Month: January 2019

Heat under the street

There are a bunch of little facts that I sort of half-learned in elementary school, and only those that came with terrific mnemonics have managed to stick. I remember the terms “Dromedary” and “Bactrian,” for example, because a D has one hump (like a one-hump Dromedary camel) and a B has two (like a two-hump Bactrian camel). But I never acquired a similar method for remembering cloud types—cirrus, cumulus, nimbus—I know the names but I forget which is which. And then there’s coal. I vividly recall learning about anthracite, bituminous, and lignite coal as a child in Pennsylvania, a state legendary for its coal production. But which type had which properties or uses? It’s all a blur now. Since I did not pursue an education or profession in which this knowledge was needed, my brain apparently decided to delete those records to make space for really important information, such as Star Trek trivia.

I do remember, though, that when I was quite young my father took me to a coal mine that offered tours to the public. I thought it was absolutely the coolest thing ever. Getting to ride in that train down into the dark tunnels, seeing all that amazing machinery, and imagining the life of a miner was exciting and mysterious. I’ve always had a fondness for caverns and tunnels—maybe that’s where it all started.

As an adult living in California, I rarely think about coal mines. I do, however, think about wildfires and forest fires, especially in the dry months of late summer. Everyone understands that these things just happen—due sometimes to natural causes, sometimes human causes (accidental or intentional). And when they occur, vast firefighting resources are unleashed to contain the fires in order to minimize the risk to homes and businesses. After all, they pose an imminent threat, plain for all to see (and smell). Of course they have to be stopped.

But Pennsylvania has the distinction of being home to the largest number of underground coal fires in the United States. And further, that some of these fires have been burning continuously for upwards of 40 years; that they’ve obliterated entire towns; that they vent an unimaginable amount of carbon dioxide and other gases into the already overburdened atmosphere; and that, for the most part, very little is being done about them. All these facts astonish and disturb me, but none more than the very possibility of the fires’ existence. How can a fire rage underground for decades or even centuries? The answer: very easily.

Fire in the Hole

Picture an abandoned coal mine—there are thousands of them in Pennsylvania. Although much of the coal has been removed, plenty still remains—perhaps just not in a configuration that’s easily extractable. Miles of tunnels, their ceilings shored up with columns of unexcavated coal, lie empty. Though the entrance to the mine may have been sealed, that seal was by no means complete or airtight. And suppose some of the coal lies very close to the surface—or is even visible in an exposed seam. Now something happens to ignite the coal. It may be a natural cause—lightning, for instance, or even spontaneous combustion given the right conditions. Or maybe a forest fire, or someone burning garbage.

Once the coal begins burning, it feeds off the air in the tunnels and the ventilation shafts that were used to supply air to the miners. Still more air seeps through natural cracks in the rock. Coal burns easily, requiring only a tiny amount of oxygen—and with millions of tons of fuel handy, it soon spreads beyond the existing tunnels and into the thick strata of coal that lie under immense tracts of land. When enough of the coal burns through, the ground above it collapses—an effect known as subsidence. The newly formed cracks or pits allow more air in, accelerating the fire’s spread. Meanwhile, carbon dioxide, smoke, and steam escape, killing plants and making the area’s air unsafe for humans and wildlife.

Our State Insect: The Firefly (no kidding)

No one can say for sure how many such fires currently rage in Pennsylvania, but the number is unquestionably in the dozens. The number is hard to pin down because coal fires that seem to be out can smolder at low temperatures for years and then flare up again; the process of checking to see whether they’re still going carries with it the risk of making matters worse by adding more air.

The largest and most infamous of Pennsylvania’s coal fires is under the town of Centralia. It started in 1962, apparently due to someone burning garbage in the town dump. For decades, a combination of bureaucratic delays, funding shortages, and ineffective containment efforts permitted the fire to grow to the point that the entire town (formerly home to 1,100 people) was condemned and basically shut down. A handful of residents remain, despite repeated government orders to evacuate. They enjoy peace and quiet for the most part, but worry about the ongoing threats of subsidence, toxic fumes, and careless tourists injuring themselves.

Down and Out

Underground coal fires are notoriously difficult to extinguish. If it were a simple matter of pumping water (or some other substance) into the old mine tunnels to suffocate the fire, they would have been out long ago. Part of the problem is simply getting to the spots that are on fire; another part is pushing out all the oxygen, given the porous nature of the coal and the rock in which it’s embedded. And then there’s the scale: the volume of underground space affected by the fire is immense (and growing all the time). Conservative estimates put the cost of containing (not extinguishing) the Centralia fire alone at well over half a billion dollars. And, of course, that’s just one fire—there’s always another. Since that sort of money is nowhere to be found, officials throw up their hands and say, “We’ll just let it burn out.” How long will that take? Experts think there’s enough coal to keep it going for another 250 years.

Pennsylvania is by no means the only place with unquenchable underground coal fires. Similar fires burn in other parts of the United States, as well as China, India, Indonesia, and elsewhere around the world. Under Australia’s Burning Mountain Nature Preserve is a coal fire that has been burning for at least 2,000 years, and possibly as long as 5,500 years. In all, there may be hundreds of thousands of active coal fires, and only in rare cases are any serious efforts being made to stop them.

By some estimates, coal fires are a bigger contributor to global warming than cars—a truly staggering thought. Although fighting them is difficult and expensive, very little money has been spent looking for technological solutions. And one of the biggest reasons is simply that the fires are, for the most part, invisible. While a California wildfire may be an obvious threat requiring immediate action, it’s hard to convince governments to put money into solving a problem that can’t be seen—especially when it’s relatively cheap simply to relocate residents and put up fences and warning signs.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on October 23, 2004.

Image credit: James St. John [CC BY 2.0], via Flickr

As everyone knows, a chowder is a thick, cream-or milk-based soup, often containing potatoes along with other vegetables and, usually, some type of seafood. I’ve made some delicious corn chowder, but clam chowder has always been my favorite. Except…one time I ordered the thing called “clam chowder” and got a bowl of red liquid with tomato chunks, some vegetables and a few pieces of clam. That was what people call “Manhattan clam chowder” which is right up there with Welsh rabbit in the list of foods whose names contradict their ingredients (or vice versa). Although I personally find “Manhattan clam chowder” inedible, anyone who wants to consume that particular combination of foodstuffs has my blessing—just don’t call it “chowder,” for crying out loud. Today, lovers of real clam chowder—that is, New England clam chowder for those who want to be sure they don’t get the wrong thing, or just “clam chowder” to any reasonable citizen—get to celebrate their rightness.

Image credit: Jon Sullivan [Public domain], via Wikimedia Commons

The incredible shrinking southern continent

As an American, I’ve always been accustomed to clearly defined state, national, and continental boundaries. The border between Canada and the United States, for example, may be an arbitrary line of latitude, but we all know exactly where it is—what’s in, and what’s out. We know exactly where North America stops and Central America starts; we also know when we’ve reached the easternmost or westernmost edge of the continent because we run into an ocean. Sure, there’s the odd island off the coast here or there, but conceptually, these cause no problems for my notion of what a continent is.

The map of South America, though, has always offended my sense of geographical tidiness. At the southern end of the continent, the land sort of swoops out to the east—but wait, that last big chunk is actually an island. Is that part of the continent? And what about the bazillions of smaller islands littering the coastline to the south and west? If I’m on one of those islands, am I on the continent or not? The geological answer is yes—I’m on the same continental plate. The political answer is also yes—any given spot of any given island is uncontroversially under the control of either Chile or Argentina. But to the average person on the street (or boat, as the case may be), these boundaries are neither visible nor intuitive. Today, we can get the answers to such questions from highly accurate maps. Hundreds of years ago, though, the answers were far less obvious. Speculation about continental boundaries led to some fanciful maps, tall tales, and grand adventures.

What Goes Around

I was standing in a museum in a town on Tierra del Fuego—a name given to the entire archipelago of little islands at the tip of South America as well as to its largest island, which is known more properly as Isla Grande de Tierra del Fuego. (For other articles I’ve written here about Tierra del Fuego, see Ushuaia, Extinction of the Yámana, and Pan del Indio.) On the wall was a map from the 16th century showing the landmass we know today as South America extending all the way south to connect with a vast southern continent much larger than Antarctica. In other words: an unbroken stretch of land all the way from pole to pole. This hypothetical continent, which also encompassed Australia, had a detailed imaginary coastline that was represented as being accurate, even though no cartographer had come anywhere near it. Europeans at the time referred to this continent as Terra Incognita (the Unknown Land)—or Terra Australis (the Southern Land). In the 4th century BCE, Aristotle had advanced the idea that a great southern continent must exist, because without it the world would be top-heavy. This view was later expanded on and popularized by Greek geographer Ptolemy in the 2nd century CE. But as of the early 16th century, no European had actually seen this land.

In 1520, Ferdinand Magellan became the first European explorer to discover a sea route from the Atlantic ocean to the waters west of South America, to which he gave the unfortunate name “Pacific ocean.” But as he was passing through what came to be called the Strait of Magellan, with South America clearly on his right, Magellan could also see land to his left. When he realized the channel went all the way through, he drew what was for him the logical conclusion: that land he’d seen to the south must be the tip of the great southern continent. He gave it the name Tierra del Fuego (“land of fire”) upon seeing the smoke rising from numerous fires built by the land’s inhabitants. This name, of course, suited the continent’s popular image as a mysterious and forbidding place. And Magellan’s discovery—apparently the first proof of the existence of Terra Australis—required only minor modifications to the maps of the time.

Down and Out

It was not until 1578 that Francis Drake, in an attempt to circumnavigate the globe, discovered the truth about Tierra del Fuego. Drake sailed through the Strait of Magellan, but his ship was blown south by a storm; he soon found himself rounding the tip of a large island chain. Now there was another way to get between the oceans—the Drake Passage. Although Drake did not sail all the way to Antarctica, he again drew the logical conclusion that it must be down there somewhere—as in fact, by chance, it was. Shortly thereafter, in 1616, Cape Horn—at the tip of Horn Island—was identified as the southernmost point of land that could be construed as part of South America. In the 18th century, captain James Cook discovered the location of Australia—and that it, too, was not the imagined southern continent, its new name notwithstanding. Only in the early 19th century did explorers first set foot on Antarctica and begin to correct the old maps once and for all.

All of the foregoing is, I’m sure, familiar to anyone who (unlike me) actually paid attention in history and geography classes. But it was a revelation to me, looking at an old map in a museum, that assumptions about the nature of the world—unsubstantiated though they were—could have led to such startling errors, such blatant (if well-meaning) fabrications, and so many years during which myths were misrepresented as fact. True or not, deeply ingrained beliefs die hard. If you never thought you could learn anything from history, keep this little lesson in mind as you read today’s news.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on February 22, 2005.

Image credit: NASA [Public Domain]

It’s Penguin Awareness Day! OK, on the count of three, everyone be aware of penguins. One…two…three! Boom. Done.

If you want to be extra aware of penguins today, here are some suggestions:

• See some penguins in person at your nearest zoo
• Read up on Magellanic penguins right here on Interesting Thing of the Day
• Watch Happy Feet or March of the Penguins
• Catch up on Bloom County
• Discover that yes, penguins actually do have knees
• Install Linux

Image credit: Pexels

Less buzz for your buck

Every day it seems medical researchers come out with a new study about coffee, how it is extremely unhealthy for you and/or full of amazing benefits. The focus of most of these studies is more particularly about the effects of caffeine on human health, caffeine being coffee’s most potent element. As caffeine is a stimulant, it can produce both positive and negative effects. It can wake you up in the morning, but it can also lead to sleeplessness, a racing heartbeat, and anxiety.

It is therefore no surprise that many people have decided to cut caffeine out of their diets. What I sometimes find surprising is how many people still opt to drink coffee, just without the caffeine. I have grown to like the taste of coffee, but to me the main purpose of drinking it is to get an extra jolt of energy.

I’ll admit to a certain prejudice against decaf, perhaps prompted by bad experiences in the past with weak and tasteless brews. It is true that the actual process of removing caffeine from coffee can degrade the taste beyond repair, but new methods of decaffeination have been developed to help the coffee retain more of its flavor in the process. In addition, researchers continue to look for and cultivate new strains of coffee plants that produce beans with a naturally low level of caffeine. This may all spell good news for those who still crave coffee without its kick.

Buzz Kill

Early decaffeination attempts involved soaking the green beans in water and then using various solvents to separate out the caffeine in the resulting water solution. The beans were then re-introduced to the caffeine-free solution in order to absorb some of the flavor they had lost. Solvents used included benzene, chloroform, and trichloroethylene, all of which were later found to have toxic effects. In the 1970s, dichloromethane came into use to replace the earlier solvents before it too was deemed possibly carcinogenic.

In response to these concerns about solvents, some coffee companies began to run the water solution through charcoal filters as a means of removing the caffeine. The so-called Swiss Water Process, developed in Switzerland in the 1930s, goes one step further. After a batch of coffee beans has been steeped in hot water, that water is filtered (the resulting solution is referred to as “flavor-charged”), and then is used to soak the next batch of beans to be processed. In this way, the beans lose caffeine as they soak, but lose less of their flavor. Currently there is only one official Swiss Water Process plant in operation in the world, located near Vancouver, British Columbia.

Yet another method that aims to safely remove caffeine from coffee beans involves a fascinating chemical process. The solvent used in this method is neither water nor one of the earlier toxic solvents. Instead, caffeine in the coffee beans is dissolved by means of carbon dioxide. In order to accomplish this, the carbon dioxide must become a supercritical fluid, created when it is compressed and heated to the point that it has the same density in liquid and gaseous forms. As this supercritical CO₂ is passed through the beans, it can penetrate them because of its gaseous properties, and yet is able to dissolve the caffeine they contain because of its liquid properties.

Hold the Caffeine

All these decaffeination methods are useful in extracting the caffeine from beans that already contain it, but how much more efficient would it be if the beans themselves contained less caffeine in their natural state? In 2004, news reports came out that Brazilian scientists had identified three coffee plants from Ethiopia that contain almost no caffeine; these plants seemingly lack an enzyme necessary to caffeine production. Since then, owing to various difficulties cultivating commercially viable versions of these plants, it seems no substantial progress has been made in bringing this coffee to market. Complications have included very low yields from the caffeine-free plants, the problem of pests (since caffeine seems to be the plant’s way of protecting itself from predators), and the inability to prevent cross-pollination with other caffeine-laden plants.

Although researchers around the world continue to search for the perfect way to cultivate caffeine-free coffee plants, for now the current methods of decaffeination will have to suffice for decaf junkies seeking their fix of coffee that not only tastes great, but won’t keep them up half the night. As for me, I do want to stay up half the night, so I’ll stick to my full-strength brew.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on June 15, 2007.

Image credit: Pixabay

I liked popcorn as a kid, and then—for reasons I am at a loss to explain—I went through a multi-decade period of not liking it. But now I’m back to liking it again. As long as it’s buttered and seasoned, that is. Or covered with caramel or chocolate or whatever. (Plain, unsalted popcorn is pretty disgusting.) I don’t know why today was designated National Popcorn Day but I do know that movies go really well with popcorn. So head on down to your local popcorn dealership today, and pick up some movies while you’re at it.

Image credit: Logicaldisaster~commonswiki [GFDL or CC-BY-SA-3.0], via Wikimedia Commons