Why the Metric System Might Be Screwed

International Bureau of Weights and Measures
International Bureau of Weights and Measures

The world’s most perfect weight isn’t so perfect anymore. And that has scientists scared.

Hidden in a vault outside Paris, vacuum-sealed under three bell jars, sits a palm-sized metal cylinder known as the International Prototype Kilogram, or “Le Grand K.” Forged in 1879 from an alloy of platinum and iridium, it was hailed as the “perfect” kilogram—the gold standard by which other kilograms would be judged.

Although it’s arguably the world’s most famous weight, Le Grand K doesn’t get out much. Since hydrocarbons on fingertips or moisture in the air could contaminate its pristine surface, it goes untouched for decades, under triple lock and key at the International Bureau of Weights and Measures. Every 40 years, however, it makes an appearance. The weight is ushered from its chamber, washed with alcohol, polished, and weighed against 80 official replicas hand-delivered from laboratories around the world. Today, whenever scientists need to verify something is precisely one kilogram, they turn to one of these replicas, over which Le Grand K reigns supreme.

This system sounds absurd, but not too long ago, lots of units relied on similar methods. The kilogram was just one of seven standards of measurement established by the French Academy of Sciences in 1791, all based on physical prototypes. These benchmarks caught on worldwide because standardization was sorely needed. At the time, some 250,000 different units of weights and measures existed in France alone, which meant that the only constant was complete chaos.

Weight Problem

While basing measurements on tangible benchmarks was an improvement, using physical standards wasn’t without its flaws. For one, they have a nasty habit of changing. In Le Grand K’s case, it’s been losing weight. At its most recent weigh-in in 1988, it was found to be 0.05 milligrams—about the weight of a grain of sand—lighter than its underling replicas. Experts aren’t sure where this weight went, but some theorize that the replicas have been handled more often, which could subtly add weight. Others postulate Le Grand K’s alloy is “outgassing,” which means air is gradually escaping the metal.

Whatever the reason for Le Grand K’s gradual wasting away, it’s got scientists scrambling for a more reliable standard. Some argue that this is long overdue, since all other units of measurement are already defined by fundamental constants of nature that can be reproduced anywhere anytime (provided you’ve got some sophisticated lab equipment). The meter, for example, used to be defined by a metal rod stored alongside Le Grand K. But in 1983, it was redefined as the distance light travels in a vacuum during 1/299,792,458 of a second.

Standardizing the kilogram has been trickier, though. Australian scientists are polishing a one-kilogram sphere of silicon, hoping that they’ll be able to count the number of atoms it contains to create a more accurate standard. American physicists at the National Institute of Standards and Technology (NIST) are attempting to redefine a kilogram in terms of the amount of voltage required to levitate a weight. But so far, neither approach can match Le Grand K’s accuracy.

Why should we care whether a kilogram in a vault is “perfect” or not? Because it’s bad news when your standard is no longer standardized. While no one’s worried whether a single kilogram of apples is a hair lighter or heavier at the produce stand, a small discrepancy can become a gargantuan one if you’re dealing with, say, a whole tanker of wheat. The kilogram is also used as a building block in other measurements. The joule, for instance, is the amount of energy required to move a one-kilogram weight one meter. The candela, a measure of the brightness of light, is measured in joules per second.

These links mean that if the kilogram is flawed, so are the joule and candela, which could eventually cause problems in an array of industries, particularly in technology. As microchips process more information at higher speeds, even tiny deviations will lead to catastrophes. Le Grand K’s unreliability “will start to be noticeable in the next decade or two in the electronics industry,” warns NIST physicist Richard Steiner. If your next smartphone is buggy, you’ll know which hunk of metal to blame.

So scientists continue to chase the perfect kilogram. “Maybe we have all been looking for too high-tech an answer,” says Stuart Davidson of England’s National Physical Laboratory. “There could be something really obvious out there we’ve missed.” The NPL’s website encourages others to give it a shot: Any better ideas on a postcard please. Until then, Le Grand K will remain king—short of true perfection, but as perfect as it gets.

Can You Tell an Author’s Identity By Looking at Punctuation Alone? A Study Just Found Out.

iStock.com/RyersonClark
iStock.com/RyersonClark

In 2016, neuroscientist Adam J Calhoun wondered what his favorite books would look like if he removed the words and left nothing but the punctuation. The result was a stunning—and surprisingly beautiful—visual stream of commas, question marks, semicolons, em-dashes, and periods.

Recently, Calhoun’s inquiry piqued the interest of researchers in the United Kingdom, who wondered if it was possible to identify an author from his or her punctuation alone.

For decades, linguists have been able to use the quirks of written texts to pinpoint the author. The process, called stylometric analysis or stylometry, has dozens of legal and academic applications, helping researchers authenticate anonymous works of literature and even nab criminals like the Unabomber. But it usually focuses on an author's word choices and grammar or the length of his or her sentences. Until now, punctuation has been largely ignored.

But according to a recent paper led by Alexandra N. M. Darmon of the Oxford Centre for Industrial and Applied Mathematics, an author’s use of punctuation can be extremely revealing. Darmon’s team assembled nearly 15,000 documents from 651 different authors and “de-worded” each text. “Is it possible to distinguish literary genres based on their punctuation sequences?” the researchers asked. “Do the punctuation styles of authors evolve over time?”

Apparently, yes. The researchers crafted mathematical formulas that could identify individual authors with 72 percent accuracy. Their ability to detect a specific genre—from horror to philosophy to detective fiction—was accurate more than half the time, clocking in at a 65 percent success rate.

The results, published on the preprint server SocArXiv, also revealed how punctuation style has evolved. The researchers found that “the use of quotation marks and periods has increased over time (at least in our [sample]) but that the use of commas has decreased over time. Less noticeably, the use of semicolons has also decreased over time.”

You probably don’t need to develop a powerful algorithm to figure that last bit out—you just have to crack open something by Dickens.

What Happens to Your Body If You Die in Space?

iStock.com/1971yes
iStock.com/1971yes

The coming decades should bring about a number of developments when it comes to blasting people into orbit and beyond. Private space travel continues to progress, with Elon Musk and Richard Branson championing civilian exploration. Professional astronauts continue to dock at the International Space Station (ISS) for scientific research. By the 2040s, human colonists could be making the grueling journey to Mars.

With increased opportunities comes the increased potential for misadventure. Though only 18 people have died since the emergence of intragalactic travel in the 20th century, taking more frequent risks may mean that coroners will have to list "space" as the site of death in the future. But since it's rare to find a working astronaut in compromised health or of an advanced age, how will most potential casualties in space meet their maker?

Popular Science posed this question to Chris Hadfield, the former commander of the ISS. According to Hadfield, spacewalks—a slight misnomer for the gravity-free floating that astronauts engage in outside of spacecraft—might be one potential danger. Tiny meteorites could slice through their protective suits, which provide oxygen and shelter from extreme temperatures. Within 10 seconds, water in their skin and blood would vaporize and their body would fill with air: Dissolved nitrogen near the skin would form bubbles, blowing them up like a dollar-store balloon to twice their normal size. Within 15 seconds, they would lose consciousness. Within 30 seconds, their lungs would collapse and they'd be paralyzed. The good news? Death by asphyxiation or decompression would happen before their body freezes, since heat leaves the body slowly in a vacuum.

This morbid scene would then have to be dealt with by the accompanying crew. According to Popular Science, NASA has no official policy for handling a corpse, but Hadfield said ISS training does touch on the possibility. As he explained it, astronauts would have to handle the the body as a biohazard and figure out their storage options, since there's really no prepared area for that. To cope with both problems, a commander would likely recommend the body be kept inside a pressurized suit and taken someplace cold—like where garbage is stored to minimize the smell.

If that sounds less than regal, NASA agrees. The company has explored the business of space body disposal before, and one proposition involves freeze-drying the stiff with liquid nitrogen (or simply the cold vacuum of space) so it can be broken up into tiny pieces of frozen tissue, which would occupy only a fraction of the real estate that a full-sized body would.

Why not eject a body, like Captain Kirk and his crew were forced to do with the allegedly dead Spock in 1982's Star Trek II: The Wrath of Khan? Bodies jettisoned into space without a rocket to change their trajectory would likely fall into the wake of the spacecraft. If enough people died on a long trip, it would create a kind of inverted funeral procession.

Even if safely landed on another planet, an astronaut's options don't necessarily improve. On Mars, cremation would likely be necessary to destroy any Earth-borne bacteria that would flourish on a buried body.

Like most everything we take for granted on Earth—eating, moving, and even pooping—it may be a long time before dying in space becomes dignified.

[h/t Popular Science]

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