Even that explanation leaves much to be desired, yeah. It’s almost circular logic. Ok, gravity is a deformation of spacetime, but that doesn’t explain how a deformation of spacetime translates into the equivalent of an attractive force.
I mean the whole “rubber sheet” illustration only works when you are in a gravity well, so it’s no demonstration at all. If you tried that out in deep space, the bowling ball and ball bearings would all just float off instead of appearing to orbit each other.
I've thought for some time that gravity might somehow work off the energy contained within 'empty' space, perhaps related to the Casimir Effect described below. In short, maybe matter, in order to exist, 'feeds' off the energy of the vacuum thereby creating a 'well' of negative pressure surrounded by the positive pressure of the local space environment. This 'positive pressure' then pushes outside objects towards the negative pressure well. Since matter and energy are supposedly manifestations of the same thing, (E=Mc^2) it might not be too off-base an idea.
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Casimir Effect: Zero Point Energy
The Casimir force arises from one of those unlikely sounding real world manifestations of quantum mechanics. It begins with considerations of what exactly is a vacuum. In the classical everyday sense we think of a vacuum as what is left after we have removed all of the stuff, molecules atoms etc. But that still leaves photons, so if we remove those as well – including all the thermal energy then surely we should now have an absolute vacuum which contains precisely nothing.
Therein lies the problem. Heisenberg’s uncertainty principle, describes the limitation on the knowledge of pairs of parameters in terms of Planck’s constant; most well known being position and momentum. An equally important pairing is energy and time, and quantum mechanics forbids the precise independent knowledge of these two parameters.
The absolute energy of a system is thus unknowable as a single parameter, including the unique value of zero. So we cannot have a vacuum of absolute zero energy because it violates the uncertainty principle.
The theoretical physics resolution of this paradox is to assume the existence of virtual particles which pop out of the vacuum and wander around for an undefined time and then pop back – thus giving the vacuum an average zero point energy, but without disturbing the real world too much.
One of the most remarkable results of Quantum Field Theory is the existence of vacuum fields, particles and zero-point energy. Vacuum is not a tranquil void but a quantum state made up of matter fields and energy fields.
https://bruceleeeowe.wordpress.com/2009/11/18/casimir-starcraft-zero-point-energy/
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In quantum field theory, the Casimir effect and the Casimir–Polder force are physical forces arising from a quantized field. They are named after the Dutch physicist Hendrik Casimir who predicted them in 1948.
The typical example is of the two uncharged conductive plates in a vacuum, placed a few nanometers apart. In a classical description, the lack of an external field means that there is no field between the plates, and no force would be measured between them.[1] When this field is instead studied using the QED vacuum of quantum electrodynamics, it is seen that the plates do affect the virtual photons which constitute the field, and generate a net force[2]—either an attraction or a repulsion depending on the specific arrangement of the two plates.
Although the Casimir effect can be expressed in terms of virtual particles interacting with the objects, it is best described and more easily calculated in terms of the zero-point energy of a quantized field in the intervening space between the objects. This force has been measured and is a striking example of an effect captured formally by second quantization.[3][4]
However, the treatment of boundary conditions in these calculations has led to some controversy. In fact, "Casimir's original goal was to compute the van der Waals force between polarizable molecules" of the conductive plates. Thus it can be interpreted without any reference to the zero-point energy (vacuum energy) of quantum fields.[5]