Reddit and its partners use cookies and similar technologies to provide you with a better experience. By this I mean that each of the constants has a certain physical unit attached to it: c represents a speed, so its unit is metres per second. So you know about blackholes, right? It's important to clarify that this line of reasoning doesn't imply that space is discrete (i.e. This is called spacetime glass quantization, as opposed to crystal quantization should the grains be regular. The Planck length is the length one obtain when one multiplies the fundamental constants c (the speed of light in a vacuum), G (Newton's gravitational constant) and h (Planck's constant). When you hear this, you may stop and think, "Surely, if I have a length, then I half it, and I repeat this over and over, I will be able to get to something smaller." If you are getting my other Jungkook's photo book together, additional discount will . Scientists are big on observability. See our. I was soon set right. Any thoughts? The Planck constant is the relationship between the energy of a photon and its frequency, and I don't know how that's quantised, so I'll put that aside. The theories, in a sense, do not really work if evaluated to the finest finest details in a rather similar sense to the gravitational force becoming infinite once you bring two masses to the same point. So, how does a tiny number such as this tie into physics? For example, our understanding of the Big Bang does not . [quote]There is a misconception that the universe is fundamentally divided into Planck-sized pixels, that nothing can be smaller than the Planck length, that things move through space by progressing one Planck length every Planck time. Im a bit out of my element talking about this, so Ill be brief. Quantum field theories are different to classical gravity because to determine the actual prediction of an experimental setup you need to sum over ALL POSSIBLE PATHS that might happen. Still, until a better theory of quantum gravity is devised, the Planck length is the best estimate we have for a minimum length. The Planck time is the time it takes for light to traverse a Planck length. G/c3, one gets a length. A Planck length is 1.6 x 10^-35 meters (the number 16 preceded by 34 zeroes and a decimal point) an incomprehensibly small scale that is implicated in various aspects of physics. The Planck length's derivation includes the gravitational constant, which doesn't feature in 'plain' quantum mechanics. Eli5; how we find patient zero when there is disease eli5 When countries swap prisoners how are they sure the ELI5: Why do we (Anglophones) use the native language Eli5: What is the difference between soldering and welding? To put this into perspective, if we scaled the proton up to the size of the observable universe, the Planck length would be a mere trip from Tokyo to Chicago. Visualizing the smallest size in the universe - Planck Length & why you can't go smallerVisualizing Planck length - why is it the smallest in the universe? Another way to think about the Planck length is that if you try to measure the position of an object to within in accuracy of the Planck length, it takes approximately enough energy to create a black hole whose Schwarzschild radius is the Planck length! The Planck length is always the same regardless of the unit used to measure it, because it is the smallest unit that can be measured using the fundamental units of the universe. How do they not work usefully anymore, and why can't you just divide it in half? What is a zeptosecond? However, from the point-of-view of a passing neutrino; with its velocity negligibly below the speed of light, that same light bulb could be producing light with wavelengths less than the Planck Length. Hypothetically, if we met a group of aliens and wanted to discuss weights and measures, we could use Planck units and theyd know what we are talking about. In fact, if an atom was the size of the earth, a planck length would be smaller than the size of an atom it would be about the size of a proton. The Planck scale, which stretches for a total of 1.6 x 10 x 35 meters, can be thought of in a variety of ways. Or your head could be on the moon and the rest of you in your chair. But absent a candidate theory based on this discrete paradigm, theres also nothing to discuss under the Physics Forums rules. So, at the Planck scale, we can't actually say that anything is there at all to measure? Physics isn't quite up to handling that, yet. Bots and AI generated answers on r/explainlikeimfive. The Planck -Balance (PB) is a table-top Kibble balance and is currently under developmen t in a collaboration between Physikalisch-Technische Bundesanstalt (PTB) and Technische Universitt. Well to measure things, we have to bounce light, or other particles off of the thing we want to measure. This basically lets us swap out the electromagnetic constants e and ##\epsilon## with the more general constants ##\hbar## and c. The Coulomb energy now looks like this: This is where the hand-waving will begin. If the Planck length is really the smallest scale at which the notion of length is meaningful, then space itself is pixelated at the lowest levels. So why is the Planck length thought to be the smallest possible length? The glassy properties of the quantization help it escape the usual problems with Lorentz invariance. On the topic of the Planck pixel, perhaps this overall idea is being rejected too sweepingly. As I mentioned earlier, just because units are natural it doesnt mean they are fundamental, due to the choice of constants used to define the units. Using the slide bar on the bottom, zoom in until you find a hydrogen atom. Now, this doesn't necessarily apply when we're talking photons. I remember in my early teens reading about the Planck time in National Geographic, and hearing about Plancks constant in highschool physics or chemistry, and thinking they were the same. So I would imagine that if someone wanted to formulate a theory that said spacetime itself was parceled into Planck pixels, they would play the usual game that in different reference frames, meaning along different world lines, the pixels would distort, but theyd still tile the spacetime in the same way. Deriving the Planck Length. I do understand the argument that the Planck length is not fundamental cause there is quite some choice left when it comes to defining such a length. Or a big beachball, which can be found near oceans and beaches all across America. I'll try to translate, glossing over the math. Once r becomes 0 this formula becomes ill defined (division by zero.). And ten times smaller than even bacteria. I could grab a measuring tape and check, but that would only tell me approximately my height - because the marks might only be as detailed as each centimeter. tional categories, is overwhelmingly irreversible. Why, though? (3) [itex]gamma approx frac{10 times 10^{12} }{1times 10^{-3}}=10^{16}[/itex]. categories never become prototypical lexical categories, and less radical. But the observer flying away would find that the wavelength of the same photon was larger than the Schwarzschild radius of the photons energy. This thread is closed. What is the most interesting object that you found and why? [QUOTE=BiGyElLoWhAt, post: 5224337, member: 496972]I cant remember what its called, even enough to search it via google, but there is actually a solution to this problem. Thank you. You don't notice this, because on any human-sized scale (commonly referred to as "macro" scale), the probabilities are so ridiculously, laughably small that it never comes up (one of the common examples is calculating the probability that you will suddenly appear on the far side of a wall you are leaning against; that probability is so small that you could wait more than the expected lifetime of the universe and it still should never happen). Simple questions sometimes require detailed answers. [/COLOR] But the claim that an objects actual mass has increased (and hence its capacitiy to pull other objects toward it by gravity) is NOT well supported by any reasoning Im familiar with. To see how the calculation works, go here: [URL]http://math.ucr.edu/home/baez/lengths.html#planck_length[/URL][/QUOTE]. You would think that we are getting close to the smallest size theorized to exist the plank length. [/QUOTE], [QUOTE=OCR, post: 5227637, member: 358681][URL]http://math.ucr.edu/home/baez/lengths.html#planck_length[/URL], Fixed that for you[COLOR=black]..[/COLOR] :oldsmile:[/QUOTE], Aww, gee thanks for the help[COLOR=black].:oldeyes:.. Now we are going a hundred times smaller than the width of a human hair. At this level, there is a number that goes so far beyond the conventional understanding of 'small' that it's truly hard to fathom. I think. And the reduced Planck Constant h bar, which links how much energy a photon carries depending on its electromagnetic frequency. Remember the gravitational force is M1 * M2 * G / r2. The gravitational constant G, which signifies the magnitude of gravitational force between two massive objects. View solution > Specific heat of hydrogen at constant pressure, C p = 2 9 joule k e l v i n 1 m o l 1 (a) Find dimensions of C p . As for myself Im taking serious the idea, that all our established physical theories (including GR and QM) are effective theories in the sense, that they dont express anything fundamental about the ultimate nature of reality, but instead are approximations to the inner workings of reality in the discrete paradigm. [/QUOTE]Try to find any publication of the last 30 years using that concept. The meter is a useful unit for measuring length, but theres nothing inherently special about it. What I dont understand is how you can take arguments from the continuous paradigm (which is theories in terms of differential equations on real numbers) and argue about the invalidity of ideas from the discrete paradigm (universe being pixelated, things moving at the speed of light one unit at a time, ). Thank you for your explication, hand-wavey or not, of the Planck length, because I was a victim of the (erroneous) Planck-length = pixel size fiction as well. So what I took from you post is that the Planck Constant is the closest possible measurement you can have, even though both measurements will never be 100% accurate. In that sense, an object could appear to move one Planck length each Planck time, and not seem to move at the speed of light, if the Planck length was interpreted broadly as also existing in the time dimension. The smaller the wavelength of light you're using, the more energy it has. A chip-scale broadband light source in silicon carbide Optical frequency combs have changed science and technology as we know it. The duckweed because it looks like a dot or something. * By taking different combinations of these variables, one can find Planck units, which are truly universal. Moving forward, I will be investigating the physics of non-covalent chemical bonds using DNA chainmail and exploring non-equilibrium thermodynamics and fluid mechanics using protein gels. It is the scale and size of the strings in string theory. The gravitational force attracting the matter, causing concentration of the matter in a small space and leaving much space with low matter concentration: dark matter and energy. This poses a problem though. Score: 4.7/5 (22 votes) . So why is it the smallest length? A photon has no mass so by definition it has no gravitational attraction to the test particle. Have you considered the idea of extremely high blueshift reference frames? Any thoughts?[/QUOTE]. 2009), but a common feature is the evolution of large and small growing ecotypes along resource and/or habitat gradients in the lake environment. Hand-wavy is the name of the game here! To get an idea of why this is important, think about the difficulties associated with expressing lengths in meters versus feet. Eur. Thank you for that insight. It is possible that at lengths smaller than the Planck scale, gravity or quantum mechanics behaves completely differently, that we may not yet know about. And roughly equal to 1.6 x 10-35 m or about 10-20 times the size of a proton. My research is at the interface of biological physics and soft condensed matter. please mark me brain mark list Advertisement Advertisement Phys. For that, we need to turn to quantum mechanics and, specifically, a thing called the Heisenberg uncertainty principle. [/SIZE][/QUOTE] at [URL]http://www.pbs.org/wgbh/nova/next/physics/fastest-neutrino-ever-detected-has-1000x-the-energy-of-the-lhc/[/URL], So with a bit of estimation, assuming (1) the rest mass energy of a neutrino is about equal to 1 meV, (2) oncoming blueshift is approximately equal to the lorentz contraction factor here. Neglecting factors of 2, we have ##m_nu m_P = 3 eV cdot E_nu## where the lightest neutrino mass is probably of the order of 1 meV. In fact a planck volume which is planck length cubed or about 4X10^-105 cubic meters is so small that there are more planck volumes inside a cubic meter than there are cubic meters in the known universe. Most likely it would be some kind of ultraviolet cutoff to doing path integrals in spacetime, or some such thing. Fixed that for you[COLOR=black]..[/COLOR] :oldsmile: BTW, Ive been there many, many times[COLOR=black]:oldwink:[/COLOR]. We are neglecting the rest masses of the charges, but those are much smaller than the interaction energy. The Planck scale combines the quantities used in relativity, quantum mechanics and gravity (c, h and G). Moreover, any effects of quantum gravity at this scale(if there are any) are entirely unknown as space itself is not properly defined. From my point of view this chain of argument is invalid, exactly because the continuous paradigm breaks down around the scale when spacetime supposedly becomes discrete. Presumably, the pixels would be in 4-D spacetime, not 3-D space, and volumes in 4-D spacetime are invariant, are they not? Why is this page out of focus? My first text that I read on SR had a thought experiment with 2 bouncing balls and 2 observers, and used it to demonstrate relativistic mass. In 1899, German physicist Max Planck proposed a universal set of units for length, time, mass, temperature and other physical qualities. Some Planck units, such as of time and length, are many orders of magnitude too large or too small to be of practical use, so that Planck units as a system are typically only relevant to theoretical physics. But Mead was curious about quantifying gravity's negligible effect. The Planck length is an extremely small distance constructed from physical constants. I would probably go the other way Obviously if your theory implies that something is turning into a black hole according to one observer, but is not turning into a black hole according to another observer, then your theory has been essentially discounted by reductio ab adsurdam. At about the Planck time after the big bang, it is thought that gravitation would separate from the three other forces of nature (strong, weak and electromagnetic forces) Thanks! So now we can apply the uncertainty principle in the perpendicular direction The text of the P X greater than or equal to h over to pie now because we know that this is the ball is initially constrained within this cube of ah, with cube side length of point zero five meters. And as you probably know, the Universe was born in the Big Bang and expansion began from that infinitely dense point. Click the atom. The only unit of time shorter than a zeptosecond is a yoctosecond, and Planck time. Though, black holes do eventually evaporate, and they evaporate faster the less mass they have. The smallest lenth theorized to be possible, the Planck length is about 4 X 10^-35 meters. Thus, the Planck length is the smallest possible unit of measurement. One of the remarkable things about Planck length is that since it is derived from the fundamental constants of the universe, which by definition applies to everything, it will be the same no matter what language you might speak, what units you might use, or even what planet you might come from. From Newtonian gravity, we can calculate the gravitational energy associated with our charges. Thanks for the link, and for the advice. Yes that means objects dont move one Planck length every Planck time, but thats obvious any such object would be perceived as moving at the speed of light. The first reason is that the Planck length and time aren't actually the smallest increment on space-time (as far as we know there is no minimal increment). This is a Premium document. It has the value: l P = 1.62 10-35 m. In SI units, measurements of length are made in metres (usually given the symbol m). Some people may argue that neutrino observers are not valid, because they have no ears, no eyes, and no souls, and that their reference frame doesnt exist. Until we have that, any theory will be pretty much guessing, in my opinion. So we solve for r. So why is the Planck length thought to be the smallest possible length? is 10-22 meters, about ten-trillion Planck lengths. Just imagine things that are about the size of your body. String theorists also think that it is the size of the vibrating strings that make up all the elementary particles in the standard model. The measuring particle is usually a photon (but not always). Want a phrase defined? Im not going to argue within the last 30 years. So to completely oversimplify things, it's the closest you can get to a particle with a quantum energy of "1" without being sucked into its own little black hole, and becoming indistinguishable from it. Recursively sort the rest of the list, then insert the one left-over item where it belongs in the list, like adding a . Most likely it would be some kind of ultraviolet cutoff to doing path integrals in spacetime, or some such thing. There was an analysis recently of gamma ray arrival times from a burst in a distant galaxy. Remind that the regular Bardeen/Hayward/Frolov black holes do not su er from this weak point because . https://www.physicsforums.com/insights/wp-content/uploads/2015/09/planck.png, https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png, What Planck Length Is and Its Common Misconceptions, 2022 PHYSICS FORUMS, ALL RIGHTS RESERVED -, Struggles With The Continuum: Quantum Mechanics of Charged Particles. Im glad to have a good article now to point people to, when it comes up again. When you scatter a particle of light off another particle say an atom the atom's gravitational attraction to the light particle causes an intrinsic uncertainty in the atom's location. It may also be true that quantum mechanics fails before you get to the Planck length. Now lets change the units around, using the definition of the fine structure constant ##\alpha##, which is roughly 1/137. If a given volume at rest has a certain amount of energy within, it will have a rest mass m=E/c##^2##. What is Planck length? I would indeed think that if one wishes to regard spacetime as in some sense coarse-grained at the Planck scale, one must use a version of coarse-graining that is Lorentz invariant, meaning that the grains are defined by their volume but not their shape. There is a surreal and amusing dialogue trying to get to the bottom of this, that you can still read in the discussion section of the Planck length Wikipedia page. This is nanometers, or one billionth of a meter. The Planck length is just the smallest we think is measurable. $$r=\sqrt{\frac{\alpha\,G\hbar}{c^3}}=\sqrt{\alpha}\ell_{p}$$. There are a lot of misconceptions that generally overstate its physical significance, for example, stating that it's the inherent pixel size of the universe. As for myself Im taking serious the idea, that all our established physical theories (including GR and QM) are effective theories in the sense, that they dont express anything fundamental about the ultimate nature of reality, but instead are approximations to the inner workings of reality in the discrete paradigm. Or you might be on the moon. As always, PM me or another mentor if you have more to add and want it reopened. On any computer screen you can't have anything smaller than a pixel, same applies for the universe with 1 Planck length. This is one trillionth of a meter. There is a misconception that the universe is fundamentally divided into Planck-sized pixels, that nothing can be smaller than the Planck length, that things move through space by progressing one Planck length every Planck time. $$\alpha=\frac{e^2}{4\pi\epsilon}\frac{1}{\hbar\,c}$$. This is on the scale of the size of molecules like DNA and the glucose molecule, that your body uses as its source of energy. Coulomb constant k. Units: ((mass)(length)3)/((time)2(charge)2) The Planck length is the distance at which quantum fluctuations lead to tiny black holes. It is defined as: This is how far light can go in a unit of Planck time, because the speed of light is the Planck speed. In SI units, this is on the order of 10-35 meters. For instance, by taking E-mail today@fnal.gov. Yes that means objects dont move one Planck length every Planck time, but thats obvious any such object would be perceived as moving at the speed of light. Just imagine things that are about the size of your body. How was Planck time determined? If I remember correctly (I very well could not), it has to do something with the geodesics of spacetime warping under the energy tensor from the relative speed of you and the mass youre observing. Units: ((mass)(length)2)/(time) One of the only physical systems where quantum gravity is relevant is the black hole. Suppose I wanted to measure my height. Also, being a black hole, or NOT being a black hole is an intrinsic feature of matter. extremely rare. I would be interested in hearing more about this. But on the extremely small "micro" scale, this squishy smearing of particles' locations becomes very significant - in quantum mechanics, you talk of them as having probability distributions or probability smears - a particle is probably in this area but it might be in these other areas instead). It seems to me what the author is saying [][/QUOTE]Hint: compare the user name with the url. I believe the problem is with the premise than an objects mass increases as it approaches the speed of light. It is roughly the distance things have to be before you start to consider hmm I wonder if theres a chance this whole system randomly forms a black hole. I did not really understand this until I convinced myself with the following derivation, which was the main inspiration for this article. But what does this length mean? If there is a rest frame in which the matrix of these Planck-pixels is isotropic, in other frames they would be length contracted in one direction, and moving diagonally with respect to his matrix might impart angle-dependence on how you experience the universe. GR does not predict the collapse of something just because it moves at high speed, independent of the reference frame chosen to describe the system. This is on the order of the wavelength of gamma rays. Light with a wavelength of smaller than the planck length has so much energy, that anything it interacts with will become a very tiny black hole. made of pixels). Light with a wavelength of smaller than the planck length has so much energy, that anything it interacts with will become a very tiny black hole. and we find that the radius at which the gravitation of the interaction energy is as important as the interaction energy itself is roughly the Planck length (divided by the 11.7, the square root of 137, but well hand-wave that away for now). The observer flying toward it would find that the wavelength of the photon was smaller than the Schwarzschild radius of the photons energy. Indeed it is. Planck length is calculated from the speed of light, the gravitational constant, and the Planck constant. Judging by the ultimate source, [URL=http://i.imgur.com/92cqoCk.png]a cursory search of reddit questions[/URL], the misconception is fairly common.[/quote]. I believe the problem is with the premise than an objects mass increases as it approaches the speed of light. However, this is an occasion where physics doesnt allow something that mathematics does. In 1964, C. Alden Mead published a paper in which he determined the effect of gravity on a phenomenon called diffraction, which describes what happens to light when you send it through a small aperture. :biggrin: Nice post! Just imagine things that are about the size of your body. [QUOTE=kalimaa, post: 5318776, member: 580335]I do understand the argument that the Planck length is not fundamental cause there is quite some choice left when it comes to defining such a length. The simple summary of Mead's answer is that it is impossible, using the known laws of quantum mechanics and the known behavior of gravity, to determine a position to a precision smaller than the Planck length. A classical 4D planck volume of one planck length in spatial directions and one planck time in time direction would be crossed by light diagonally, as light moves by one planck length per planck time. I am interested in using tools provided from biology to answer questions about the physics of soft materials. . Im pretty sure Ive seen this point made explicitly in some texts, but at 43, Im well into my fifth decade of memory failure.[/QUOTE]. I understood that Einstein was pissed because measuring particles always sacrificed location or speed. Disclaimer: I'm just interested in particle field theories from an amateur point of view. But we are nowhere close. Or a big beachball, which can be found near oceans and beaches all across America. The reason is that to measure a length you must have something with a wave length no larger than the object. This is where it is important: if things are interacting at distances close to the Planck length, you will have to take quantum gravity into account. In some cases, a Planck unit may suggest a limit to a range of a physical quantity where present-day theories of physics apply. Students also viewed. It's not the smallest possible measurement of length - you can always define a new unit that is half a plank length, or a quarter. The more accurate you measure something, the more energy/mass you need to counter inaccuracies. It is also smaller than you can imagine. At the nuclear level, the magnitudes of energy are very small. The Planck length is the fundamental unit of length in the system of Planck units. A slightly more technical explanation can be found here. The Planck length does have physical significance, and Ill talk about what it is, and what it isnt. So suppose we send one particle shooting at another particle we want to know the location of. Why is it significant?It is the smallest length at which gravity would have an effect. The Planck Length is the smallest length at which our current laws of physics still work. Also, if we think of the Planck pixels as being in spacetime, their 1-D version also takes on some kind of meaning. Probably end up more like an "Explain Like I'm 15" too. Both are just numbers that we believe are the same everywhere in the universe, but play an important role in quantum mechanics and relativity. Ao, if we ever come across aliens from another world and compare notes, we both will have the same length for the smallest length possible in the universe. Because gravity is so incredibly weak compared to the force that governs the behavior of light (the electromagnetic force), its effect is completely ignored in diffraction calculations. I have an idea as to where the misconception might arise, that I cant really back up but I will state anyway. Darn my memory, and Im only 23! Body length and sexual maturity status were recorded in . This is quite possible. [USER=268035]@JDoolin[/USER]: That neutrino would need an incredible energy. Im not a fan of this theory, but there is an idea that spacetime is divided into pre-existing [I]irregular[/I] grains of 1 Planck volume. So why is the Planck length thought to be the smallest possible length? So until we find out what happens at such small scales, we will need to wait for a future Einstein to reveal this to us. This is called spacetime glass quantization, as opposed to crystal quantization should the grains be regular. Learning electronic charge density fingerprints for material property prediction using 3D neural networks. Planck himself said in his paper to the Prussian Academy of Sciences, "These necessarily retain their meaning for all times and for all civilizations, even extraterrestrial and non-human ones, and can therefore be designated as 'natural units.'". 3s, 3p and 3d ) are Before we place electrons into atomic . Roderich Moessner, Joel E. Moore - Topological Phases of Matter-Cambridge University Press (2021) - Free ebook download as PDF File (.pdf) or read book online for free. So I think what we really need are experiments that are capable of looking for evidence of discreteness. #plancklength Now we are exploring a universe that we cant see with optical telescopes. If it turns out that at very small lengths, some other version of quantum mechanics manifests itself or the law of gravity differs from our current theory, the argument falls apart. These are things like the shrew, or a chicken egg.Now lets go a thousand times smaller than the scale of a human being, on the order of 1 millimeter or one thousand of a meter. By accepting all cookies, you agree to our use of cookies to deliver and maintain our services and site, improve the quality of Reddit, personalize Reddit content and advertising, and measure the effectiveness of advertising. That's a decimal point followed by 20 zeroes and a 1, and it looks like this: 0.000 000 000 000 000 000 001. What is the smallest possible time? The Planck length is not useful for measuring any length, but is there anything special about it? J. In a sense, you could say that, even if we were to develop methods of measurements that took us down to these scales, we would never be able to measure anything smaller despite any sort of improvements to our equipment or methods. FACT: Planck time is the time it takes a photon to travel, in a vacuum, a distance of 1 Planck length.A Planck length can be derived from an equation that considers the gravitational constant and light. This is 1X 10^-15 or one quadrillionth of a meter. Since the photon will never come out predictably, you can't measure that which is smaller than the planck length. There is a push towards making our human units based on physical constants, like defining the meter in terms of the speed of light, but at this time the kilogram is still the mass of a brick in France. Things like the giant earthworm that lives along streams in Australia. smaller distances may exist but can not be measured with higher accuracy, high enough resolutions. In fact, the first iteration of string theory was theorized to explain nuclear physics rather than gravity, and the length-scale of the strings was much much larger. Is that true? [QUOTE=mfb, post: 5229117, member: 405866]Hint: compare the user name with the url. How is Planck length defined? It is brand new, only opened to see the random photo card. The example provided on the wiki page that I remember used larger masses, as opposed to photons. The example provided on the wiki page that I remember used larger masses, as opposed to photons. Medium. "The Planck length is the scale at which classical ideas about gravity and space-time cease to be valid, and quantum effects dominate. This black hole will evaporate immediately, belching out the photon you tried to measure it with, but in a random direction. At that distance, ordinary geometry completely fails. This is because contrary to how it seems in day-to-day life, objects do not have a single point location. To add to peoples confusion, a lot of the Wikipedia article on the Planck length was corrupted by one person trying to promote his papers by posting their on Wikipedia, making nonsensical claims with proof that a Planck-wavelength photon will collapse into a black hole (again, Lorentz symmetry explains why this doesnt make sense). Copyright , Camden Media Inc All Rights Reserved. Nothing. I guess it's all downhill from here =/. Prototypical functional. Cards are in perfect condition. For example, think about moving faster than the speed of light. The simplest reason that Planck-pixels dont make up the universe is special relativity and the idea that all inertial reference frames are equally valid. This black hole will evaporate immediately, belching out the photon you tried to measure it with, but in a random direction. Why can't we measure smaller than a Planck length? It is really small. ELI5: Why do pidgeons appear to peck the ground even when ELI5: Why is it considered unhealthy if someone is ELI5: if procreating with close relatives causes ELI5: What prevents people in a coma from waking up? Don't Panic! We received an email from Bill G., an inquisitive reader: "It is said that the Planck length is the smallest length possible. Planck units are defined based on physical constants rather than human-scale phenomena. [/quote] The measuring particle will transfer some energy to the test particle but it will be from its kinetic energy not gravitational attraction. [QUOTE=john baez, post: 5227634, member: 8778]Nice post! That said, this is the most straightforward argument I've seen for it. http://math.ucr.edu/home/baez/lengths.html#planck_length. The question now is: at what distance is the electrostatic energy equal to the gravitational energy it causes? The 14-hour flight may seem long to you, but to the universe, it would go completely unnoticed. I've never understood this so I took a stab at the related Wikipedia articles to try to digest it. A modern treatment of Planck's work begins with the speed of light c, gravitational constant G, reduced Planck constant , Coulomb constant k and Boltzmann constant kB. If a minimum length scale exists in the universe there's a very good chance it's equal to the Planck Length Lp, which is why 1/Lp = 6.187 x 10^34 is my choice for #MegaFavNumbers. Neglecting factors of 2, we have ##m_nu m_P = 3 eV cdot E_nu## where the lightest neutrino mass is probably of the order of 1 meV.[/QUOTE]. The smaller the wavelength of light you're using, the more energy it has. Thanks to John Baez and Nima Lashkari for answering some questions about quantum gravity. Pay attention to that repeated word "known." Basically it says that as you approach the speed of light and pass a large mass, it can't turn into a black hole due to your reference frame. This is the highest energy electromagnetic radiation, consisting of the most energetic photons. You have to go a quadrillion times smaller than one quadrillionth of a meter, or 1 X 10^-30 of meter.and you would still need to go another 100,000 times smaller than that, or 1 X 10^-35 meters. Another way to think about the Planck length is that if you try to measure the position of an object to within in accuracy of the Planck length, it takes approximately enough energy to create a black hole whose Schwarzschild radius is the Planck length! An objects MOMENTUM increases as [tex]p = frac{m}{sqrt{1 (frac v c)^2}}v[/tex]; I feel that has been pretty well reasoned out. There is nothing in established physics that says this is the case, nothing in general relativity or quantum mechanics pointing to it. Consider the energy (E) between two charges (lets say theyre electrons) at some distance r. Doesnt really matter if theyre attracting or repelling right now. Going beyond established physics, is there more of a roll for the Planck length? In fact, Planck's constant changes over time, since it is associated with the electromagnetic field through which interactions in the atom take place. When calculating the entropy of a black hole, Hawking and Bekenstein found that it was equal to the number of Planck areas (Planck lengths squared) that can fit in the cross-sectional area of a Schwartzschild black hole (or a quarter of its total surface area), in units of the Boltzmann constant. The smallest lenth theorized to be possible, the Planck length is about 4 X 10^-35 meters. How can it have any gravitational pull? ELI5: Why are fridges in cold climate countries not Press J to jump to the feed. Planck Length: Smallest Thing in the Universe.This video gets to the Planck at around 4:00, it's a good common language introduction. Could be Theres no way of disproving the possibility. However, the Planck number has proved useful in a number of different equations that have helped us to calculate and probe some of the deepest mysteries of the Universe. [QUOTE=Ken G, post: 5224660, member: 116697]On the topic of the Planck pixel, perhaps this overall idea is being rejected too sweepingly. false false Insertion sort: Split the input into item 1 (which might not be the smallest) and all the rest of the list. Any thoughts? You could never figure out both at the same time. 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