Category: fun things

The next big thing in space travel

If you wanted to cross the ocean by ship, you’d probably choose an engine-driven vessel over a sail-driven vessel. The engine will get you where you’re going faster; it enables the ship to be much larger than it could be if it were driven by a sail; and it requires much less manual intervention to keep it going. Besides, you won’t be at the mercy of unpredictable winds. In oceangoing vessels, the technological progression from sails to internal-combustion engines solved a great many problems while creating only a few new ones, such as the need to obtain and store significant quantities of fuel and the pollution that results from burning that fuel. Of course, since the planet is conveniently spherical, you’re always a finite distance from the nearest port where you can fill up. If, on the other hand, you wanted to circumnavigate the globe without stopping for fuel, sails would be the way to go. The trip would take longer and the ship would be smaller, but you’d never have to worry about running out of gas.

This is the very thinking behind an ostensibly retro design for spacecraft: by ditching the fuel and engines you can enable much longer journeys, albeit with some trade-offs. Outfit your ship with a giant sheet of lightweight and highly reflective material, and you’ve got a solar sail, a propulsion system that can take you to the distant reaches of the galaxy without any fuel—pushing you along with the gentle power of light from the sun.

What Goes Around

Solar sails are by no means a new idea. In fact, German astronomer Johannes Kepler floated the idea by Galileo in 1610. Kepler imagined “heavenly breezes,” though, and had no concept of the scientific principles that would actually come into play. In 1871, James Clerk Maxwell, a Scottish physicist, predicted that electromagnetic radiation (including light) should exert a small amount of pressure when an object absorbs or reflects it; Russian physicist Peter Lebedev first demonstrated the effect in a laboratory in 1900.

A little more than 20 years later, another Russian physicist named Fridrikh Tsander proposed using this radiation pressure to push a spacecraft along using a large but very thin mirror. In the early 1970s, NASA funded research into solar sails, and for a while proposed that they be used to propel a probe that would rendezvous with Halley’s Comet in 1986 (though the necessary technology turned out to be unavailable at the time). Today, NASA and numerous other groups are actively developing solar sail designs, and several spacecraft powered by solar sails have already been deployed.

Light Pressure

The whole idea of light exerting pressure seems counterintuitive. I’ve personally stood in front of some very bright spotlights without so much as a wobble. And I know from my rudimentary understanding of physics that photons, the particles that make up light, have no mass. Nevertheless, under the right circumstances, light can indeed provide a push. The math, frankly, is beyond me, but according to scientists who seem to know what they’re talking about and can back it up with impressive-looking equations, photons do indeed exert a gentle pressure on objects they hit—and the pressure is roughly twice as great if the object reflects the light than if it absorbs the light, so solar sails would effectively be giant mirrors. But the key word here is gentle. I’ve read various analogies for the strength of the sun’s push, but one I particularly liked, on a NASA webpage, said that if you had a mirror the size of a football field, the pressure of the sun’s light would be about the same as the weight of a first-class letter.

In space, a small amount of pressure goes much further, because other factors such as gravity, air friction, and wind don’t get in the way. Even so, if a solar sail is going to push a spacecraft of any significant mass, it must be enormous. And therein lies a problem: with greater size comes greater mass—not so much from the sail itself but from the support structure that’s needed to keep it rigid and connect it to craft’s payload. The greater the mass to be pushed, the greater the size of the sail that’s needed, and so on. Thus, in solar sail design, thinner and lighter materials are almost always better. Sail thickness is measured in micrometres (µm)—millionths of a meter—with some being as thin as 2 µm. (By comparison, the average human hair is about 80 µm thick.) This brings up a second problem: fragility. You’ve got to fold or roll up a huge sheet of material that’s a zillionth of an inch thick, get it into space, and then unfurl it perfectly—without ripping or mutilating it, and without creating a support structure so massive that it’ll cancel out the sail’s low mass. One promising material is a type of porous carbon fiber that’s much thicker than the polymer films most researchers have used, and yet lighter in weight because of its unusual structure; it’s also highly rigid, durable, and heat-resistant.

Still More Uses for the Force

Proposed solar sail designs have used a wide variety of shapes, from simple squares to disks to pinwheels. As with wind sails, you can change the angle of a solar sail in order to steer the craft; designs that incorporate numerous smaller sails provide greater directional control. But one thing you will not see is a solar sail shaped like a parachute—since light travels in straight lines, that would make for a highly inefficient design. Interestingly, that’s exactly the shape of a certain fictional solar sail—the one used by Count Dooku’s spaceship in Star Wars: Episode II—Attack of the Clones.

Besides having an inappropriately shaped sail, that ship somehow managed to zip across the galaxy at a startling speed as soon as the sail unfurled. Real solar sails, because they generate so little force, accelerate quite slowly. On the other hand—and this is what makes them an intriguing option for long-term missions—the velocity continues to increase over time, there being no friction to counteract it. The result is that over a period of months or years, a craft powered by a solar sail could reach speeds far in excess of any rocket-powered design. However, as the craft gets farther and farther away from the sun, the radiation pressure also decreases, so it’s not as though the rate of acceleration can continue to increase indefinitely. Even so, a vehicle with a very lightweight solar sail could reach the orbit of Pluto in about 7 years. (The Pioneer 10 probe, launched in 1972, took 11 years to reach that point.)

Sail On

After many years of ground-based and suborbital testing, as well as a few noteworthy failures, an interplanetary solar sail spacecraft (Japan’s IKAROS probe) was first successfully deployed in 2010. NASA launched the NanoSail-D2 later in 2010. And The Planetary Society launched and successfully tested a small solar sail-powered spacecraft called LightSail 1 in 2015; LightSail 2 is scheduled to launch in June, 2019. Numerous other solar sail projects are in various stages of planning.

Among the future missions envisioned for spacecraft propelled by solar sails are probes sent to explore the inner planets, monitoring stations near the sun, and deep-space exploration. Some proposals even use a giant laser here on Earth, instead of the sun, to push the craft along. Manned missions, however, are a much more distant possibility; a spaceship big enough to hold passengers would require an unfathomably gargantuan sail, and the slow acceleration would be rather inconvenient considering human lifespans. But if we ever encounter a ship sent a long time ago from a galaxy far, far away, it may very well have been carried along by a solar sail.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on June 19, 2006.

How do you want to be remembered by future generations? You can make a will to handle your physical possessions, but what about your digital life—photos, videos, email, documents, and the like? What about all your passwords, social media accounts, backups, and every other aspect of your digital life? Over the years, I got so many questions about this sort of thing that I decided to write a book about it—Take Control of Your Digital Legacy—and it has turned out to be one of my post popular titles.

If you’re not at the stage of life where you can think about this for yourself, consider that you may have to do so for your parents or other relatives. It’s not all about posterity either, since following my advice will also help loved ones access your key accounts and important info if you’re incapacitated, which can happen at any time—or even if you just decide to go on a long vacation.

This book, like all Take Control titles, comes as an ebook, and you can download any combination of formats—PDF, EPUB, and/or Kindle’s Mobipocket format—so you can read it on pretty much any computer, smartphone, tablet, or ebook reader. The cover price is $15, but as an Interesting Thing of the Day reader, you can buy it for 30% off, or just $10.50.

Old marketing gimmicks never die

Hark back with me to the Dark Years (or the Good Old Days, depending on your point of view)—the time before any object a person desired could be delivered to one’s door within days (if not hours), with no more effort than a few taps on a smartphone screen. I’m old enough to remember a time before Amazon.com—indeed, before the internet itself—when discovering, locating, and procuring a variety of any particular type of merchandise actually presented a challenge. Way back in the days when we had to wait for checks to clear and then allow 6–8 weeks for delivery, the notion that a previously unknown specimen of one of our favorite things would arrive automagically on our doorstep once a month was quite compelling.

I had experienced, and then long forgotten about, thing-of-the-month clubs when, in the early 2000s, my Christmas gift from my mother was a subscription to the Fruit of the Month Club. Once each month, Airborne Express arrived at our door with a box of fresh fruit. The selection changed each month. In December, for example, it was Mandarin oranges; in April it was kiwi and pineapple. The fruit was always of good quality, and the shipments were just infrequent enough that I was always slightly surprised when each package arrived. Although the shipments were fairly small, they were always a welcome treat that didn’t require a trip to the market—and the subscription was something I never would have thought to purchase for myself.

They Deliver for Me

Before my fruit started arriving, I had heard of the Book-of-the-Month Club but had only a vague notion that other kinds of things were available on a monthly subscription plan. Now, however, I seem to find ___-of-the-month clubs every time I turn around. In most cases, the general idea is the same: for a fixed fee, you get a six- or twelve-month subscription, with a different selection of your chosen product arriving each month. This can be an easy way to experience new tastes and broaden your horizons a bit. (You can also, of course, have Amazon or another retailer automatically send you refills of exactly the same staple items on the schedule of your choice, but that’s different from having someone select a different item in a given category for a monthly surprise.)

What other sorts of ___-of-the-month clubs are there? A quick web search turned up hundreds, ranging from the delightful to the bizarre. Things you can receive by monthly subscription include: candles, chocolate, coffee, cookies, craft beer, fruit, gourmet cheese, hot sauce, jam, leggings, oysters, pasta, pastries, pickles, potato chips, socks, tea, trout flies, wine…well, I could go on, but you get the idea. I haven’t seen armchair-of-the-month or vaccine-of-the-month clubs, but with very few exceptions, it appears one can now receive a curated monthly example of virtually any item needed for survival or leisure by subscription.

Reader’s Dozen

And then, of course, there are books, the item-of-the-month that started it all. The original Book-of-the-Month Club was founded in 1926, designed as a way to get new books into the hands of people living in rural areas without easy access to bookstores or libraries. A panel of judges selected a new volume each month, sent at a respectable discount to subscribers. The following year, The Literary Guild—another variation on the same theme—started business. Many decades later, after a series of mergers and acquisitions, both clubs still exist. If you enjoy reading the types of books the book-of-the-month club offers, it can be a convenient way to stay on top of the latest bestsellers and keep your library well-stocked at a reasonable price. As for me, I already accumulate books far faster than I can read them, so I’m more likely to subscribe to consumable products.

Notwithstanding the fact that I write a ___-of-the-day column, I find the notion of monthly subscription clubs strangely appealing—in an endearingly retro sort of way. Since it’s easy to purchase almost anything instantly online these days, this type of subscription program is a bit of an anachronism. My suspicion is that clubs like these continue to thrive not so much for the convenience they provide but because people like novelty…and they like getting packages. If you can justify a subscription by convincing yourself that you’re saving money, all the better—but when you get right down to it, there’s just nothing like opening a box of goodies.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on May 11, 2003, and again in a slightly revised form on October 24, 2004.

Modern-day alchemy

Well, I’ve got some good news and some bad news. The good news is that there may be an elegant solution on the horizon to the gigantic problem of garbage—and not just the kind that gets dumped in landfills, but hard-to-recycle plastics, too, along with agricultural wastes, used tires, and just about everything else. More good news: we might get to reduce dependence on foreign oil and pay less for gasoline in the process. The bad news? More cheap oil to burn means more carbon dioxide going into the atmosphere, perpetuating the already dire problem of global warming.

The technology that makes it possible to do this is called the thermal depolymerization process, or TDP for short. It was developed for commercial use a couple of decades ago by a company called Changing World Technologies (now owned by Canadian firm Ridgeline Energy Services), and its first full-scale plant operated for a number of years in Carthage, Missouri. Now various other firms are taking the same technology in other directions. In any case, the idea behind TDP is not new—in fact, it’s millions of years old. Take organic matter, subject it to heat and pressure, and eventually you get oil. Of course in nature, “eventually” is usually an inconvenient number of millennia; TDP shortens that time to hours, if you can believe that.

A Well-Oiled Machine

TDP is a surprisingly straightforward five-step process. First, raw materials are fed into an industrial-grade grinder where they’re chopped up into extremely small bits and mixed with water. The mixture is then subjected to heat and pressure, breaking molecular bonds and reducing the material to simpler components in as little as 15 minutes. The next step is reducing the pressure dramatically to drive off the water; in the process, some useful minerals such as calcium and magnesium settle out as valuable byproducts. The remaining slurry is sent into a second reactor, which uses even higher temperatures to produce a hydrocarbon mixture. Finally, a distillation step divides the hydrocarbons into vaporous gas (a mixture of methane, propane, and butane), liquid oil (similar to a mixture of gasoline and motor oil), and powdered carbon.

All that to say: garbage in, (black) gold out. The process itself produces no waste materials, unless you count water, which can be recycled in the system. The gas can be used to produce heat for the machine itself; oil can be sent to refineries to be made into a variety of useful products; carbon can be turned into everything from water filters to toner cartridges; and the remaining minerals can be used as fertilizer.

Virtually any organic material can be fed into a TDP apparatus. By making adjustments to the combinations of temperature, pressure, and cooking times, various input products (referred to as feedstock) can produce a wide range of output products; the proportions of, say, gas to oil to carbon will depend on the composition of the feedstock. The first fully operational TDP system was used to recycle the waste at a turkey processing plant. All the turkey parts that weren’t used as meat—skin, bones, feathers, and so on—were fed into the machine, thus solving a serious waste problem (up to 200 tons per day) while creating commercially valuable products. But TDP can also process discarded computers, tires (even steel-belted radials), plastic bottles, agricultural waste, municipal garbage…you name it.

Almost nothing is too messy or too scary for TDP to handle. It can make clean, safe materials out of sewage, medical wastes, dioxins, and other biohazardous materials. Even anthrax, for crying out loud. Apparently the only kind of material this system can’t handle is nuclear waste—I guess you can’t have everything.

Pouring Oil on Troubled Water

Thermal depolymerization is still finding its footing for commercial use, though similar processes have been known for many years. The problem was that they were always too expensive to operate; it cost more for the fuel to decompose the garbage than the resulting materials were worth. The inventors of TDP claim that it is highly energy-efficient—better than 85% in most cases. If that is true, if it continues to be true on a large scale, and if demand is sufficiently high, then TDP may eventually be able to produce oil more cheaply than drilling, and get rid of garbage as a convenient side-effect—or vice-versa, if you prefer.

As fantastic as TDP sounds, the process does have its critics. Some engineers have expressed skepticism that the energy efficiency could be even close to what proponents claim. Even supposing that it were, the oil needs of the United States are currently so massive that if all the agricultural waste in the country were processed into oil, it would still be just a drop in the bucket (so to speak). In other words, so the argument goes, the process holds more promise as a method of recycling and waste reduction than it does as a source of fuel.

The more optimistic viewpoint is that if TDP comes into widespread use, we won’t run out of oil as long as we have garbage. But that also means there will be less incentive to reduce oil consumption or seek out cleaner alternative power sources. Ah, but I suppose every silver lining must have its cloud.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on August 3, 2003, and again in a slightly revised form on June 4, 2004.

Triassic Park in Argentina

I have a special fondness for deserts and other barren landscapes. Partly, I’m sure, it’s because of their rugged natural beauty, but I also find the lack of people and the coinciding lack of noise quite refreshing. I’ve spent plenty of time in desert regions of North America, South America, and the Middle East. One spot I missed during my trip to Argentina back in 2004 would undoubtedly have made it onto my list of favorite desert places. Located in the San Juan province in northwest Argentina, Ischigualasto Provincial Park is remote, hot, amazingly dry, and generally inhospitable, but nevertheless manages to draw over 30,000 tourists each year.

Smorgasbord of Fossils

The park takes its name from the Ischigualasto Formation, a large basin of sedimentary rock that was once a lush tropical swamp and is now a paleontologist’s playground. It contains a vast number of fossils, but its significance runs much deeper than that. It’s the only known place on the planet that contains a complete fossil record for the entire Triassic Period—a span of about 45 million years at the start of the Mesozoic Era, which began roughly 245 million years ago. What’s so significant about this period of time is that it’s when the first dinosaurs and the first mammals appeared. As a result, Ischigualasto is the best place to look for fossils of intermediate species.

A great many of the fossils in Ischigualasto are of plant-eating reptiles called rhynchosaurs, while many others are of cynodonts. Several websites I consulted unhelpfully explained that cynodonts are a group of therapsids, which are of course an order of synapsids. In English, cynodonts were a type of mammal-like reptile, a species that nicely illustrates evolution in progress. The word cynodont means “dog teeth,” referring to their mammal-like tooth structure. They walked on two legs, were covered with hair, and were warm-blooded—yet, like reptiles, they still laid eggs. You can also find some dinosaur fossils in Ischigualasto, and although there aren’t as many of them, they’re extremely significant because they’re among the oldest dinosaur remains in the world.

It’s the Rocks, Stupid

The fossils, however numerous and significant they may be, are not Ischigualasto’s biggest attraction. Tourists come to see the park’s rock formations. The Ischigualasto Formation is nicknamed “Valley of the Moon,” and although the pictures I’ve seen don’t remind me of the moon, they do certainly have an otherworldly appearance. As in Sedona, Arizona, many of the rocks and hills have a striking reddish cast, due to large concentrations of iron oxide. One rock formation, known as The Mushroom, has a broad stone cap sitting atop a much narrower column. This basic geometry, which in some cases appears to defy gravity, is typical of the formations, some of which have evocative names like The Sphinx, The Worm, and The Submarine. One particularly unusual area is a relatively flat expanse called The Ball Court, which is is covered with hundreds of natural stone spheres that evoke images of soccer balls. The park also contains petroglyphs and other artifacts of the area’s ancient human inhabitants.

Owing to its great scientific importance and its uniquely beautiful landscape, UNESCO named Ischigualasto Provincial Park, along with neighboring Talampaya National Park, a World Heritage Site in 2000. This recognition has helped to publicize the park’s existence, though the great majority of tourists come from within Argentina. Most visitors take a guided driving tour, which lasts two to four hours. People do sometimes camp in the park, but those who do are strongly urged to bring plenty of food, water, sunscreen, and shade, and to prepare for extreme temperatures (not only hot during the day but also very cold at night) and a persistent wind. Also bring your own soccer ball: kicking stone spheres puts you at an evolutionary disadvantage.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on July 26, 2006.

Engineering marvel of the Canal Age

Before I knew much about aqueducts (whether ancient or modern), I imagined they would be constructed to bring water to areas that had none. While they can serve that purpose, I’ve since learned that aqueducts have been built in places with plenty of water—such as a river valley.

One example of this is a first-century aqueduct system constructed by the Romans in Southern France to carry water from the Eure spring in Uzès to a water tower in Nîmes, about thirty miles (fifty kilometers) away. In this case, it was the spring water in particular that the Romans coveted, using it to supply the fountains, sewage systems, and spas of the flourishing town. As part of the aqueduct system, the Romans built the now-famous Pont du Gard, a bridge that enabled the channel of water to cross over the Gard river and to continue on its way to Nîmes. In a way, it was like they built a river (or stream, if you will) above another river; rather remarkable to a non-engineer like me.

The Pont du Gard is remarkable for a number of other reasons, including: its longevity, having remained largely intact over the last two thousand years; its size, being the highest aqueduct ever built by the Romans (at 49 meters in height); and its incredible engineering, being composed of large stones that fit together without the use of mortar. Now it’s a UNESCO World Heritage Site, and every year large numbers of visitors from around the world come to see this amazing construction (including me in 2013—it was an awesome sight). Originally built to serve the social and business interests of Nîmes, the Pont du Gard now serves as a potent reminder of human ingenuity.

Channeling Ideas

A slightly less famous and considerably younger version of the Pont du Gard can be found in Northeast Wales. The Pontcysyllte Aqueduct, built between 1795 and 1805, was created to carry the Llangollen canal over the valley of the River Dee; another river-over-a-river construction. In this case, the Llangollen canal, which connects three major rivers—the Dee, the Severn, and the Mersey—was originally part of the Ellesmere canal, a route built to connect the coalfields and ironworks of the town of Wrexham with the sea.

The creation of the Pontcysyllte Aqueduct (about which more in a moment) was one among a series of large-scale construction projects that began in the late 1700s and continued into the 1830s. These projects were sparked by the opening of the Bridgewater canal in 1761, created by the third Duke of Bridgewater (a great example of an aptonym if ever there was one) to provide an efficient means of transporting coal from his coal mines in Lancashire to the booming industrial city of Manchester. This canal, which included a large aqueduct over the River Irwell, proved so profitable to the Duke that it encouraged many others to build canals of their own.

Canal Knowledge

Before the development of railroads, canals were the first means of mass transport of goods in Britain. The canal-building craze started by Bridgewater helped to fuel the so-called Industrial Revolution, which saw a change from a primarily agrarian society to one in which trade and manufacturing could be undertaken on a massive scale. The reason for the incredible success of the canal system lay in its great improvement over the traditional method of transporting goods.

While Britain had always relied upon waterways as a means of transport, being surrounded by water and possessing many large navigable rivers, those areas of the country not in proximity to a body of water could be accessed only by road. However, roads at that time were mostly built of mud, and could become impassible in bad weather. In addition, there was a limit to how much cargo could be transported by horse and cart, usually around one to two tons. In comparison, the new canals could accommodate boats carrying 30 tons, with only one horse needed to pull the load as it walked beside the boat on specially created towpaths. This dramatically increased the rate at which goods could be shipped, and brought incredible profits to the companies that operated the canals.

There were limitations to this mode of transport, though; in order to save costs, canals were often built quite narrow. This meant only specially designed “narrow boats” could navigate the canals. In addition, because canals are constructed bodies of water with no current, the speed of travel was limited to the speed of the “horsepower” involved, although this problem was less prominent in later years as steam and electric powered boats were developed.

Gradually, with the rise of the railroad, the canal system came to be less and less economically viable. Although the canals were still in commercial use well into the 20th century, their dominance was greatly overshadowed by other modes of transport. Unlike other European countries, such as France, Germany, and the Netherlands, which modernized their canal systems to accommodate larger vessels, the British system did not undergo the same kind of overhaul and fell more and more into disuse.

Fortunately, the canal system in Britain was reborn in the 1960s and ’70s when it came to be associated with holiday travel. Now these historic canals are frequently used by boaters and tour operators seeking a new form of vacation activity.

Canal Retentive

The first commercial canal built by Bridgewater was designed by James Brindley, a man with very little formal education, but who nonetheless went on to become one of the best-known engineers of the 18th Century. Following in his footsteps, Thomas Telford was only four years old when the Bridgewater canal was opened, but came to prominence after he oversaw the construction of the Pontcysyllte Aqueduct from 1795 to 1805.

The aqueduct has many notable features, including its great length (1007 feet; about 300m), its structural ingenuity (in its use of tapered support columns), and the construction of the metal trough in which the water is carried. In order to reduce the weight of the masonry pillars, they were built wider at the bottom than at the top, allowing the aqueduct to reach a great height. The masonry was held in place by a mortar made of lime, water, and ox blood. The metal trough carrying the water (and the boats) was built from cast iron sections joined together and caulked using flannel dipped in boiling sugar, and then sealed with lead.

Canal Plus

In 2005, the Pontcysyllte Aqueduct celebrated its 200th Anniversary, and in recognition of its cultural importance, was submitted to UNESCO as a potential World Heritage Site (which it was awarded in 2009). Like the Pont du Gard, it receives many visitors and has become a significant tourist attraction. Boat rides along the aqueduct are popular, often traveling to and from the town of Llangollen, the site of the International Eisteddfod, a music festival that takes place every year in July.

As with the Pont du Gard, a purely commercial endeavor has now become something to celebrate. Although the canal system, including the Pontcysyllte Aqueduct, no longer drives the economic engine of Britain, the ingenuity of those who designed these marvels continues to amaze and inspire all who see them.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on June 21, 2006.

Fairy castles in the air

When people accuse you of building castles in the air, they are not usually congratulating you on an incredible engineering feat, but more likely trying to bring you back down to earth with a thud. Synonymous with daydreams, pipe dreams, and all other dreams unlikely to come to fruition, castles in the air are at best a hopeful vision, and at worst, a hopeless illusion.

Although the phrase “castles in the air” (the original phrase was “castles in Spain”) is most often used to describe imaginary constructions, it can also be used to describe a very real optical phenomenon—the fata morgana effect—in which different levels of hot and cold air distort the appearance of objects on the horizon to make them look like, well, castles in the air.

Tempting Fata

Fata Morgana is the Italian name for Morgan le Fay, the half-sister of King Arthur in Arthurian legend. Reputedly a sorceress and able to change shape at will, Morgan le Fay was sometimes said to live below the sea in a crystal palace that could also rise above the surface. The fata morgana effect was so named for the superstitious belief among sailors that she created illusory visions to lure men into a false port and to their death. The term first entered English usage in 1818, when it was used to describe an occurrence of the phenomenon in the Strait of Messina, a narrow body of water between Sicily and the region of Calabria in southern Italy.

Technically, fata morganas are a type of mirage, related to those visions of water in the desert, or less exotically, to those seeming pools of water on the highway on a hot day. However, the latter two are examples of inferior mirages, while fata morganas are classified as superior mirages. It’s not that fata morganas are inherently better than the others; the difference lies in the way each mirage is produced.

Refract Up

Although the word mirage is derived from the French verb se mirer, meaning “to be reflected,” a more apt description of a mirage is that it is refracted. As light passes through layers of air with varying densities (density being determined by factors such as pressure and temperature), it bends, or more specifically, refracts, according to each layer’s characteristics.

In the case of inferior mirages, light bends upwards when it moves from a denser layer of cold air into a less dense layer of hot air, like that created above a highway on a hot day. As light hits the surface of the road and bends upwards, it looks to our eyes as if we are seeing a reflection in the road of what is just above it—in this case, the blue sky. This is because we perceive that light travels in a straight line to our eyes, even when that is factually not so.

Lake Superior

A superior mirage is the reverse of this; what we perceive to be higher in the sky is actually lower to the ground. Light is bent downwards when it hits a layer of cold air, making it appear as if what is below our sight line is actually straight ahead or above us because we are seeing the inverted image of what is on the horizon projected above it. This can be further complicated when there are multiple layers of hot and cold air, creating a highly distorted image as the light refracts through them.

Superior mirages occur wherever the surface temperature is colder than the air above it, usually over bodies of water and areas with ice or snow on the ground. The term fata morgana is most often used to describe superior mirages occurring over water. In these instances, objects on the horizon, such as ships, islands, cliffs, or icebergs, appear taller than they are because their inverted image is reflected above or superimposed on them. This elongation of objects on the horizon may make it appear as if there are turrets or towers rising up from the water, leading to the description of fata morganas as castles in the air.

As this effect can occur with ships, making them look higher above the horizon than they are, some have speculated that this is the origin of the Flying Dutchman legend, in which a ghostly ship is doomed to sail the seas for eternity.

There are many other types of superior mirages; one of them, the fata bromosa, or “fairy fog,” is created under the same conditions as the fata morgana, but has a different appearance. It appears as a bank of fog, with varying degrees of brightness, but without the fine detail of the fata morgana.

Fata Complete

Since its introduction into regular usage, the term fata morgana has come to mean more than just an optical phenomenon; although it has kept its original meaning of referring to something that is illusory, its use has been expanded throughout popular culture. It provided the title for a Henry Wadsworth Longfellow poem, an 1868 polka by Johann Strauss, and an Agatha Christie crime novel. It’s the name of a French publishing house, a character in Sergei Prokofiev’s opera, The Love for Three Oranges, and a film by Werner Herzog composed solely of desert landscape images.

The enduring popularity of the term shows how compelling it is as an idea—that there are mysterious phenomena, benign or malevolent, that are beyond our understanding. Or it may be that we continue to be enamored of our castles in the air, despite the knowledge of their illusory nature, as the last stanzas of Longfellow’s poem conclude:

So I wander and wander along,
And forever before me gleams

The shining city of song,
In the beautiful land of dreams.

But when I would enter the gate
Of that golden atmosphere,
It is gone, and I wonder and wait
For the vision to reappear.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on July 24, 2006.

This week, another book just for Mac users! As the amount of data we store continues to grow, figuring out where to put it and how to access it becomes more complicated. Every Mac includes internal storage in the form of a hard drive, SSD, or Fusion drive. But you may also have one or more external devices (such as hard drives, flash drives, SD cards, or RAID devices), not to mention network-attached storage (NAS) devices or cloud storage (like Dropbox or iCloud Drive). Making sense of all your options, managing your stored data, choosing new devices or services when you’re running out of space, or even just figuring out what’s where can drive anyone to distraction.

Jeff Carlson covers all this and much, much more in his book Take Control of Your Digital Storage. For example, the book helps you choose a new (internal or external) hard drive, SSD, or hybrid drive; determine how much storage space you need; understand APFS, Apple’s new filesystem; format, partition, and repair disks using Disk Utility; choose and use a NAS, RAID, flash drive, or SD card for use with your Mac; work with disk images; and decide among local, network, and cloud storage for various types of files.

This book, like all Take Control titles, comes as an ebook, and you can download any combination of formats—PDF, EPUB, and/or Kindle’s Mobipocket format—so you can read it on pretty much any computer, smartphone, tablet, or ebook reader. The cover price is $14.99, but as an Interesting Thing of the Day reader, you can buy it this week for 30% off, or just $10.49.

The controversial theory of Peak Oil

Whatever your feelings about the cost of oil, the means of obtaining it, or the effect that burning it has on the environment, one thing’s for sure: there’s a finite amount of it, so sooner or later it has to run out. At least, I hope so, because once all the oil’s gone, perhaps the planet will finally have a fighting chance against global warming. Many people, however, would take a decidedly negative view of the impending disappearance of the world’s oil reserves for all the obvious reasons. Either way, just how long will the oil last?

In 1956, a geophysicist named Marion King Hubbert developed a theory to predict future oil production. He assumed that for any given oil field, production follows a bell curve. After the well’s discovery, production quickly ramps up as new wells are added. But eventually, as the oil is drained from the underground reservoirs, the production rate hits a peak after which it begins to decline, eventually returning to zero. And what is true of an individual oil field should, Hubbert reasoned, be true for the entire planet as well. Using these assumptions and the best data he had available at the time, he plotted historical oil production on a curve and estimated that oil production in the United States would peak by 1970, and worldwide by the mid-2000s. The moment at which global oil production peaks came to be known as Peak Oil (or Hubbert’s Peak), while the overall theory that production of oil (or other products based on non-renewable natural resources) follows a bell curve in this way was called the Hubbert Peak Theory. After that time, there would of course still be plenty of oil, but the production rate would drop at about the same rate it rose, until eventually it was all gone.

Peak Performance

So now, over 60 years later, how did those predictions work out? Within the United States, at least, Hubbert’s prediction seemed for a while to have been off by just a year, as domestic oil production did indeed peak in 1971. But after several decades of decline, the number started rising again, and in 2018, U.S. oil production reached an all-time high. That false peak was due, in part, to the development of new techniques for extracting previously unreachable oil (such as hydraulic fracturing, commonly known as fracking, and the exploitation of oil sands). Presumably, if Hubbert had access to current data and knowledge of the latest technologies, he’d have had to revise his date forward considerably.

What’s true in the United States also goes for worldwide oil production. Although it appeared for a while that we had in fact already passed the peak worldwide—perhaps in 2004 or 2005—newer estimates put the peak far in the future, though experts are seriously divided as to how far. For every apologist of Peak Oil there’s also a naysayer, and the arguments against the theory are both wide-ranging and passionate.

Numerous researchers have taken exception to Hubbert’s math as well as his fundamental assumptions. To some extent, it appears that he started with a theory and tried to come up with data to support it, rather than the other way around. There’s no particular reason to assume, a priori, that oil production should follow a bell curve. It could have any number of dips and spikes, for many different reasons, over a long period of time; the aforementioned development of new extraction techniques is a case in point. Another type of claim is that anyone who buys into Peak Oil must have an agenda, either political or financial in nature; oil simply can’t, mustn’t, and won’t disappear any time soon. In any case, most critics admit that yes, there must logically be a worldwide peak in oil production eventually—with an end to oil production some time long after that—but that whenever this happens, it will be so far in the future as to make worrying now seem silly.

Increasingly, commentators have noted another factor: demand. Hubbert didn’t envision decreasing demand for oil, but if that occurred, then ipso facto, production would also decrease. Indeed, it looks increasingly likely that within our lifetimes, that will happen—even if peak production capacity has not occurred. In other words, “peak” doesn’t necessarily mean what Hubbert thought it meant.

Just Add Oil

But the most surprising criticism of Peak Oil is based on the claim that Earth can never run out of oil, because it simply keeps manufacturing more. We all learned in school that oil is a fossil fuel, created over many millennia by heat and pressure acting on the remains of plants and animals that lived and died eons ago. Because all that biological matter hasn’t been regularly replenished, once the planet’s supply of fossil fuel is gone, it’s gone. But according to supporters of the abiogenic petroleum origin hypothesis, oil never came from biological matter at all. It’s produced within the Earth’s crust and mantle by heat and pressure acting on ordinary and plentiful substances such as carbon dioxide, hydrogen, and methane. And what’s more, the production of new oil has never stopped: look in the right places in the right ways, and you’ll see oil reservoirs being replenished. This hypothesis first appeared in the 1870s, but it has never had much traction outside Russia and the Ukraine. Still, that hasn’t stopped Peak Oil opponents from using it to bolster their position.

Well, what if oil did run out—and what if that happened within, say, the next few decades? Once again, the reactions to this scenario vary dramatically. Some predict it will lead to a collapse of the worldwide economy, mass starvation, and perhaps even the end of the human race. Most pundits say it won’t be that bad; between now and then, we’ll develop the necessary technology to replace oil with something else for large-scale applications such as transportation; given the rapid progress in electric vehicles, that seems entirely plausible. And in between are survivalists who fear the worst but are figuring out how to live petroleum-free lives when the day comes.

Peak-a-Boo

What I find most striking about this entire debate is its emotional intensity. Websites both pro and con often consist of extremely long, sometimes boring, and often inscrutable rants accusing the other camp of all sorts of diabolical motives, along with insults and name-calling a-plenty. And all this over a theory that might never be proven one way or another—we could always end up finding massive, unexpected oil reserves (or easy ways of getting at more of the existing oil) far in the future, creating an entirely new production curve. Meanwhile, we already have the technology to generate our own oil from garbage, an infinitely renewable resource.

In short, if you want to worry about the price of oil, fine. If you want to worry about global warming, fine. I heartily support any and all efforts to develop alternative energy sources, conserve fuel, and protect the environment. But I can’t bring myself to worry about running out of oil. Either it will happen or it won’t, and if it does, it’ll be either sooner or later. But my money is on much later, by which time I fully expect the world will have either gotten over its oil dependence for other reasons or destroyed itself in any of several increasingly plausible ways. Either way: nothing to worry about.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on July 17, 2006.

A little piece of Spain in France

As an American, I’ve always felt a bit embarrassed at my limited grasp of foreign languages. I have friends in Europe who speak four or five languages fairly fluently, and they rightly boggle when they hear that most Americans are monolingual. But for complicated historical, cultural, and political reasons, that’s just the way things turned out. However, I did take French classes in high school (and picked up quite a bit more during the years I lived in France), studied linguistics as a grad student, and picked up a handful of phrases in half a dozen other languages here and there, all of which probably makes me slightly less clueless as a tourist than many of my compatriots. I usually know at least enough to recognize which language I’m listening to. Years ago while driving through Europe, we stopped at a gas station in Austria near the Italian border, and when we asked for directions to a certain castle, the clerk’s response included French, German, and Italian words in the same sentence. I got the general drift of what he was saying, but I marveled at how intertwingled the languages had become in this border region.

All sorts of interesting things happen around international borders, especially when those borders are not clearly defined. While looking at France and Spain in an actual printed atlas (remember those?), I saw something I’d never noticed before: a tiny region in southern France surrounded by what appeared to be an international border, but without any label whatsoever to tell me what it was. Andorra, a small country that straddles the border between France and Spain, is nearby, but this little blip was farther east in the Pyrénées and clearly something different. The light bulb went on shortly thereafter when I was reviewing my list of suggested topics readers had sent in: someone wanted to see an article about a curious place called Llívia. That was the blip! Due to a series of weird historical, geographical, and linguistic flukes, an entire Spanish town ended up completely within the borders of France. But that’s just the beginning of the story.

All Around Town

Officially, Llívia is considered a Spanish enclave within France. It’s a small town of about 5 square miles (13 sq km), situated less than a mile (about 1km) from the Spanish border and connected to the rest of Spain by a single, small road. The town’s official website lists its current population as 1,456, though I’ve seen considerably lower and higher numbers. Whatever Llívia’s population may be, it’s historically important that it be considered a town rather than a village.

Llívia was a strategically important area as far back as the time of the Roman empire, and was considered the capital of the region known as Cerdanya, which includes portions of modern-day France and Spain. But it wasn’t until 1528 that Roman Emperor Charles V (known in Spain as Carlos I) formally designated Llívia a town—apparently more for reasons of history than of population. This decision was to prove momentous a little more than a century later, when France and Spain signed the Treaty of the Pyrénées and thus settled the dispute over the border between the two countries that had been the cause of decades of war. According to the terms of the treaty, the border was to run primarily along the main crest of the Pyrénées, and all villages north of that line were to become part of France. Spain insisted that, according to the letter of the law, Llívia must be excluded from French rule because it was not a village but a town—and that’s why Spain continued to control a parcel of land entirely inside France.

Llivid About That Border

In 1868, the border between the two countries was finally surveyed and delimited explicitly with a series of bordermarkers, numbering in the hundreds, including 45 just for Llívia. Most of these markers are simple chunks of stone, numbered consecutively and marked with “LL” on the Llívian side and initials representing the nearest French village on the French side; a few markers were made by carving numbers and letters into existing rocks. Locating and photographing these markers with the aid of maps or GPS has become a common tourist pastime.

Despite the seemingly conclusive nature of the bordermarkers, and despite the fact that Llívia is just a stone’s throw from the Spanish border, the two countries have tangled over the details of the border numerous times, with little pieces of land going back and forth according to the terms of the most recent lawsuit. One conflict involved the short road connecting Llívia to the rest of Spain: it was supposed to be neutral, but a certain French road crossed it. Each country felt its citizens should have right of way at the intersection, and ignored the other’s stop signs. Eventually an overpass had to be built, at Spain’s expense, to make the issue moot. At another, smaller intersection, a similar conflict was resolved by constructing a roundabout.

Que Parla el Català?

Good information about Llívia in English is hard to come by, though you can find some coverage on the web in French and even Dutch. When I first visited Llívia’s official website, though, I assumed it would be in Spanish. The text had a familiar look to it, but some of the words appeared to be Spanish while others appeared to be French. It took me a while to figure out that I was actually looking at neither Spanish nor French, but rather Catalan, one of the three official languages of the region of Spain known as Catalonia. Catalonia, which also encompasses Barcelona, is one of Spain’s 17 autonomous communities, with its own government and police force and considerable latitude to function, in many respects, independently of the nation as a whole. Thus, culturally speaking, Llívia is more of a Catalonian enclave than a Spanish enclave. (Times have changed since that first visit, by the way—the website is now also available in English, French, and yes, Spanish.) There’s now a popular movement pushing for Catalonian independence from Spain, which—if it ever takes off—could make Llívia’s status ambiguous once again.

Modern Llívia is scenic and quaint, known regionally for its annual music festival in August and a museum that contains Europe’s oldest pharmacy. You can stay in a three-star hotel and, during the colder months, enjoy good skiing nearby. If you happen to be passing through the Pyrénées, be sure not to miss it. (Helpful hint: going north, take the first right at Andorra and follow the signs…assuming you can figure out what language they’re in.)

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on June 12, 2006.