planck42 said:
The reason that gravity doesn't push us away from Earth is due to the anthropic principle; if it did, we couldn't exist!
Nobody's saying Earth pushes us away. See below.
pallidin said:
Yeah, my bad. I'm usually more professional. Sorry.
Anyway, for any theory that counters accepted theory, one must provide "acceptable" evidence that the new theory is worthy of further thought.
What would be interesting is if you could use your undoubtedly creative mind to design an experiment that supports this theory. Not that you have to build it, as it might be prohibitively expensive for an individual, but properly propose it for others to MAYBE take it up.
In my mind, Newton, Einstein, and others never committed to a pull or push theory of gravity, they simply weren't sure. I'm not a historian when it comes to Physics, but I don't know that pull gravity has shown any more evidence than push theories. They'd behave mostly the same.
I know, this is all speculation, but that's what science does, it thinks, looks at evidence, makes predictions, tests those, thinks again, etc... I'm just thinking, I really have no stake in the subject, beyond the fact that I kinda like gravity, it's a handy dandy thing to have in this universe.
As for a test, it would be a prohibitively expensive test, or likely would require incredibly sensitive equipment. But if a push theory of gravity is true, there's a few things that would hold true. But first let me state a few assumptions I'm making:
1) Pushing would be done by something, as yet unknown. Particle or radiation, I don't know, but I would lean towards radiation, not going to get into it right now, it's all speculation.
2) The source of the "pushing" objects is mostly uniform throughout the universe, and replenishes itself somehow (if radiation, it absorbs radiation that other source objects emitted previously). Again, all speculation, but just stating the presumptions.
3) Mass and matter (or the most fundamental objects of matter) would absorb a very small fraction of this energy, most of it would simply pass through.
4) Since some of it is absorbed, that has the effect of "lessening" gravity to all objects on the "shaded" side of any object. The more massive object, the more it "shades", hence, why we are attracted or pushed to the earth.
Now, to the test(s). If a push theory were true:
1) There would be a theoretical maximum weight of an object. At some point, all the "pushing" material coming from one direction would be absorbed by a sufficiently massive object. This may be an incredibly massive object (no clue how large, maybe a planet made of heavy elements the same diameter of Antares, I don't know...) If this were true, adding additional mass to the supermassive object would not increase the apparent weight of any object being attracted to it. How to test this, no clue.
2) With current pull theories, during a solar eclipse, the gravitational effect in the direction of the sun would be effectively the gravitational effect of the Sun + Moon. With a push theory, the effective gravitational effect would be slightly smaller than the combined effect of the Sun + Moon. This effect would be even more pronounced (if even so miniscule) during a solar eclipse if you were to test the effect from the exact opposite side of the Earth that is witnessing the eclipse. In this case, pull gravity would be Sun + Moon + Earth. With a push theory, it would be slightly less than that sum. How much less I have no clue.
3) With sufficiently sensitive equipment, and a sufficiently long rod, this theory would also be testable: A long, thin rod would weigh more laying on its side than it weighs standing up. Let's say a rod 1 cm in diameter and 1 km long. If this is large enough to verify, or what level of sensitivity of equipment is required I have no clue. On its side, it would weigh a certain amount. Standing up, it would weigh slightly less, maybe 10^-15 percent less, who knows, but in a push gravity theory, that would be the case.
The reason #2 and #3 would show those effect is because at any given point, there is a certain amount of pushing objects/energy going into that object. If the object were "shadowed" by a kilometer of metal directly above it, then only 99.99999999999999999% (pick a number) of those pushing objects/energy are available to push on the object, leaving a slightly lower probability of interaction than if it were at the top (or on its side), and hence weighing slightly less.
Testing #2 or #3, if these effects were seen, would in my mind lean towards a push theory of gravity. However, not seeing these effects wouldn't necessarily prove that the effect isn't there, it simply may mean the equipment or the objects weren't sensitive or massive enough respectively.
