Breif History of Time, Hawking talks about shape of electron and half spin numbers, can any one explain this ?
540930
Well it can be explained with a simple example take two coins ,fix one of the with your hand and rotate the other on the surface of the first coin .You will see that coin will have complete revolution in 180 degrees but in ordinary situations 360 degrees = one complete rotation .This new phenomenon is because of the property of the surface of the first coin. For explaining the spin of electron which takes 720 for complete revolution can be explained by a ballarina spinning on her toe while rotating a wine glass in her hand simeltaniously.
1147679
Quantum numbers are used to describe every single electron in an atom or molecule. Each electron is assigned it's own set of four different quantum numbers. no electron in the same atom or molecule can have the same set of quantum numbers.\n\nIn atoms:\nn = the principle quantum number. It is an integer, starting with 1, then 2, then 3, and so forth. This tells the principle energy level that the electron occupies. On the periodic table, the row number tells the higest principle quantum number an electron in that elemet can have. For example, the lone electron in hydrogen is always in the n = 1 energy level. However, an element like iodine in the 5th row can have electrons all the way up to the n + 5 energy level.\n\nl is the angular momentum quantum number. It is an integer that ranges from 0 to n-1. This number determines the shape of the electrons orbital. 0 is a sphere. 1 is dumbell shapped. 2 is two dumbells. 3 is 6 dumbells. These orbital shapes are usually represented with letters: 0 = s, 1 = p, 2 = d, 3 = f, 4 = g, and so on. s,p,d,f are the most commonly seen. Since l can range from 0 to n-1, n determines which orbital shapes the electrons in a given atom can have. In the first row, only s is possible. The second row adds p orbitals, and the third row adds d orbitals. Even though no atoms in the third row have occupied d orbitals in the ground state, they are still avaliable for bonding or excited state electrons (which explains why sulfer can and often does form more than 4 bonds)\n\nm is the magnetic quantum number. It simple tells the orientation of the orbitals. It ranges from -l to l. s orbitals have l = 0, so there is only one orientation. p orbitals have l = 1, so there are three, corresponding to m = -1, m= 0, and m = 1. d orbitals have 5 orientations, and f orbitals have 7. The number of orientations is also equal to the number of each type of orbital an atom (1 s orbital, 3 p orbitals, 5 d orbitals, 7 f orbitals) per energy level.\n\nm sub s (written as an m with a subscript s) is thespin quantum number. Every orbital can hold two electrons, however due to Pauli's Exclusion Principle, they can't have the same set of quantum numbers. The spin quantum number is either +1/2 or - 1/2, and it determines the direction of the electron's "spin." This isn't spin in the normal sense, as electrons don't spin like tops.
446048
You have classical physics (before the 1900s) and you have modern physics (after 1900).  Modern physics is when Einstein developed his E = mc^2 theory.  He and several other scientists of the time developed quantum physics to answer questions that classical physics couldn't answer.  When a quantity is quantized it means that it is converted from the classical quantity to the quantum quantity (involves complicated math).  This is a quick version answer to your question.  Hope it helps.\n\nG
389263
stephen hawking has said that balck holes indeed behave like black bodies, emitting some radiation, usually gamma and x rays. \nAlso, when matter falling into the black hole causes the black hole to spin. This creates a magnetic field like that of Earth's, emitting the high energy particles in the form of jets through the north and south poles of the rotating blackhole.\n\nSo, some kind of info might be released from a black hole, thats if the spaceship can detect these signs.
1066095
In quantum mechanics, particles are desribed by a quantum state that is characterised by a series of "quantum numbers". A closed system of particles obeys one of two sets of rules, depending on the sort of particle. Entanglement is actually easiest to understand for the class of particles called Fermions (particles like electrons and protons) rather than bosons (particles like photons).\n\nFermions obey a rule that says no two of them in a system can have exactly the same quantum state. Spin is a useful quantum number to use here, because it can have only one of two values for a particle - up or down.\n\nImagine creating a system in a very long box with just two electrons in it, one at either end, that are in their lowest possible energy state. They will be identical in all respects except that one will have spin up and the other spind down. There is no way of knowing which is which.\n\nNow imagine measuring the spin of the electron at one end of the box. Lets say its up. This *must* mean that the spin of the electron at the other end of the box is down. So we have "instantaneously" found out the spin of a remote particle, which relativity (which insists information cannot travel faster than light) says cannot happen. Einstein-Podolsky-Rosen argued that this created a paradox at the heart of quantum mechanics.\n\nThe paradox was resolved experimentally by showing that particles whose states are entangled in the way described above do indeed behave as quantum mechanics predicts. These experiments are often carried out with photons. In this case a single photon is broken down into tow or more photons whose quantum states must clearly add to give the state of the original photon (quantum numbers are preserved). \n\nSo say we split a photon into two new photons that differ in polarisation, and send them off in different directions to person a and person b. Person a measures the polarisation of theirs and instantly knows the polarisation of the one person b got. And this is precisely what happens.\n\nThis does not violate relativity because there is no way that person a can communicate to person b the result of their measurement faster than light, so no information can pass faster than the speed of light. This means if the two arrange to measure their photons as soon as they get them, each has exactly the same 50/50 probability of getting either polarisation.\n\nThis seems paradoxical because it is counter to classical intuitive feelings about how the world works. But classical and intuitive feelings are often unreliable, and experiment has shown that the paradox is not really a paradox but ironically a description of how the world really works.\n\nQuantum entanglement is being research for use in cryptography because it impossible to fiddle with. Lets say I split a load of photons and send half to a and half to b as keys to encrypt a message. When a makes his measurements on the photons he will know the results b will get and so can communicate with b securely. But if anyone tries to intercept the message to say b they will destroy the entanglement. They may get the key, but it is useless because they cannot communicate it to b - ie it will be obvious that there has been an interception.
72098
Some new ideas in physics posit that there are more than the obvious 3 spatial and 1 temporal dimension. These theories are intended to explain all four fundamental forces in nature (electromagnetism, the strong nuclear force, weak nuclear force and gravity) by serving as a bridge between quantum mechanics and general relativity.\n\nIt turns out that one way that - perhaps - QM and GR can be connected is to postulate some extra dimensions, with an extra 7 spatial dimensions for a total of 11. If such extra dimensions exist they may be too small to interact with our standard 3D+time word.\n\nSo, in this case, a 6th dimension would be one of these smaller extra dimensions.\n\nIt should be noted, though, that thus far string theories are very theoretical, and there is no real physical evidence (yet), nor even a complete theory. Its still very much up in the air.\n\nA nice, simple guide to string theory basics can be found here:
902950
Basically the same as the model of the hydrogen atom, but with more of everything!\nEach of the electrons follows it's own path, which are all perfectly circular orbits and are arranged so as to have the maximum distance between orbits possible. I'm not sure about the energy levels, or if the orbits all have the same radius...
469511
To quote dilbert: "Early Civilisations never had a concept of zero" (hey, you wanted it thorough right?) And they started the number system at one. .... Hmm, pretty much the panel cuts out... \nRemember, the ones and zeros are really the positive and negative polaritys on a magnetic disk. That is the key to your computer informations. Do not take a magnet to your computer.
271484
yeah, you get a bit off on a deep tangent towards the end there... but I don't think Einstein asserted anything more than the idea that time, space, and matter are related and not independant.  two systems of matter travelling in wildly different velocities relative to one another also have different processions of time and different masses, from the perspective of the other.  It only applies to things moving close to the speed of light- I think it's the Schroedinger Equation that covers the inter-relation.  But there's no real analogy to it in the observable world, unless you work at a particle accelerator, so I leave it to the doctorates of physics to debate.
941720
Doesn't that have something to do with Einstein's e=mc^2?  It sure looks like it.  The rest of seems to be an example of an explanation of the inefficiency of practical mass to energy conversions.  I could be wrong.\n\nOh, by the way:  what are you asking?
182928
check this out for info on spin\nhttp://en.wikipedia.org/wiki/Spin_(physics)
807032
Have a read at Steven Hawkings "A Brief History of Time"  There is an on-line version somewhere so you don't have to buy it.  It is a long book but is a good effort at explaining very complex mathematics in lay persons terms.  I'm no genius and even I managed to grasp the majority of it.  \n\nIt runs through the history of mathematics and physics, big bang theory (singularity), dark matter, black holes, the lot.  Just don't let your friends find out.  They'll think you're a dweeb!
811637
Here we need to clarify the concept of angular momentum as it applies to sub-atomic particles. The key concept is called "spin", which refers to the angular momentum "intrinsic" to a body, as opposed to orbital angular momentum, which is the motion of a body's center of mass about an external point.\n\nIn classical mechanics, the angular momentum of a body is associated with the rotation of the body around its own center of mass. In quantum mechanics, spin is particularly important for systems at atomic length scales, such as individual atoms, protons, or electrons. Such particles and the spin of quantum mechanical systems ("particle spin") possesses several unusual or non-classical features, and for such systems, spin angular momentum CANNOT be associated with rotation but instead refers only to the presence of angular momentum, which is a truly intrinsic physical property, like electric charge and mass.\n\nIn atoms, the atomic orbitals are the quantum states that electrons surrounding an atom may exist in. These quantum states can be described by 3 sets of orbital quantum numbers: n, l, and m, where n is the principal quantum number which determines the size and energy of the orbitals, l is  azimuthal quantum number which determines an orbital's shape, and m is the magnetic quantum number which determines its orientation. So here "l" is NOT equal to the "angular momentum" or "spin" of the atomic orbitals.\n\nSo to answer your question, yes, it is possible for 2 electrons to occupy the same energy states, beause they have different spin. For electrons, it's spin can be ±1/2.
846625
This theory is formulated by lot of laws and was given by a theory of relativity in which Albert Einstein says that if two things travel in opposite direction with or greater than the speed of light you could look into the future..\nbut it sounds to be impossible ...\nwhile some scientists say that if a object goes near a black hole and a small torque is given to that it starts rotating at a speed nearly equal to light...\n           you can refer theory of relativity for more answers...
956852
The significance of Einstein's Field equation (EFE) is that it describes how stress-energy causes curvature of spacetime, and that spacetime can be treated together as a 4-dimensional surface or manifold.\n\nEinstein's Field Equation is fairly well understood today, and many solutions have been found. However, EFE being a non-linear differential equations, it is very difficult to obtain an exact solution.\n\nThe components of curvature tensors such as the Einstein tensor have, in geometric units, the dimensions of sectional curvature. So do the components of the stress-energy tensor. Therefore the Einstein field equation is dimensionally consistent in these units.\n\nWhat this means is that the units of distance, time, mass, energy, etc., have all been converted into geometric units. In physics, especially in the general theory of relativity, geometric units constitute a physical unit system in which all physical quantities are identified with geometric quantities such as areas, lengths, dimensionless numbers, path curvatures, or sectional curvatures. In this system, the base physical units are chosen so that the speed of light, c, and the gravitational constant, G, and other relevant physical constants are set to equal one.
1087038
lets see there are different theroies about the fundamental particles............but answering you qestions i will say the "strings" are the fundamental particles and we physicist now belive that all the fundamental particles which we have establish through some experiments are basically made up of these strings......a string in a perticular mode behaves as a perticular fundamental particle like protron neutron electron or quarka etc
929295
It wasn't Hawking who came up with the theory, but at the core of a black hole is a body of super dense matter wherein even the space between the nucleus  of an atom and its electrons has been compressed into nothingness.\n\nImagine all the matter that composes a large cruise ship occupying a space less than the size of a tear-drop.\n\nAll still theory, though the evidence has gotten pretty convincing over the last 60 years.