no Gravitation

[alexvorn2]

it is possible that an object on earth to not be attracted by earth, to make the weight = to 0?

[BobHegwood]

it is possible that an object on earth to not be attracted by earth, to make the weight = to 0?

Short answer is NO I believe...
Even in space, the satellites and astronauts are still affected by Earth's gravity. They are only weightless because they are falling towards
the Earth at a rate which conforms to the speed at which they are circling the Earth. They don't fall to the ground because - as they fall -
they are moving around the Earth at a velocity which matches the rate at which they are falling. That's the best way that I can explain it.

You can achieve a similar (but not the same) state in a swimming pool when you are balanced against the Earth's gravity by a flotation device.
Doctor Schrempp? Is this an adequate explanation, or am I just Brain-Dead again?

Thanks, Bob

[Fightspit]

it is possible that an object on earth to not be attracted by earth, to make the weight = to 0?

The light has no mass but it can be "attracted" in earth not as strong as that near of a black hole , maybe am I wrong ?

[MKruer]

it is possible that an object on earth to not be attracted by earth, to make the weight = to 0?

Its possible IF the fundamental partial the Graviton exists http://en.wikipedia.org/wiki/Graviton. This has not been proven to date, and is one of the reasons for the new CREN experiment. IF the Graviton exists, then it should have an anti-particle, This would be considered anti-gravity.

[ajtribick]

it is possible that an object on earth to not be attracted by earth, to make the weight = to 0?

Its possible IF the fundamental partial the Graviton exists http://en.wikipedia.org/wiki/Graviton. This has not been proven to date, and is one of the reasons for the new CREN experiment. IF the Graviton exists, then it should have an anti-particle, This would be considered anti-gravity.

Not all particles have antiparticles. The uncharged gauge bosons (photon, Z) do not. There would be no antigraviton.

[t00fri]

it is possible that an object on earth to not be attracted by earth, to make the weight = to 0?

Its possible IF the fundamental partial the Graviton exists http://en.wikipedia.org/wiki/Graviton. This has not been proven to date, and is one of the reasons for the new CREN experiment. IF the Graviton exists, then it should have an anti-particle, This would be considered anti-gravity.

Not all particles have antiparticles. The uncharged gauge bosons (photon, Z) do not. There would be no antigraviton.

All known gauge bosons are self-conjugate, ie equal to their anti-particles, which is also required for consistency. To get the argument right, a little group theory is needed...

The Photon is the gauge boson of an electromagnetic U(1) gauge symmetry group. The Photon's vanishing electric (U(1) - ) charge guarantees self-conjugacy wrto U(1) symmetry.

The 3 weak gauge bosons W+, W- and W0 form a triplet of the weak SU(2) gauge group. (Of course electro-weak mixing of the weak neutral W0 with the neutral Photon produces the Z boson as the physical state). Note that the triplet representation is real (as opposed to complex!) and hence the W triplet is also self-conjugate, although the W+ and W- carry electrical charge.

The 8 strong gauge bosons, ie the Gluons of Quantumchromodynamics form an octet of the strong SU(3) gauge group. An octet is again a self-conjugate representation of SU(3), although each individual gluon carries a non-vanishing color charge! Note that the quark triplet of r,g,b quarks is a complex representation of SU(3) and hence NOT self-conjugate. Quarks and anti-quarks are therefore physically distinct!

Note that gauge bosons typically form the adjoint representation of the respective gauge group, hence the self-conjugacy is automatic!

Gravitation may also be formulated as a gauge theory with the Graviton as gauge boson...
Guess whether there will be Anti-gravitation?

Fridger

[MKruer]

Guess whether there will be Anti-gravitation?

Fridger

So the Anti-gravitation would still be the gravitation because the antiparticle is the Graviton itself correct?

[Scytale]

...so then there was death, taxes, and gravitation. Man, I hate this universe...

[t00fri]

...so then there was death, taxes, and gravitation. Man, I hate this universe...

In the part of the Universe where you are located, the taxes at least were (are) quite negligible compared to more western standards...

Fridger

[BobHegwood]

Gravitation may also be formulated as a gauge theory with the Graviton as gauge boson...
Guess whether there will be Anti-gravitation?

Wow...
I understood not one whit of your explanation, but am I correct in thinking that scientists now agree that
such (anti-gravity or the negation of gravity) is possible?

To quote a well-known television character here, "Fascinating."

[t00fri]

Gravitation may also be formulated as a gauge theory with the Graviton as gauge boson...
Guess whether there will be Anti-gravitation?

Wow...
I understood not one whit of your explanation, but am I correct in thinking that scientists now agree that
such (anti-gravity or the negation of gravity) is possible?

To quote a well-known television character here, "Fascinating."

Bob,

sorry for having been a bit more technical than usual, but I wanted to spell out the correct argument for self-conjugacy for once. Doesn't work without using a tad of group theory...

NO anti-gravity with action different from gravity!

The situation is quite unlike Electromagnetism, where attraction or repulsion occurs, depending on the relative signs of the electric charge of the participating objects!
The analog of the electric charge is the mass in gravity. Masses ALWAYS attract. NO gravitational repulsions in any decent theoretical framework (so far in agreement with experiment, too)!

Fridger

[BobHegwood]

NO anti-gravity with action different from gravity!

The situation is quite unlike Electromagnetism, where attraction or repulsion occurs, depending on the relative signs of the electric charge of the participating objects!
The analog of the electric charge is the mass in gravity. Masses ALWAYS attract. NO gravitational repulsions in any decent theoretical framework (so far in agreement with experiment, too)!

Well thanks very much for the explanation for the Brain-Dead. Still "fascinating."
Even the mandatory? attraction of mass is very interesting in its own right. What an amazing Universe we live in.

[MKruer]

Well thanks very much for the explanation for the Brain-Dead. Still "fascinating."
Even the mandatory? attraction of mass is very interesting in its own right. What an amazing Universe we live in.

To quote a well-known television character here, "Row, row, row your boat, Gently down the stream. Merrily, merrily, merrily, merrily, Life is but a dream.

Thank you, I will be here all weak.

I guess the another question is it possible to have a partial, that reduces the effects of mass. From the above explanation, the answerer would seem to be no unless it could be pulled through a diffrent multiverse where mass has the opposite effect.

[ajtribick]

You know, I would really like to know just why group theory is useful. The bit of group theory I did in my university course went something along the lines of "This is what a group is. Let's go straight to representation theory!", which left me somewhat confused as to what all the fuss is about.

[t00fri]

You know, I would really like to know just why group theory is useful. The bit of group theory I did in my university course went something along the lines of "This is what a group is. Let's go straight to representation theory!", which left me somewhat confused as to what all the fuss is about.

The Standard Model of elementary particles and many extensions thereof are based on (non-abelian) Lie groups as gauge groups. Doing research in theoretical partical physics without being VERY firm in group theory and representation theory is therefore simply unthinkable. Believe me . But even on a much more elementary level of Quantum Mechanics, where Clebsch Gordan coefficients due to e.g. angular momentum/spin couplings occur, one needs it heavily. Whenever one has to consider multiparticle quantum states, one has to compose the resulting physical state according to the rules of group/representation theory (using tensor products of representations, followed by a reduction of the result to irreducible representations etc).

In case of the above self-conjugacy argument, the fact may be misleading at first that some members of (non-abelian) gauge boson multiplets do carry some non-vanishing charge. Nevertheless, knowing that gauge bosons always span the self-conjugate adjoint representation immediately proves the self-conjugacy. The trick is of course that under anti-particle conjugation, some charged members go to other charged members SUCH that the whole multiplet remains invariant.

E.g. the weak SU(2) triplet transforms as follows

(W+, W0, W-) --> (W-, W0, W+), which is unitary equivalent to the original triplet....

Someone without knowledge of group/representation theory might incorrectly conclude that the charged members break the rule...

Incidentally, for a theoretical physicist knowing group theory is just the "tip of the mathematical iceberg". A thorough mathematical knowledge is absolutely required in theoretical research. This includes MUCH more of modern math, of course.

Fridger