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

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

#651

Post by zorked »

dmichulke wrote: post #648
rsp1984 wrote: post #603

Macroeconomics. Central banks are "creating" a trillion here, a trillion there, like nobody's business. But what are the consequences? What is the thought process that central bankers have gone through to make these decisions? Also why, exactly, are they buying the exact assets that they are buying (govt. debt, high-yield bonds, etc..) and why not others (e.g. stocks or put money into startups)? And then, what happen…

One approach is reductio ad absurdum: If Central Banks can create money without negative effects, then - why tax people? - why even work? Can't we just print enough money for everyone and live happily ever after? I realize these questions are quite provocative and their answering only explains if it will work but not how or when it will fail.

It's possible that they can create money up to a point with positive effects and beyond that point the effects are negative.

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

#652

Post by inopinatus »

CamperBob2 wrote: post #593
inopinatus wrote: post #528

Earlier quoted context omitted.

That is indeed one of the authoritative explanations, and in a few seconds of ad-hoc search we may find at least two refutations from authoritative sources. For example, gyroscopic-forces-as-stabiliser don't need the Schwab paper's "ton of math" to be undermined. A simple counter-rotating wheel was used empirically at Cambridge to show as much, alongside notes that gyroscopic forces are relevant to the dynamics of a…

Sorry, I don't buy anything beyond what I stated. Those papers are exercises in violating Occam's Razor. Your quantum model makes more sense. :) When you learn to ride a bike, you're simply training the feedback mechanism. Much like a PID controller, your brain has to keep track of the amount of error and null it out with proportional and integral terms (at least). Once those constants are dialed in, it's "just like…

Occam’s razor is for hypotheticals. You’re rejecting an actual physical demonstration, by a reader of engineering dynamics and vibration at Cambridge.

The feedback mechanism you’ve described is likely correct, and also a complete furphy, since the central nervous system is not part of the bicycle.

All of which is par for the course and rather confirms the point, viz. that people will happily hold forth on any explanation they care to latch on to, secure in the knowledge that the total absence of consensus makes it impossible to say, definitively, “that is wrong”

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

#653

Post by crispyambulance »

madhadron wrote: post #357
lisper wrote: post #117

Earlier quoted context omitted.

> Electrons aren't really spinning, right? Correct. > But why do we call it spin? Because it is a physical quantity whose units are those of angular momentum, and we have to call it something . > What are the possible values? +/- h/4pi where h is Planck's constant. (It is usually written has h-bar/2 where h-bar is h/2pi.) > Is it a magnitude or a vector? It's a vector that always points in a direction corresponding t…

> It's a vector It's not exactly a vector...

> It's not exactly a vector...

That's right. It's not a vector because it doesn't "transform" like a vector.

If you take a vector and rotate about an axis by 360 degrees, you get the same vector.

If you take a spinor and rotate it by 360 degrees you get a spinor which is "flipped". You have to rotate the spinor by 720 degrees to get back to the same spinor.

This is intrinsically weird, but that's QM.

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

#654

Post by zorked »

memset wrote: post #293

Crypto and practical security. I get tired of the circular “don’t roll your own crypto unless you’re qualified”. How does one become qualified? I don’t feel like I know how to evaluate many of the arguments people make for or against technologies people argue about on HN, such as Signal or different password managers. I feel like “security through obscurity” is a bad thing, and “layers of security” are a good thing,…

The proper way of interpreting the sentence about "don't roll your own crypto" is that it actually means "don't roll out your own crypto until it has been peer reviewed by many experts". At which point it kind of stops being "your own", in a way.

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

#655

Post by sideshowb »

dmichulke wrote: post #648
rsp1984 wrote: post #603

Macroeconomics. Central banks are "creating" a trillion here, a trillion there, like nobody's business. But what are the consequences? What is the thought process that central bankers have gone through to make these decisions? Also why, exactly, are they buying the exact assets that they are buying (govt. debt, high-yield bonds, etc..) and why not others (e.g. stocks or put money into startups)? And then, what happen…

One approach is reductio ad absurdum: If Central Banks can create money without negative effects, then - why tax people? - why even work? Can't we just print enough money for everyone and live happily ever after? I realize these questions are quite provocative and their answering only explains if it will work but not how or when it will fail.

I agree this is a good starting point for understanding the financial system! For anyone with a programming background I recommend thinking of the whole financial/economic/political system as an algorithm for distributed decision making: who does what, what physical resources get committed to what projects, etc. You can then start to figure out how each component (money, banks, central banks, government, stock market, derivatives market, limited liability, interest, inflation, etc) serves to guide decisions.

The main purpose of a central bank imo is to keep money creation at arms length from government, so a rubbish government can't fiddle with the financial system too much.

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

#656

Post by bunya017 »

Asynchronous programming

With the addition of async to django core, I felt its time to finally learn the concept. I first took interest in async early last year when I re-read a medium post on Japronto; an async python web framework that claims to be faster than Go and Node.

Since then, I've been on the lookout for introductory posts about async but all I see is snippets from the docs with little or no modifications and a lame (or maybe I'm too dumb) attempt at explaining it.

I picked up multi threaded programming few weeks ago and I understand (correct me if I'm wrong) it does have similarities with asynchronous programming, but I just don't see where async fits in the puzzle.

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

#658

Post by mikorym »

dmichulke wrote: post #648
rsp1984 wrote: post #603

Macroeconomics. Central banks are "creating" a trillion here, a trillion there, like nobody's business. But what are the consequences? What is the thought process that central bankers have gone through to make these decisions? Also why, exactly, are they buying the exact assets that they are buying (govt. debt, high-yield bonds, etc..) and why not others (e.g. stocks or put money into startups)? And then, what happen…

One approach is reductio ad absurdum: If Central Banks can create money without negative effects, then - why tax people? - why even work? Can't we just print enough money for everyone and live happily ever after? I realize these questions are quite provocative and their answering only explains if it will work but not how or when it will fail.

Another thing to realise, along these lines, is that economic theories try to explain the world's economy, not dictate it.

I would say that some mathematicians went into economics to win Nobel prizes (which they did win) and I guess they would probably be quick to point this out at well.

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

#659

Post by bronzeage »

jddj wrote: post #640
sideshowb wrote: post #637

Earlier quoted context omitted.

Whoever defaulted spent the money on something else, so it's still in circulation somewhere, just not in a form the original creditor can get hold of.

That would be my intuition too. But if you go down almost any "this crisis won't cause inflation because..." rabbit hole on hacker news, you should see multiple unopposed claims that defaults lead to deflation through the destruction of money. I'm pretty ignorant in this field, and usually I've been a day or so behind the posts (missing the window to press for more information), but I feel like there's definitely som…

The difference is that it's the liquidation process from defaults that causes deflation, not the defaulting itself. Without the liquidation process, if you assume defaulting had no consequences, that's indeed inflation - as everyone is allowed to create money without consequence.

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

#660

Post by panic »

contravariant wrote: post #123
sam wrote: post #78

Mach's principle. Why is there a "preferred" rotational frame of reference in the universe? Or as stated in this Wikipedia article, "You are standing in a field looking at the stars. Your arms are resting freely at your side, and you see that the distant stars are not moving. Now start spinning. The stars are whirling around you and your arms are pulled away from your body. Why should your arms be pulled away when th…

The unsatisfying mathematical answer is that it is impossible to have a uniform distribution of rotational speeds, therefore there must be a preferred one. It's the same reason the universe has an average speed (unlike what you might expect from special relativity), although it is unclear if this is true for the entire universe or just the portion we can see. We can measure how fast we're moving w.r.t the cosmic micr…

This is an interesting argument! Wouldn't it also work for positions, though? That is, either the universe is finite, or, since there can't be a uniform distribution over an infinite space of positions, there must be some preferred "center" of the universe?
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