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Registered Senior Member
PhysBang:
Thankyou for clarifying.
This then automatically involves the usual GR expert arguments treating small enough regions of spacetime as "essentially flat". If that orthodox GR expert argument is valid, then I am prompted to ask:
1) How much GR GW effects and energy transfer do you assert happens in the small spacetime region occupied by a 'bead'?
2) If the overall collection of circular arrangement of many beads is then considered, then how much does the interconnecting/intervening spacetime react to the alleged GR GW energy transfer to that overall spacetime encompassed by that circular arrangement of beads?
3) In what way does that overall region distort and in what way can those beads move despite the very small bead-occupied sub-regions themselves are individually considered "essentially flat" as per the usual GR expert argument I mentioned?
If you are alluding to Hulse-Taylor binary Neutron Star systems, I have long understood that the main active factors are the local electro-magnetic forces interplay between the two Neutron Stars' magnetic and electric features; which interplay cause EM friction losses that radiate away as EM energy of various wavelengths/frequencies, not necessarily as exclusively Gravitational energy; and that this EM interaction causes 'orbital decay' related energy loss from the system because of the orders of magnitude greater forces and energy involved in the EM forces interplay than in the gravitational interplay (which latter is balanced due to the very nature of orbital motion). Any claims that gravitational wave energy loss is responsible for such orbital decay related energy losses in such systems are therefore still speculative until the local EM energy states and extents and losses as described can be quantified and any continuing discrepancy (if any) can be attributed to gravitational energy loss as hypothesized.
Can you clarify; when you say, "the LIGO system", are you referring to the spacetime 'leg' distance traveled by the laser beam; or to the test masses themselves? I ask because the whole point of GR GW interferometry as per LIGO system is "in the legs" not the test masses, as I explained. So we may be talking at cross purposes until that distinction is agreed between us.
And his OP title and posted argument imply that he challenges just that: ie, challenges that GWs can exist as extrapolated from and claimed by the GR theory mathematics; which puts the question of whether any energy can be imparted by non-existent GWs front and center for further physically based discussion only once the first part of the argument (ie, the OP itself) is refuted or not without making assumptions/conclusions which are merely 'begging the question' arguments unless and until that first part is settled.
Thankyou again PhysBang for your patient clarification efforts for my benefit on this aspect of the discussion between you and Q-reeus.
Thankyou for clarifying.
The system in question is his loop of beads.
This then automatically involves the usual GR expert arguments treating small enough regions of spacetime as "essentially flat". If that orthodox GR expert argument is valid, then I am prompted to ask:
1) How much GR GW effects and energy transfer do you assert happens in the small spacetime region occupied by a 'bead'?
2) If the overall collection of circular arrangement of many beads is then considered, then how much does the interconnecting/intervening spacetime react to the alleged GR GW energy transfer to that overall spacetime encompassed by that circular arrangement of beads?
3) In what way does that overall region distort and in what way can those beads move despite the very small bead-occupied sub-regions themselves are individually considered "essentially flat" as per the usual GR expert argument I mentioned?
I'm just following the original Feynman argument as well as the published papers based on it. They can be found through the wikipedia link that Q-reesus provided in his OP. There exist these derivations and there are systems observed that lose energy exactly equal to the predictions of GR, so I have some confidence in these derivations.
If you are alluding to Hulse-Taylor binary Neutron Star systems, I have long understood that the main active factors are the local electro-magnetic forces interplay between the two Neutron Stars' magnetic and electric features; which interplay cause EM friction losses that radiate away as EM energy of various wavelengths/frequencies, not necessarily as exclusively Gravitational energy; and that this EM interaction causes 'orbital decay' related energy loss from the system because of the orders of magnitude greater forces and energy involved in the EM forces interplay than in the gravitational interplay (which latter is balanced due to the very nature of orbital motion). Any claims that gravitational wave energy loss is responsible for such orbital decay related energy losses in such systems are therefore still speculative until the local EM energy states and extents and losses as described can be quantified and any continuing discrepancy (if any) can be attributed to gravitational energy loss as hypothesized.
I believe that the energy transferred to the LIGO system is very minute and thus of no import to the detection method. Q-reesus is attempting to claim that the gravity waves of GR cannot possibly transfer energy, not that gravity waves do not exist.
Can you clarify; when you say, "the LIGO system", are you referring to the spacetime 'leg' distance traveled by the laser beam; or to the test masses themselves? I ask because the whole point of GR GW interferometry as per LIGO system is "in the legs" not the test masses, as I explained. So we may be talking at cross purposes until that distinction is agreed between us.
And his OP title and posted argument imply that he challenges just that: ie, challenges that GWs can exist as extrapolated from and claimed by the GR theory mathematics; which puts the question of whether any energy can be imparted by non-existent GWs front and center for further physically based discussion only once the first part of the argument (ie, the OP itself) is refuted or not without making assumptions/conclusions which are merely 'begging the question' arguments unless and until that first part is settled.
Thankyou again PhysBang for your patient clarification efforts for my benefit on this aspect of the discussion between you and Q-reeus.
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