Posts Tagged ‘Facts’

Bones in the Paris catacombs

Man-made calcium deposits

Paris is a shockingly large city. There are many fine vantage points from which to view the panorama, including the Montparnasse Tower, Sacré Coeur, the Eiffel Tower, or the bell towers of Notre Dame. I’m sure everyone who looks out over the vast expanse of Paris has a different impression; mine has been, overwhelmingly, “Gosh, that’s a lot of limestone.” With very few exceptions, the buildings of Paris are uniformly beige, limestone being the preferred building material—and not just for the buildings either, but for bridges, sidewalks, and monuments. As far as the eye can see in every direction, the earth is covered with stone. A splash of green, like a park, or gray, like the Seine, seems strangely out of place. All that stone had to come from somewhere, but it never occurs to most people to wonder where that might have been. Most of it was quarried locally, and what’s particularly interesting about this is that the empty spaces left when the limestone was removed—mind-bogglingly huge volumes of space—are largely still vacant, hidden beneath the city streets.

The Other French Empire

On visits to Paris and during the years I lived there, I spent a good bit of time underground. I took countless trips on the Paris Métro, of course, and I’ve spent several enjoyable afternoons exploring the public portion of the vast Paris sewer system, not to mention visiting the archeological crypts near Notre Dame. But these are merely the tip of the iceberg. Underneath Paris the real action—so to speak—is in the hundreds of kilometers of abandoned limestone quarries, part of which have been turned into a depository for the bones of millions of former citizens. As with all the underground attractions in Paris, only a portion of the catacombs is officially open to the public; this visitor-friendly section is known as the Denfert-Rochereau Ossuary, or simply the Catacombs.

Unlike the many lavish museums, cathedrals, and tombs in Paris, the entrance to the catacombs is a simple black door in a small building that you could easily miss if you blinked while walking by it. On our first visit, it took some time to find it because we were expecting something much more prominent. After we paid our entrance fee, we passed a sign reminding visitors that flash photography is strictly forbidden, then descended a long spiral staircase and entered a small gallery of photographs and drawings. Leaving the gallery, we began walking through long, dark, damp tunnels whose only significant features were signs at intervals stating when they had been built. Tourists zipped past us, talking loudly and snapping flash photos. I began to feel like the day would have been better spent sitting in a café drinking coffee and eating croissants. But then we passed through a larger chamber with a sign over the entrance to a dark hallway that said: “Arrête! C’est ici l’empire de la mort.” (“Stop! This is the empire of death.”).

Dem Bones, Dem Bones, Dem Dry Bones

Beyond that sign was another world—and one of the creepiest things I’ve ever seen. What at first appeared to be walls built of small stones were in fact huge, orderly piles of human bones. Tibias and femurs by the thousands were stacked neatly, interspersed with rows of skulls, which were sometimes arranged quite artistically in a cross or other pattern. There were no intact skeletons; the goal of the arrangement had clearly been maximum compactness. I could only assume that the ribs, spines, and other bones filled in the spaces behind the walls of large leg bones. Most of the stacks of bones rose to a height of about 5 ft. (1.5m), and while some were just a couple of yards deep, there was at least one area where the bones stretched back for a good 20 yards (18m), as you could see from the narrow gap left on top. The tunnels of bones stretched on and on; many side passages were blocked with locked gates, but even the path designated for tourists was about a mile (1.5km) long.

The bones began accumulating in the catacombs in 1786, just as momentum for the Revolution was building in Paris. Real estate was scarce while the cemeteries were becoming severely overcrowded. The government decided to reclaim the large swaths of land used for cemeteries by relocating the remains of the departed citizens to the empty limestone quarries, whose tunnels were at that time on the outskirts of town. The process of disinterring the bones from the cemeteries, moving them solemnly into the quarries, and arranging them there took several decades. No attempt was made to identify or separate individual bodies, but each set of bones was marked with a plaque signifying the cemetery they came from and the year in which they were moved. By the time the relocation was finished in 1860, an estimated five to six million skeletons had been moved to the catacombs.

The Outer Limits of the Twilight Zone

Even so, the bones filled only a tiny percentage of the empty quarries. As far as I know, none of the modern maps of the catacombs are exhaustive, but explorers have estimated that there are at least 185 miles (300km) of tunnels in the entire network of catacombs—that’s in addition to the 1,300 miles (2,100km) of sewer tunnels and 124 miles (199km) of subway tracks in the Métro system, though the three systems crisscross and interconnect at various points. Among a certain Paris subculture, exploring these forgotten tunnels is considered a sport. Despite the best efforts of maintenance workers to seal off illicit entrances and police patrols that slap heavy fines on trespassers, the maze of tunnels is so extensive that it is simply not possible to keep ahead of the so-called cataphiles.

The catacombs are eerie—quiet (except for the sounds of water dripping from the ceiling and tourists chatting), dark (except for the dim floodlights and camera flashes), and in many ways, downright depressing. It’s hard not to notice that the bones of these millions of people are all pretty much the same. The skull of a revolutionary may be resting on the leg of an aristocrat; noble and corrupt, young and old, wealthy and poor, all are indistinguishable now. It can give you an entirely new perspective on the concept of human equality. It also, needless to say, gives visitors a very keen sense of their own mortality. It made me wonder fleetingly whether, centuries from now, someone might walk by my bones among millions of others and think, “Gosh, that’s a lot of calcium.”

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on June 11, 2003, and again in a slightly revised form on June 5, 2004.

Source: Interesting Thing of the Day

Six degrees of separation diagram

Is it a small world after all?

At family reunions, my mother used to joke about the fact that actress Shirley Jones (of “The Partridge Family” fame) never showed up. Apparently someone had figured out that Jones was a distant relation by marriage, and more than once I heard of plans by one of my cousins to invite her to a reunion just for fun. Whether an invitation was ever actually sent I don’t know, nor can I recall the exact chain of relatives that supposedly connected me to Jones. But I always enjoyed the thought of being related, however distantly, to a celebrity. I imagined showing up at a dinner or award ceremony where I’d be introduced to the rich and famous: “This is Joe Kissell, my third cousin-in-law, once removed.” I didn’t suspect it at the time, but if a prominent sociological theory is correct, I may have indirect social connections to millions or even billions of people.

The theory in question, of course, is that of “Six Degrees of Separation”—roughly, the notion that anyone can form a chain of personal contacts leading to any other person, with no more than six links in the chain. Nearly everyone has heard of this idea, thanks to John Guare’s 1990 play “Six Degrees of Separation” and the “Six Degrees of Kevin Bacon” game that became popular in the late 1990s. But what many people don’t realize is that this game has its roots in serious sociological research, and that work is currently underway to establish the validity of the theory scientifically.

Network (of) Associates

The late Stanley Milgram, a Harvard social psychologist, performed an experiment in 1967 to determine the extent of social networks in the United States. In his study, it took an average of six steps for a letter sent to a random resident of Omaha, Nebraska to reach a target person in Boston—using only personal contacts to form a chain. This was the origin of the “six degrees of separation” idea, but Milgram’s small experiment was hardly conclusive, restricted as it was to a very small sample size (and with all participants within the United States).

Nearly four decades later, as part of the Small World Research Project at Columbia University, sociologists attempted a modern version of the experiment using email. The project worked like this. You registered on Columbia’s website, providing demographic information about yourself and answering a range of questions to help the researchers make sense of their results. You were then presented with the name and location of a target person somewhere in the world. The idea was to send a specially formatted email message to someone you know who you think is closer to the target (in one way or another) than you were. When this next person in the chain received your message, the process repeated until, the researchers hoped, a chain formed all the way from you to the target person. Among other things, the experiment hoped to determine what the average length of such a chain is, providing some statistical validation or refutation of the “six degrees” notion.

Connect Four

The experiment ended after a couple of years, producing some very interesting results (only some of which were ever published). In all, more than 60,000 people from 166 countries participated in the experiment’s first round. Although over 24,000 chains were started, only 384 of them successfully reached their targets. Most of the unsuccessful chains were broken simply because someone along the way chose not to participate. The high number of incomplete chains skews the otherwise impressive results: the successful chains required an average of only four links. However, when they factored in how long the broken chains most likely would have been, had they been completed, the researchers estimated that people are separated by five to seven degrees—with shorter chains expected between people living in the same country. In other words, there’s apparently nothing magical about the number six, but it does happen to be pretty close to the average number of social links most people have to most other people, at least among the 4.2 billion or so of us with internet access.

One of the main goals of this project was to determine which factors people consider in trying to form associative links. Every time participants selected a new message recipient, a form asked why they chose that person—for example, due to geographic proximity or a shared profession or hobby—as well as what their relationship to the person is (friend, coworker, relative, etc.). The experiment found that participants considered geographic proximity and similarity of occupation to be primary factors in choosing how to continue a chain. And although people most frequently chose friends as the next link, professional relationships were much more likely to lead to a successful chain. I participated in a couple of chains in the experiment’s first round, and although I consider myself relatively well-connected, neither of my chains successfully found its target. But the question is not whether there is a link between any two people; it’s how you go about finding it. Email may or may not be the best discovery method, though it certainly does have a kind of efficiency that casual conversation or letter writing do not.

Supposing it turns out that everyone on the planet is indeed connected to everyone else by no more than six steps, so what? Sooner or later, given the sheer number of people on Earth and the ways in which people form networks, the six-degrees-of-separation theory must become nearly certain mathematically. But does that actually mean anything? Will it lead to world peace, or will it just facilitate the spread of viruses—biological or digital? I don’t know, but I’m sure it will lead to something. I mean, Weird Al Yankovic knows a guy who knows a guy who knows a guy who knows a guy who knows a guy who knows Kevin Bacon…and I know a guy who knows Weird Al! Meanwhile, Kevin Bacon is only two degrees from Shirley Jones. I’ll be expecting to see them all at the next family reunion.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on May 10, 2003, and again in a slightly revised form on June 21, 2004.

Image credit: By Daniel Walker [GFDL or CC BY-SA 3.0], from Wikimedia Commons

Source: Interesting Thing of the Day

A glass of bourbon

Because I believe in doing proper research for the articles we run here on Interesting Thing of the Day, I am, as I write about National Bourbon Day (June 14), consuming a glass of Old Forester Kentucky Straight Bourbon Whisky (“The First Bottled Bourbon, Estd 1870,” reads the bottle). I’m doing this for you. Because I care.

Bourbon, which by definition can be made only in the United States, has a specific legal definition. According to the U.S. Code of Federal Regulations, Title 27, Chapter I, Subchapter A, Part 5, Subpart C, §5.22, paragraph (1)(i):

“Bourbon whisky”… is whisky produced at not exceeding 160° proof from a fermented mash of not less than 51 percent corn… and stored at not more than 125° proof in charred new oak containers….

In other words: whisky distilled mostly from corn, aged in oak barrels. Yes, I’m deliberately yada-yada-ing some details, but you can look them up if they’re really important to you. What’s important to me is the flavor (delicious) and the intoxicating effect (significant and rapid). I’m told it’s also useful in certain cocktails, but I prefer mine unadulterated, if it’s all the same to you. Cheers!

Image credit: ctj71081 [CC BY-SA 2.0], via Flickr

Source: Interesting Thing of the Day

A moonshine still

I’m not sure what it is about June that requires so much hard alcohol. But in addition to National Moonshine Day (the first Thursday of the month), we can also look forward to World Gin Day (June 9), National Bourbon Day (June 14), and National Martini Day (June 19). In any case, we start with the hardest and most notorious of these—moonshine, which is a high-proof alcoholic beverage distilled mainly from corn mash. That sounds innocent enough, I suppose, but moonshine is typically associated with illicit production (most notably during Prohibition), and until 2010, moonshine was entirely illegal in the United States. Now it can be distilled legally with a proper license, and indeed, brands like Midnight Moon can be found wherever spirits are sold. It can also—under just the right circumstances—be used to fuel a car. But how you obtain your moonshine and what you do with it is none of my business.

Image credit: By Brian Stansberry [CC BY 3.0], from Wikimedia Commons

Source: Interesting Thing of the Day

A radio telescope

The real-life quest to find E.T.

As a card-carrying, Star Trek-watching computer geek, I have naturally known about a project called SETI, the Search for Extraterrestrial Intelligence, for as long as I can remember. I’ve noticed countless SETI references in movies, TV shows, books, newspapers, and magazines. It’s old news, one of those things everyone has at least a basic understanding of, however little knowledge they may have of the specifics, right? Well, as my wife pointed out to me, SETI is the type of thing that simply wouldn’t impinge on the awareness of a great many intelligent, educated people, having been automatically and unconsciously filtered out by the same sort of mechanism that keeps us all from being overwhelmed by the tragedies of the daily news. And yet, whatever opinions you may have (or come to have) about this rather controversial project, I think it’s something fascinating enough—for so many reasons—that it should be part of everyone’s cultural lexicon.

A Needle in a Galaxy of Haystacks

First, the short version. SETI is a cooperative effort by a great many astronomers, engineers, mathematicians, and other scientists to find evidence of the existence of intelligent life in outer space. Their best-known tactic is using powerful radio telescopes, pointed at very specific regions of space, to listen for any radio signal that stands out from all the background noise and exhibits non-random patterns that may suggest an intelligent source. They’ve been at this for decades, and as yet have found no reliable evidence of what they’re looking for. But then, space, as Douglas Adams pointed out, is really big. If there is anyone out there, it’s bound to take some time to find them.

But isn’t that whole belief-in-aliens thing beneath the dignity of respectable scientists? What would drive people to spend their careers—and millions of dollars—on such a quixotic project? The why and how constitute a longer story.

The idea for SETI goes back to the early 1960s, when an astronomer named Frank Drake devised a mathematical way to estimate how many other intelligent civilizations there may be in our galaxy with whom we could conceivably communicate. The Drake Equation basically says that if you take the number of stars in the galaxy (hundreds of billions) and estimate the fraction of those that could have a planet circling them with the conditions necessary to support life, the fraction of those on which intelligent life could plausibly exist, and the average amount of time a civilization could expect to survive, then you can predict the likely number of intelligent alien races we might actually be able to encounter. And that number is…heavily disputed. Because all the variables that comprise the Drake Equation are ultimately based on educated guesses, different people have calculated wildly different results. Initial estimates ranged from as low as 20 to as high as 50,000,000; more recent guesses put the maximum closer to 16 million. Still other scientists say the predicted number is far smaller than 1, despite the fact that we have at least anecdotal evidence of one somewhat intelligent civilization—namely, our own.

The privately funded, non-profit SETI Institute, founded in 1984, favors the more optimistic estimates. And Drake, by the way, who conducted the first SETI-like experiments in 1960, was chairman of the Institute’s Board of Trustees from 1984–2003 and currently serves as the director of SETI’s Carl Sagan Center for the Study of Life in the Universe,.

Needless to say, even if there are thousands of other planets inhabited by intelligent beings, they’re inconveniently far away, so going to visit them is pretty much out of the question. We could, however, at least discover whether they exist in various ways, such as listening for their radio broadcasts. Actually decoding or understanding an alien broadcast is entirely outside the scope of SETI; the point is simply to search for signals that could only have been generated artificially. To do this, astronomers use gigantic radio telescopes, such as the Arecibo Observatory in Puerto Rico, to scan millions of frequencies coming from the vicinity of some of the stars deemed most likely to support planets with life. All this data is crunched by computers—a truly gargantuan task, given the amount of data being gathered. So thanks to a project sponsored by the University of California, Berkeley, the general public can participate in the SETI program. Millions of ordinary home and office computers around the world run free software as part of the SETI@home project to help process data from the radio telescopes during the spare cycles when the computers are not being used to do ordinary work.

Can You Hear Me Now?

Of course, there are some difficulties with the whole notion of listening for radio broadcasts from space. What if an intelligent civilization doesn’t happen to use radio broadcasts? Or what if they do, but the broadcasts are just not powerful enough to reach us? As even the SETI Institute admits, if another planet many light-years away pointed radio telescopes at Earth similar to the ones we’re pointing at them, they’d probably pick up nothing—with only a few exceptions, the strongest radio signals generated on our planet are far too weak to be sorted out from background noise over that sort of distance. So what SETI is really listening for right now is signals far more powerful than we ourselves could generate—or, and this is a long shot to say the least—a directional signal aimed straight at Earth. In the future, the SETI Institute hopes to make use of receivers that are far more sensitive and thus, perhaps, capable of detecting fainter signals. (More recently, the Institute has also begun looking for optical signals in the form of brief flashes of light.)

Meanwhile, some scientists are highly critical of SETI on the grounds that it isn’t science in the strictest sense of the term. The scientific method requires that one form a hypothesis, make predictions based on that hypothesis, and then conduct tests to see whether the predictions are true or false, providing support or counterevidence for the hypothesis. But the hypothesis that there is intelligent life in outer space is not falsifiable—it can’t be disproved, even in theory. If SETI operated for centuries, it would only be able to listen to the tiniest portion of the observable universe, and even then, a lack of evidence would not be the same as proof of the nonexistence of intelligent life beyond our planet.

Given such a slim hope of success, why does anyone bother? For the same reason people play the lottery—the odds may be terrible, but the reward, if you happen to hit the jackpot, is huge.

If we do find out that we’re not alone in the universe, that’s bound to make a lot of people very unhappy. But some of us would be relieved to know there’s intelligent life somewhere.

Image credit: By Noodle snacks [CC BY-SA 3.0 or GFDL], from Wikimedia Commons

Source: Interesting Thing of the Day