If according to quantum physics, a particle moving from point A to point B takes every possible path. Is it possible to apply this to macroscopic objects?
For instance if I throw a ball up in the air, is it true to say that it also takes every possible path and so in one it went to the moon and back?
If not then why?
... according to quantum physics, a particle moving from point A to point B takes every possible path ...
This is a somewhat "pop science" way of describing the wave function of a quantum system. Even if it makes sense to say that a particle "takes every possible path", the different paths certainly do not all have the same probability, and almost all of them cancel out with other paths due to destructive interference.
Is it possible to apply this to macroscopic objects?
Yes, in principle - but it is even worse than you think because you have to include every possible separate path for every individual fundamental particle within the macroscopic object. In practice, we know that almost every possibility has negligible probability and/or cancels out with other paths - so we just use classical physics for macroscopic objects.
There is nothing in quantum physics that suggests that a particle takes every possible path. No one knows what is happening “under the radar” since that depends on which interpretation of quantum mechanics you believe in. We don’t even know if reality is fundamentally probabilistic or if it’s just a way for us to model the world due to a lack of knowledge.
I feel like there are two questions being asked,
a) Do macroscopic objects experience quantum effects?
b) What is the interpretation of path integrals?
These questions are definitely different, because fully classical theories admit path integral descriptions. In fact, the path integral was invented by Wiener to study Brownian motion: a classical thermodynamics problem.
The answer to (a) is yes. All objects experience quantum effects, it's just that macroscopic objects do so in a limit where Newtonian physics is more convenient to use.
The answer to (b) is philosophy. Path integrals encode a probability distribution, if one has an extremely low probability trajectory should we still consider it? Physically, I would expect other factors to contribute far before one needs to consider an event with exponentially suppressed probability, but at least on principle there is nothing wrong with thinking that it happens (presupposing some many-worlds interpretation of probability).
As mentioned in the comments, there is definitely a philosophical side to your question. In the science of the path integral viewpoint: all possible paths contribute to the final outcome, due to interference effects.
Even if you were considering a single particle going to the moon as one of the paths: I would not say it actually goes to the moon from time to time. But that path is a factor, even if negligibly small. And obviously, going from a one particle system to even a few particles - much less something macroscopic - reduces the effects of those trips to the moon to virtually nothing.
But we should remember: the net effect of the various paths is itself quite real, and can be demonstrated experimentally. So technically, there is no precise cut-off; even though it might be shown that those crazy trips to the moon cancel out each other out.
In quantum theory in general what happens to all of the possible states of a system during the experiment contributes to the outcome. This is called quantum interference. For an example see section 2 of
https://arxiv.org/abs/math/9911150
In general if information is copied out of a quantum system during an interference experiment interference is suppressed: this is called decoherence
https://arxiv.org/abs/1911.06282
For any object you see in everyday life, information is copied out of that system on scales of space and time much smaller than those over which they change significantly, e.g. - light reflecting off my keyboard, air molecules interacting with it, pressure from objects such as my fingers etc. On smaller scales such as the atoms making up the keyboard, interference is still significant.
Some textbooks say that all but one of the possible states is eliminated by a process called collapse, but this alleged process is incompatible with the equations of motion of quantum theory. Some physicists have tried to modify quantum theory to include collapse for a review see
https://arxiv.org/abs/2310.14969
Decoherence already implies you wouldn't see interference for objects in everyday life so it's a bit difficult to see why this change is necessary and such theories don't reproduce many of the predictions of quantum theory:
https://arxiv.org/abs/2205.00568
Without collapse if we work out the implications of quantum theory as we would for any other theory, in everyday life reality looks a approximately like a collection of autonomous classical universes:
https://arxiv.org/abs/1111.2189
https://arxiv.org/abs/quant-ph/0104033
This is commonly called the many worlds interpretation. Some physicists don't like the MWI. For a sample of the kind of criticisms they have see
