can someone explain gravitons?

Question

explain it like ur trying to explain it to a 7 year old. bc i cant understand physics and what not so plz spare me the mumbo jumbo

u didnt explian what the hell they r!

Answer 1

In physics, the graviton is a hypothetical elementary particle that transmits the force of gravity in the framework of quantum field theory. If it exists, the graviton must be massless (because the gravitational force has unlimited range) and must have a spin of 2 (because gravity is a second-rank tensor field).

Gravitons are postulated because of the great success of the quantum field theory (in particular, the Standard Model) at modeling the behavior of all other forces of nature with similar particles: electromagnetism with the photon, the strong interaction with the gluons, and the weak interaction with the W and Z bosons. In this framework, the gravitational interaction is mediated by gravitons, instead of being described in terms of curved spacetime like in general relativity. In the classical limit, both approaches give identical results.

However, attempts to extend the Standard Model with gravitons run into serious theoretical difficulties at high energies (processes with energies close or above the Planck scale) because of infinities arising due to quantum effects (in technical terms, gravitation is nonrenormalizable.) Some proposed theories of quantum gravity (in particular, string theory) address this issue. In string theory, gravitons (as well as the other particles) are states of strings rather than point particles, and then the infinities do not appear, while the low-energy behavior can still be approximated by a quantum field theory of point particles. In that case, the description in terms of gravitons serves as a low-energy effective theory.

Since gravity is very weak, there is little hope of detecting single gravitons experimentally in the foreseeable future


Gravitons and models of quantum gravity
When describing graviton interactions, the classical theory (i.e. the tree diagrams) and semiclassical corrections (one-loop diagrams) behave normally, but Feynman diagrams with two (or more) loops lead to ultraviolet divergences; that is, infinite results that cannot be removed because the quantized general relativity is not renormalizable, unlike quantum electrodynamics. In popular terms, the discreteness of quantum theory is not compatible with the smoothness of Einstein's general relativity. These problems, together with some conceptual puzzles, led many physicists to believe that a theory more complete than just general relativity must regulate the behavior near the Planck scale. Superstring theory finally emerged as the most promising solution; it is the only known theory in which the quantum corrections of any order to graviton scattering are finite.

String theory predicts the existence of gravitons and their well-defined interactions which represents one of its most important triumphs. A graviton in perturbative string theory is a closed string in a very particular low-energy vibrational state. The scattering of gravitons in string theory can also be computed from the correlation functions in conformal field theory, as dictated by the AdS/CFT correspondence, or from Matrix theory.

An interesting feature of gravitons in string theory is that, as closed strings without endpoints, they would not be bound to branes and could move freely between them. If we live on a brane (as hypothesized by some theorists) this "leakage" of gravitons from the brane into higher-dimensional space could explain why gravity is such a weak force, and gravitons from other branes adjacent to our own could provide a potential explanation for dark matter. See brane cosmology for more details.

Some proposed quantum theories of gravity do not predict a graviton. For instance, loop quantum gravity has no analogous particle

Gravitons and experiments
Detecting a graviton, if it exists, would prove rather problematic. Because the gravitational force is so incredibly weak, as of today, physicists are not even able to directly verify the existence of gravitational waves, as predicted by general relativity. (Many people are surprised to learn that gravity is the weakest force. The dominance of gravity at large scales is due to the fact that the nuclear forces have a limited range, and the electromagnetic force often largely cancels due to the existence of positive and negative charges. In contrast, gravitational charge -- i.e., mass -- is positive or zero for all known forms of matter.)

Gravitational waves may be viewed as coherent states of many gravitons, much like the electromagnetic waves are coherent states of photons. Projects that should find the gravitational waves, such as LIGO and VIRGO, are just getting started.


Problems with the Graviton
Many believe the graviton does not exist, at least in the simplistic manner in which it is envisioned. Superficially speaking, quantum gravity using the gauge interaction of a spin-2 field (graviton) fails to work like the photon and other gauge bosons do.

But more importantly the spin-2, linear wave (classical gravitational wave) is only a perturbation on certain, highly restrictive metrics. In general there are wave-like fluctuations, but they are non-linear, as is often the case in General Relativity. Maxwell's equations always admit a spin-1, linear wave, but Einstein's equations rarely admit a spin-2, linear wave, and when they do it is only perturbative and not exact.

The more analogous gravitational object to the electromagnetic wave is actually the Weyl curvature. In classical electromagnetism the fields are determined by sources along with source-free electromagnetic waves. In gravitation, the Ricci curvature is determined by the stress-energy tensor along with the source-free Weyl tensor which contains the gravitational waves.

Answer 2

Let's give it a shot. Now as a 7 year old, you do not know what matter is made out of. Everything around us is made of atoms. There are many types of different atoms that have very distinct properties. These different properties arise because of the different number of even smaller particles contained n the atoms. Every atom is made up of a combination of smaller particles called protons, neutrons and electrons. For many years, this is the limit that we thought no one could break. In more recent years, we have actually seen smaller pieces of matter so let me describe these to you. If you go down a notch after protons, neutrons and electrons, you will get to quarks. For now we are gonna stop here along the visualization chain because nothing else is required. At the level of quarks, there are many different types of particles that have been found to exist. Some particles are ejected through collisions of protons with nuclei, other can just be found in nature. However, we can divide these particles in 2 groups. Particles that are force-carrier particles and others that are not.

In nature, there are 4 forces: Strong nuclear, weak nuclear, Electromagnetic and gravitational. Every force has its carrier particle. In order, they would be (Gluons (observed), Weak gauge bosons (W+, W-, Z0 observed), photons (observed) and gravitons (NOT observed)). Isn't it bizarre how gravitons are the only force carrying particle that hasn't been observed ??? So this is pretty much the graviton picture. Hope I didn't lose you along the way.

Answer 3

A graviton is a theoretical particle that 'carries' a type of information we call gravity. It follows that a graviton will 'tell' an object it interacts with that there is a gravitational force acting on it. Gravity is a very weak force, so the graviton must have a very very low energy. This is a possible reason why it has not been discovered, because our instruments and technology cannot detect an energy that low... yet.

Answer 4

well you see, there's a ton, and then there's a graviton. A graviton.. obviously has to do with -gravity. so .. you have.. -gravity, and then you have a ton. So two tons would be a.. go on... yea, a 2 gravitons. NOT, because a graviton is not the same as a ton. You see, long ago, ArchisoccerTees decided to throw an apple at newton, and newton was hit in his right mind and said OUCH! so he went to beat ArchisoccerTees but ARCH was scared so he tried to bribe newton. 'I'll give you free soccer teeshirts!' but no, newton was a man of science. so he bribed him with knowledge! he said: 'Could I interest you in gravity?' and so never got beat up. anyways newton learned about gravity and played a prank on arch and threw an apple at him and then he died and he's like ' no what have i dun' and he published his works. so then he sed no it's not a ton, that's a graviton. and.. where was I? Oh! You're sleeping! your 7 year old mind won't remember any of this when you're older and wiser, I hope, and uncle Maziar will have nothing to worry about. Sleep tight!

Answer 5

A Fundamental particle postulated in order to explain the very week gravitation inter-action, in a way that fits in with quantum mechanics. Graviton having zero rest mas and travel at the speed of light.

Answer 6

The graviton is a theoretical particle that conveys the force of gravity. The thing is, the force of gravity is so weak (on small scales) that detecting this "wave" or "messenger particle" is not yet possible with today's technology. So, the graviton is still theory. Sorry, that's as simple as I can put it.

Answer 7

Matter and energy are the same thing. In string theory, all matter and energy are manifestations of six-dimensional strings of energy. All strings appear as particles, so even energy fields, such as gravity are actually particles. Particles of gravity are callled gravitons. There is no way a 7 year old can understand., but I'll recommend a book by Brian Greene that can help. His writing is designed for regular folks like you and me.

Answer 8

it is the rigidity of charm that attracts issues in the direction of count number. As for what causes it or what that is, it is the million dollar question. Gravitons are a theorized reason, yet have not been detected yet. you do not opt to take heed to about that, although, so i do not comprehend what you're truly hoping to get from this question.

Answer 9

No, no one can explain it yet. When they do, everyone will place them besides Einstein and Hawking. Right now, Gravitons are a "guess" that hasn't been proven yet. However, it sounds "plausible" so we're hoping it proves correct. Someday . . .

http://en.wikipedia.org/wiki/Graviton