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Why Is Gravity the Weakest Force?
StartsWithABang writes: If you calculate the forces between two fundamental particles separated by subatomic distances, you find that the strong, electromagnetic or weak nuclear force could all be the strongest, dependent on the particulars of your setup. But throw gravity in there, and it turns out to be weaker by some 40 orders of magnitude. This discrepancy, that gravity is such an oddball, is known as the hierarchy problem, and is by many measures the greatest unsolved problem in theoretical physics. Yet the new, upgraded run of the LHC has the potential to uncover any one of four possible solutions, some of which we have hints for already.
I tried reading that article on my mobile device (doesn't support ad-blocker). Got ten ads. The first was a full-screen block that, after I clicked through, didn't even take me to the article. The other 9 all caused the article to "repaginate" under my fingers when I reached them (or at least, recalculate vertical spacing) and all blocked further text until they'd spent their 1-2 seconds loading.
What a terrible experience. So sure that I never got to the actual substance of the article before I gave up.
Oh, also a permanent title bar that takes too much of my small device's limited screen real estate.
Forbes is a disaster on mobile.
It doesn't really make sense to compare the fundamental forces that way. Only the electromagnetic field and gravity propagate far enough to exhibit an inverse square law. This is simply because the field covers a bigger spherical area at larger distances.
The strong force stays roughly constant at growing distances. This is because the color field absorbs the energy used to separate the quarks, and interacts with itself via the color force (generating virtual gluons and quarks). When the separation gets too large (i.e. sub atomic distances), the field energy condenses into new quarks close to the original quarks, and the field between the original quarks disappears (almost, but not completely. The leakage makes nucleons stick together).
The weak force is even harder to describe in this way, since it doesn't really behave like a classical force.
So how do physicists compare these forces then? Each force is associated with a quantum field, and each field has some probability to interact with some particles. This probability is a constant number called a coupling constant, and can be determined by experiment. The fact that C14 has a certain half-life for example is caused by the weak interaction having some probability of turning a neutron in a proton (by changing the flavor of one of its quarks).
So it's the value of the coupling constants that determines the strength of the force, and on average the many quantum interactions between a field (or the bosons that are its quanta) and other particles (which are also just quanta of a field) manifest as a classical force that exhibits an inverse square law.
No, I really meant constant, not linear. It is indeed odd, and known as color confinement.
But this property only exists at very small distances (sub atomic, nucleus scale), because once the field energy becomes too high with bigger distance, the energy is converted to mass, and these new quarks close the distance.
Outside the nucleus, the color field strength (and thus the strong force) is almost zero, because the colored quarks and gluons in the nucleus have a neutral color charge on average, similar to how positive and negative charges almost completely cancel each other out.