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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?

#681

Post by iamevil »

andrepd wrote: post #338
JabavuAdams wrote: post #319

Earlier quoted context omitted.

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...

QFT says it's all fields because it is. Particles simply cannot explain the conjunction of quantum mechanics with special relativity.

I am not so sure about that. When you imagine a "particle", what do you see? Do you see a collection of balls?

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

#682

Post by locuscoeruleus »

arkanciscan wrote: post #173

Quantum Computers. Not like I'm five, but like I'm a software engineer who has a pretty decent understanding of how a classical turing machine works. I can't tell you how many times I've heard someone say "qubits are like bits except they don't have to be just 1 or 0" without providing any coherent explanation of how that's useful. I've also heard that they can try every possible solution to a problem. What I don't u…

Pseudo-code for quantum computers is currently linear algebra. Fortunately, most programmers have the required linear algebra to get a thorough understanding of the basics! Check this out https://quantum.country/qcvc. Fair warning, I did have to brush up on my linear algebra a bit, but it's worth it imo. Friends in the know say that when you understand this article, you understand quantum computers.

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

#683

Post by TheOtherHobbes »

mikorym wrote: post #658
dmichulke wrote: post #648

Earlier quoted context omitted.

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.

Economics is a branch of moral philosophy and very consciously uses persuasive rhetoric to dictate policy. One of the tools used is hand-waving hidden inside differential equations to produce models that would be useless in any other discipline.

I don't think I've ever seen a mainstream economic prediction that was actually correct.

It's not hard to understand why. Reducing all the sectors of a complex economy to crayon-drawn measures like "inflation" and "unemployment" - which aren't even measured with any consistency - is like trying to predict the weather in the Bay Area using a single weather station for the entire continental US, which is conveniently located on the wall of a cow shed in Kansas.

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

#684

Post by scld »

Time dilation with regards to the "no absolute rest frame" in physics.

The famous twin thought experiment where one gets in a spaceship, accelerates away from the planet, turns around, and comes back.

The twin that stayed on earth is old and the traveling twin is young still.

On one hand, I know that time will "pass differently" for each twin....but why is it the twin in the spaceship that ages less? Why isn't it true that the entire universe accelerated away from the spaceship and then returned, leaving the entire earth young?

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

#686

Post by Rerarom »

robertakarobin wrote: post #370

If I buy a stock, does the price at which I agreed to buy it become the new share price on the stock exchange? Every article on "Where do stock prices come from?" seems to just talk at a high level about supply and demand. But where does the price come from at a nitty-gritty level? Is it an average of all existing offers or something? Do different exchanges and stock-ticker websites have different formula for calcula…

I think a lot of questions that people have about economics/finance/money are about the nitty-gritty mechanics, and a lot of answers are instead about the big picture / general laws. That's what leads people to say they can't understand economics.

(Also it's strange that sometimes there is disagreement about the mechanics between actual practitioners, see the recent confusion about whether fractional reserve banking is true.)

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

#687

Post by dennis_jeeves »

Interesting that you mentioned exosome, and no one else did. That in itself should give a hint on why people cannot do a better job at explaining stuff. It's complicated, , not well understood, extremely messy and does not fit well in a textbook.

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

#689

Post by logicslave »

Erlich_Bachman wrote: post #580
logicslave wrote: post #386

Earlier quoted context omitted.

The answer to this is really easy. Go to any mental institution and get to know the patients. An institution where they are allowed out, but are still in an enclosed area. A majority of the patients will have had some sort of heavy drug use in their past. Sure, whats causation and whats correlation, but its pretty clear that drugs cause mental breaks. How do I know this? I have mental illness in my family and have sp…

> Sure, whats causation and whats correlation, but its pretty clear What? How is it clear? As you wrote yourself, correlation is not causation.

I was just protecting against the inevitable counter argument. The proof is what I have seen with my own two eyes

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

#690

Post by robertakarobin »

traK6Dcm wrote: post #586
robertakarobin wrote: post #370

If I buy a stock, does the price at which I agreed to buy it become the new share price on the stock exchange? Every article on "Where do stock prices come from?" seems to just talk at a high level about supply and demand. But where does the price come from at a nitty-gritty level? Is it an average of all existing offers or something? Do different exchanges and stock-ticker websites have different formula for calcula…

The short answer: What exactly the "price" shown on the exchange website is depends on the exchange. Typically it's the last trade price or the mid price (average of best bid and offer). There really is no such thing as a single "price" because the price will depend on the quantity and direction you are transacting in. Long answer: You need to understand how the Limit Order Book works. I wrote up something about this…

Thank you! So each exchange has its own formula for determining the price that gets shown on the ticker?

Let's say someone owns shares in a very low-volume stock — one that gets a couple trades a day, at most. Could they artificially increase the share price by offering their shares at a high price, then using a second account under their control to immediately buy them at the inflated price?

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