Fourier Transforms. I'd wish I had a intuitive understanding of how they work. Until then I'm stuck with just believing that the magic works out.
It's magic. But here's a fun interactive explanation: http://www.jezzamon.com/fourier/
Ask HN: What scientific phenomenon do you wish someone would explain better?
161–170 of 839 posts
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#162What happens when you actually fall inside a black hole and what is the singularity. I never really understood what happened really when the guy fell inside it in Interstellar and how come he started seeing all those photos. I just accepted it as Hollywood bs. I know my question is based on a movie but would still like to know what will someone witness (assuming of course they somehow live)
Singularity in AI?
No they kept saying that the center of it is called singularity IIRC.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#163Earlier quoted context omitted.
It directs air moving horizontally downwards, by conservation of momentum the wing must get additional upwards momentum, called lift.
That can't be the explanation, otherwise wings wouldn't need to be curved - flat wings could fly, as long as they're tilted to redirect the air.
Paper airplanes fly, and they have flat wings!
It turns out that flat wings work just fine, but the airfoil shape we see on airplanes is more efficient:
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#164Why does time slow down/go faster with movement compared to another object. The well known example that if you travel into space you'd gain let's say 5 years and people on earth 25 in the same time or so. I just don't get it and I can't find any logic explanation. For instance: Two twins who came to live exactly at the same moment in the year 2000 and both die on their 75th birthday at the same time. One travels into…
All things in the universe have four measures of velocity. Three of these are easily observable to us in terms of x, y, and z movement. To understand time dilution we need to realize that we are also physically traveling through time.
The total velocity of our vector will always be equal to the speed of light constant, c. You can think of something that has no physical movements as moving forward in time at the speed of light. As x, y, or z increases the magnitude of t will decrease so that the speed of light constant is always achieved.
Why this link has to hold is more complex and I cannot explain it well, but hopefully this gives some insight into time slowing as velocity increases.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#165I've always had trouble following Searle's Chinese Room argument as it applies to the nature and identification of intelligent action. I've never understood how the Chinese Room shows what its adherents say it shows, so that would be one topic I'd like to see more perspectives on.
"Searle understands nothing of Chinese, and yet, by following the program for manipulating symbols and numerals just as a computer does, he sends appropriate strings of Chinese characters back out under the door, and this leads those outside to mistakenly suppose there is a Chinese speaker in the room. "
I have trouble with this too. I think it's actually incorrect, or at least misleading. I think what it's _trying_ to say is that even if an entity can perform a complex task doesn't mean it can understand a complex task.
I think the more important result of this argument is that certain complex tasks can be "pre-baked" into rulesets _by an existing intelligence_. To me this just means that intelligent entities can sort of copy parts of their intelligence into other entities which are not intelligent i.e. computer programming.
I think with this argument they're trying to say "a series of sufficiently complex if statements isn't necessarily intelligent" by choosing something we know computers are good at - string manipulations and applying it to something we consider intelligence - language translation.
The argument holds that the computer is obviously not intelligent because it's just a function that takes a character and outputs another character.
But it needs to be a convincing translation, right? The computer would then be able to spit out not just accurate translations but also properly converted cultural idioms and new combinations of words where one didn't exist in the other language. That requires context of surrounding characters, memory of common language use, statistical analysis and creativity.
One implication that arises from this argument is actually about humans. How do we know that we aren't all just incredibly detailed rulesets ourselves without any actual understanding?
Well, first off - we technically can't prove it for anyone other than ourselves. More pragmatically, it's obvious that we, unlike the computer translator, can probe ourselves and be probed by others on whether or not we understand the subject. It's not like we're a bunch of Boltzmann's Brains that just happened into existence. We evolved intelligence in order to survive, not to "trick" other intelligent beings into thinking we're more intelligent than we are. There's no need for that. There's no one smarter around that we need to "trick".
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#166Fourier Transforms. I'd wish I had a intuitive understanding of how they work. Until then I'm stuck with just believing that the magic works out.
This really depends on the level of math you're expecting for your intuition, but for me it really clicked when I understood it in terms of linear algebra. A function is like a vector, but instead of having two or three dimensions you have a continuous number of them. Adding functions component-wise works just like adding vectors. Just like regular vectors, you can choose to represent functions in a different basis.…
What's the difference between the coefficients of the furier basis and the weights of a neural network ? Both are ways to approximates functions, aren't they?
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#167Quantum entanglement. How do they know it's happening?
The Quantum Computing for Computer Scientists video by Microsoft Research (https://www.youtube.com/watch?v=F_Riqjdh2oM) really hammered it home for me. It goes slowly and the presenter, in his own words "shuts up and does the math".
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#1681. Carbon dating. Sure, I get that carbon decays over time and this changes the proportion of isotopes. But why does this give you any information? That carbon didn’t come into existence just to be in that bone, it was made in the sun billions of years before that, so why does the age of the carbon tell us anything about organic matter? The key fact, which I think is not emphasized enough, is that the ratio of isotopes in atmospheric carbon is kept at a constant equilibrium by cosmic rays. So you can use carbon dating to tell roughly when the carbon was pulled out of the atmosphere. Without this additional fact, the concept of carbon dating makes absolutely no sense.
2. The tides. The explanation I was given is roughly something like “the tides happen because the moon’s gravity pulls the water toward it, so you have high tide facing the moon. There’s also a high tide on the opposite side of the earth, for subtle reasons that are too complicated for you to understand right now and I don’t have time to get into that.”
The first problem with this explanation is this: gravitational acceleration affects everything equally right? So it’s not just pulling on the water, it’s also pulling on the earth. So why does the water pull away from the earth? Shouldn’t everything be accelerating at the same rate and staying in the same relative positions?
The second problem is that, when viewed correctly, the explanation for why there is a high tide on the opposite side of the earth as the moon is equally simple to why there is a high tide on the same side as the moon.
The resolution to both these problem is this: tides aren’t actually caused by the pull of the moon’s gravity per se, but are actually caused by the difference in the strength of the pull of the moon’s gravity between near and far sides of the earth, since the strength of the moon’s gravitational pull decreases with distance from the moon. The pull on the near water is stronger than the average pull on the earth, which again is stronger than the pull on the far water. So everything becomes stretched out along the earth-moon axis.
3. This one isn’t so much a problem with the explanation itself, more about how it’s framed. I remember hearing about why the sky is blue, and wondering, “ok, more blue light bounces off it than other colours. But isn’t that essentially the same reason why any other blue thing is blue? Why are we making such a big fuss about the sky in particular? ” A much superior motivating question is “why is the sky blue during midday, but red at sunrise / sunset”? I was relieved when I saw this XKCD that I’m not the only one who felt this way:
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#169Earlier quoted context omitted.
Annoyingly I've always struggled with the precise definition of spin, but to my understanding angular momentum is only conserved if you take spin into account as well. Being quantum mechanical there is some ambiguity in the direction, but in principle it is a vector (except it's a superposition of several vectors, and this superposition is also equal to superpositions of different vectors, I think there is usually on…
> angular momentum is only conserved if you take spin into account as well. Do you know an example of a process that moves angular momentum from one kind of spin to the other?
Thinking of it as different 'kinds' of spins isn't quite right.
It's more akin to the direction or axis of the spin being changed, and simply measuring the spin along a certain access will change it: https://en.wikipedia.org/wiki/Spin_(physics)#Measurement_of_...
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#170I would like to understand how cellular biology processes actually work. Like, how do all the right modules and proteins line up in the right orientation every time? Every time I watch animations, it seems like the proteins and such just magically appear when needed and disappear when not needed [0]. Sometimes it's an ultra-complex looking protein and it just magically flys over to the DNA, attaches to the correct sp…
Any time something "magically lines up", it means that those molecules randomly float around until the right ones bump into each other.
Once they are in close enough proximity to bump into each other, intermolecular forces can come into play to get the "docking process" done.
For something like transcription, once they are "docked", think of it like a molecular machine - the process by which the polymerase moves down the strands is non-random.
There are also several ways to move things around in a more coordinated fashion. Often you have gradients of ion concentration, and molecules that want to move a certain direction within that gradient. You also have microtubules and molecular machinery that moves along them to ferry things to where they need to be. You can also just ensure a high concentration of some molecule in a specific place by building it there.