Planck Definition and 381 Threads

I was thinking about the special theory of relativity and how as one approaches the speed of light, ones length contracts. what I would like to know is: If I had an object and I accelerated it towards the speed of light and it contracts in the direction of travel, what happens when it reaches...

Hello there, Plack law of radiation $$ B(\nu) = \frac{2\,h\,\nu^3}{c^2(e^{h\nu/kT}-1)} $$ I want to show that for small frequencies, Reyleigh-Jeans law: $$ B(\nu) = \frac{2\nu^2kT}{c^2} $$ is correct. I take the limit of Planck law as ##\nu \to 0## using l'hopital rule: $$ \lim_{\nu \to 0}...

Planck dust modeling has been released [re: http://arxiv.org/abs/1409.2495] . It appears to be consistent with the assumptions of BICEP2, but, that is an unsupported assumption. I expected an immediate reaction from the BICEP2 team, or other interested parties. Perhaps I am merely impatient, or...

Suppose you meet a layman who has not even had Freshman-level college physics, but who has HEARD of or read something about Planck units and is curious about them. How would you go about explaining? Maybe it's obvious to some people how to do it, or maybe you have already had that experience...

All - my first post, and as a lay person interested in quantum physics, forgive me if my questions are naive or ill-informed. Is it possible that the Universe inflated then exploded into being from a singularity smaller than Planck length? If I understand the concepts properly, the Planck...

I see there are new BH theories: "Planck stars" and "no Hawking radiation but a bounce in slow motion" What's about old BH puzzles from that point of view: rotating BH, overextreme BH, naked singularities? Do these theories favor Einstein-Cartan over classic GR?

If so, is 'its half' also not a real size of space? What I am asking is pretty much; what is the meaning of the notion of a 'smallest possible' 3d area? What is the meaning of that cusp between 2d and 3d? Almost like asking what is in between 1.999999999999(repeating) and 2. Must...

Every time i see it it's different. I want the full Planck constant(every number) and is there any proof for the constant?

After reading an article on Planck length, I began to wonder whether or not the theoretical limit implied that position could be quantized in whole integer multiples of Planck length? To demonstrate what my question is asking mathematically I hope you will scrutinize the equations below: If...

Recently I have taken an interest in physical constants (and, through it, an interest in SI units and the upcoming redefinition of the kilogram). I actually have a list of almost all of them now, standard uncertainties included. After a bit, I decided to have a bit of fun messing around with the...

An interesting blog post arguing the reason that BICEp 2 and PLAnck are in tension is becuase BICEP 2 underestimated galactic foreground emission. http://resonaances.blogspot.co.uk/2014/05/is-bicep-wrong.html

To estimate polarized emission from the galactic dust, BICEP digitized an unpublished 353 GHz map shown by the Planck collaboration at a conference. However, it seems they misinterpreted the Planck results: that map shows the polarization fraction for all foregrounds, not for the galactic dust...

This paper; http://arxiv.org/abs/1404.4614, Negative running prevents eternal inflation, claims Planck and BICEP2 data favors negative running of the spectral index of curvature perturbations from inflation at the 2 sigma level. It further asserts this is sufficient to preclude eternal inflation.

Hi Bear with my possible ignorant. I am puzzled over this dilemma. If General Relativity states that gravity is the curvature of spacetime, that is, no spacetime no gravity, and the cause of curvature is matter (mass), it means that if no matter, there is no gravity. I understand that...

Is there a relation between these two distributions ?

Hi all. This is my first time posting so forgive me If I am doing something wrong. I am a year 7 student interested in all types of physics and my question is, if nothing can be smaller than Planck length then wouldn't past a certain point the digits of pi become obsolete? Simply because the...

While Planck time is usually regarded as the shortest unit of time, isn't the shortest unit of time that can exist is the time it took to go from absolute time, the big bang, to everything after that i.e. local time? Did local time exist at the instant of the Big Bang?

Just curious. The Planck length is lpl = (hG/c3)1/2 = 10-33cm And it seems intuitive that it's c cube because space has three dimensions for the action. But the Planck time is tpl = (hG/c5)1/2 = 10-43s So is there some obvious physical reason why c is to the power of five here?

Homework Statement Starting from the Planck-Body Law I_{λ}dλ = \frac{2\pi c^{2}h}{λ^{5}} \frac{1}{e^{hc/(λkT)} - 1}dλ where λ is the wavelength, c is the speed of light in a vaccuum, T is the temperature, k is Boltzmann’s constant, and h is Planck’s constant, prove that the total energy...

Planck star is a proposed new idea which, if it gains support, will change how we think about "black holes". One can think of a Planck star as a slow-motion bounce that because of extreme time-dilation can take hundreds of billions of years to mature. When it finally does, the star breaks...

I just logged this on the biblio thread. This is in case there are questions, or things people want to discuss. http://arxiv.org/abs/1401.6562 Planck stars Carlo Rovelli, Francesca Vidotto (Submitted on 25 Jan 2014) A star that collapses gravitationally can reach a further stage of its...

So, the three very small quantities: Planck length Planck mass Planck time Does the physical interpretation actually mean for example that when something moves, the smallest distance it can move is one Planck length, that there's no such thing as moving half a Planck length? And further...

Is it true that the energy in electromagnetic waves can only be released in "packets" of energy? Or is this only the case for a system where a standing wave change from one mode to another which results in sending out an electromagnetic wave (photon). In other words if I ride on my bike...

This is part b) of an assignment question. In part a) we were asked to derive the Fokker Planck relation for the biased random walk. The answer is: dP/dt = -vdP/dx + D d2P/dx2 Where the first term is the drift term due to the biased motion and the second term is the diffusion term. Then...

I worked out the Planck Black-Body Radiation Formula using Bose-Einstein Statistics, but I feel there is something conceptual I am missing here. When Planck derived the formula, he started out with the Boltzmann distribution function, and assumed that there were discrete energy levels...

Hello, I have recently been reading some texts focusing on modern physics. Both include sections on Planck and how he arrived at the conclusion that energy is not continuous. However I am confused as to what conditions inspired him to make this leap. I am aware of the Ultraviolet Catastrophe...

I was thinking, given than h, c and G have different units, I can not compare a unit to other. But when we say that the quantum path integral recovers classical mechanics for very small h, there it seems we have a sense of how small h is. So, h is small... respect to what? Is it respect to E...

Is there any experimental or observational evidence that conclusively shows gravitational forces acting on mass that is less than the Planck mass? thx

Does anyone know if Max Planck knew about the Boltzmann distribution before he published his results in 1900? Also, when Planck introduced h, did he also give the value?

what if the evolution of the universe over time and the expansion of space a series of binary events such that the same quantity of energy is divided geometrically from one into two, four, eight, sixteen pieces, such that each Planck time is equivalent to one such split and each Planck length is...

What are the properties of a photon with Planck energy? Is it even possible to interact with it, or does it just travel trough all matter?

Meissner et al just posted a paper where they see those circles in the high res. microwave sky of Planck. Who knows if this is real, or what it would mean if it were confirmed? Meissner has a followup paper in preparation with Penrose and others. Either way I think it's pretty interesting...

Hope someone can clear this up for me, is Planck time the shortest possible time in which a particle or quark or anything can perform some kind of action? Also is Planck length the shortest distance in which an object can actually move? Anything shorter than that and the object doesn't mean...

I have always understood Planck time as being the the smallest amount of time that has any physical significance and the Planck scale as being the region where space and time collapse on each other and all of our mathematics fail. Why are these seemingly magic numbers the end all be all of...

Ive been reading lately about the Planck constant and have been trying to learn more about it if possible. The way I understand it, the constant came about from experiments with black body radiation. Planck noticed that the experimental data fit the equation e=hf. My first question: how...

has it been proven that space and time are quantized in the Planck length and Planck time?

Is there an intuitive explanation of why E/w = 2*L, where E/w is the ratio of the energy of any photon to its angular frequency and L is the magnitude of the spin of any electron? Evidentially there is a mathematical derivation of L=hbar/2 from some base assumptions, and evidentially E=hbar*w...

From Wikipedia: http://en.wikipedia.org/wiki/Googolplex A Planck space has a volume of a Planck length cubed, which is the smallest measurable volume, at approximately 4.222×10^-105 cubic meters = 4.222×10^-99 cubic cm. Thus 2.5 cubic cm contain about a googol Planck spaces. There are only...

I don't know whether this has much general interest. I am interested by communication horizons in cosmology, or causal horizons if you prefer. This paper claims to study several cases including how far apart two quasars would have to be to have been out of contact ever since the end of the...

Homework Statement The average energy of a harmonic oscillator is written using Boltzman statistics as: <ε> = (<n> +.5) = \frac{\sum_{n} ε_{n} exp \frac{-ε_{n}}{kt}}{\sum_{n} exp \frac{-ε_{n}}{kt}} Expand the expontentials and hence derive the Planck Occupancy <n> = n(ω,T)...

I've recently heard of Planck Time.. I read that it is the minimum time interval that can EXIST. What exactly changes in time intervals that are less than Planck time? And if I am not mistaken by the meaning of Planck Time; What is the reason that there is such a limit? For Example, the...

Homework Statement The information is on the attachment the plank is uniform meaning the mass of the plank is uniformly spread so the center of gravity is in the mid point of the plank.The plank is in equilibrium.Find the weight of the plank,Let the weight be w. Homework Equations...

http://pirsa.org/13040123/ Results and highlights from Planck Speaker(s): Kendrick Smith Abstract: Cosmological results from Planck, a third-generation satellite mission to measure the cosmic microwave background, have just been announced. These results improve constraints on essentially all...

Homework Statement Prove that the Planck function increases monotonically with temperature. Homework Equations Bv(T) = 2hv3c-2(ehv/kT - 1)-1 The Attempt at a Solution I first went through this piece-by-piece, but I am not a mathematician so I don't know if this constitutes...

Planck team published several sets of of basic cosmic parameters in their report http://arxiv.org/pdf/1303.5076v1.pdf see for example Table 5 on page 22. The rightmost column of Table 5 is labeled "Planck+WP+highL+BAO". That seems to be the set of numbers that Ned Wright chooses to report, for...

I figure that we need a thread specifically for this topic, while we try to sort out just how minimal physics could be, in the wake of the Moriond conference on the Higgs and the data release from the Planck collaboration. Fedor Bezrukov has written many papers on Higgs inflation, and curiously...

Here's a sample history from fairly far back in the past, going up to the present (S = 1) in 20 expansion ratio steps, and then in another 20 expansion steps, going out a good stretch into the future, when distances will be 25 times what they are today. I could have asked for a wider expanse of...

Universe as an Infant: Fatter Than Expected and Kind of Lumpy http://www.nytimes.com/2013/03/22/science/space/planck-satellite-shows-image-of-infant-universe.html?nl=todaysheadlines&emc=edit_th_20130322the universe may be 13.8 B years old [a bit older than thought] and expanding more slowly...

The Planck mission has revealed some interesting features of the universe. I will attempt to recap some of the highlights from preprint papers at http://www.sciops.esa.int/index.php?project=PLANCK&page=Planck_Published_Papers . XV: there is a 5-10% deficit in low mode [l<40] power...

Just watching tweets come out of the conference, apparently there is a large scale anomaly that has come out of PLanck . One tweet says challenge to inflation, another says could be pre big bang physics. Obvioulsy I am just reading tweets, so not sure what's real yet. But this could be exciting...