane. This, however, isn’t exactly accurate.
Pluto, for example, has an orbit around the sun that is tilted by over 17 degrees out of the plane of the ecliptic (an imaginary flat plane around which the Earth orbits the sun). Mercury has an inclination of seven degrees. Even Venus likes to misbehave and has an orbital inclination of over three degrees. If all the material that built the planets originated from the same protoplanetary disk that was — as all the artist’s impressions would have us believe — flat, what knocked all the planet’s out of alignment with the ecliptic?
Until now, it was assumed that, during the early epoch of our solar system’s planet-forming days, dynamic chaos ruled. Planets jostled for gravitational dominance, Jupiter bullied smaller worlds into other orbits (possibly chucking one or two unfortunates into deep space), and gravitational instabilities threw the rest into disorderly orbital paths. Other star systems also exhibit this orbital disorder, so perhaps it’s just an orbital consequence of a star system’s growing pains.
But there might be another contribution to the chaos: perhaps wonky star systems were just born that way.
Cue a recent observation campaign of the nearby baby star L1527. Located 450 light-years away in the direction of the Taurus Molecular Cloud, L1527 is a protostar embedded in a thick protoplanetry disk. Using the Atacama Large Millimeter/submillimeter Array (ALMA), in Chile, astronomers of the RIKEN Cluster for Pioneering Research (CPR) and Chiba University in Japan discovered that the L1527 disk is actually two disks morphed into one — both of which are out of alignment with one another. Imagine a vinyl record that has been left on a heater and you wouldn’t be far off visualizing what this baby star system looks like.
The RIKEN study, published on Jan. 1 in Nature, suggests that this warping may have been caused by jets of material emanating from the star’s birth, kicking planet-forming material into this warped configuration and, should this configuration remain stable, could result in planets with orbital planes that are significantly out of alignment.
“This observation shows that it is conceivable that the misalignment of planetary orbits can be caused by a warp structure formed in the earliest stages of planetary formation,” said team leader Nami Sakai in a RIKEN press release. “We will have to investigate more systems to find out if this is a common phenomenon or not.”
It’s interesting to think that if this protoplanetary disk warping is due to the mechanics behind the formation of the star itself, we might be able to look at mature star systems to see the ancient fingerprint of a star’s earliest outbursts or, possibly, its initial magnetic environment.
It’s possible “that irregularities in the flow of gas and dust in the protostellar cloud are still preserved and manifest themselves as the warped disk,” added Sakai. “A second possibility is that the magnetic field of the protostar is in a different plane from the rotational plane of the disk, and that the inner disk is being pulled into a different plane from the rest of the disk by the magnetic field.”
Though orbital chaos undoubtedly contributed to how our solar system looks today, with help of this research, we may be also getting a glimpse of how warped our sun’s protoplanetry disk may have been before the planets even formed.
Creating the conditions of interstellar space in the lab has led to a sweet discovery
What do you get if you combine water with methanol and then bombard the mix with radiation? It turns out that the resulting cocktail is where the building blocks for life are found. But these chemicals aren’t bubbling out of the puddles of primordial goo pooling on some alien planet; the cocktail shaker is the frigid depths of interstellar space and the mixologist is the universe.
As described in a new study published on Tuesday in Nature Communications, a team of NASA scientists took what they knew of interstellar space and recreated it in a laboratory experiment. Interstellar space may not seem like a place where the chemistry of life could gain a foothold, but given enough time and the right ingredients, chemical reactions do happen — albeit very slowly. And if there’s one thing the universe has it’s time, and we’re beginning to understand that the cosmos we reside in could be a vast organic experiment.
“The universe is an organic chemist,” said Scott Sandford, a senior scientist in the NASA Ames Astrophysics and Astrochemistry Laboratory and co-investigator of the study. “It has big beakers and lots of time — and the result is a lot of organic material, some of which is useful to life.”
To see what chemistry might be going on in the void between the stars, the researchers simulated this extreme environment inside a vacuum chamber at Ames that was cooled to near-absolute zero. Inside, they placed an aluminum substance and then added the gaseous mixture of water vapor and methanol, a very common carbon-based molecule that is known to exist throughout our galaxy. Holding the aluminum at such low temperatures caused a frosty layer to form upon it. Then, they irradiated the substance with ultraviolet light — a form of radiation that is abundant in stellar nurseries, for example — and found that some interesting chemical reactions had occurred.
They discovered that a variety of sugar derivatives had formed on the substance — and one of those sugars was 2-deoxyribose. Yes, the same stuff you’d find in deoxyribonucleic acid. That’s the “D” in our DNA.
But this isn’t the first time an essential ingredient for life has been created in the lab while simulating the conditions of interstellar space. In 2009, the same team announced the discovery of uracil in their laboratory experiments — a key component of ribonucleic acid (RNA), which is central to protein synthesis in living systems. Also, in 2016, a French group discovered the formation of ribose, the sugar found in RNA.
“For more than two decades we’ve asked ourselves if the chemistry we find in space can make the kinds of compounds essential to life. So far, we haven’t picked a single broad set of molecules that can’t be produced,” said Sandford in a NASA statement.
Although these are significant discoveries that provide new insights to how and where the most basic ingredients for life may form, it’s a long way from helping us understand whether or not life is common throughout the universe. But it turns out that some of the coldest spaces in the cosmos could also be the most fertile environments for the formation of a range of chemicals that are essential for life on Earth. It’s not such a reach, then, to realize that the protoplanetary disks surrounding young stars will also contain these chemicals and, as planets form, these chemicals become an intrinsic ingredient in young planets, asteroids and comets. Over four billion years ago, when the planets condensed from our baby Sun’s nebulous surroundings, Earth may have formed with just the right abundance of molecules that form the backbone of DNA and RNA to kick-start the genesis of life on our planet. Or those ingredients were delivered here later in the frozen cores of ancient comets and asteroids.
The building blocks of life are probably everywhere, but what “spark” binds these chemicals in such a way that allows life to evolve? This question is probably well beyond our understanding for now, but it seems that if you give our Cosmic Mixologist enough time to concoct all the chemicals for life, life will eventually emerge from the cocktail.