SCI-TECH

A metal detector hobbyist discovered a centuries’ old coin while scouring an abandoned sports field—and the coin  is especially rare for the area. In the southern Australian province of Victoria, treasure hunting enthusiast Angus James recently spotted a well-preserved 100 Mon Tenpō Tsūhō, a 19th century Japanese coin likely deposited during Australia’s decades’ long gold rush.

“You never know what you’ll find next,” James posted to social media on January 25th, along with photos of his recent haul.

Australia’s gold rushes began in 1851, and quickly became transformative events in its history. Although already home to many diverse Indigenous groups, the United Kingdom had overseen penal colonies on the continent for nearly 100 years prior to the precious metal’s discovery. However, once word of the gold spread, people from around the world raced over to stake their own fortunes. By 1871, Australia’s total population had risen from around 430,000 to over 1.7 million inhabitants.

The majority of new arrivals were Europeans, but the gold rushes also attracted hopefuls from elsewhere, including nations like Japan. During the mid-19th century, Japanese commerce frequently relied on low denomination Tenpō Tsūhō coins. These were first minted by the Tokugawa government in 1835, and remained in circulation for 40 years until the Meiji Restoration’s introduction of the yen. Many numismatists seek out Tenpō Tsūhō coins today, and in Japan they’re sold as good luck charms.

James’ find features Chinese characters, but they aren’t a fluke. At that time, Japanese monetary design was largely influenced by the neighboring nation’s various coins. In this case, “Tenpō” refers to the era of government, while “Tsūhō” roughly translates to “circulating treasure” or “currency.”

It’s yet another reminder to keep those metal detectors at the ready.

The post Metal detectorist finds 19th century Japanese coin in Australia appeared first on Popular Science.

Every ski and snowboarding event at the 2026 Winter Olympics is won through a combination of sheer athleticism, quick thinking, creativity, and persistence. But like so many other sports, competitors know their choice of equipment can mean the difference earning the gold or silver medal. A ski is built for function over form, and manufacturers have spent decades adapting and honing their products to ensure wearers get the best results.

The fine tuning has very clear results, too. If the 1964 Winter Olympic gold medalist for downhill alpine skiing faced off against every qualifying participant in the same event at the Beijing games in 2022, Egon Zimmermann would have returned to Austria solidly in last place. While his antiquated accessories wouldn’t be the only limiting factor, they would play a major part in his hypothetical humiliation. Aside from better made components, today’s ski shapes are also dramatically different from their forebears.

“The shape determines stability and the maneuverability of the ski,” Northwestern University physicist Stefan Kautsch explained in a recent profile.

For example, racers will likely opt for straighter and lengthier skis if they anticipate longer, wider turns on a giant slalom. Faster and tighter pivots, meanwhile, necessitate shorter and often curvier footwear. But no matter the shape, racers must always account for one common physics denominator.

“It’s all about the friction. The lower the friction coefficient is, the faster the person can go,” said Kautsch.

Kinetic friction is an inevitable byproduct of two objects sliding against one another. The molecular surface interactions are a response to exerted force, resulting in resistance and a reduction in speed. However, many people often misunderstand the implications of this. One may assume the trick to a record-breaking alpine run is simply strapping on the thinnest equipment available, as less surface area means less friction. In actuality, it’s more to do with a smooth ski than the width of the skis themselves.

“Simply, the smoother the material is, the less granulated the surfaces, the lower the friction coefficient is and the faster the person can go,” Kautsch summarized.

To illustrate the concept, Kautsch used a pair of differently sized Lego bricks. When sent down an inclined wooden board at the same time, both bricks reached the bottom simultaneously. The same result happens on a smoother plastic surface—but faster.

While friction isn’t the only influence on the slopes, it is definitely something at the top of a skier’s mind—especially when they’re staring down their race from the top of a very large hill.

The post Downhill skiing’s biggest hurdle? Friction. appeared first on Popular Science.