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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?

#541

Post by unexaminedlife »

vijay_nair wrote: post #483

• Magnetism. There are plenty of videos out there calling it the result of a relativistic charge imbalance. But I've never been able to use this point-of-view to practical use cases like understanding how permanent magnets work or how increasing the number of windings in inductors boosts the magnetic field strength. There were more situations I tried to put this POV into use but I can't remember them off the top of m…

re: Qualia

I can't say this will necessarily assuage your curiosity about consciousness, but I mostly stopped being overly curious about this once I realized that, it's likely only a manifestation of the aggregation of all of the individual sensory experiences our bodies have.

In other words, when you think about planet-scale phenomena such as how humans more or less all feel "connected" and non-hostile because civilization (in the most advanced countries) has reached a point where hostility is no longer essential for survival. That "experience", for each of us, is ours alone but it seems to be so ubiquitous that we can't take credit for that experience or insight as individuals. It leads me to believe a large part of our conscious experience of the world is shared and independent of the brain's capacity. More precisely, humans are (universally) experiencing phenomena that are independent of our brain's capacity to process and understand them.

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

#542

Post by govg »

dijit wrote: post #533
TrackerFF wrote: post #515

Earlier quoted context omitted.

I think the other answers have been good at explaining HOW stock prices are determined at the exchange, but if you're wondering WHY someone would say "That stock is worth $xx.xx", then that's a more complicated question, with equally complicate answers. At the very lowest level, it could be gut feelings from a potential buyer. They see electric cars more frequently, combustion engines going out of fashion, and simply…

> On a higher level, some potential buyer will look at the companies financial statements, and figure out if the share price is too high / low for how the company is performing, from a financial standpoint. This is called "fundamental analysis", and you can easily find step-by-step analysis reports of such on various companies. How does this work if a company doesn't pay out dividends? There's no investment to return…

There are multiple ways to do this analysis, and not all of them come from evaluating them as investments. Stocks represent an ownership stake in the firm, and you can use any method you want to give a number to what the firm's "value" is. This could be by reading financial statements, comparing it to other existing companies, seeing how much their operating cash flow is and so on.

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

#543

Post by badpun »

alasano wrote: post #380
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…

If you see a single share price listed, that is the price of the last sale that occurred. Now that can either mean that someone bought a share that someone else was selling or that someone was selling a share to someone who was offering to buy. The shares are listed as a series of buy and sell orders in what's called an order book. If the price a share was sold at was 100$ and you think it will go a bit lower, you co…

What happens if the stock sees almost no volume of trades, and we have a situation where the lowest sell is at $90 and highest buy at $100 (i.e. both parties are overgenerous)? Does the stock exchange make them split the difference, i.e. makes the trade at $95?

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

#544

Post by [deleted] »

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…

[deleted]

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

#545

Post by badpun »

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...…

> 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?

My good friend took "something" once (hard to tell what the dealer is selling you) and ended up in a mental institution, and is now in fact officially mentally disabled and on drugs for life. The drugs keep him stable enough that he's able to work, although he's still just a shadow of his former self.

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

#546

Post by stopping »

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…

It's not so much "magic" as it is the sheer rate of molecular collisions in the cytosol. There are so many collisions happening that at least one of them will do what you want. Here's a back-of-the-napkin example, admittedly with many simplifications:

A tRNA molecule at body temperature travels at roughly 10 m/s. Assuming a point-sized tRNA and stationary ribosome of radius 125 * 10^-10 m, the ray casted by the moving tRNA will collide with the ribosome when their centers are within 125 * 10^-10 m of each other. The path of the tRNA sweeps a "collidable" circle of the radius of 125 * 10^-10 m, for a cross-sectional area of 5 * 10^-16 m^2. Multiplied by the tRNA velocity, the tRNA sweeps a volume of 5 * 10^-15 m^3 per second. Constrained inside an ordinary animal cell of volume 10^-15 m^3, the tRNA would have swept the entire volume of the cell five times over in a single second. Obviously the collision path would have significant self-overlap, but at this rate it's quite likely for the two to collide at least once any given second.

Now, consider that this analysis was only for a single ribosome/tRNA pair. A single ribosome will experience this collision rate multiplied by the total number of tRNA in the cell, on the order of thousands to millions. If a ribosome is bombarded by tens of thousands of tRNA in a single second, it's very likely one of those tRNA will (1) be charged with an amino acid, (2) be the correct tRNA for the current 3-nucleotide sequence, and (3) collide specifically with the binding site on the ribosome in the correct orientation. In actuality, a ribosome synthesizes a protein at a rate of ~10 amino acid residues per second.

Any given molecule in the cell will experience millions to billions of collisions per second. The fact that molecules move so fast relative to their size is what allows these reactions to happen on reasonable timescales.

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

#547

Post by shadowprofile77 »

the fundamentals of computer science. Unlike many who comment here regularly, I am not a programmer or developer and though it might seem silly, the way in which a bunch of code written in a programming language of any sort translates to a computer physically or electrically causing things to "happen" because of it has always been a bit fuzzy. I know that electronic systems and machines translate all instructions to binary code but still, from there how does the rest happen? such as an OS on my laptops working the way it does, or more specialized: an unmanned spacecraft autonomously navigating its way through the solar system and doing complex physical tasks. Anyone have a suggestion for a good starting point on learning through these fundamentals and on upwards?

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

#549

Post by aeternum »

Buttons840 wrote: post #497

Flight. How can a plane fly when it's thrust to weight ratio is less than one? It's like, if you can produce 10 pounds of thrust, who would look at that and say "ah ha, we can use this to keep a 100 pound machine miles in the air indefinitely"? I understand flight from a mathematical point of view. I've actually read a few books on the subject, and I could explain how flight works to someone. However, I'm still fishi…

Many descriptions of flight focus on pressure differentials. I think it's much easier to think about in terms of Newton's 3rd law. The plane simply needs to redirect enough air downward to compensate for its weight. The energy cost change the direction of the air (via the wing) is very low (similar to how a train does not lose much speed when the tracks curve).

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

#550

Post by ur-whale »

shadowprofile77 wrote: post #547

the fundamentals of computer science. Unlike many who comment here regularly, I am not a programmer or developer and though it might seem silly, the way in which a bunch of code written in a programming language of any sort translates to a computer physically or electrically causing things to "happen" because of it has always been a bit fuzzy. I know that electronic systems and machines translate all instructions to…

It's a long road to the top (i.e. something like a python program), but you can start at the bottom and try to understand how basic hardware gates (and/or/xor/register) work and can perform extremely elementary yet useful tasks.

Then it's just a "simple" matter of stacking up a billion of the things to get them to do complex programs.

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