7 ms·
What made them mysterious? Aren't there always some fraction of atoms or molecules with sufficiently high energy to escape the object?
by dataflow 3y ago
What made them mysterious? Aren't there always some fraction of atoms or molecules with sufficiently high energy to escape the object?
- mvdtnz 3y agoThe fact that you, a random internet guy, knows this makes me believe that the world's top experts on measuring this exact thing probably thought of it, and if there is a mysterious divergence this probably doesn't account for it.
- dataflow 3y agoI figure as much, but that's kinda why I'm asking what made it mysterious. I actually hadn't heard of it being seen as mysterious until today - that comment is the first time I've seen that. Until today I thought it had been was unsurprising for scientists.
- yetihehe 3y ago> I figure as much, but that's kinda why I'm asking what made it mysterious. You expect simple explanations to VERY complex problems from random internet commenters. I think you expect too much.
- quickthrower2 3y agoNot on HN sometimes some gems of comments are made by experts
- yetihehe 3y agoSometimes: when you least expect them. Not expecting them is a good strategy here.
- quietbritishjim 3y agoI think the real question is: where is the evidence that scientists find it mysterious? That doesn't need any sort of explanation, just a reference for a claim made by a commenter. As with the other commenter, I've heard about the mass divergence before, but never that anyone found it surprising.
- deleted 3y ago[deleted]
- gumby 3y agoAs has even been discussed on HN over the years (!), the cause is unknown.* This is one of the motivations to replace the official kilogram with a definition based on measurable natural quantities, as had been done with the second and the meter. It took until 2018 to do so: https://www.nist.gov/si-redefinition/kilogram-introduction https://www.nist.gov/si-redefinition/kilogram-introduction * it’s not like there aren’t good theories but you can’t experiment directly on “the” kg because you can’t risk changing it!
- dataflow 3y agoI'm neither seeing the cause being mentioned as unknown in that link, nor would the cause being unknown imply anything being mysterious? Like if you find that your car has broken down after 200k miles, you might not be able to determine the cause, but it wouldn't exactly be some kind of mysterious physical phenomenon that would puzzle scientists. Obviously, something wore out. Why/how is this any different?
- gumby 3y agoDid you click on the other kilogram links (or other metric links which are also interesting?) A useful paragraph is the following: "The trend during the past century had been for most of BIPM's official copies to gain mass relative to the IPK, although by somewhat different amounts, averaging around 50 micrograms (millionths of a gram) over 100 years. But an alternative explanation is that the IPK was losing mass relative to its copies. Even more likely, it was a combination of both." Those pages are for the lay audience but you can do your own web search (probably even an algolia search of HN) to know more. In general, it's often easy to come up with an explanation of some new phenomenon, but to answer the question you still have to do science...which often simply confirms intuition but not always. My comment was less on the reason and more on the difficulty of doing experiments on what was literally the kg, no matter how it fluctuated.
- vanderZwan 3y agoI don't disagree with you, but on the other hand: if people claim something in a discussion thread we need to be able to ask them to back those claims up. Otherwise anyone can just assert anything. Sure, the explanation might not fit in the margins here, but then a link to a source that does attempt to explain it would be fine too.
- gcr 3y agoOne reason why questions like this are important is because it gives the audience around the asker an opportunity to learn something new. Isn't it important to be able to express curiosity, especially for the benefit of others?
- Guvante 3y ago50 ug over 130 years is way too fast > The reason for this drift has eluded physicists who have dedicated their careers to the SI unit of mass. No plausible mechanism has been proposed to explain either a steady decrease in the mass of the IPK, or an increase in that of its replicas dispersed throughout the world https://en.m.wikipedia.org/wiki/International_Prototype_of_the_Kilogram https://en.m.wikipedia.org/wiki/International_Prototype_of_t...
- satvikpendem 3y agoThey're not being arrogant, as it seems like the parent is genuinely curious as to why such weights diverged, as am I. It is still a good question to ask, since I also have not heard a good answer to that question.
- iainmerrick 3y agoRight -- and they're not even asking for the answer, they're just asking what the interesting mysterious phenomenon is.
- ramblerman 3y agoI've heard of an appeal to authority, but an appeal to ignorance is new. OPs question is not ridiculous, nor does he suggest it to counter the "mysterious" claims
- lordnacho 3y agoNot new, Efficient Markets Hypothesis is like this. "I haven't heard of a way to make money from trading so there isn't one" is my caricature of it.
- cnity 3y agoIsn't it more like: "exploitation of a market inefficiency renders the market efficient over time", or something to that effect? Or rather, (others) making money from trading is what makes it hard (for you) to make money from trading.
- lordnacho 3y agoSure, depends on how you encounter it. Most often on forums someone will show up wanting to hear about how to write a strategy, and they are rebuffed with "nobody would ever publish that".
- cnity 3y agoI love encountering nay-sayers because it means either: 1. I am wrong and could learn something new. 2. They are wrong and their opposition fills me with defiant determination. The difficulty comes when you view something as case 2 but it is actually case 1 and you embarrass yourself. I do this all the time.
- sam0x17 3y agoI find that it saves time to just start by assuming the experts haven't thought of X because of how many times I've seen assuming that they _have_ thought of X turn out to be a poor assumption, across many domains.
- bookmark1231 3y agoThat’s incredibly specious reasoning.
- justinclift 3y agoProbably gets a better result than the alternative though. ;)
- Widdershin 3y agoCan you give any examples of times you’ve easily anticipated X when a whole field of subject matter experts have demonstrably overlooked it?
- sam0x17 3y ago* [insert every example of "15 year old unknown vulnerability in X found" here] * have to be a bit vague here, but while working as a research scientist for the US Department of Defense I regularly witnessed and occasionally took part in scenarios where a radical idea turned "expert advice" on its head, or some applied thing completely contradicted established theoretical models in a novel or interesting way. Consistently, the barrier to such advancements was always "experts" telling you that your thing should not / could not work, blocking your efforts, withholding funding, etc., only to be proven wrong. Far too many experts care more about maintaining the status quo than actually advancing the field, and a concerning number are actually on the payroll of various corporations or private interests to actively prevent such advancements. * over the last 30 years in the AI field, there have been a few major inflection points, Yann LeCun's convolutional neural networks and his more general idea that ANNs stood to gain something by loosely mimicking the complexity of the human brain, for which he was originally ridiculed and largely ignored by the scientific community until convolution revolutionized computer vision; and the rise of large language models, which came out of a whole branch of AI research that had been disregarded for decades and was definitely not seen as a thing that might ever come close to something like AGI, natural language processing. * going back further in history there are plenty of examples, like quantum mechanics turning the relativistic model on its head, Galileo, etc etc. The common theme is a bunch of conservative, self-described experts scoffing at something that ends up completely redefining their field and making them ultimately look pretty silly and petty. This happens so frequently in history that I think it should just be assumed at all times in all fields, as this dynamic is one of the few true constants throughout history. No one is an expert, no one has perfect knowledge of everything, and the next big advancement will be something that contradicts conventional wisdom. Admittedly, I derived these beliefs from some of the Socratic teachings I received very early in life, around 6th grade or so back in the late 90s, but they have continually borne fruit for me. Question everything. When debugging, question your most basic assumptions first., "is it plugged in?" etc, etc It's sort of at a point these days where if you want to find a fruitful research idea, probably best to just browse through conventional wisdom on your topic and question the most fundamental assumptions until you find something fishy.
- aaron695 3y ago[dead]
- NoLsAfterMid 3y agoDid you ever pause to think "is this comment worth posting"? Maybe you should.
- notjoemama 3y agoCan they perform the calculations to estimate the fluctuations? Can they write an informal explanation about what happens to the gluons? I think the experience of seeing a factoid on the internet is being given too much weight here.
- edgyquant 3y ago[flagged]
- dotnet00 3y agoIf it were simply a matter of losing particles, I'd expect that one of the many very capable metrology labs around the world would've devised an appropriate experiment, e.g. storing two exact same masses at slightly different temperatures near absolute zero and characterizing the difference in mass (since presumably the higher temperature sample would lose slightly more mass if it were down to high energy particles). A test for this theory would have to involve a means of accounting for these kinds of fluctuations.
- dataflow 3y agoI mean I just gave one example of how it might lose mass. There are other obvious ways (like when they're picked up etc.). My point wasn't to present a hypothesis for people like myself here to rebut. I can do that just fine myself. I was trying to understand what about this has been confusing for scientists.
- deleted 3y ago[deleted]
- chasd00 3y ago> like when they're picked up etc. Wouldn’t just moving an object change its mass? Any change in potential energy would mean a change in mass from good old e=mc^2
- mcpackieh 3y agoMake sure to store them very deep underground down a mineshaft, so random cosmic rays don't ever knock a few atoms loose.
- analog31 3y agoLook for material condensed on the inside of the jar.
- irjustin 3y ago> Aren't there always some fraction of atoms or molecules with sufficiently high energy to escape the object? Can someone help me understand this? I thought that things were supposed to be stable given the elements used for le grand k. That they don't decay on their own and it would have to be another mechanism to explain the divergence? [0] https://en.wikipedia.org/wiki/International_Prototype_of_the_Kilogram#Stability_of_the_IPK https://en.wikipedia.org/wiki/International_Prototype_of_the...
- pants2 3y agoIn a system of particles, due to random Brownian motion and the nature of Gaussian energy distributions, a small number of particles occasionally gain significantly higher energy than average through statistical fluctuations. Maybe enough to escape the binding energy of le grand k. However I would think this is a very very small effect in platinum.
- irjustin 3y agoSure, radioactivity. But, Le grand K is made of naturally occurring platinum of which most of the isotopes are observationally stable[0] and the one isotope that isn't has a half-life of 6.5×10^11 and only makes up 0.012% [1]. So yeah I don't buy the unstable explanation to even begin to show the divergence, let alone "weight gain". [0] https://en.wikipedia.org/wiki/Stable_nuclide#Still-unobserved_decay https://en.wikipedia.org/wiki/Stable_nuclide#Still-unobserve... [1] https://en.wikipedia.org/wiki/Isotopes_of_platinum https://en.wikipedia.org/wiki/Isotopes_of_platinum [Edit] Wait are you describing evaporation?
- shwouchk 3y agoEdit: yes
- bowsamic 3y agoYes, he's describing evaporation. Here's a thread about it, basically the answer is "we don't know" https://physics.stackexchange.com/questions/77130/why-does-platinum-evaporate-if-left-long-enough https://physics.stackexchange.com/questions/77130/why-does-p...
- marcosdumay 3y agoIt's well known that they tend to gain weight, not lose it. And yeah, the mystery is just what mechanism exactly affected each one. (AKA, not much of a mystery.) The possibilities are very well understood.
- dataflow 3y ago> And yeah, the mystery is just what mechanism exactly affected each one. (AKA, not much of a mystery.) The possibilities are very well understood. Ahh, that makes more sense. Thanks!
- analog31 3y agoIf the object is evaporating, look for material condensed on the inside of the jar.