source of earth's gravity...

[Mart]

F = -grad(U) for conservative forces. U is potential energy.

 

So in geometrical terms is it a tangent type thing - gradient of 3-D surface? And at a fundamental level what is the potential energy relative to?

[swansont]

So in geometrical terms is it a tangent type thing - gradient of 3-D surface? And at a fundamental level what is the potential energy relative to?

 

gradient is normal, not tangent.

 

 

Not sure I understand the question regarding PE.

[Mart]

Thanks for the link to the Maths site. I shall explore it when I have the time.

[The Rebel]

a magnetic feild is just two objects exchanging photons. as for gravity' date=' there are multiple theories. one is that is is the curvature of space and another has to do with gravitons, but any attempt to combine them has met nasty infinities.

 

as for thefinaltheory, i REALLY hope you were joking. it was written by an ignorant fool. there are other threads discussing it that are slightly less harsh, but have the same point.[/quote']

 

I realise this thread has more or less extinguished but the remergance of Mark McCutcheon and his "The Final Theory" book has begged the question...

 

Where did you get the above from about the magnetic fields being formed by photon energy and how gravitons distort space.

 

I want a better understnading but I don't want to fall into the trap of reading literature by the likes of McCutcheon, and equally I don't trust the physics books I have because they are simplified for A-levels to the extent of being economical with the truth. And the detail/justification for the theories doesn't look convincing.

 

Do you have any links to theories explained by actual scientists who don't leave bits out or make assumptions for the sake of simplicity.

[swansont]

Do you have any links to theories explained by actual scientists who don't leave bits out or make assumptions for the sake of simplicity.

 

You have to find an actual scientist who does not make assumptions for the sake of simplicity first. Good luck.

[The Rebel]

Ok forget the assumptions bit, show me the way to a scientist that isn't making it up as they go along, but is in agreement to the theories science has produced and has accepted as true.

 

For example, although we could all come up with different ways deciding what 1kg is, the only effective way is by comparing to the accepted international prototype of the kilogram.

 

Do we have these baselines in physics or is what we have purely conjecture and the "truth" is what the majority agree with. I.e. the majority of people believe light is constant and have various ways of proving it over the minority, therefore it must be constant.

[swansont]

Ok forget the assumptions bit' date=' show me the way to a scientist that isn't making it up as they go along, but is in agreement to the theories science has produced and has accepted as true.

 

For example, although we could all come up with different ways deciding what 1kg is, the only effective way is by comparing to the accepted international prototype of the kilogram.

 

Do we have these baselines in physics or is what we have purely conjecture and the "truth" is what the majority agree with. I.e. the majority of people believe light is constant and have various ways of proving it over the minority, therefore it must be constant.[/quote']

 

Any theory has to agree with experiment and make predictions for further experiment. c is constant by theory, and you can test this in a number of ways. Maxwell's equations work - an EM wave is still a wave when the source or receiver is moving. That's one confirmation. Relativistic measurements of time dilation are another. All are dependent on c being the same for all inertial observers.

[Saint]

Yes' date=' we do understand pretty well how gravity works, just not in special cases (very small distances and very high energies). And we understand how magnetism works extremely well - amazingly so that there has never ever been an experimental observation of magnetism which we cannot explain with the theory.

QUOTE']

 

Hey Severian - I guess this is the same question I had for Swansont. I was under the impression that we didn't understand the mechanism that drives the gravitational force. We have modelled the results of gravitational interactions very accurately, but I didn't think we had modelled the gravitational mechanism. Is that a true statement?