I speculate at times that there is a link between the strong force and gravity. Both have a key interaction with mass : the strong force binds the nucleons that account for most of a particle mass, while gravity results from mass . I have always been impressed by the sheer strength of the strong force, so powerful that it binds protons in spite of staggering electrical repulsion. What could be the link between the strongest and the weakest force? How could the strongest force not radiate beyond the nucleus? Why would it act at Planck level and, in spite of its immense power, stop dead at the border of the nucleus without any transition? It has been argued that it is precisely because of its strength that the force has such a short realm. I am not so sure it really stops as I can’t think of other examples or such containment of immense power.
An analogy comes to my mind of a similar case of tremendous power somewhat contained in a finite volume : black holes. They contain a tremendous amount of gravitational energy. Hawking has demonstrated that it leaks slowly but surely to the point of emptying the black hole after trillions of years. If a nucleus behaved like a black hole, it would “ooze” and we know it does. Neutrinos regularly escape from the constant neutron/proton switch. They have mass, so they generate gravity , as quantic as the nucleons they come from.
So, what would be the link between gravity and strong force. Why would the strong force need gravity? Or vice versa. Later on, we could switch to the question of why do the 4 forces exist? I don’t believe they came randomly, but, if they did, they survived because they cohabitated to create a functional universe. In other words, they complement each other to create a lasting universe. Much like DNA is at the core of our human life, and from there, creates the balance of proteins, energy absorption and consumption which sustain life, why not envision that the 4 forces work in tandem, each fulfilling a role in “sustaining” the universe, in working as its operating system. It is daunting that we have a pretty good idea of the operating system of the human body, yet a limited understanding of the operating system of the universe.
Let’s go back to the link gravity/strong force. We know that the creation of stars involves strong gravity near their core to first merge protons into helium, in the process, converting gravity into strong force. It goes on all the way to neutron stars where gravity is even so much more intense that it also crushes electrons and protons into neutrons, with the grand finale being the supernova explosion of all neutrons into quarks, I guess. So there is a pattern where gravity converts into strong force. With that perspective, gravity would be a fractional conversion of strong force, with the emission of neutrinos acting to balance conservation of mass and energy?
The four forces would work in tandem to execute changes to the universe, i.e. allow sustainable states to occur, maintaining in balance a certain equilibrium so that the universe survives. The electromagnetic forces would allow the conveyance of energy , (ATP equivalent in the human body) , the strong force would create lasting observables, the weak force would tweak massive particles to fulfill more diversified tasks and gravity would act as the ribosome of the system, a small but indispensable tool to alter observables from birth to death.