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Dandelion Seeds Fly Using ‘Impossible’ Method Never Before Seen in Nature

nature.com

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Re: Dandelion Seeds Fly Using ‘Impossible’ Method Never Before Seen in Nature

#71

Post by onion2k »

creep wrote: post #62
sixstringtheory wrote: post #44

Earlier quoted context omitted.

A syncretization of technology and scientific thought, hearkening back to our more animistic tendencies, sounds both poetic and plausible.

I don't think worship is an "animistic" quality. I think the tendency to worship is very much a refined trait in highly intelligent organisms.

You're right in the sense that ritualised, repeated behaviour performed for no obvious gain is something very unusual. Most animals don't waste energy on things that don't have a material impact on their life.

I'd disagree with your point about intelligence though. It's simply that we have more resources than we need. Even the stupidest animals would develop rituals if they could afford to.

Re: Dandelion Seeds Fly Using ‘Impossible’ Method Never Before Seen in Nature

#72

Post by mclehman »

taneq wrote: post #46
kakarot wrote: post #42

> Never Before Seen in Nature > Many insects harbour such filter-like structures on their wings or legs, suggesting that the use of detached vortices for flight or swimming might be relatively common I sense a bit of disconnect between the article and the headline.

Also: > When some animals, aeroplanes or seeds fly, rings of circulating air called vortices form in contact with their wings or wing-like surfaces. > Researchers thought that an unattached vortex would be too unstable to persist in nature. I guess those animals and seeds aren't natural then?

Aren't those two sections contrasting "in contact" with "unattached"?

Re: Dandelion Seeds Fly Using ‘Impossible’ Method Never Before Seen in Nature

#73

Post by salty_biscuits »

2_listerine_pls wrote: post #36
lordnacho wrote: post #12

Earlier quoted context omitted.

Yes, the seed is falling, but the vortex slows the fall enough for it to be useful in distributing the seed as far as possible.

My intuitive understanding is that the vortex is a consequence of the slower flow through and not the other way around.

Potential energy from gravity goes to kinetic energy of stable vortex ring rather than kinetic energy of falling down.

Re: Dandelion Seeds Fly Using ‘Impossible’ Method Never Before Seen in Nature

#74

Post by kissickas »

taneq wrote: post #46
kakarot wrote: post #42

> Never Before Seen in Nature > Many insects harbour such filter-like structures on their wings or legs, suggesting that the use of detached vortices for flight or swimming might be relatively common I sense a bit of disconnect between the article and the headline.

Also: > When some animals, aeroplanes or seeds fly, rings of circulating air called vortices form in contact with their wings or wing-like surfaces. > Researchers thought that an unattached vortex would be too unstable to persist in nature. I guess those animals and seeds aren't natural then?

What makes a vortex unattached?

Re: Dandelion Seeds Fly Using ‘Impossible’ Method Never Before Seen in Nature

#75

Post by tajen »

mindfulhack wrote: post #31

It's like nature's had millions of years to crunch through its own AI / machine learning of evolution and adaptation, and we're about to unleash the same thing on an impossibly faster scale. Imagine the technological breakthroughs that are going to happen. I'm optimistic.

Well we do have more full-time researchers now than we’ve had in total since 0 B.C.

Re: Dandelion Seeds Fly Using ‘Impossible’ Method Never Before Seen in Nature

#76

Post by mdda »

nl wrote: post #70
seandavidfisher wrote: post #67

> Previous studies have found that dandelion seeds always have between 90 and 110 bristles, says Nakayama Those poor research assistants. Imagine counting hundreds of dandelion bristles every day. Probably still not possible with AI/image recognition either.

That would 100% be possible with image recognition. Segment using UNet, then measure the remaining joined pixels. (Well thanks for the downvotes. I do this as my job, so I guess I'm doing the impossible or something)

Perhaps people are wondering how your UNet is going to see the bristles on the other side of the dandelion seed.

Re: Dandelion Seeds Fly Using ‘Impossible’ Method Never Before Seen in Nature

#77

Post by jacobush »

btrettel wrote: post #41
namirez wrote: post #28

Earlier quoted context omitted.

Probably not! This phenomenon is not scale-independent. There is a parameter called the Reynolds number (Re for short) which is the ratio of intertial forces to viscous forces. For a dandelion seed Re is small which is the key to the stability of the vortex. For a parachute, the Re number is much higher which makes the dynamics of the flow chaotic (called turbulence). There is a critical Re number beyond which There…

You're most likely right, but there is at least one caveat which might be able to help if we're lucky. (I'm a fluid dynamicist, though not an aerodynamicist.) The Reynolds number is only part of the picture. You also need a measure of the strength of the turbulence. A common measure is the "turbulence intensity", which you can think of as the standard deviation of the velocity divided by the mean of the velocity. (Th…

Could it work at higher speeds, like a craft in re-entry from space? Like a dandelion pre-chute.

Re: Dandelion Seeds Fly Using ‘Impossible’ Method Never Before Seen in Nature

#80

Post by comex »

mdda wrote: post #76
nl wrote: post #70

Earlier quoted context omitted.

That would 100% be possible with image recognition. Segment using UNet, then measure the remaining joined pixels. (Well thanks for the downvotes. I do this as my job, so I guess I'm doing the impossible or something)

Perhaps people are wondering how your UNet is going to see the bristles on the other side of the dandelion seed.

Take photos from multiple angles?
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