Tag Archives: bridge

The Rollercoaster Bridge — why Eshima Ohashi is so steep and so impressive

In southwestern Japan, the prefectures of Tottori and Shimane were separated by a lake. The lake, called Nakaumi, made it hard for people to get from one side to the other, so in 1997, Japanese engineers and architects started working on a bridge. But there was a catch: ships also sailed the lake, so the bridge had to be tall enough to allow ships to pass beneath. That’s how the terrifyingly steep Eshima Ohashi bridge came to be.

Looking towards the bridge from the Shimane Prefecture Side. Image credits: mstk east.

The bridge has a slope gradient of 5.1% on one side and 6.1% on the other. It’s a mile long (1.6 km) and 144 feet tall (44 meters). It’s one of the tallest rigid frame bridges in the world, connecting the two busy cities on opposite sides of the lake.

Before the bridge was built, every time a ship would pass, traffic would have to be restricted for up to 8 minutes, and only vehicles under 14 tons were allowed to cross the bridge. There was also a limit of 4,000 vehicles that could cross per day. So traffic between the two Japanese prefectures was often delayed, and traversing the lake was a drag. The Eshima Ohashi bridge solved most of those problems, by being tall enough that ships can go under it — the only downside is that the bridge had to be high and steep.

In truth, it’s steep but not that steep. Many of the photos you see of it were taken from a distance using a telephoto lens, which distorts the perspective and makes it look like the bridge is steeper than it is. Images of the bridge have widely circulated, and a popular commercial was also shot in the area, carefully designed to make the bridge look as steep as possible by forcing the perspective of the images. The place became a sort of a legend, but as it’s often the case, reality doesn’t look exactly like the photos.

In some images, the bridge looks a bit like the upward slope of a roller coaster, creating the illusion that cars are going up a cliff. However, that’s also a bit of an optical illusion, or rather a distortion in the visual field of perception. The telephoto lenses often used to take these photos “flatten” the visual field, making it seem like the lowest point of the bridge is much closer to the highest point of the bridge than it really is, creating an illusion of extra steepness.

Example of how forced perspective can seemingly distort an object.

Here is how different the bridge looks from the perspective of an observer (first video) and from the perspective of a driver crossing the bridge (second video).

Still, the bridge is nothing to scoff at, and in Japan, it’s often referred to as a betabumi-zaka — ‘a pedal-to-the-metal slope’. Depending on your car, you may not need to push the gas all the way down, but it’s still a slope to be considered carefully. It’s not the only betabumi-zaka in Japan, several other such structures exist in Tokyo and Osaka.

Special provisions are in place, especially in the winter, to make sure that the surface doesn’t become ice- or snow-covered. However, while you may want to be sure your brakes are working before going on the bridge, it’s not exactly a rollercoaster

The bridge has sidewalks going up on both sides. Image credits: mstk east.

The bridge has become something of a tourist attraction in its own right. It’s fairly easy to reach: you can either drive on it or use a taxi to get you to it and then walk on it (there is a sidewalk on both sides). If you want to recreate the famous photos, there is a convenience store at the intersection on the Shimane side. If you do walk or cycle on the bridge, make sure to also climb to the top and enjoy the lovely view of the lake and Daikon island (telescopes and binoculars are freely available for tourists).

The nearby Daikon island itself is an interesting site. It’s a Japanese garden and the country’s largest producer of peony seedlings. Around 20,000 peonies of 250 different species are raised here and historically, growing and peddling seedlings was a job for the women on the island.

All in all, the Eshima Ohashi bridge may not be as incredibly steep as some photos make it out to be, but it’s still a sight to behold, and an important engineering accomplishment. It has connected two cities and bridged the gap between the relatively isolated Sanin region and the rest of Japan, helping the area develop economically in the past few decades. Like we’ve come to expect from Japan, it’s good, solid, and useful engineering.

New fossil insect species points to a Canada-Australia land route 50 million years ago

A tiny fossil insect found near the city of Kamloops, British Columbia, points to a possible land connection between Canada and Australia.

The fossil (A, B) and a diagram of its venation (C).
Image credits Archibald, S. B., & Makarkin, V. N., (2020), The Canadian Entomologist.

Current relatives of this species live exclusively in Australia, the team explains, suggesting the possibility of a former connection between the two landmasses. The fossil, which the team describes as an insect from the “split-footed lacewing” family, is estimated to be 50 million years old.

Old ties

“These fossils are rare,” says Vladimir Makarkin of the Russian Academy of Sciences in Vladivostok, corresponding author of the study describing the fossil. “This is only the fourth one found from this time-span world-wide, and it’s the most completely preserved. It adds important information to our knowledge of how they became modern.”

The discovery is the latest in a series of fossil finds that are pointing to a Canada-Australia connection, the team explains. Furthermore, it raises some interesting questions regarding the global movement of animals and how it is impacted by shifts in climate and the position of continents over time

The split-footed lacewing family is very poorly documented, although we do know that it survived for at least 66 million years after the dinosaurs went extinct. The fossil’s identity — a new genus and species, Epinesydrion falklandensis — was determined as belonging to the split-footed family from the hallmark network of veins covering its wings.

Previous fossil insects of comparable age found in British Columbia and Washington have ties to families that currently inhabit Pacific-coastal Russia to the west and Europe, as these northern continents all used to be connected.

“Fifty million years ago, sea levels were lower, exposing more land between North America and Asia, and the Atlantic Ocean had not widened, leaving Europe and North America still joined across high latitudes,” says lead author Bruce Archibald.

However, we don’t know of any ancient land route between British Columbia and Australia. Compared to its position today, the land down under was closer to Antarctica and farther from Asia, meaning that any migrating animals needed to travel over vast stretches of ocean to reach Canada’s west coast.

Archibald says that “a pattern is emerging that we don’t quite understand yet, but has interesting implications”. They hypothesize that the issue might be tied to climate. The forests of the ancient British Columbian temperate upland (when this lacewing lived) had mild winters, probably without frost days. The climate of modern Australia shares these mild winters even in temperate regions.

“It could be that these insect groups are today restricted to regions of the world where climates in key ways resemble those 50 million years ago in the far western Canadian mountains,” says Archibald.

The team explains that understanding this species’ life and how it ended up on both of these modern continents can help us better piece together the history of our climate and continents.

The paper “A new genus and species of split-footed lacewings (Neuroptera) from the early Eocene of western Canada and revision of the subfamily affinities of Mesozoic Nymphidae” has been published in the journal The Canadian Entomologist.

1000 ft Long, 600 ft High Suspension Bridge Opens in China – and it’s Transparent

A 300 meter long (984 ft) glass suspension bridge, 180 meters (591 ft) above the ground has recently opened in Hunan, part of China’s Shiniuzhai National Geological Park. As if that wasn’t scary enough, the entire thing is made of glass-like material, and it’s transparent.

Eloquently named Haohan Qiao or ‘Brave Men’s Bridge’, the bridge is an adventure in itself, as the first visitors found out. The bridge was initially meant to be made from wood, but authorities it wouldn’t have been strong enough, so they used a type of reinforced glass.


Another glass bridge is set to open in the same area soon, in the Zhangjiajie Grand Canyon area. When complete, it will measure be the world’s highest and longest glass bridge at 430 meters (1411 ft) long and 300 meters (984 ft) high. Would you dare to cross it?


Watch these drones build a rope bridge that’s safe to walk on

Drones are often feared as instruments of destruction, and as John Oliver pointed out, in some parts of the world, people fear blue skies because that’s when the drones strike. But this technology isn’t only used to destroy – it can also be used to create, as demonstrated by these very efficient quadrocopters building a rope bridge.

Flying machines, by definition, offer a big advantage over traditional construction machines: they can fly and reach basically any desired point, flying in and about them. Tensile structures fit very well with this characteristic, and researchers, as researchers from ETH Zurich have shown. As seen in the video below, the bridge was entirely built by the flying machines. Every knot and braid in the 7.4 meter (just over 24 feet) bridge was tied by the UAVs (unmanned aerial vehicles) using Dyneema rope, a strong, resilient variety of rope – the bridge can easily carry a man. The technology could be replicated for larger bridges.

Aerial construction requires UAVs to physically interact with their environment, and in this case, the room was outfitted with motion capture devices that offer positional measurements which were then fed back to the drones. In a real case scenario, the drones would interact with their environment as well as with humans, and so far, this works as a great proof of concept.

I could definitely see it implemented in remote areas or areas struck by disaster in which a quick way of access needs to be improvised. Hopefully, drones will one day become an image of salvation, not of destruction.


Computer squares off against professional poker players – and loses badly

Even the best chess players are no match for computers these days, but computers are still struggling when it comes to games that have a random or unknown component. In games like Bridge or Poker, humans still hold the crown. Scientists from the Carnegie Mellon University tried to change that, by designing Claudico – a computer program built to defeat humans. But Claudico lost, badly.

“We knew Claudico was the strongest computer poker program in the world, but we had no idea before this competition how it would fare against four Top 10 poker players,” explains CMU professor computer science Tuomas Sandholm. He directed the development of the Claudico program, adding, “It would have been no shame for Claudico to lose to a set of such talented pros, so even pulling off a statistical tie with them is a tremendous achievement.”

The four pros each played over 20,000 hands with the software, and even though it lost, computer scientists believe the experiment was a complete success; according to them, it’s not a matter of if computers can ultimately win at poker, it’s a matter of when.

“I wouldn’t bet on the humans for too much longer,” said Michael Bowling, a computer science professor at the University of Alberta, Canada, who has developed one of the leading poker programs. “I would say now, after this [tournament] it will take one to three years” for a computer to beat top players, he said. “Up to this point, we just didn’t know how close we were.”

Needless to say, the poker man-vs-AI showdown was watched closely both by poker and AI enthusiasts alike. Humans won 9 of the 13 days of tournament, with a total difference of $732,713 (theoretical money). But when you consider that the total sum involved was over $150 million, that difference suddenly doesn’t seem that big.

“It’s definitely been a good run,” said Bjorn Li, who finished with the biggest lead over Claudico, $529,033. That earned him $44,676 from the $100,000 prize pot that the casino and co-sponsor Microsoft put up for the players to divide based on the outcome of the tournament. Doug Polk, the world’s No. 1-ranked online player, won $26,734; Dong Kyu Kim won $18,589; and Jason Les won $10,000.

Li too seems to believe that humans will eventually start losing at poker against an AI, but for now, he enjoys the fact that humans still rule the tables.

“We know theoretically that artificial intelligence is going to overtake us one day, But at the end of the day, the most important thing is that the humans remain on top for now.”

Doug Polk on the other hand believes that while the computer is definitely a formidable adversary, it still can’t replace humans, and it sometimes behaves completely erratically.

“Betting $19,000 to win a $700 pot just isn’t something that a person would do,” he says.

So why is it that computers destroy chess players, but not poker players? Does that signify that poker is somehow more complex then chess? Not really – the difference is in the nature of the game.

“In chess it’s a game of complete information, so when it’s your turn to move you know exactly what the state of the world is, what the state of the game is,” Sandholm said. “In poker, you don’t. This is really to be able to assist humans and companies in interacting, let’s say in negotiation,” Sandholm said. “Wouldn’t it be nice if you had an agent that helped you strategize in the world when you’re buying a car or buying insurance?”

A poker playing AI that would help me buy better insurance? Yep, that sounds good, but for now, researchers need to tweak Claudico’s algorithms.

Photo: headoverheels.org

Why you feel the urge to jump off a ledge. No, you’re not suicidal

Photo: headoverheels.org

Photo: headoverheels.org

A few months ago I went hiking with some of my friends in an absolutely stunning mountain setting. We climbed a country road for half an hour or so on foot, then reached a chalet right in the middle of a pine tree clearing and had a few beers with the keeper there, who was gracious enough to show us around. He told us about this incredible place only a few minutes walks away where we would find a 500foot waterfall the likes of which we’ve only dreamed about. Naturally, we went for it. It took us a hell of a lot more (but I thank him for lying, in retrospect), but here we were, right at the head of the waterfall, staring down as champagne-like water crashed into the rocks. Everybody around me was talking out loud how cool this whole place is. I could only think about jumping off. Not in a “hey, I’m sick of this world, I wanna die!” way. It was more like I was drawn to do it, be one with the water and simply flow. Luckily, my survival instincts didn’t fade me, so in the next instant I got the self-destructive thought flashing through my head, I backed off. But was this a matter of self-destruction of something else?

It took us a hell of a lot more (but I thank him for lying, in retrospect), but here we were, right at the head of the waterfall, staring down as champagne-like water crashed into the rocks. Everybody around me was talking out loud about how cool this whole place is. I could only think about jumping off. Not in a “hey, I’m sick of this world, I wanna die!” way. It was more like I was drawn to do it, be one with the water and simply flow. Luckily, my survival instincts didn’t fade me, so in the instant after I got the self-destructive thought flashing through my head, I backed off. But was this a matter of self-destruction of something else?

The experience made me reflect. I realized afterward that this wasn’t the first time I had this sensation. I occasionally had the feeling when I was near cliffs, rooftops, bridges and so on. I swear I’m not suicidal, though. So what does that make me? The perfect lab rat for a group of psychologists at Florida State University, it seems.

“We were talking one day in a lab meeting and some of us had experienced it,” recalled psychology doctoral student Jennifer Hames. But when the lab searched the psychology literature, they could find no mention of it. “So we thought, What a great study!”

Death wish or life wish?

In 1920, famous psychologist Sigmund Freud published Beyond the Pleasure Principle, where he writes about the “opposition between the ego or death instincts and the sexual or life instincts”, namely the so-called “death drive”. Practically, Freud says, some people wish for death and that some suicides are purely impulsive, absent any sign of depression or even sadness.The assumption of the existence of an instinct of death or destruction has been met with resistance even in analytic circles, and to this day Freud’s theory has remained highly controversial. But the “jump off the bridge” sensation poses an interesting connection, so the Florida State researchers delved deeper.

The team surveyed 431 college students, asking them about urges to jump from high places and thoughts of suicide. Beforehand, the participants’ levels of depression, suicidal thoughts and their sensitivity to anxiety were measured. A third of the participants confessed they’d felt the urge to jump at least once. Those who had had suicidal thoughts were more likely to say “yes”, but even so half the participants who had never considered suicide also said they experienced the feeling. What’s going on? Is Freud right?

Not necessarily. The leading hypothesis is that those who experience this sort of sensation are actually misinterpreting their instincts. More precisely, the researchers believe the sensation arises when people become over anxious when faced with a potential danger (falling off a bridge), but become confused when they consciously find there’s no reason to be anxious about anything (you check the ledge, see that it’s sturdy, so what’s the problem?).

This conflict leads the person to believe that he actually wanted to jump and this is what sparked his survival instincts. If anything, the researchers conclude, the results suggest that people who experience this sort of feeling are actually expressing a will to live, not the other way around. This is definitely good news for me, but the conclusions are a bit speculative, to say the least. Other researchers who were not involved in the study believe the sensation could be caused by a number of things. The simplest explanation is that people are in it for the thrills.

Next, the researchers plan on placing participants (students of course) in a rooftop setting, measure their anxiety sensitivity and response, and further study the phenomenon. The present findings were reported in Journal of Affective Disorders.

The science (or art?) of growing tree root bridges

In the depths of northeastern India, in one of the wettest places on earth, bridges aren’t built—they’re grown.

Photo by Arshiya Urveeja Bose.

India has over 1 billion people, and many of them live in poverty – 21% of all people in India fall below the international poverty line of US$ 1.25 per day. In many parts of the country, especially in the north-east, it always seems to rain, roads are hard to build and are dangerous to ford – it’s one of the wettest places on Earth. The steady precipitation combined with the rugged terrain, steep hillsides and abundant forests make it very difficult to travel from one place to another – crossing rivers is a dangerous adventure. But the inventive, creative people of India found a spectacular solution – though one that requires a lot of patience at first: they “grow” tree root bridges.

Photo by Ashwin Kumar.

Photo by Ashwin Kumar.

It’s not clear who came up with this idea and when, it all started when someone from the Khasi people noticed the way that the trees in the area grew.  Growing on boulders on almost sheer cliff faces, laterally above the ground, in very surprising ways. After they secure the way in their primary locale they would extend roots down to the water. At first, the roots are slender and flexible, but in time, they grow to be big and powerful – powerful enough to support dozens of people.

Over time, they gradually “trained” the roots to grow in the direction they want – across the gap until the other side, forming a natural, sturdy bridge. Over time, the Khasi people became better and better at this technique, and they have tree root bridges which even span 30 meters long.

It’s not clear when all this started, but it’s certainly a few centuries old! Some of the biggest bridges are estimated to have been around for 500 years!

Photo by Arshiya Urveeja Bose.

But how exactly do you build this kind of root bridges? The first thing you need is roots which exhibit a similar root behavior, like the Indian Banyan (Ficus benghalensis) and the Rubber Tree (Ficus elastica). But how do you make them grow the way you want? The key here is another plant – the betel nut. The betel nut is a shrub; the Khasis take a trunk and slice it, hollowing out the middle – like a tube. I’m not sure if there is something specific about this plant, you could probably use a number of other solutions, but it’s just something suitable that grows a lot in the area. They then take this hollowed trunk and use it as a guidance system for the roots. Once the roots reach the end of one of these guides, you simply add another one at the end. Since there’s a lot of rain, the roots grow a lot, searching for some place to grow in the ground. After they reach the other side of the river they take root there, establishing the natural bridge.

Of course, all of this takes a lot of time – you have to wait for the trees to grow. It usually takes somewhere between 10 and 20 years for the bridge to take shape, but once it’s built, it really lasts a lot, several centuries, and it’s secure – they can usually hold at least a dozen people. Depending on the tree, the conditions, and the size of the desired bridge the time frame can vary (faster than 10 years or slower than 20), but usually, it takes just over a decade.

The solution is also sustainable, eco-friendly, and doesn’t cost any money – so truly an ideal solution for this area. One special root bridge, believed to be the only one of its kind in the world, is actually two bridges stacked one over the other and has come to be known as the “Umshiang Double-Decker Root Bridge”, which you can see both above and below.

The trees are incredibly useful. Crossing a river without the bridge is somewhere between very unpleasant and dangerous (potentially even life threatening in the rainy season). Many children have to walk great distances to get to school, and without these bridges, it would be impossible for them. The utility of this technique is undeniable.

Now, as Western Civilization starts to discover these bridges, they also have a potentially touristic value. The local population which already favors them to modern bridges has been alerted to their potential worth and kept them from being destroyed in favor of steel ones.

The Indian state of Meghalaya, where most of these trees can be found, is one of the poorest, but most beautiful places on Earth – “Meghalaya” literally translates as “abode in the clouds.” It’s a remarkable place, with remarkable people – it’s where human ingenuity meets the implacable forces of nature.

So now, I ask you: is growing tree root bridges a science, or an art?