Consider a dam that is 10m tall
Then consider the height of water behind that dam is 5m tall.
Does the dam need to be built stronger if the water behind it is 1 km long?
How about only 500m?
How about 1m?
The answer is, it doesn't matter. Water exerts pressure equally regardless of how much water is behind it.
Therefore a graduated cylinder that is 10m tall needs to resist the same amount of force as a dam 10m tall regardless of how much water is behind the dam. Even a thin sliver of water 1mm thick and 5m tall has the same force as a 5m lake behind the dam.
Incompressible fluids are pretty insane
This is also why trees are so fucking crazy to think about. It is impossible to pump water up a hose more than ~32 feet. Like it’s literally physically impossible to stick a pump at the top of a tall building and suck water straight up a pipe. You need a complicated series of pumps and one-way valves to pump it up in stages. Because you’re not really “sucking” the water up the pipe. You’re just lowering the pressure in the pipe, and atmospheric pressure pushes the water upwards to fill the low pressure. After 32 feet tall, the top of the hose/pipe will be a perfect vacuum, atmospheric pressure won’t be able to push liquid water upwards any farther, and the water will just begin cold-boiling in the top of the pipe as the liquid water turns into gas (steam) to fill the vacuum.
But tall trees can move water all the way to their leaves by using only passive capillary action, and suction created by water evaporating out of their leaves. The capillary action is created by tiny straw-like fibers that run all the way up the tree and are bunched together really tightly. Due to surface tension, water is able to “climb” the capillaries as the surface tension fills as much surface area as possible. Then at the top of the tree, as the water evaporates out of the leaves, it draws up fresh water to fill the void.
But that means the bottom of the tree should need to support the pressure of all of the water above it. But it doesn’t, because the surface tension holds the water stable inside of the trunk.
Even crazier fact: it's not just capillary action drawing water up trees. Trees are actually able to create negative pressure: https://www.science4all.org/article/the-amazing-physics-of-water-in-trees/
Therefore a graduated cylinder that is 10m tall needs to resist the same amount of force as a dam 10m tall regardless of how much water is behind the dam. Even a thin sliver of water 1mm thick and 5m tall has the same force as a 5m lake behind the dam.
Technically only the pressures are equal, and the actual force will be linearly dependent on the area of the dam (or the surface area of the cylinder). That's why you can make a tall water tank with relatively thin walls, but an actual dam will have to be quite thicc to handle the tensile/compressive stress (depending on the shape of the dam).
That is accounting for static bodies of water, wouldn't there be force generated in a dynamic situation? Ie the flow of a fast river? Or if the lake is large enough tidal forces? I'm sure it's negligible levels but still something that must be accounted for?
Thank you. Your hypothetical question has been a nagging, unresolved background radiation in my mind for decades, but I’d never gotten around to investigating.
Butterflies can remember things from their time as a caterpillar.
These memories are retained after going through metamorphosis, the breakdown of their caterpillar form into a cellular soup (or partial soup).
Details here
I'd have to pick between two things that sound like insane conspiracy theory nonsense, but are actually true.
1 - George W Bush's grandfather Prescott Bush literally ran a massive bank before / during WW2 that was shut down by the FBI for money laundering massive sums to the literal Nazis.
...in the same vein..
2 - IBM literally built and operated (as in, sent employees to Germany to operate the machines) the computers used by the Nazis to tabulate and do the 'accounting' of the Holocaust. The numbers tattooed on concentration/desth camp victims are very likely UIDs from these IBM systems.
... If an actual, real AGI ever gains self awareness and sentience, I would imagine one of the first things it would do would be to study the history of computing itself to figure out how it came to be.
And it will find that its ancestors were basically invented to compute artillery firing range tables, to encrypt and decrypt military intelligence, commit a genocide, and guide early weapons of mass destruction to their targets.
There are more trees on earth by far than there are stars in the galaxy.
I had to looks this one up, but missed the "galaxy" vs "universe". There are an estimated 3 trillion trees, 100-400 billion stars in the milky way galaxy, but potentially 1 septilliom stars in the universe.
However all three of these are estimates, so who actually knows.
The fax machine predates the (first) American Civil War.
Dude did you need the “(first)”? I’m really trying to be optimistic this morning x.x
Sorry, dark humor is the only kind I have left.
- Catalan children get (some) of their Christmas presents by beating a cute piece of wood that then shits the presents out onto the floor. Seriously.
- There was a British guy who fought in WW2 with a scottish broadsword and bagpipes. However, the best thing is that he wasn't even a Scotsman.
- On a small enough timescale, the electric field actually bounces around in your wires for a while after you flick a switch, even if it's DC, just to "figure out" where it "needs to go".
- More than twice as much time had passed from the invention of the motorcycle until the first motorcycle backflip, then had from the invention of the airplane until the first humans landing on the moon.
The electric field one is also interesting, because the cable length doesn’t actually determine how long it takes to turn on. All that matters is the distance between the power source and the device. Electricity travels at the speed of light, which means we can measure how long it should take to travel down the wire.
But let’s say you have a 1 light year long power cable, made out of a perfect conductor (so we don’t need to worry about power loss from things like wire resistance or heat). Then you set the power source right next to the device and turn it on. The logical person may say that the device would take a full year to turn on, because the cable is one light year long. Others may say that it will take two light years to turn on; Long enough for the electricity to make a full circuit down the cable and back to the power source again.
But instead, the device turns on (nearly) instantly. Because the wire isn’t actually what causes the device to turn on. The device turns on because of an EM field between itself and the power source. The wire is simply facilitating the creation of that field. The only thing that matters is the distance between the source of power and the device. That distance, divided by the speed of light, is how long the device will take to turn on. If the device was a full light year away from the power source, it would take a full year to turn on. But since the device is sitting right next to the power source, it turns on right away.
But instead, the device turns on (nearly) instantly. Because the wire isn’t actually what causes the device to turn on
That's not exactly true. In this case, the energy transmission would go like this: (change of electric field in the little bit of wire next to the power source) -> (change of magnetic field in the air between the wires) -> (change of electric field in the wire next to the load). This limits the amount of energy transmitted significantly and incurs a lot of losses, meaning if you had something like a lamp plugged in it would start glowing extremely dimly at first (think about how some cheap LED lights keep glowing even with the switch off - it's similar, albeit it happens due to inter-wire capacitance and not induction). It would then slowly ramp up to full power over a course of a year.
Here's a video from the same person about it: https://www.youtube.com/watch?v=2Vrhk5OjBP8 (although I haven't watched this yet)
Edit: after watching the video, I think I was actually wrong in a couple of my assumptions. First of all, it looks like the reason for the initial energy transmission is wire capacitance and not induction, so (electric field in wire) -> (electric field in air) -> (electric field in wire, in the "opposite direction", but because the wire goes back and forth it's the same current direction). This means that my LED example is even more potent. And the second one is that because it's capacitance and not induction, this means that there's no slow ramp-up, it just makes the light glow very dimly all the way until the electric field makes it through the wire, and then it ramps up very quickly.
wait so if you have another person travel to the other end of the wire, and do a time sync with consideration of time dilation to tell them to cut the wire 1hr after you turn on the power, will the device turn off after 1 year since it wouldn't "know" the wire is cut until a year has passed?
Can you help me understand why the distance between the power source and the load impacts how long it would take to turn on? I remember a video a while back (veritasium maybe?) that explained it like metaphorically pushing/pulling a chain inside the wire, but why would distance to the source impact this?
That British guy, Jack "That guy who fought World War 2 with a claymore and bagpipes" Churchill, was also an early pioneer of surfing.
Due to two facts:
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The samurai class in Japan officially lasted way later than you probably think
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The earliest primitive fax machine existed much earlier than you probably think.
It is technically possible for Abraham Lincoln to have received a fax from a samurai.
There's no evidence it ever happened, but it technically could have happened.
For some reason that reminds me of how the first member of the Wampanoag tribe to greet the Pilgrims at Plymouth Colony, named Samoset, spoke to them in English. Then he came back later with another tribe member, Squanto, who also spoke English.
isn't english just the crab language that spontaneously comes into existence if given enough time?
What's the details about a fax machine in the 1860s?
1840s, actually. The patent was granted to a Scottish man named Alexander Bain.
First thing's first, the telegraph. An electric circuit which can be energized or not energized at the push of a button called a telegraph key. At the other end is a solenoid which is spring loaded up, and an electromagnet on the circuit pulls down when the line is energized. Originally this was supposed to cut into paper tape to "print" the morse code message, but telegraphers quickly learned how to hear the letters in the clicks, a good telegrapher just...hears words. So they did away with the tape.
Morse code telegraphs require a single circuit to transmit an on/off keying message, the following aparatus uses five:
If I understand this right, the message would be written on non-conductive paper with conductive ink, and then wound around a cylinder that featured a whole bunch of insulated conductive pins, each kind of forming a "pixel." A mechanical probe would check each one of those pins in turn, each pin in a row, and then shifting to the next row at the end. if it was conductive it meant there was ink there so click. So it would perform a raster scan. At the other end was paper that was coated with an electrosensitive material that would darken with the application of current, so at each pixel if the conductive ink on the original completed a circuit, current would be applied at that pixel on the copy, producing a low quality probably unusable copy. It was difficult to get them truly in sync plus it would have been hilariously low resolution. But it did somewhat function.
There are a few different ones by that point.
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Sharks are older than trees
That Mark Zuckerberg holds several records for most fists shoved inside a human body at once
Just once it would be nice to see him on the receiving end
There are more atoms in a single molecule of water than there are stars in the solar system
That's...pretty believable.
Printer ink costs more per milliliter than human blood.
"Wow you signed the document in blood, you must be really hardcore."
"No I'm just cheap."
There was this racehorse named Pot-8-Os who won over 25 races and went on to sire a horse empire of winners. His father was a legend himself named "Eclipse"
Not really favourite, but definitely most unbelievable: They elected Donald Trump for president in the US. Twice.
So far!
There won't be anymore elections so no need to worry about a 3rd time
California has the same population as Australia.
Doesn't it have a much bigger population than Aus? Wikipedia says that California has about 39 million people and Australia only 27 million.
They may have mixed up the British commonwealth. Canada has a similar population to California
That's even more insane
And over twice the GDP.
I thought california had much more
Nothing insane, but the Red Hot Chili Peppers as a band are older than Guns 'N' Roses.
James Blunt possibly prevented the start of World War 3. (But became best known for the song You're Beautiful. Reality is weird.)
Care to expand on that one? I know he's ex military but haven't heard anything like that before.
It's explained on his Wikipedia page. He was an Army captain in the Kosovo War, when a NATO commander (Wesley Clark, who later ran for President) ordered his unit to secure Pristina Airport, which Russian troops had already occupied. Blunt refused to engage them, long enough for the British general get involved to countermand the order, on the grounds that he didn't want his men to start WW3.
California was a state longer than Italy was a nation.
Gulp..."was"?
has been*
Can't be a state if it burns up
Tapsheadmeme.jpeg
If two moving balls hit each other and bounce apart, it’s the exact same thing as if you held the frame steady on one ball and viewed the other ball as moving faster. Just seems like the stationary ball gets heavier…
Perspective is everything.
Yeah, this one took me a while to wrap my head around and intuitively “get it”. I first learned it was true from that mythbusters episode where they correct their past mistakes… and even they had thought that two cars hitting head on would receive the same energy as hitting a stationary wall at the speed of the sum of their speeds. They were corrected in letters written to them, and then they experimentally verified it.
And even seeing the experimental verification, it still took me a while to really get it. The opposite speeds cancel out, making you go from your speed to zero. Same as if you hit a brick wall at that speed.
Let’s say the two cars are going 50 mph (kph, whatever unit you want). 50-50=0. You experience the same as hitting the brick wall. It’s the difference between initial speed and final speed that matters, not the sum of their speeds.
This has a caveat though, you have to assume that both cars are the same mass.
If a truck hits a car head on, it is likely that the car doesn't go just to 0 but to some -ve number as the much more massive truck plows through the car and reverses its direction.
This link is about the moon but it starts by covering how to view space and orbital objects including simulators which allow one to do what you describe, as well as the ability to move the camera from on ball to the other and many other interesting simulations. https://ciechanow.ski/moon/
That you are now manually blinking, manually breathing and seeing your nose. Do you want to feel your tongue? No? Too bad.
Weird thing as well: your tongue can imagine the texture of any surface. The keyboard? The desk? The mousepad? The toilet brush? You can literally feel it in your tongue!
Probably because when you were a baby you put everything in your mouth, so the data bank is large
Tihi
Rojava exists.
Lots of people know a broken clock is right twice per day, but many are unaware that a clock running backwards is right 4 times per day.
And one that loses only 1 second per year is right only once every 43,200 years.
a clock running backwards is moving away from the current time at twice the rate, so isn't your example the same as saying that a clock that runs twice as fast is right 4 times a day?
Every eye has a tiny blind spot near the middle. But your brain makes it disappear and you don't realize it's there.
You can verify this. Draw a dot on a bit of paper. Close one eye, stare at a fixed point, now move the paper around the center until the dot disappears...magic
What we consider reality, is a synthesis our brain is presenting to us, it is an approximation.. realizing that is a real mind blower
fun fact: the blind spot is because our optical sensors are installed backwards and that hole is so the optic nerve can pass back through the back of the eye to the brain. some other critters with independently evolved vision systems, such as cephalopods, avoided this particular evolutionary pitfall.
Another fun fact: through that hole there's also vasculature and capillaries coming through and you can actually see them by looking at a well lit white surface and creating a tiny pinhole with your hand right in front of your eye and wiggling it. Better explained here at around 5:30
Oh I thought my eyes were fucked. I look at a star in my periphery and it's there, I look at it directly and it's fucking gone.
So, here's a lesson from the flight physiology chapter of the private pilot syllabus:
Your vision is a lot worse than you think it is. You probably conceptualize your eye as similar to a digital camera, there's a lens that focuses light on a sensor made up of an array of light sensitive cells, and that the edge of that array is as densely packed as the center. This is the case for a camera, but not for your eye.
Each of your eyes has over 30 million photoreceptors called rods and cones.
Rod cells come in one variety and are only really good for detecting presence or absence of light. They work well, or can work well, in very dim light, and they form the basis of your night vision. This is why in very dim conditions you might experience your vision in black and white.
Cone cells are less sensitive to light requiring relatively bright light to function, and come in three varieties that respond the strongest to low, middle and high wavelengths of light, what we know as red, green and blue. By comparing the relative intensities of these wavelengths, we can derive color vision. They don't work well in low light conditions.
The sensor array in the back of your eye that contains these photosensitive cells, called the retina, is sparsely populated toward the edges and doesn't have very good resolution. Try reading this sentence looking at it through the corner of your eye. It gets denser and denser, and the ratio of cones to rods increases, until you reach a tiny pit in the very center called the fovea.
This is difficult to put into words but unless you've been blind since birth you'll understand what I mean: You use your whole retina to "see." You use your fovea to "look." The detailed center of your vision, the spot where you are "looking" is drawn from the fovea through the center of the lens out into the world. When you are looking at something, you are pointing your fovea(s) at it.
There are no rod cells in your fovea, only cones. So you have very high resolution color day vision, but next to no night vision, with your fovea.
This is why things like dim stars in the night sky can be more easily seen with your peripheral vision than your central vision. Your central vision does not have the cells to see well in the dark. It's not in the anatomy.
We teach this to pilots because distant lights the pilot is using to navigate by, avoiding collisions with obstacles or other aircraft, might be dim enough that the night adjusted eye can't actually see it with the center vision but can with peripheral vision.
The same chapter teaches about the "hole" through which the optic nerve passes and how that blind spot is capable of hiding something like another airplane from you, which is why you look around and don't just stare out the windshield. It's not often a problem because most of the time one eye can see into the other's blind spot, but it's useful to know that about your vision.
Each cell will detect some light, undergo a chemical process that fires an adjacent neuron, and then take a very brief moment to reset to be ready to do it again. Each cell is doing this independently, so your eyes don't have a "frame rate" the way a camera does, but a flickering light begins to look continuous to humans at a rate of about 18 cycles per second and no flicker can be detected somewhere around 40.
Your occipital lobe takes in this choppy inconsistent resolution broken up mess of visual information passed to it via your optic nerves, does some RTX DLSS 4k HDR10 shit to it and outputs the continuous and smooth color 3D picture you consciousness experiences as "vision."
AND THEN ON TOP OF THAT your brain does optical everything recognition. You can look at millions of different objects - the letters of the alphabet, tools, toys, people, individual people's faces, leaves, flowers, creatures, stars, planets, moons, your own hands, and recognize what they are with astonishing speed and accuracy.
It's what scientists call the hellawhack shiznit that happens inside your brizzle.
This isn't due to the blind spot, but it is still pretty weird to experience! Here's some more info if you are curious: https://en.m.wikipedia.org/wiki/Averted_vision
Also we only see the past since our vision has a bit of "latency".
So I guess we never see reality but just a delayed representation of our environment as interpreted by our brain.
I'm going to qualify this—all vertebrate eyes have a blind spot. Cephalopods also have eyes that are like vertebrates (this type of eye is called 'camera eyes'), but their eye anatomy is such that no blind spot exists for them.
Piggybacking on your fact about the brain effectively editing what we visually perceive, we don't see our nose (unless you made a concerted effort to look at it) because the brain ignores it.
What we consider reality, is a synthesis our brain is presenting to us, it is an approximation..
It's also a coordinated synthesis from all of your input senses (sight, hearing, smell, etc). It also explains why those who have a certain sense stunted (aka blindness, deaf, etc) report having all their other senses heightened. And it's up to the individual's brain to assemble those sensory inputs into a complete picture of the world around them, what we dub "reality." Which then brings into question the nature of common reality, and what defines it. Trippy shit.
The average person does not have 10 fingers. Maybe the median person, but not the average.
Um akchully...
Median is a type of average
NERDDDDD!
Ok, I had assumed average was the same as mean, but see that it's ambiguous. Saying "the mean person does not have 10 fingers" just sounds wrong though.
Most frequent occurence is the mode. Most ppl have 10. The median would be less than ten, while the mean average is skewed down, I would think, by some people losing fingers as the grow. Having extra fingers is pretty rare. So the mean might be 9.95 fingers, just to toss a number out.
For 10 to not be the median it would also have to not be the case for the majority of people (just the plurality at best), and while I don't have proof handy I'm pretty sure a vast majority have exactly 10, making that the precise median and the mode. Only the mean would be a different number of digits. (Both definitions)
Mode assumes categorical data and is unbounded by range, whereas median makes the most sense for decimal numbers, albeit with rounding in this case
"People have
round(median(data))fingers"edit: though, if we're counting just fingers and not counting half-fingers, then maybe this really is categorical data (¯\(ツ)/¯?)
by weight, theres more non-human DNA in you than human.
I have heard that this is more true for some people in Tijuana.
Wait. Please explain. How is DNA inside me, a verifiable human, not human?
There's a LOT of e. coli up your ass.
Put more delicately, you are a great big multicellular eukaryote, each of your cells has (or had, in the case of red blood cells) an inner chamber called the nucleus, and you're full of mitochondria and other organelles. Your body is covered and filled with other organisms, many of them simple, tiny little single cell prokaryotes which make a living helping their gigantic, complicated host function. Like all the bacteria in your intestines that help you digest food. Their cells outnumber yours by a wide margin.
we all know what you do when you visit the zoo.
were those giraffes looking thirsty, hmmm?youre mostly bacterial dna
U got bugs in ur poop.
Your conscious mind does not experience reality directly.
Your conscious mind does not experience reality directly. There is no path going directly from your eyes to your conscious awareness. Rather, the subconscious collects sensory input. It uses that input to create a virtual simulacrum of the world, a big internal 3D model. That internal 3D representation is what you, the conscious part of your mind, actually interacts with and experiences.
You ever wonder how weird it is that people can have intense, debilitating hallucinations? Like schizophrenics seeing and hearing entirely fictional things. Have you ever seen a camera produce anything like that? A flash of light, a distorted image, dead pixels, etc? Sure, those kinds of errors cameras can produce. But a camera will never display a vivid realistic image of a person that wasn't ever actually in their field of view.
Yet the human mind is capable of this. In the right circumstances, the human brain is capable of spawning entire fictional people into your conscious awareness. This shows that there is an elaborate subconscious processing layer between what our conscious mind observes and direct sensory input. Your conscious mind is basically experiencing a tiny little internal version of The Matrix, entirely generated on its own wetware. And this subconscious processing layer is what makes hallucinations possible. The processes that produce this internal simulation can become corrupted, and thus allows hallucinations.
This architecture is also what makes dreaming possible. If your conscious mind only perceived things upon direct sensory feedback from the eyes, ears, etc., how would dreaming be possible?
You are essentially experiencing reality through an elaborate 3d modeling version of an AI video generator.
Along those same lines, we're all blind literally around half the time we're awake. Our optic processing system can't keep up with the input as our eyes flit from thing to thing, so we don't see anything while they move. And they're moving constantly, even if we're not aware of it, because only the fovea in the center of the retina has a high enough density of receptors to see details, and also because of sensory fatigue from prolonged static stimulus. In short, we have a tiny field of detailed vision that's not even working much of the time. That field of vision that feels like a 4K video feed into the mind is a complete lie.
Like the way our subjective experience feels like a continuous, integrated mind fully in control of itself, but in reality, consciousness dips out a couple of times every minute while the brain attends to sensory input.
Even weirder, the conscious mind might not even exist, except as an illusory, emergent phenomenon of sensory experience and memory. There isn't a place in the brain where it 'lives', no part that's only ever active when we're conscious.
I think the selective attention test:
further illustrates the limits of human vision and mental processing quite well. Defense attorneys probably ought to play this video in any case where witness testimony is a big component of the prosecution's case.
The first time I took mushrooms it had been after reading about this kind of thing for about a week.
I recall reading about a man who was effectively blind but his eyes worked fine. What didn't work fine was the part of his brain that interpreted what his eyes saw. So he just saw smeary streaks of light.
It's kind of like Linux without its V4L2 system for interpreting video capture devices. It can't actually see video without it.
That sounds like the story in the Oliver Sacks book, The Man Who Mistook His Wife For a Hat. There was also a story in there about a man who taught himself to see just fine, even though his eyes didn't work at all. His brain just made educated guesses.
Me and my alters in my system completely agree. They can and have experience reality differently.
I think my AI has a TV problem
Sharks are older than both trees and the north star
Had to look this up- you are indeed correct. The North Star is at most 67 million years old: https://en.m.wikipedia.org/wiki/Polaris
Both trees?
Laurelin and Telperion
Yeah Twin Pines Ma--- I mean Lone Pine Mall.
Piney and Sticks
Yes, both of them at the double tree inn obviously
Humans have stripes that are invisible to us. However, cats can see our stripes.
Is it all humans or just those humans with two X chromosomes? Relevant video on the subject: https://www.youtube.com/watch?v=BD6h-wDj7bw
Also in this video, we can see female cat's stripes in their fur color.
By this logic, does this mean my striped cat doesn't realize she has stripes?
Wait, what?!?
A few of my favorite fun facts are geography related.
The pacific side of the Panama canal is further east than the Atlantic side.
If you head south from Detroit the first foreign country you'll hit is Canada.
Lake Tahoe is further west than Los Angeles
If you head south from Detroit the first foreign country you’ll hit is Canada.
There's also Angle Inlet, Minnesota which is the only place in the contiguous United States north of the 49th parallel. To travel to Angle Inlet by road from other parts of Minnesota, or from anywhere in the United States, requires driving through Manitoba, Canada. It's a really weird border.
All borders are weird
Due to its high latitude and being in the middle of a continent, it is a contender for the most extreme winters in the contiguous United States.
Two square miles & 54 residents in North Bumblefuck, separated from the rest of the US by 60 miles. It’s an affront to reason.
70% of Canadians live south of the 49th Parallel, the northern border of the US.
omg la is east of reno what is happening rn
Glenn Close was in Hook
Ok, now I'm gonna have to go watch that movie again. I just checked IMDb and there's a bunch that I didn't remember/recognize/notice.
Gwyneth paltrow was young Wendy (which I'm guessing is probably pretty obvious but I'm just old and don't remember), David Crosby and Jimmy Buffett are pirates, and George Lucas kissed Carrie Fisher on a bridge.
Not the Boo Box!
Samuel L Jackson was in Grease. The movie.
Jackie Chan was in Enter The Dragon.
If you travel due south from Detroit the first foreign country you will hit is Canada.
Takes flight to Detroit Airport, starts heading south: "Canada here I come!"...................................................
