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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?

#331

Post by yters »

vikramkr wrote: post #211
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.

I'll take a shot at trying to explain that to the best of my ability. I'm starting from the point where we have organisms and dna, since nobody knows how exactly abiogenesis happened yet. First, two general points. The most important thing to keep in mind is time. Life has had insane amounts of time. Billions of years. Beyond human comprehension amounts of time. The second most important thing is that complicated !=…

The more I learn about the genetic code, how proteins get translated from DNA, the nature of DNA itself, bioinformatics, biochemistry, etc., the less like a random jumble it seems.

I also wonder why we cannot reproduce evolution's effectiveness computationally. Genetic algorithms and the like are not very good, no where near capable of matching biological systems, even though we can match evolution timescales and populations with our computing power today.

As far as I can tell, we have absolutely no idea why and how evolution works, let alone works so well.

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

#332

Post by richardbrevig »

aazaa wrote: post #236

Sort of meta, but I always shudder when someone says that science has "proven" something. What sets science apart from most other methods of seeking answers is its focus on disproof . Your goal as a scientist is to devise experiments that can disprove a claim about the natural world. This misconception rears its head most prominently in discussions at the intersection between science and public policy. Climate change…

It kind of floors me that we're taught science the way it is. Much simpler: Karl Popper's conjecture and refutation. So I tell people that science mandates "I believe something, so I should try to prove it wrong." I think understanding that is significantly more beneficial than repeating the arbitrary n- steps of a scientific method. It's two steps. Keep it simple.

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

#333

Post by MichailP »

ncmncm wrote: post #53

I like that for a full decade, people discussed measurements at reputable labs indicating that certain radioactive species decayed at rates that varied >0.1% depending on the season, and explored possible neutrino flux influences. The measurements were finally shown to be effects of the immediate environment on the measurement apparatus. That detectors used in labs may vary with time by >0.1%, unknown to their users,…

Because people live in a busy world, where knowledge is not transferred with enough love and integrity. And also people are afraid to say "I don't know" and what little they know they tend not to share.

To make things more specific, those labs had uncertainty budget with something like 20 terms for the things they measured. Each of those terms had associated probability distribution etc. They had uncertainty budgets for all the methods they did etc., and some of those where probably dated, done by someone else, etc. etc. Who checks that? Is the check rigorous enough? Are some assumptions made that don't hold to scrutiny?

So it is actually very easy for error to creep in, I would say actually very likely.

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

#334

Post by SAI_Peregrinus »

eranation wrote: post #252

Lot's of quantum related phenomenon here, but what keeps bothering me is that while I get it that light is both a wave and a particle, but I have no clue what that means. I mean, a wave of sound, is made from air particles, a wave of ripples in a pond is made of movement of water molecules. In the double slit experiment, it's explained that the single photon has to be "interfering with itself", so I don't get it if b…

> while I get it that light is both a wave and a particle, but I have no clue what that means.

Because it's wrong. It's a quantum of the electromagnetic field. It's neither a wave nor a particle. It just happens to have some properties of both.

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

#335

Post by JabavuAdams »

Dutchie85 wrote: post #71

Why does time slow down/go faster with movement compared to another object. The well known example that if you travel into space you'd gain let's say 5 years and people on earth 25 in the same time or so. I just don't get it and I can't find any logic explanation. For instance: Two twins who came to live exactly at the same moment in the year 2000 and both die on their 75th birthday at the same time. One travels into…

Imagine the hands on an analog clock. As the hands rotate, there is an invariant -- the length of the hand. We are completely unsurprised that as a hand on the clock rotates and becomes less horizontal, it must become more vertical. It can't both increase its "verticality" and its "horizontality".

Now imagine horizontal as space, and vertical as time. In this case a 2D spacetime, but we can't really visualize 4D.

The reason they always talk about space-time in relativity is that you can't separate the two. If you want to travel faster through time, you have to travel slower through space. If you want to travel faster through space, you have to travel slower through time. There's an invariant like the length of that rotating clock arm called the "spacetime interval" that remains constant under the transformations that you have to do to go from one observer's perspective to another observer's perspective.

Problem is its in 4D so it's hard to visualize. There is a mathematical framework that can explain all of the transformations leading to length-contraction and time-dilation as simple rotations in a 4D spacetime (3 space + 1 time). It requires a bit more math, but then unifies things in a conceptually simple way.

But maybe just remember: "If you go faster through space, you go slower through time" "If you go faster through time, you go slower through space"

Your maximum speed in space is the speed of light, at which others will observe you as having no time passing.

Your maximum speed through time is one second per second, at which others will observe you as being stationary relative to them. Look up Alex Fluornoy's youtube video lectures. I'll edit this and link the specific one here later, if I can find it.

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

#336

Post by knzhou »

AmericanOP wrote: post #327

Why is there no evidence of black matter annihilation in astronomy?

You mean dark matter annihilation? There are some hints: an excess of gamma rays detected by Fermi-LAT, an excess of X-rays detected by Chandra, excess ionization detected by EDGES, and excess positrons detected by AMS-02. However, all of these anomalies are contentious and could well be explained by systematic effects or unknown astrophysical sources.

If none of these hold up, it could be that dark matter just doesn't annihilate. That's not weird or anything -- I mean, your room is full of matter right now, and it's not annihilating itself either.

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

#338

Post by andrepd »

JabavuAdams wrote: post #319
kcolford wrote: post #301

Earlier quoted context omitted.

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...

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

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

#339

Post by kccqzy »

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,…

I recommend Serious Cryptography by Jean-Philippe Aumasson. After reading it, you will gain enough understanding to compose cryptographic primitives and build your own secure system based on well-known best practices, as long as you don't deviate too much from the golden paths. Although with that, you still won't know how to design or implement these primitives yourself. It's like having a nice toolkit of screwdrivers, hammers, spanners etc to build your thing, but you can't build those tools themselves.

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

#340

Post by ncmncm »

zarkov99 wrote: post #302
ncmncm wrote: post #133

Earlier quoted context omitted.

Coroutines are most easily understood as a way to write a state machine in a way that looks like a function. I.e., it's just a notational trick to make one function do different things according to when it's called. To see it, imagine you have a struct with a data member for each local variable of your function, and replace your function with a member function that has no local variables, but uses "this" to get at wh…

I think I get coroutines in theory. It's the C++ specific complexity that is the hardest barrier. Thanks for the explanation though

Yes, a lot of extra junk is needed to make them actually work, but the extra junk goes a long way toward obscuring what you actually need to know.

Ultimately, though, you are right that you have to understand it all, once, even if you can't remember it all a month later. The explanations I find online are not good at presenting just the details you need when you need them, and building up to the full picture.

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