Gauge theory.
Ask HN: What scientific phenomenon do you wish someone would explain better?
221–230 of 839 posts
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#222Genetics. I still have no intuition for how combining my wife’s and my DNA has resulted in children with traits from both of us. My brain always tries to imagine interleaving two binaries and hoping for a resulting program that works a bit like the two sources, which it of course wouldn’t.
I mean that's close, but not compiled binaries, just merged in very similar source code in a pull request, where sometimes an && is added to a conditional statement to express a gene that had skipped a generation.
Both sexes have haploid gametes, which form a zygote when combined. I think this can steer your research when you look into what gametes contain and chromosome combination.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#223Can anyone explain disc loading and solidity in a propeller and if there are any equations governing them?
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#224Genetics. I still have no intuition for how combining my wife’s and my DNA has resulted in children with traits from both of us. My brain always tries to imagine interleaving two binaries and hoping for a resulting program that works a bit like the two sources, which it of course wouldn’t.
Don't think if it as a monolith. It's more like thousands of microservices and thousands of different binaries all interacting in a whole bunch of different and convoluted ways. Sexual reproduction is jumbling together two different people's thousands of microservices and seeing what happens. Or, each program is relying one library, imagine just randomly mixing around different libraries. Genes and proteins are discrete parts that can be swapped out and in.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#225Earlier quoted context omitted.
The best way to understand the Fourier transformations is to think of them as change-of-basis operations, like we do in linear algebra. Specifically a change from the "time basis" (normal functions) to the "frequency basis" (consisting of a family of orthonormal functions). Here is the chapter on Fourier transforms from my linear algebra book that goes into more details: https://minireference.com/static/excerpts/four…
> As for the math, there really is no other way to convince yourself that sin(x) and sin(2x) are orthogonal with respect to the product int(f,g,[0,2pi]) other than to try it out https://live.sympy.org/?evaluate=integrate(%20sin(x)*sin(2*x... . Try also with sin(3x) etc. and cos(n*x) etc. I disagree with that. It's pretty easy to prove it in general by calculating \int_0^{2\pi} sin(mx)sin(nx) dx etc. for m ≠ n.
I would count an analytic solution as in the "trying out" category (actually the best kind of trying out!).
The "no other way..." was referring to me not having an intuitive explanation to offer about why an sin(x) and sin(2x) are orthogonal.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#226Earlier 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.
Flat wings can fly. E.g. kites.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#227Earlier quoted context omitted.
>The top of a wing is curved, making it longer than the bottom of the wing. This means that air takes longer to go over it, meaning it has to spread out further to go the same distance as the air under the wing. As a result, the air going over the top of the wing is less dense, (aka lower pressure). The wing tries to equalize the pressure by moving in the direction of the low pressure, which is Up. We call this Lift.…
For years I thought I was crazy or stupid, whenever I heard this story of "air has to go faster" I was like "but how does air know?? It's not like it has a Google maps plan telling it it needs to reach the other end of the wing at a precise time!" By chance, in the last few years I've started reading more and more comments debunking this absurd explanation. Not that I understand perfectly now, but at least I know I'm…
In fact that "air has to go faster" silliness only works if you completely neglect air friction entirely, because then the air can be said to part around the wing like butter around a hot knife.
But of course anyone who's seen snow billowing off the back of a car knows that air doesn't just close up behind the object like a ziplock bag: it's messy and turbulent and gets all over your windows while you're tailgating.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#228Earlier quoted context omitted.
The issue with these animations is that they're getting rid of all the thermal noise. In reality, single proteins are flying around the whole length of the cell many times a second, just from their thermal motion. And when processes like DNA transcription happen, they're not like a regular conveyor belt -- a fraction of the time the machine will even accidentally run steps in reverse ! However, if any of this were sh…
just once i would like to see the realistic animation though even if it's impossible to understand
It would be pretty boring, proteins bouncing around randomly and occasionally honking up, substrates flying around like rifle bullets sometimes hitting the target, and everything smooshing around in random directions. If you’ve seen Brownian motion, you’ve seen what is happening to all the molecules but at 1/100 the length scale. Nothing stays put. Everything is moving fast and far on the scale of proteins and small molecules.
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#229Why are clouds flat on the bottom?
Re: Ask HN: What scientific phenomenon do you wish someone would explain better?
#230Why are clouds flat on the bottom?
Same reason a loaf of bread is. Clouds rest on the "surface" of the higher-density air below them, and flatten on the bottom because of their own weight.