## venerdì 5 febbraio 2010

### What about weight ?

Weight definition : P = m g where m is a constant and g variable. In other words weight is the “effect” of gravitational acceleration on a body with mass equal to m.
More complex is to define clearly the concept of mass. In general way the mass could be explained as the quantity of matter into the volume of a body. So, on equal volume, weight is proportional to the quantity of matter contained, that is density. Then the more compact bodies are the more heavy too. The thrust that we feel under our foot is the reaction of the surface on which we are pushed on. This effect is as bigger as greater density and, consequently, smaller the compressibility. The deformations generated by a force aging on a elastic body, in fact, induces also an internal state of tensions as bigger as greater Elasticity Modulus distinctive of the material constituting the body.

For Einstein every body is in freefall. The Sun towards the centre of the galaxy, the Earth towards the Sun, Moon towards the Earth and us towards the centre of the Earth. The reason would be that space – time is curved by masses, and curvature is greater where mass density is bigger. So would be a curvature gradient bending the “lines of universe”. When a surface opposes resistence to freefall motion we feel the weight as on earthly surface. Really also all along our body would be a curvature gradient, therefore going on deeply underground we would be more and more bent and we would see our clock going more and more slower, with our brain getting old more quickly then our feet. But how can it’s possible if in the local system space time stands plane ?

An observer on the earthly surface is subject to a gravitational acceleration field directed toward the center of the Earth then, for the second postulate of GR, stands on a non-inertial platform. It should therefore also stand in a curve space - time. In reality there is no free fall motion of the observer toward the center of the Earth and without relative motion relativity is not applicable, then space-time is flat. All that unless we postulate that all bodies are by themselves in free fall, a nice "trick" that, howeever, doesen't work. Infact a mass is in free fall only if another mass has previously curved spacetime. But going back in time the first mass/energy created in the Big Bang would be also space and time. There aren’t, in fact, time and space without matter, but you can not say that the matter is first and then space/time and not the other way. They coincide in the same event BB. So there couldn’t be any free fall mass/energy motion due to the spacetime curvature, or curved space-time due to the presence of mass/energy. BB event, in Einstein thought for a "continuous" space-time, was instantaneous.This did not apply to the Copenhagen school, according to which space-time was quantized ; infact GR doesen’t work at quantum sizes as mathematically "diverges" (and is not "renormalizable") in the surroundings of the space-time singularity that, really, BB is. The cat chasing its tail or even the chicken and egg dilemma: who came first ?
In brief a logic "fallacy".

Really, for the same RG, we wouldn’t must feel weight here on the Earth as on a black hole horizon of events.

In this gravitational theory the weight of a body on the Earth is generated by a pressing force equally distributed on its surfaces, from ionosphere to nucleus, with much intense pressures as smaller surfaces.

Stefano Gusman