5 ms·
It's impossible to measure because it has no real existence. The one-way speed of light is as metaphysical of a quantity as the British pound. Numerical speeds
by whatshisface 3y ago
It's impossible to measure because it has no real existence. The one-way speed of light is as metaphysical of a quantity as the British pound. Numerical speeds can be whatever you want them to be in an arbitrarily curved coordinate system - and the speed of light is defined in the "flattest" one of them.
- MiguelX413 3y agoThe British pound is 0.45359237 kg, no?
- edgyquant 3y agoWhat exactly is a kg?
- MOARDONGZPLZ 3y agoBasically 1,000 grams.
- edgyquant 3y agoWhat is a gram?
- ForOldHack 3y agoA gram is the division of a standard Kilogram (Kg ) into 1000 divisions. It's a poor description to both be circular about it, but the Kg is the standard measure of mass. Look to The definition of the standard kilogram. "Since the revision of the SI on 20 May 2019, we can now compare the gravitational force on an object with an electromagnetic force using a Kibble balance. This allows the kilogram to be defined in term of a fixed numerical value of the Planck constant, a constant which will not change over time." "A Kibble balance is an electromechanical measuring instrument that measures the weight of a test object very precisely by the electric current and voltage needed to produce a compensating force. It is a metrological instrument that can realize the definition of the kilogram unit of mass based on fundamental constants." "One important reason for the change is that Big K is not constant. It has lost around 50 micrograms (about the mass of an eyelash) since it was created. But, frustratingly, when Big K loses mass, it's still exactly one kilogram, per the current definition. When Big K changes, everything else has to adjust."
- kibwen 3y agoBasically 1 gram.
- bbojan 3y ago1/12th of the weight of 6.02214076×10^20 carbon 12 atoms.
- gumby 3y agoI think you mean that 1000 grammes is precisely a kg, the weight of which fluctuates a bit, not that anyone can do anything about it.
- IanCal 3y ago> the weight of which fluctuates a bit, Not sure if this is a joke about weights changing over time or in different places due to gravitational differences - but if you mean mass that was true until fairly recently, the kg is no longer defined by the mass of a specific physical item.
- Uehreka 3y ago(Pulls off edgyquant’s mask) Sorry Derek from Veritasium, you’re only getting one video linked in this thread.
- gumby 3y agoUh-huh, precisely, in Paris.
- whatshisface 3y agoIt could have been 0.5639472942kg just as easily.
- gumby 3y agoI think we need an investigation into why the British Pound isn't allowed to float. The fixed exchange rate between pounds and kg is obsolete and inappropriate for a modern economy and is the kind of thing BREXIT was supposed to free us from.
- bee_rider 3y agoI’m pretty sure a pound could float, as long as it was made large enough.
- Geisterde 3y agoThats, you, what? The british pound is a currency, it is fiat, its exchange value freely floats against other world currencies, it has no objective measure in mass of anything.
- gumby 3y agoOh, how exciting: there are special units of measure for currants, as there are for wood, paper, gold, and so on? Is the the same in all regions where currants are cultivated? It's wonderful that we have different miles and feet for different purposes, and even different exchange rates between them. Let the Europeans suffer under the yoke of the rigid and procrustean french measurement system. Let freedom of expression flourish!
- kbenson 3y agoOr 1.27 USD. Today. According to Google. Which is pegged to some market rate at some time. Which may differ based on your exact location and the conditions in the area. And is expected to be different a short time from now.
- ForOldHack 3y agoSpeed has no existance in space, it requires the passage of time. The one way speed of light can be measured, and is very important to the design of curcits. Anytime you wish to argue this point, take it up with RtAdrm Grace Hopper. I count myself as very very bright, but I do not hold a burning punch card to Hopper. "Since 1 July 1959, the international avoirdupois pound (symbol lb) has been defined as exactly 0.45359237 kg. In the United Kingdom, the use of the international pound was implemented in the Weights and Measures Act 1963. (a) the yard shall be 0.9144 metre exactly; (b) the pound shall be 0.45359237 kilogram exactly." "The kilogram is defined by taking the fixed numerical value of the Planck constant, ℎ, to be 6.626 070 15 × 10-34 when expressed in the unit J s, which is equal to kg m2 s−1, where the metre and the second are defined in terms of the speed of light, , and the hyperfine transition frequency of the caesium-133 atom..." Nothing new. Rando hacker news poster, vs say... the International Standards Organization on Weights and measures. Hmm... I am going to place my faith in say... a group of people who's degrees far outnumber most of the colleges I studied at. No, the speed of light is not defied in the "flattest" one of them. Please do your homework. "The speed of light is a universal constant denoted by c." In my second college physics class, the final exam was one single question: "Derive the speed of light." I got a grade of 4/10, which put me at the top two students in the class. The class was a 5 1/2 month exercise in brutality of math. I would suggest you get a few college physics classes under your belt.
- dilyevsky 3y ago> The one way speed of light can be measured Incorrect. It is two-way you’re measuring. Always. Yes, including in circuit designs
- TheOtherHobbes 3y agoI suspect you may be missing one or two subtleties in this discussion.
- maskedinvader 3y ago> The one way speed of light can be measured. Nope it can't. See https://www.youtube.com/watch?v=pTn6Ewhb27k&t=0s https://www.youtube.com/watch?v=pTn6Ewhb27k&t=0s for a good explanation.