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?

#831

Post by abecedarius » Fri, May 01, 2020, 1:37 AM UTC

mncharity wrote: post #827

abecedarius wrote: post #811

Earlier quoted context omitted.

Coincidentally I'm previewing PBotC just now. It looks really promising. Do you know roughly when the new edition is expected? Or if you have any favorite books on how things work at that scale, I'd be grateful for the pointer. (I've read a popular book by David Goodsell and am halfway through a somewhat deeper one.)

> PBotC [...] when the new edition No idea, sorry. > favorite books on how things work at that scale I've found the bionumbers database[1] very helpful. Google scholar and sci-hub for primary and secondary literature. But books... I'd welcome suggestions. I'm afraid I mostly look at related books to be inspired by things taught badly. The bionumbers folks did a "Cell Biology by the Numbers" book... the draft is onlin…

Thanks! I guess I'll try the bionumbers book first.

I'll keep you in mind, too.

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

#832

Post by Viliam1234 » Fri, May 01, 2020, 5:10 PM UTC

borramakot wrote: post #812

Viliam1234 wrote: post #650

Earlier quoted context omitted.

One thing that rubs me the wrong way about this "no proof ever, only disproof" attitude is that it advantages the new hypotheses too much. Any hypothesis that I invent at this very moment, is from this perspective in the best position a hypothesis can ever be. There is no disproof. There is even no coherent argument against it, because I literally just made it up this second, so no one had enough time to think about…

I've not read Popper directly, so I'd be interested in his actual argument on this. But, I wonder if you can describe H1 as being a stronger hypothesis than H2 by virtue of withstanding more and higher quality attempts to disprove it?

"Withstanding more arguments" can be gamed by throwing thousand of silly arguments at your favorite hypothesis. And "higher quality" is the part people would disagree about.

I think that when people are essentially honest and trying to find out truth, they can agree on reasonable rules. But there is no way to make the rules simultaneously philosophically satisfactory and bulletproof against people who are willing to lie and twist the rules in their favor.

For example, in real life you usually cannot convince crackpots about being wrong, but that is okay because at some moment everyone just ignores them. If you try to translate this into a philosophical principle, you end up with something like "argument by majority" or "argument by authority". And then you can have Soviet Union where scientific progress is often suppressed using these principles. But what is the alternative? No one can ever be ignored unless you disprove their hypotheses according to some high standard? Then the scientific institutions would run out of money as they would examine, using the high standard, the 1000th hypothesis of the 1000th crackpot.

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

#833

Post by knzhou » Fri, May 01, 2020, 5:44 PM UTC

stevebmark wrote: post #341

knzhou wrote: post #253

Earlier quoted context omitted.

> If light is emitted at a constant wavelength independent of the stretching of the universe, doesn't that imply light is traveling through a higher spatial dimension, otherwise the emitter itself would be stretched with the universe and we'd never be able to observe differences in the speed of light? If I understand this paper, once light is emitted, it's "stuck" to space and will stretch along with it. But if the e…

I've read this paper twice now and it's very good. I still don't have a fundamental understanding, I'm having trouble visualizing what happens over time with the stretching and squashing of space vs the light in the tunnel. I've come away with this paper with more questions than answers, but I think all of it is there if I study it hard enough. - It sounds like (based on the answer you linked) the "expansion" of the…

Hi, sorry, but I don't have time to answer all the questions (because each answer would have to be at least 10x longer than the question, so my answer would have to add up to at least 5000 words)! However, these are all good questions and I would urge you to check out a resource like Physics StackExchange (the physicist's equivalent of StackOverflow). Many of these have been asked before, and the new ones could get very informative answers.

> - Maybe I don't fully understand why LIGO needs two arms. If you had a clock that could accurately measure light wave crests, could you do it only with one arm?

Yes, that's absolutely right. The two arms cancel out the frequency fluctuations of the laser itself. If we had a perfectly stable laser, we could make do with just one arm.

Regarding the question about what stretches and what doesn't, I think the general rule is that rigidity prevents "stretching". For example, a hydrogen atom in expanding space would lose momentum over time, because it redshifts, but the atom itself wouldn't get any bigger. There's no need to invoke a higher dimension here, just some things are rigid (like laser cavities and the Earth) and some things aren't (like electromagnetic waves). In fact, in general invoking higher dimensions without a strong reason to is discouraged when discussing general relativity, simply because the math is already very complicated in 4D.

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

#834

Post by ric2b » Fri, May 01, 2020, 7:37 PM UTC

Hongwei wrote: post #670

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…

The consequences are supposed to be inflation. Instead, we seem to only get asset inflation (houses, stocks) and not consumer goods inflation (flour). From a former econ prof who I spoke to recently: the central bankers aren't thinking about inequality or inflation right now, they're just trying to avoid the apocalypse. The liquidity injected is supposed to be taken out later, thus removing the inflationary distortio…

> Instead, we seem to only get asset inflation (houses, stocks) and not consumer goods inflation (flour).

That doesn't sound surprising when all that injected money goes directly to banks instead of individuals.

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

#835

Post by ionflow » Fri, May 01, 2020, 8:12 PM UTC

tabtab wrote: post #713

cousin_it wrote: post #601

Earlier quoted context omitted.

I think there's no way to understand quantum computing without first understanding some linear algebra, specifically tensor products. How ten 2-dimensional spaces give rise to a 1024-dimensional space, how the Kronecker product of three 2x2 matrices is an 8x8 matrix, and so on. If you're comfortable with that, here's a simple and precise explanation of quantum computing: 1) The state of an n-qubit system is a 2^n dim…

What about some kind of interactive simulation, kind of like playing with a graphing calculator? People tend to relate to things better by tinkering and playing with parameters to observe the impact on results. Analog experimentation is how we learned most Newtonian physics.

https://quantumjavascript.app/

You might find this useful. Along with the author's write-up:

https://medium.com/@stew_rtsmith/quantum-javascript-d1effb84...

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

#836

Post by 8bitsrule » Sat, May 02, 2020, 3:18 AM UTC

vlasev wrote: post #783

8bitsrule wrote: post #779

Low, medium, and high-frequency radio waves (below 30MHz, wavelengths longer than 10 meters) are a form of EM radiation. Which means that an antenna is 'transmitting' low-energy, long-wavelength photons. (Which gets us into the whole wavicle question.) But the signal from a radio station appears to be continuous. So: how to picture this? Is the signal made of discrete 'photons' overlapping, or combined somehow? Or is…

A radio station in the 1MHz range is transmitting in the 10s of kW range. The energy of a single photon is tremendously small. So if you divide out the large transmitting power by the energy of a single photon, you'll see that an unimaginable number of photons is being released, giving the impression of a continuous process. More detail: Say you have an AM station that transmits at frequency f = 650kHz and uses power…

Thanks, Vlasev, helpful ... easy to scale down to my hometown's measly 2,000 gallon AM station. I guess I'll need to go back to the radio physics math and puzzle it out more (directional arrays, groundwaves, and the like.) The idea of a photon with such a miniscule energy yet a wavelength of a thousand meters is a tad non-intuitive to me.

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

#837

Post by mda » Mon, May 04, 2020, 8:39 AM UTC

klmadfejno wrote: post #752

mda wrote: post #342

Earlier quoted context omitted.

I found the comic not very good either. Kid suddenly blurts "Wait a minute, that means a qubit corresponds to a unit vector in 2 dimensional Hilbert space" Yeah.

Not quite what I meant. I think the comic is excellent. In case its not painfully obvious, the joke is equating lay people's poor understanding of quantum mechanics to a child's misunderstanding of sex. It's not trying to dumb down the concept of quantum computers at all, it's just trying to point out how incorrect how dumb pop science simplifications of it are. The 'qubits are bits with a range of value between 0 an…

Well my point is Gp is asking for good material for explaining the subject, this comic is not it. I found it only irritating Tbh.

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

#838

Post by mtrovo » Sat, May 09, 2020, 9:45 PM UTC

odyssey7 wrote: post #781

nicoburns wrote: post #665

Earlier quoted context omitted.

> - why tax people? Printing money is actually more or less equivalent to a tax, because it reduces the value of the existing money supply. > - Can't we just print enough money for everyone and live happily ever after? No, because printing money redistributes wealth, it doesn't create it.

Not just any tax, but a wealth tax affecting anybody who has US dollars, regardless of their citizenship or location.

That's a really good point and I never thought about it this way. It just makes me think how powerful is for US the world relying on dollars as an international currency.

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

#839

Post by meridion » Sun, May 10, 2020, 9:26 PM UTC

AgentME wrote: post #305

Crazyontap wrote: post #149

What 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)

>What happens when you actually fall inside a black hole and what is the singularity. Black holes were sometimes called "frozen stars", because time slows down at the event horizon to a stop. If light could escape from black holes and somehow the material continued to emit/reflect light despite time being stopped for it, then as outside observers, what we would see is the star at the moment it collapsed to the size o…

In another comment on this thread they explained that space and time are parts of the same vector, , with velocity being the speed of light. Here you mentioned time is frozen at the black hole event horizon - does this have to do with the theory that we can use black holes as "portals" to distant parts of the galaxy? So if time is 0 and we have , does this mean we travel at the speed of light?