>> The engine is powered by proton motive force, i.e., by the flow of protons (hydrogen ions) across the bacterial cell membrane due to a concentration gradient set up by the cell's metabolism <<
Because nature and engineers are good at different things. Nature is good at flexible materials and the control systems that drive their reciprocating impulses. Engineers are good at making rotary things go brrr and reach high speeds.
Yeah, I though that flagella were just little whippy things that corkscrewed somehow... but then I looked at that page this morning and I'm still gobsmacked.
I'd suggest the logic test before sitting down to write the thing. "But it's the internet and everyone has the right to hear my opinion" is too strong to resist.
Wheels aren’t all too useful without roads and fixed cleared paths. Any prey can escape a wheeled predator easily and a predator could push wheeled prey to unmanageable terrain. A wheeled jaguar can’t get you when you are swinging through the trees.
Exactly. I once did a 3-day, 150-mile, solo bike trip. My first day I thought a lot about how magical bicycles were. The next day my mind turned to how much that was really due to roads. The last day what I was really amazed by is the social systems that create and maintain systems of roads.
Without humanity's unique ability for cooperation toward long-term goals, the main use of a wheel would be a wheelbarrow.
Heh, or get better wheels. I've got a dual suspension (160mm front and rear) and 2.6" tubeless tires. I love getting away from things, exploring areas that would take a few days hike but are a day trip on a bike. Far enough out that the "trails" I end up on are game trails instead of human made roads/trails. Sure it's slower than being on a road, but way more fun to explore. A fair bit of the planet is passable on decent mountain bike, don't think humans (or lack of) would make much difference.
In most mountain areas I'd rather be on a game trail, than a road.
There is no way in Hell that this is an ad in the sense that The Economist was paid to publish this article. It is being covered because of the potential implications of this or similar technologies, which may have long-term implications for shipping and the military, of interest to its readers.
The paid advertising inserts in this magazine are clearly marked. This isn't one of them.
> "The bacterial flagellum is driven by a rotary engine (Mot complex) made up of protein, located at the flagellum's anchor point on the inner cell membrane. The engine is powered by proton motive force, i.e., by the flow of protons (hydrogen ions) across the bacterial cell membrane... The rotor transports protons across the membrane, and is turned in the process. *The rotor alone can operate at 6,000 to 17,000 rpm*[!], but with the flagellar filament attached usually only reaches 200 to 1000 rpm."
Not only do many organisms have propellers in the form of flagella, but many like myxococcus xanthus are themselves propellers, using shaped proteins to corkscrew through water. It's baffling that both the author and their editor could be so ignorant.
this is a case in favor of well rounded life experience.
the events occuring at the cellular and bacterial level dont scale up saliently.
if we were to exploit molecular rotational engines or dynamos they would be engineered as an array, the final device would not reveal its molecular organisation as saliently as a wheel and axle assembly does.
muscle tissue is one example, although not constructed of rotational elements,
the underlying structure is likened to a linear track motor, and could perhaps be cyclized to form a stator and rotor like mechanism.
Have a large portion of HN readers never taken grade school biology? Have a large portion of HN readers never seen sperm?
That aside, the baffling part is the author thought himself well enough informed to write the article in the first place, and then that these foolish ramblings made it to the HN front page.
The material longevity is definitely going to be a factor in this design. Flexible materials like this occurring in nature generally have the advantage of being alive, and able to self-repair. On the other hand, it can presumably be replaced, much like a tire.
Nature has a millions of years head start in engineering. We've figured a lot out in a short time, but everything we do is very heavy and inefficient by comparison.
Ruby-throated hummingbirds, for example, migrate 500 miles over the Gulf of Mexico in a single flight. Imagine trying to build a drone that weighs 20 grams and can fly 500 miles.
We've got a lot to figure out in terms of intelligence, energy efficiency, and material science.
Nah. Trains e.g. sure are heavy, but they're also ridiculously energy efficient when it comes to moving stuff around. And yet they're also typically faster than any land animal.
Building roads or tracks doesn't make sense for animals, and freely rotating parts difficult on larger organisms. On the flip side, our human engineering often hasn't put energy efficiency so high up the priority list.
Oh sure, rail is great... but you can't exclude the amount of energy that goes into things like laying tracks, paving roads, and maintaining engines. Plus most of them still use human operators.
Even considering land animals, look at African Elephants. They can walk for days without water and weigh ~6,000 - 10,000lbs. Considerably slower than a truck with a similar weight, but still likely several times more efficient traveling over unpaved dirt.
We optimize for different things, and can be more efficient under very specific circumstances (consider Voyager, for example :P). But when it comes to packing efficiency into a small package we don't hold a candle to nature.
We'll get there eventually, and much faster than evolution did, but our technology is still in its infancy. Consider brains! What you get out of even a tiny mouse brain is bonkers when you consider what little fuel it needs.
Or build me a machine that can roll vs build me a machine that can walk uphill. What nature gave is actually much harder for anyone to engineer. We landed on solutions that are conceptually simple and then built from there. Nature didn’t have that benefit.
The reason one does not see freely rotating bodies such as wheels or propellers in nature comes down to perhaps the most fundamental aspect of biological systems: they're alive. Because they're alive, resources need to be supplied to them and waste needs to be removed. Propagating nutrients across a freely rotating interface can be an intractable problem, and this is not even considering the question of _how_ one could induce free and unbounded rotation in a biological joint. Think of how muscles work, with discrete attachment points and it becomes clear that free rotation isn't possible with muscles. The only method of inducing rotation I can come up with off the top of my head is some sort of turbine design, with rotation being driven by fluid flow.
The notable exception to the absence of free rotation in nature is the flagellum, which solves the nutrient supply issue by being so small and self-contained that it doesn't need nutrients, just the presence of an ion concentration gradient.
Here is an idea: make the rotating part dead (like mollusk shell), and use muscles to push a paddle to add impulse to rotation, like pedaling a bicycle. Should be doable.
That part is easy, actually: make the bearing surface alive, and regenerate it upon wear. It might exude some lubricant too while we’re at it, should not be hard to evolve.
If you can excuse the overt sexuality of his work, Piers Anthony depicted an interesting alien race of beings with a biological ball-bearing method of propulsion in one of the Cluster series books - I forget the title.
> The most notable feature of the mulefa was their use of seed pods as wheels. Once a zalif reached puberty, they were able to fit their spurs into the disc-shaped pods, and propelled themselves along "roads" of solidified lava with their side legs.
This is definitely a possibly solution to the problem of keeping your propeller/wheel alive, but does present some problems in its own right. As another commenter stated, dead objects like teeth, hair, nails, claws, and scales tend to break and once broken cannot be repaired without entirely replacing the object. As well, growing a structure with a complex form like a propeller requires providing nutrients and removing waste from the structure while the cellular scaffolding is forming. Thus we are still faced with the issue of nutrient transfer, though I can imagine a multistage process in which the structure is initially non-rotating and then the connective tissue atrophies to free the now-nonliving rigid body.
Maple seeds spin like an autogyro propeller. This is possible because they are no longer attached to the tree. An aeronautical engineer once told me that a single blade propeller is theoretically most efficient by some metric. It would seem the trees have found that solution.
Great point! I think a valuable thing to understand is that wheels and propellers are very obviously more efficient than legs and wings, respectively. There's a reason ornithopters are at most a curiosity outside of fiction (looking at you Dune!)
Maple seeds are able to take advantage of the efficiency gains of revolute motion by having their entire body rotate rather than using a static body with a freely-moving prop.
Why can't someone invent a system to raise and lower a propeller or Outboard to follow the contour of the waterbed lessening the need and expense of channels?
Why make the propellors go up and down? You could just fix them in the Up position, and make them as big as you can in that position. And they do; we're at that engineering limit.
Evolution values survival. Efficiency is defined as life and death. People value survival, but it's complex. Economical aspects come into play. The technical complexities of some natural systems are amazing (read about tuna in https://www.amazon.com/Song-Blue-Ocean-Encounters-Beneath-eb... for an example).
Wind is free. Once you start carrying cargo, there's a tradeoff between cost and speed. When the cost of mechanical propulsion became low enough, it was widely adopted.
If the company in the article can evolve their technology to the point where it's cheaper, including maintenance, the fact that not everybody is going know how to work on it (always a barrier for new technology), it will get adopted.
64 comments
[ 3.9 ms ] story [ 190 ms ] threadhttps://en.wikipedia.org/wiki/Flagellum#Bacterial
>> The engine is powered by proton motive force, i.e., by the flow of protons (hydrogen ions) across the bacterial cell membrane due to a concentration gradient set up by the cell's metabolism <<
https://en.wikipedia.org/wiki/Molecular_motor
Regardless of how interesting a concept or development may be, check the logic of what you're writing before you hit publish.
Without humanity's unique ability for cooperation toward long-term goals, the main use of a wheel would be a wheelbarrow.
In most mountain areas I'd rather be on a game trail, than a road.
https://tardis.fandom.com/wiki/Death_Wheel
The paid advertising inserts in this magazine are clearly marked. This isn't one of them.
https://en.m.wikipedia.org/wiki/Flagellum
> "The bacterial flagellum is driven by a rotary engine (Mot complex) made up of protein, located at the flagellum's anchor point on the inner cell membrane. The engine is powered by proton motive force, i.e., by the flow of protons (hydrogen ions) across the bacterial cell membrane... The rotor transports protons across the membrane, and is turned in the process. *The rotor alone can operate at 6,000 to 17,000 rpm*[!], but with the flagellar filament attached usually only reaches 200 to 1000 rpm."
Nature never ceases to amaze.
[] https://www.nature.com/articles/nrmicro744
the events occuring at the cellular and bacterial level dont scale up saliently.
if we were to exploit molecular rotational engines or dynamos they would be engineered as an array, the final device would not reveal its molecular organisation as saliently as a wheel and axle assembly does.
muscle tissue is one example, although not constructed of rotational elements, the underlying structure is likened to a linear track motor, and could perhaps be cyclized to form a stator and rotor like mechanism.
That aside, the baffling part is the author thought himself well enough informed to write the article in the first place, and then that these foolish ramblings made it to the HN front page.
Ruby-throated hummingbirds, for example, migrate 500 miles over the Gulf of Mexico in a single flight. Imagine trying to build a drone that weighs 20 grams and can fly 500 miles.
We've got a lot to figure out in terms of intelligence, energy efficiency, and material science.
See https://www.nytimes.com/2020/09/08/science/hummingbirds-torp...
Building roads or tracks doesn't make sense for animals, and freely rotating parts difficult on larger organisms. On the flip side, our human engineering often hasn't put energy efficiency so high up the priority list.
Even considering land animals, look at African Elephants. They can walk for days without water and weigh ~6,000 - 10,000lbs. Considerably slower than a truck with a similar weight, but still likely several times more efficient traveling over unpaved dirt.
We optimize for different things, and can be more efficient under very specific circumstances (consider Voyager, for example :P). But when it comes to packing efficiency into a small package we don't hold a candle to nature.
We'll get there eventually, and much faster than evolution did, but our technology is still in its infancy. Consider brains! What you get out of even a tiny mouse brain is bonkers when you consider what little fuel it needs.
Hooves are better than t[iy]res in one way: they're self-renewing.
The notable exception to the absence of free rotation in nature is the flagellum, which solves the nutrient supply issue by being so small and self-contained that it doesn't need nutrients, just the presence of an ion concentration gradient.
https://hisdarkmaterials.fandom.com/wiki/Mulefa
> The most notable feature of the mulefa was their use of seed pods as wheels. Once a zalif reached puberty, they were able to fit their spurs into the disc-shaped pods, and propelled themselves along "roads" of solidified lava with their side legs.
Maple seeds are able to take advantage of the efficiency gains of revolute motion by having their entire body rotate rather than using a static body with a freely-moving prop.
OK not “propeller” but near enough.
Wind is free. Once you start carrying cargo, there's a tradeoff between cost and speed. When the cost of mechanical propulsion became low enough, it was widely adopted.
If the company in the article can evolve their technology to the point where it's cheaper, including maintenance, the fact that not everybody is going know how to work on it (always a barrier for new technology), it will get adopted.