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Topic: Planck length

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  Planck length - Wikipedia, the free encyclopedia
The Planck length is deemed "natural" because it can be defined from three fundamental physical constants: the speed of light, Planck's constant, and the gravitational constant.
Ignoring a factor of π, the Planck mass is roughly the mass of a fl hole with a Schwarzschild radius equal to its Compton wavelength.
Although quantum mechanics and general relativity were unknown when Planck proposed his natural units, it later became clear that at a distance equal to the Planck length, gravity begins to display quantum effects, whose understanding would require a theory of quantum gravity.
en.wikipedia.org /wiki/Planck_length   (443 words)

 Planck units - Wikipedia, the free encyclopedia
In physics, Planck units are physical units of measurement defined exclusively in terms of the five fundamental physical constants shown in the table below in such a manner that all of these fundamental constants take on the numerical value of 1 when expressed in terms of these units.
Planck units are only one system of natural units among other systems, but might be considered unique in that these units are not based on properties of any prototype, object, or particle but are based only on properties of free space.
With the exception of the Planck momentum and Planck impedance and the possible exception of the Planck mass, base and derived Planck units are impractical for empirical science, engineering, and everyday use, unless rescaled by many orders of magnitude.
en.wikipedia.org /wiki/Planck_units   (2030 words)

 Planck's length the uncertainty principal and four spatial dimensions   (Site not responding. Last check: 2007-11-06)
Planck's length the uncertainty principal and four spatial dimensions
It can be shown the Heisenberg's uncertainty principle and Schrödinger's probability wave function is related to Plank's length and a quantum characteristics of a "standing" matterenergy wave on a "surface" of a three-dimensional space manifold with respect to a fourth *spatial* dimension.
Chapter one postulated a volume of space is composed of a continuous non-quantized “field” of mass and energy.
home.comcast.net /~jeffocal/chapter6.htm   (574 words)

 A New Kind of Science: The NKS Forum - Planck length and golden mean as the ultimate cell
The universal cellular automaton seems to be capable of updating its entire memory in a single clock cycle, which according to Occam’s razor could be nothing else than the Planck time as the relation between the velocity of light and the Planck length, the latter fixed at the value of the golden mean.
What the planck length concerns, the idea is not a new one that this length could or should be a fundamental constant.
In a similar way we could replace the planck length by the golden mean, but the result of such an identity is not easiness of calculation but a firework of possibilites for any automaton running the world.
forum.wolframscience.com /showthread.php?s=&threadid=168   (1160 words)

 Planck length - Wikipedia, the free encyclopedia   (Site not responding. Last check: 2007-11-06)
The Planck length is the natural unit of length, denoted by \ell_P.
The Planck mass is a mass whose Schwarzschild radius and its Compton length are equal distances.
By the Heisenberg uncertainty principle of standard quantum mechanics, an object whose position was accurate to the Planck length would have an uncertainty in momentum approximately 3.2629 kg m / s.
www.novato.us /project/wikipedia/index.php/Planck_length   (233 words)

 The Naked Scientists Science Discussion Forum - More On Particles, QM and Relativity...   (Site not responding. Last check: 2007-11-06)
In length contraction, you can theoretically contract an object to a length that is smaller than the Planck Length if you move it fast enough.
Planck length does this and would require a form of quantum gravity at this small length.
Its length jumps from 10 PL to 9 PL, and can't be any length in between.
www.thenakedscientists.com /forum/topic.asp?TOPIC_ID=2352   (539 words)

Natural units for length, time, energy and mass, obtained by combining the fundamental natural constants that govern space-time, the strength of gravity and the quantum world: the gravitational constant, Planck's constant and the speed of light.
Natural length that can be obtained by combining the fundamental natural constants that govern space-time, the strength of gravity and the quantum world: the gravitational constant, Planck's constant and the speed of light.
At such length scales, both the effects of quantum theory and those of general relativity should become important, in short: whatever concerns such scales can only be described adequately using a theory of quantum gravity.
www.einstein-online.info /en/navMeta/dictionary/p   (1811 words)

 Threepenny Planet: the Planck units
Another is their concreteness: One of the power-of-ten multiples of the Planck length happens to be about a mile and another is the thickness of a penny--if there is a penny in your pocket you have with you a decimal Planck cousin.
The Planck speed, for instance, simply consists of traveling the Planck length during the Planck interval of time--and it is the speed of light.
The Planck length links your two lengths, just as it does those of the youngster, just as it relates the analogous two lengths associated with a proton, and just as it links the analogous two lengths associated with a quantum of light.
www.planck.com /threepenny/html/chap01.html   (4165 words)

This essential Planck level quantization is a fundamental idea in Loop Quantum Gravity as pursued by Lee Smolin, which owes its genesis to a formulation of QCD due to Kenneth Wilson, in terms of loops.
The Planck length and time are so small as to be beyond the reach of current experimental possibility.
The Schwarzschild diameter for the Planck mass is the Planck length.
graham.main.nc.us /~bhammel/PHYS/planckunits.html   (2410 words)

 sciforums.com - Planck????
But I thought Planck length is the length at which there is no difference between space and time, i.e.
The Planck length is the scale at which classical ideas about gravity and space-time cease to be valid, and quantum effects dominate.
The Planck time is the time it would take a photon travelling at the speed of light to across a distance equal to the Planck length.
www.sciforums.com /showthread.php?t=8581   (394 words)

 Gregor’s World » Blog Archive » The Physical Theory of Domains   (Site not responding. Last check: 2007-11-06)
Suppose that as more and more mass/energy is concentrated into a volume of space, eventually the Planck length reaches a point at which it is comparable in size to the particles, and the particles cease to exist as distinct entities, and become part of a growing energetic singular domain.
There is a gradient of increasing Planck length along the line between the two bodies (from each pointing at the other), most contributed by the fl hole, and a miniscule amount contributed by the object.
The larger the Planck length, the larger the Planck time has to be to keep the local speed of light constant.
www.focusresearch.com /gw?p=33   (1594 words)

 The Planck scale: relativity meets quantum mechanics meets gravity. (from Einstein Light)
According to Special Relativity's time dilation and length contraction, two observers with relative motion are condemned to eternal disagreement about times and lengths.
Anyhow, these lengths and times are very small, but they are results solely of the values that appear naturally in our physical laws.
If these lengths and times are observable as physical lengths and intervals in moving frames, it appears that we shall need to modify Special Relativity to include them.
www.phys.unsw.edu.au /einsteinlight/jw/module6_Planck.htm   (1217 words)

 Planck length
The planck units are the planck units, ignoring minor jiggling factors, and they are getting more and more used as the years go by.
If the planck length is the smallest measureable distance, and that distance smaller than this would have no meaning, then any line between two points perhaps has a finite number of points between the end points, measured in planck length units, each "point" becoming a unit one planck length in size.
Indeed as it happens the formula for the planck unit of area is slightly simpler than for length, and so the area is "closer" to the fundamental constants c, hbar, and G. Sorry this is so vague but just wanted to say that your intuition is not alone about this.
www.physicsforums.com /showthread.php?p=262807   (2253 words)

 How did Max Planck determine the planck length?
General relativity is concerned with two constants of nature: G (the gravitational constant, which determines the strength of gravity) and c (the speed of light).
Quantum field theory, on the other hand, is concerned with c (the speed of light) and h (Planck's constant, which determines the amount of uncertainty in our knowledge).
This gives the Planck length its meaning, because physicists suspect that it is the distance at which the effects of quantum gravity will become apparent and may even be the smallest meaningful length that exists.
www.physlink.com /Education/AskExperts/ae644.cfm   (288 words)

 Planck length: Encyclopedia topic   (Site not responding. Last check: 2007-11-06)
The Planck length is the natural unit (natural unit: in physics, planck units are physical units of measurement originally proposed by...
This unit was first developed by Max Planck (Max Planck: German physicist whose explanation of flbody radiation in the context of quantized energy emissions initiated quantum theory (1858-1947)) who wished to create a system of measurement based on natural units.
The Planck mass (Planck mass: more facts about this subject) is a mass whose Schwarzschild radius (Schwarzschild radius: the schwarzschild radius or gravitational radius is a characteristic radius associated...
www.absoluteastronomy.com /reference/planck_length   (319 words)

 10exp-16 down   (Site not responding. Last check: 2007-11-06)
Planck's constant is the fundamental constant of quantum physics as determined by Heisenberg's uncertainty principle.
By appropriately combining these three universal constants, it is possible to arrive at a fundamental unit of length called the Planck length.
There is a corresponding Planck time associated with the Planck length -- simply divide by the speed of light.
www.wordwizz.com /pages/10exp-16.htm   (212 words)

 Day 2 The Quark Model   (Site not responding. Last check: 2007-11-06)
Planck length: the smallest measurement of length that has meaning.
Planck mass: the mass of a hypothetical particle which would have an equivalent wavelength, according to quantum theory, equal to 1 Planck length.
Planck's constant, h: relates the particle nature of a quantum entity to its wave nature through the equation E=hf.
www.gchs.com /teachers/mhaight/quark.htm   (693 words)

 Physics Today November 2001
A minority held that there could be no fundamental length at all, but most were then convinced that a fundamental length L´, of the order of the proton Compton wavelength, was the wave of the future.
Crudely, it happens because refined length measurement requires large momentum, according to Heisenberg's uncertainty principle, but when the momentum becomes too large, its gravitational effect becomes strong, curving space-time and distorting the interval one seeks to measure.
It nicely supplements the article, in which the Planck length was introduced in a somewhat different way.
www.physicstoday.org /pt/vol-54/iss-11/p15.html   (740 words)

 Orders of magnitude (length) - Wikipedia, the free encyclopedia
Planck length; size of a string; lengths smaller than this do not make any physical sense, according to current theories of physics
length of the longest pine cones (produced by the sugar pine)
average length of a rapier, a fencing sword
en.wikipedia.org /wiki/Orders_of_magnitude_(length)   (1001 words)

 Planck's Units
The naturality of c as unit binds units into families among which ratios are powers of c; thus time and length are members of one family, along with area/time and the inverse of accellerations; while mass, momentum and energy are members of another family.
That means a Planck-mass mist drop's proper period is the Planck length (or time, as you wish); this is a factor of 10**30 smaller than the physical dimensions of the mist drop, which has much to do with why one doesn't much notice quantum effects on raindrop-sized things.
However, the form of Planck's units thus far is based on the constants in the field equations themselves, rather than on the bodies controlled by these: though better (by virtue of its real irreducibility), it is defined in the same spirit as the atomic mass unit, rather than in terms of the field equations.
www.chaos.org.uk /~eddy/physics/planck.html   (2120 words)

 The Planck Era
This is called the Planck era, and the corresponding scales of distance, energy, and time are called the Planck scale.
The corresponding lengths, energies, temperatures, and times are displayed in the adjacent table (the unit GeV stands for 1 billion electron volts of energy).
However, the Planck scale is so incredibly small that this presumably only had meaning in the initial instants of the creation of the Universe.
csep10.phys.utk.edu /astr162/lect/cosmology/planck.html   (313 words)

 Notable Properties of Specific Numbers at MROB
The best interpretation for most people is that the Planck time is the shortest measurable period of time; any two events that are separated by less than this amount of time can be considered simultaneous.
This is the Planck length in meters; it is related to quantum mechanics.
The best interpretation for most people is that the Planck length is the smallest measurable length, or the smallest length that has any relevance to events that we can observe.
home.earthlink.net /~mrob/pub/math/numbers.html   (2176 words)

 Planck Length   (Site not responding. Last check: 2007-11-06)
Brian Green on the Planck length and t-duality:
"...the universe cannot be squeezed to a size shorter than the Planck length in any of its spatial dimensions." p.
"String theory claims that all physical processes in the Garden-hose universe in which the radius of the circular dimension is shorter than the Planck length and is decreasing are absolutely identical to physical processes in which the circular dimension is longer than the Planck length and increasing." p.
home.comcast.net /~smalluniverse/planck.htm   (186 words)

 The Planck Length
Planck noted that apart from numerical factors there is a unique way to use these constants to define units of length, time, and mass.
The Schwarzschild radius is roughly the distance scale at which general relativity becomes crucial for understanding the behavior of an object of a given mass.
The Planck mass is intermediate between these: about the mass of a largish cell.
math.ucr.edu /home/baez/planck/node2.html   (1840 words)

INTERPRETING THE PLANCK MASS Abstract The Planck mass is shown to be a lower bound on the regime of validity of General Relativity.
Empirically, the Planck mass is greater than the masses of elementary particles in the regime of Quantum Theory, and so the the regimes of validity of GR and QT are disjunct, casting severe doubts on the meaning of quantizing the gravimetric field of the Einstein equations.
It seems more reasonable and precise then to view the Planck mass as that which provides a lower bound in mass on the validity of GR, and separates GR from the as yet to be unfolded theory of quantum gravity.
graham.main.nc.us /~bhammel/PHYS/planckmass.html   (2958 words)

 The Big Bang - Above Top Secret Conspiracy Community
One unit of Planck length in one part of the universe will be shorter (due to gravitational distortion on space-time) than a unit of Planck length elsewhere in the universe.
But it is easier to consider two geometric points that are separated by the Planck length to be, in essence, one and the same.
Planck time is as far back as we can "go" in our understanding of the Big Bang at this point in time.
www.abovetopsecret.com /forum/thread206921/pg2   (3392 words)

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