Ask HN: What scientific phenomenon do you wish someone would explain better? • Hacker News Board

Re: Ask HN: What scientific phenomenon do you wish someone would explain better?

#311

Post by keldaris » Mon, Apr 27, 2020, 12:58 AM UTC

harimau777 wrote: post #246

I don't know if this would be my "one question" if I could ask the most brilliant minds in science, but something that always bothered me: When I took physics they basically said "at first scientists were disturbed by the fact that magnets imply that two objects are interacting without any physical contact, but then Faraday came along and said 'the magnets are actually connected by invisible magnetic field lines' and…

I'm a physicist specifically working with magnetic systems, but I have very little pre-graduate teaching experience, so take this attempt to answer the question with a grain of salt.

The reason some people regard Faraday's original explanation of the eponymous law (it is worth noting that at the time it was widely regarded as inadequate and handwavy) as illuminating is because Faraday visualized his "lines of force" as literal chains of polarized particles in a dielectric medium, thereby providing a seemingly mechanistic local explanation of the observed phenomena. Not much of this mindset survived Maxwell's theoretical program and it has very little to do with how we regard magnetism today. Instead, the unification of electricity and magnetism naturally arises from special relativity, whereas the microscopic basis of magnetism requires quantum mechanics. There isn't really any place for naive contact mechanics in the modern picture of physics, so in that sense I would regard Faraday's view as misleading.

Finally, I can't end any "explanation" of magnetism without linking the famous Feynman interview snippet [1] where he's specifically asked about magnetism. It doesn't answer your question directly, but it's worth watching all the more because of it.

[1] https://www.youtube.com/watch?v=MO0r930Sn_8

Re: Ask HN: What scientific phenomenon do you wish someone would explain better?

#312

Post by linksnapzz » Mon, Apr 27, 2020, 1:00 AM UTC

graycat wrote: post #300

ivansavz wrote: post #118

Earlier 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…

Some quite careful math for Fourier series is in Rudin, Principles of Mathematical Analysis . Fourier series applies to a function on the whole real line that is periodic , that is, repeats exactly once each some number of seconds. For the math, need only one period so in effect throw away the rest of the function and, indeed, really need the function defined only on the interval of some one period. For some intuitio…

Thank you, that's very helpful!

Re: Ask HN: What scientific phenomenon do you wish someone would explain better?

#313

Post by rockmeamedee » Mon, Apr 27, 2020, 1:02 AM UTC

Kalman filters. The explanations always start easy and then get too confusing.

Re: Ask HN: What scientific phenomenon do you wish someone would explain better?

#314

Post by vmception » Mon, Apr 27, 2020, 1:02 AM UTC

knzhou wrote: post #260

vmception wrote: post #202

Has someone that thought they were taking LSD ever turned into a permanent schizophrenic zombie or in a mental institution, or is it all urban legend. If someone that didn't know they were predisposed to mental illness, is it applicable to dismiss their experience in order to maintain how safe LSD is? If any of this is true, are there any sources aside from "my friend's friend's brother took too much and now he is...…

This entertaining article lists what happened to the early LSD researchers: https://slatestarcodex.com/2016/04/28/why-were-early-psyched...

entertaining, the comments are a good addendum but are just as speculative. maybe there just isn't good information, its just more of the contradictory information.

"lasting permanent changes, obviously"

"I’ve personally seen several people experience total amnesia after tripping on high doses." No further information.

"Not lasting permanent changes"

what.

Names, sources, medical records, news reports, court cases, there has got to be something out there!

Re: Ask HN: What scientific phenomenon do you wish someone would explain better?

#315

Post by yters » Mon, Apr 27, 2020, 1:04 AM UTC

sloaken wrote: post #259

yters wrote: post #132

A non handwavy explanation of how does evolution result in such complicated and carefully orchestrated mechanisms, way beyond our engineering capability. The computer analogy of genetic algorithms certainly doesn't explain much, they are not very effective, and if they were, we should be able to generate marvels of engineering with GAs and current computational power.

A whole LOT of time, a whole lot of space. So estimate 1 minor good random mutation per 10,000 population. Assume 1 major mutation per 1000 years, per 10,000 population.

That's essentially the same kind of explanation as 'god did it'.

Re: Ask HN: What scientific phenomenon do you wish someone would explain better?

#316

Post by JabavuAdams » Mon, Apr 27, 2020, 1:04 AM UTC

kcolford wrote: post #301

JabavuAdams wrote: post #284

Earlier quoted context omitted.

They don't. This is a pet-peeve of mine, and it's reinforced by animation after animation. Everything is being jostled around randomly. The molecules don't have brains or seeker warheads. They can't "decide" to home in on a target. The only mechanisms for guidance are: diffusion due to concentration gradients, movement of charged molecules due to electric fields, and molecules actually grabbing other molecules. It's…

Even diffusion isn't some magical force guiding chemicals through the medium. It's just random movement that statistically results in the chemical being spread out. This is the same principle that the 2nd law of thermodynamics is based upon. There's nothing magic to it, it's just the statistically likely end result over many particles.

Yes. It's interesting how powerful and clarifying this model of its-all-just-atoms-bumping-into-atoms is. It's interesting how many people take science courses, but don't really get this.

In the context of Covid19, I see so many people wearing PPE, but failing to act as though they understand that the actual goal is to prevent this tiny virion dust from entering your orifices. Like wearing gloves and a mask, but then picking up unclean item in store then using now unclean gloves to adjust mask and make it unclean.

People seem to think of things as having essences or talismanic effects. Like gloves give you +2 against covid and a mask gives you +5 when it's really all about preventing those virus things from bumping into your cell things.

Re: Ask HN: What scientific phenomenon do you wish someone would explain better?

#317

Post by JabavuAdams » Mon, Apr 27, 2020, 1:06 AM UTC

knzhou wrote: post #143

umvi wrote: post #119

I 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…

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…

Yes to getting rid of thermal noise. No ish? to single proteins flying around the cell that fast. The cytosol is incredibly jam-packed and things are getting hung up on other things so we'd expect the mean free path to actually be quite small for the larger biomolecules.

Re: Ask HN: What scientific phenomenon do you wish someone would explain better?

#318

Post by gavinray » Mon, Apr 27, 2020, 1:07 AM UTC

vmception wrote: post #307

gavinray wrote: post #295

Earlier quoted context omitted.

Permanent schizophrenic zombie, maybe a bit extreme, but severe and traumatic long-lasting psychological damage is a not-uncommon phenomena. I had a fling with psychedelics in my teens, and everything was great until the one time it wasn't. I was taking psychedelics pretty much every weekend, and by my count have tried over a dozen of them. Had an experience with LSD which completely shook me to my core and gave me s…

Did you try LSD after that time in your teens? I think it is a bit too reductive to say they're neutral, just yet, but I am willing to say they can be used responsibly if the right information actually existed - but like with any science I am open to changing that if the conclusions were found to be different. Again let's just stick with acid instead of all psychedelics.

I tried once or twice after that, both times it turned immediately into flashbacks and led to horrid experiences so I called it quits for good.

I had done it probably ~20-25 times by that point, along with a bunch of other stuff.

    LSD
    Mushrooms
    2C-B
    2C-C
    2C-I
    DMT
    4-AcO-DMT
    5-MeO-DMT
    5-MeO-MiPT
    DOM

There might be some others I've forgotten, it's been a long time.

> Again let's just stick with acid instead of all psychedelics.

What you won't find in academia or textbooks is that, at a high enough dose, all psychedelics feel the same. You reach a point where it's indistinguishable and the unique properties vanish. It's hard to describe if you don't have experience with a bunch of them, but there's this "peak psychedelic state" where they all sort of converge, which is what I only assume is the result of your serotonin receptors getting completely bombed/saturated.

Personally, I was much more of a fan of phenethylamine psychedelics (particularly the 2C series), they're more clear-headed and "light"/enjoyable. The time dilation from psychedelics makes the 12-16 hours from LSD feel like days, and by the end of it, generally the last 4-6 hours you just want to be finished with it already.

It's really difficult to make a blanket-statement like "can be used responsibly" about psychedelics, because it's a dice roll. No matter how cautious you are, there's always the possible that this time, things go sideways. Though most people (when I was in that scene as a teen) couldn't really empathize after my bad trip because they'd never had one, so it's a rare occurrence. Maybe I was psychologically predisposed, who knows.

But I do think that people stand to gain a lot from having a psychedelic experience in their life, and from having an experience taking MDMA and talking with someone they love.

Re: Ask HN: What scientific phenomenon do you wish someone would explain better?

#319

Post by JabavuAdams » Mon, Apr 27, 2020, 1:08 AM UTC

kcolford wrote: post #301

JabavuAdams wrote: post #284

Earlier quoted context omitted.

They don't. This is a pet-peeve of mine, and it's reinforced by animation after animation. Everything is being jostled around randomly. The molecules don't have brains or seeker warheads. They can't "decide" to home in on a target. The only mechanisms for guidance are: diffusion due to concentration gradients, movement of charged molecules due to electric fields, and molecules actually grabbing other molecules. It's…

Even diffusion isn't some magical force guiding chemicals through the medium. It's just random movement that statistically results in the chemical being spread out. This is the same principle that the 2nd law of thermodynamics is based upon. There's nothing magic to it, it's just the statistically likely end result over many particles.

Man, you and the other what-are-fields post just started me thinking about whether diffusion and fields are just things bumping into things. I know that at the QFT level things like the classical E-field can be expressed as interchange of mediator particles. But then QFT says it's all fields. Hmm...

Re: Ask HN: What scientific phenomenon do you wish someone would explain better?

#320

Post by garmaine » Mon, Apr 27, 2020, 1:09 AM UTC

Retric wrote: post #248

umvi wrote: post #119

I 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…

Cells are tiny and the speed of sound is how fast air molecules move. Proteins are also not bouncing around as fast but it’s very still quick relative to their size. Next, often there are multiple copies of each component. That’s half the story, larger cells also have various means to clump things together to improve the odds. https://en.wikipedia.org/wiki/Endoplasmic_reticulum PS: Speed of sound is 343 m/s, diameter…

Speed of sound in water is faster.