Tiny Crystal Provides a Big Clue

Lab-grown crystal of blue ringwoodite, about 1.5 times the size of a salt grain (~150 micrometers) Photomicrograph by Jasperox, Wikimedia Commons.

Lab-grown crystal of blue ringwoodite, about 1.5 times the size of a salt grain (~150 micrometers) Photomicrograph by Jasperox, Wikimedia Commons.

Is there an immense ocean, far beneath the surface of the Earth, that replenishes the oceans above? Recent news items describe a deep reservoir containing as much as three-quarters of the Earth’s water supply. Most of these news stories are careful to note that this isn’t some great sloshing underground pool, and you won’t find any fish living there. Rather, the water is “bound up” in mineral deposits and released when these minerals are put under immense pressure. Some news stories compare the minerals to sponges, which is not something you usually associate with rocks. (Here are a couple of examples of the news items: Daily Digest News, The Guardian.)

What’s really going on here? Last March, a research paper in the journal Nature reported the discovery of a tiny crystal of a mineral called ringwoodite, encased in a diamond that was plucked out of shallow river gravel by artisan miners near Juína, Brazil. A research team led by Graham Pearson (University of Alberta, Canada) found the ringwoodite crystal (60 microns, less than the thickness of a sheet of paper) inside a dirty-looking brown diamond that they had bought for about $20 (US), according to an article in Sci-News. (Here’s the article, with a photo of the diamond and ringwoodite crystal.).

This month, a paper in Science used this discovery, along with geological measurements, lab studies, and models, as evidence to support an idea that geologists had been looking at for many years. (Here are a couple of press releases, from the the University of New Mexico and Northwestern University, where the two lead authors are located.)

Scientists suspect that ringwoodite may be common in a “transition zone” that lies 410 to 660 km (250–410 miles) below the Earth’s surface, based on seismic measurements, which track changes in the speed and direction of earthquake vibrations. Ringwoodite has been made in the lab and found in meteorites, but this was the first time that anyone had found a naturally occurring crystal from inside the Earth.

green olivine sand

Green olivine sand on black volcanic rock. Photo by Brocken Inaglory, Wikimedia Commons.

Why do we care about this elusive mineral? Because it’s a high-pressure form of another mineral called olivine. As the name suggests, many forms of olivine are dark green (it can range from yellow to black). The dark-green sands on Papakolea Beach, Hawaii are mostly olivine, and this mineral is common all over the world. At very high pressures, like those you would find more than 660 km beneath the Earth’s surface, olivine transforms into another mineral called perovskite. The presence of one form or another affects the way that earthquake vibrations travel through the Earth. These two minerals have been studied intensively, and geologists use seismic signals as clues to help them map mineral forms and geological activity far beneath the surface, where it’s hard to get the information any other way.

Water and hydroxyl radical

Water molecule (H2O, left) and hydroxyl radical (OH, right). Courtesy of NIST.

Ringwoodite is intermediate between olivine and perovskite. Because of the way its crystals form, they can contain as much as 3% by weight of something called hydroxyl radicals (OH•). (The crystal reported in the Nature paper had 1.5%.) This “radical” has nothing to do with political activism or unorthodox beliefs. Used in a chemistry context, the term refers to a water molecule (HOH, more commonly written H2O) that has one hydrogen atom stripped away, leaving behind a spare electron that it can share with something else, in this case, the elements in ringwoodite’s crystal structure.

Olivine doesn’t contain hydroxyl radicals. When olivine is put under pressure, water from the surrounding environment can be converted into OH•, forced inside, and incorporated into the framework of atoms, forming ringwoodite. The more OH• trapped in the framework, the faster the sound waves travel through it, which is why geologists had suspected that there was a water-containing mineral intermediate between olivine and perovskite.


Perovskite collected by A.E. Foote from Magnet Cove, Arkansas. Mineral collection of Bringham Young University Department of Geology, Provo, Utah. Photo by Andrew Silver, USGS.

Put ringwoodite under even more pressure, and it converts into perovskite. The hydroxyl radicals are forced back outside again, where they recombine with hydrogen (which is just about everywhere) to form liquid water. This water causes the perovskite to melt a little, in much the same way that sprinkling salt on ice causes the ice to melt. The scientists who published the paper in Science had actually seen this melting behavior in the lab, when they used a device called a diamond anvil cell to put immense pressure on a ringwoodite crystal and convert it to perovskite.

Geologists had seen seismic waves suddenly slowing down in regions where they had other clues that one rock layer was sinking down below another. A layer of partially melted perovskite that was taking a dive would slow down a seismic wave like this.

Previous examination of ancient minerals called basalts, taken from mid-ocean ridges, suggested that Earth’s upper mantle has a water content of 0.005 to 0.02% water by weight. Lab and modeling studies show that ringwoodite and a related mineral, wadsleyite, can hold between 1 and 3% water by weight. Seismic evidence suggests that the water content below 660 km is much less. Thus, if these studies are right, the transition zone is where most of the water is. If this zone extends all over the world, and its average water content is 1% (a conservative estimate that needs to be verified), this translates into nearly three times as much water as the oceans contain, which is where the news reports got their three-quarters number (three-quarters in the transition zone, one-quarter in the oceans).

Geologists have been working for decades to create a model that “balances the books” on where water comes from and where it goes — a “whole-Earth water cycle”. They had long suspected that there was a subterranean source that acts as a buffer zone to keep the amount of water in the oceans fairly constant. This latest evidence provides more clues to help them fill in the missing pieces.

What Is a Drone?

Second posting in a three-part series (see previous post)

Recent news stories have familiarized us with military drones bearing names like Predator and Reaper. Popular television shows feature tiny spy drones, conjuring images of CIA black ops. You could be forgiven for assuming that drones are a new and pernicious misuse of government power. But what are drones, really, and how are they being used?

The word “drone” is a popular term for any one of several types of unmanned vehicles that fly, swim, or travel over land. Most drones have some type of human guidance, whether it’s a kid at the other end of the kite string or a soldier or sailor sitting at a control panel hundreds of miles away. The variety of functions and capabilities is reflected in a menagerie of abbreviations: UAV (unmanned aerial vehicle), UAS (unmanned aerial system), RPV (remotely piloted vehicle), ROV (remotely operated vehicle), RPA (remotely piloted aircraft), UUV (unmanned underwater vehicle), and the list goes on.

Unmanned ground vehicles range from the Roomba automated vacuum cleaner to DARPA’s Big Dog robotic “pack animal”. REMUS vehicles (Remote Environmental Monitoring UnitS, operate underwater, taking orders from a human at a simple laptop computer or traversing a preprogrammed route. REMUS vehicles have patrolled Puget Sound, monitoring the temperature and salinity of the water. Specially adapted REMUS vehicles have surveyed New York City’s public water mains to check for leaks.

Aerial drone use is certainly not new. You might say that Benjamin Franklin used a drone kite to carry his metal key aloft during his experiments with lightning.

Oil burn experiment

1993 Newfoundland Oil Burn Experiment (Canadian Coast Guard photo)

More recently, miniature helicopters known as ROVs (remotely operated vehicles) flew through a smoke plume and monitored the air during the 1993 Newfoundland Offshore Burn Experiment, a collaboration between the U.S. and Canada in which a contained oil spill was set on fire in order to observe the effects on the surroundings and examine the after-products. (The helicopter in the photo at right is a full-sized, passenger-carrying helicopter carrying support crew for this event.) The Predator drones used in military operations are about the size of a glider plane. Some military surveillance drones are small enough for one person to launch by throwing them into the air (photo below). The U.S. Army is funding development work on hummingbird-sized drones that can fly into small spaces and avoid being noticed.

hand launched drone

Pvt. Patrick Hernandez practices launching a RQ-11B Raven. (USDOD photo by Pamela Redford, Fort Riley Public Affairs)

The Drone Next Door“, a May 7 Future Tense presentation at the New America Foundation (Twitter #FTdrones), focused on aerial drones. These unmanned vehicles operate with various degrees of autonomy. Automated aerial drones can operate without a human steering them, but they follow a specific set of instructions: fly this high, go that fast, travel this far in a specified direction. Autonomous drones can operate independently, executing a mission while making its own decisions under uncertain circumstances: locate and retrieve a specific package, but find your own way past any obstacles and recover from any mishaps you might encounter on the way.

Flying cameras are old technology, said Missy Cummings, associate professor of aeronautics and astronautics at MIT, and one of the U.S. Navy’s first female fighter pilots. What’s new about drones is their ability to make aerial imaging cost effective. The main limitations for drone-mounted sensors are weight and power requirements.

Is there any way of avoiding drone surveillance? Cummings facetiously mentioned anti-UAV hoodies. She noted that for every technology, there is an anti-technology. The Navy is very concerned with GPS denial technology, and is working to develop a drone that does not rely on GPS for navigation. Michael Toscano, president and CEO of the Association for Unmanned Vehicle Systems International, noted that signal interference, intentional or not, could pose a safety issue by disorienting the drone and possibly causing it to crash.

Drones are in widespread use for military operations, but are we in danger of being overrun with drones once their commercial use becomes legal in the U.S.? Konstantin Kakaes, a Schwartz Fellow at the New America Foundation, cited several examples where military technologies failed to make the transition to the civilian world. Nuclear-powered airplanes and nuclear explosions as excavation tools never caught on. President Kennedy pushed for supersonic passenger jets, but the Concorde was a European project, and it was not a commercial success. One success story, GPS navigation, was not predicted to make the transition from military-only use. It succeeded because it provided unique capabilities, and the price came down as it became more widely used.

The KMAX, and unmanned cargo helicopter, proved useful in the remote regions of Afghanistan, but it was not as useful in the U.S. Barriers to technology adoption include production costs and infrastructure requirements such as refueling stations, said Kakaes. A technology that provides a unique capability in a remote, primitive, or hazardous area could lose out to cheaper and better competitors in a modern city.

Drones could, however, prove themselves useful in an urban setting if they could effectively increase capabilities and reduce costs for search and rescue missions (finding survivors of a building collapse, for example), crime scene investigation, traffic accident reporting, and missing person searches, according to Captain Don Roby of the Baltimore County Police Department.

Current FAA rules prohibit commercial use of drones, but under the new rules in 2015, they could reduce costs for traffic reporting and monitor environmental changes, said Matthew Waite, the University of Nebraska-Lincoln professor who founded the Drone Journalism Lab. Waite was not especially concerned about the possibility of airborne paparazzi on every street corner in the near future. “Journalists are horrible pilots,” he said, citing his and his students’ misadventures.

What about scientific research? “Cost is the biggest hurdle for science,” said Robbie Hood, Director of Unmanned Aerial Systems at NOAA. You’re looking at established technology, she said, with the UAV as just another observing system, a “force multiplier for science”. Satellites can provide snapshot views of the ground below, but UASs can stay with a weather system as it develops, providing a more detailed picture. This could enable NOAA to observe a hurricane as it first forms over the open ocean. As climate change opens up shipping lanes in the Arctic, drones will monitor shipping activity, oil spills, and detailed weather reporting that could help prevent ship strandings.

Carter Roberts, president and CEO of the World Wildlife Fund, described how airborne drones are being used to monitor political unrest in areas where sensitive wildlife populations could be harmed. Drones also check for poaching activity, which WWF reports to the governments of the affected areas. Drones provide more immediate feedback than satellite collars, which can cost $10,000 each. Transmitter chips attached to an animal can send text messages to drones overhead much more cheaply. Thermal imaging can be used to reveal the presence of poachers at night, when they are most active. This opens up the possibility of pre-empting the poachers before they make their kill.

Previous post: Don’t Drone Me, Bro 

To come: Hashing it all out: How will we deal with the practical effects of having more unmanned vehicles in our daily lives?

Can We Talk?

(Reprinted from Flying Lessons: verbal-aviation.blogspot.com)

My year off is officially over. I’m still at home, but I’m actively looking for work. Maybe that will be a job in the conventional sense of the word, or maybe it will be a more creative way to bring in income. I’m not sure. I’ve tried telling myself that I ought to be checking the job ads more assertively, mailing brochures to potential clients, making cold calls and all. But it just doesn’t feel right. I have chastised myself, telling myself to just get over my inertia and start the wheels moving again. Don’t be such an introvert, I say. Which is kind of like telling myself to stop having such blue eyes or stop being so short.

I have found a much better source of motivation, though. It comes through in the morning when I am writing in my journal — or sometimes at 3AM when I am wishing that I could get back to sleep. In the deep stillness of my room, little ideas make their way to the surface. Concrete, definite actions that I could take. Actions with energy and enthusiasm behind them. Actions based on what I do naturally, what I enjoy, what gives me satisfaction.

There’s a stillness born of time away from the daily commute, the meetings and deadlines and periods of boredom interspersed with crises. In that space has come an appreciation of things that I have been doing for years, but have not integrated into the way I make my living. With that realization has come a desire to more fully integrate the marketable skills with the calling of what is most important to me.

I have come to acknowledge more fully my talent for talking about scientific and technical issues in language that is engaging and easy to understand. I might not get the story first, but I get it in context and I do my best to get it right. That’s a real talent. It’s much harder than summarizing one’s research in the specialized language of one’s own field. It goes beyond opening up a stream of data in the hopes that the more information you throw at people, the more likely they are to come around to your point of view. It’s very different from “dumbing it down”. Good science writing requires me to respect my reader’s intelligence and convey an accurate, nuanced picture in language that is both precise and accessible.

Good science writing is an act of empathy. When I’m conducting interviews for an article, I have to do my homework ahead of time to know who it is I’m talking to and have some basic knowledge of their work. I don’t want to waste this person’s time asking basic questions that could be answered easily with a little online research. It’s incumbent on me to know and convey to the person I’m interviewing the purpose of the article I’m writing and to ask for information that makes my article into something worth reading. I’m responsible for communicating to my source just why it is that he or she is exactly the person who can best help me learn and convey the specific information I’m going after.

I have to use my skills in asking questions to encourage my sources to talk about the most interesting, relevant, or important parts of their work. I have to listen carefully to what my sources are telling me. I can’t assume that I know in advance what they are going to say. I can’t shape their answers into what I think they should have said. I can’t be reluctant to ask for clarification — even if I think I understand what they meant to say. This requires a certain humility on my part — a willingness to relinquish any concept of myself as an expert and to let my sources speak for themselves. My expertise comes in organizing and conveying the voices of all my sources as accurately and understandably as possible.

Empathy requires me to know something about the audience I’m writing for. What this audience is most interested in might not be the same thing that most interests my sources. Depending on the type of article I’m writing, I might have to spend some time educating my audience, but I can’t be overly didactic without losing their attention. Everyone is busy these days, and a multitude of information sources compete for my reader’s attention. I have to make it worth my reader’s time to read my writing. I have to show my readers something new or present a different point of view on something familiar. Some part of what I say has to be relevant to the world they inhabit.

I have to be trustworthy. If I come across as selling a particular point of view or advocating for a particular cause, I might capture the attention of those who already agree with me. But I will lose those readers who disagree with me — the very readers who might have an “aha!” moment or engage others in a constructive dialogue after having read my article. On the other hand, false balance is just as misleading as blind advocacy. On some issues (climate change is one notable example), the scientific consensus is so strong that giving equal weight to a small opposing minority is a distortion of the facts.

Trustworthiness also requires clarity. “Baffle them with bullshit” is not an acceptable approach here. Few intelligent readers come away convinced that because an issue is presented in dense technical prose, it must be important and correct. On the other hand, talking down to one’s readers, using lazy metaphors, or affecting a false hipness only makes the writer look incompetent. The goal is to convey a message and convey it well.

Conveying a message also requires an understanding that we are not completely rational beings. Two reasonably sane, intelligent, well-intentioned people can look at the same set of facts and draw very different conclusions. We all operate within our own social, historical, and experiential frameworks, and we interpret what we see accordingly. A good writer must provide enough context and perspective to inform, but not overwhelm, her readers.

Our emotions affect how we react to information, whether or not we are aware of it. Thus, humor, diplomacy, and yes, empathy are far more than ways to “spice up” an article. They are necessary elements in connecting with one’s audience and opening a space for dialogue — or perhaps drawing the lines for battle.

The work I enjoy best draws on all these skills, but some of my previous jobs have required a “just-the-facts” approach. For some purposes, that’s enough. An activity report for a government agency is not the right place to hone one’s skills in humorous narrative nonfiction. But since I have all of these skills, it’s up to me to find an outlet for them. Leave the cut-and-dried work to those who excel at it.

Lately, I’ve been exploring social media (FaceBook, Twitter, and the like) as a means of staying in touch with the people I’ve met through my travels, career, and various stages of my life. This has evolved into a means of conversing with people whom I have never met face-to-face, but with whom I share common interests and affinities. I’m exploring the nuances of brief written communications and asking myself how well it is possible to know another person through electronic interaction alone. Electronic communities are changing the way we understand friendship and the way information (or misinformation) spreads.

Increasingly, interest groups, businesses, and other organizations use these channels to shape what we think and how we talk to each other in ways that go far beyond the pop-up ads and “you might be interested in…” suggestions. Skilled communicators realize that this is where their audience is, and they seek out the people they want to reach in this way. Perhaps the entire message can be conveyed right there on the spot. Perhaps a brief note on Twitter alerts readers to a more detailed account elsewhere. Perhaps flinging an idea into the fray sparks a conversation or elicits a wealth of crowd-sourced information, an exchange of diverse points of view. In any case, it’s a matter of going out and engaging in dialogue with readers where they are rather than passively waiting in the backwaters of the information stream.

If this is so interesting to me in my personal interactions, why not investigate ways to build this into my profession as a science writer? After all, one of the reasons I took 2012 as a year off was to discover ways of integrating the various values and interests I have into a means of supporting myself while contributing something worthwhile to the world.

Signal to Noise Ratios

turn down the noise

Photo by Nancy McGuire

Back to the science metaphors today. I got to thinking about how radically I have emptied out my schedule this year, and how it’s helping me pay attention to things too long ignored. Improving the signal-to-noise ratio, as it were.

Right after grad school, I spent three years as a postdoc at Los Alamos National Lab. I was studying the way that surfaces influence the structure of thin coatings, to see if you could set up a surface that could direct a thin film to form with the properties you wanted. In order to pick up any kind of a signal at all on my instruments, I had to start out with substrate materials that had a whole lot of surface area, just to have enough of the thin film to make a detectable signal.

I had to make sure that the substrate surface was as clean as humanly possible, to eliminate interference from contaminants — including air. For every sample I made, I had to start by baking my substrate material at a high temperature, under vacuum. This required custom-built glass furnace tubes that had to be made in the lab’s glass shop, by the resident glass-working experts. My fellow researchers showed me how to set up the furnace and vacuum pump setup, and they clued me in on putting a cold trap between the two parts, so that pump oil would not back-flow into the furnace tube. They also told me that the copper coil I needed for this could be found at a local auto supply store.

After I baked out my samples, I had to close off the glass tube and transfer it to one of those big glove boxes that you may have seen on TV shows where people are working in a lab. The man in charge of keeping the glove box maintained had very large hands, so the gloves were sized to fit him. I have very small hands, so I had to learn to manipulate tiny tweezers and allen wrenches using thick rubber gloves that were several sizes too big for me.

Coating the sample surface was an exercise in patience. Meter in a little gas, let it condense onto the surface, wait for things to settle down, meter in a little more, repeat. Do this until the gas pressure gauge shows that no more gas is condensing down onto the surface. This sometimes took hours. Once, I tried to put two layers down on a surface, and I stayed at it for 36 hours straight before I finally gave up.

After I collected data from my instrument, I used a computer program (written by another colleague) to tease out the tiny signal from the thin film from the much larger signal from my supporting surface. Another computer program would interpret the resulting pattern, but the specific material I was studying hadn’t been studied much as a thin film, so I had to piece together what I could from existing information and make reasonable assumptions.

I did manage to put together a general picture of what the surfaces were doing to the thin films. It’s been almost 25 years, and others have gone much farther than this than I could.

What I’m getting at is this. In order to see anything at all out of this year-long experience of mine, I had to set up a situation in which I had a lot of time just for me — my supporting substrate surface. I had to clear out any interfering noise from this time — residual stress from a long day at work and commuting, much of my extracurricular activity, anything that would take away from what I’m trying to find. After the initial clearing-out, I had to protect my time from re-contamination. Only then could I begin to let in the things that I want to pay attention to.

I’m getting a lot of advice and assistance from friends and colleagues, but ultimately, I’m having to put this thing together myself. And now that little hints of answers are starting to come in, I’m having to try and make sense of what I’m finding out. Looking at what other people have done is giving me a general direction, but ultimately, I’m having to take what I can find and make some reasonable assumptions about the rest.

Very slowly, a little pattern is starting to emerge from the background. Other people may do this more elegantly or simply, but this is my project, and I am having to put together an answer that applies to me. The learning how to do it, the actual process of doing it, and the friends and mentors I’m meeting along the way are just as important (if not more so) than whatever answers I may come up with.

Reprinted from Flying Lessons blog, which I also write. (verbal-aviation.blogspot.com)