toward certain directions. In addition, strings may bring their intrinsic energy to physical objects when those objects absorb them or otherwise encounter them, if the collisions are imperfectly elastic. Forces carried by longitudinal and transverse waves effect even distant objects, because they can propagate even through a vacuum, and therefore are clearly the carriers of the universal fundamental forces.
Because strings also exert forces on nearby objects, they represent local forces that are very familiar to us as well. The shapes of the strings involved play a critical role in this situation. If some string shapes are in dynamic states, they can influence other strings either by attracting or repulsing them. If these shapes lie at the surfaces of subatomic particles, then such particles exert their total force there. That's why we have three kinds of primary particles in relation to local forces. The first is neutral, the second positive, and the third negative. The influence of the strings they carry form a field of that particular force.
Let's take a closer look, starting with String Theory as proposed by modern-day theoretical physicists.
When traveling waves gain speed during propagation through a
material object, the object is pulled toward the source of these waves.
Longitudinal waves do this, exerting a gravitational force upon objects.
In the case of absorption of traveling waves or inelastic collisions,
the material object gains some internal energy. We register the
increased movement of atomic particles—the change in internal energy—as
Particles of ordinary matter have strings of different shapes on their surfaces. They can be straight-line shapes, vortical shapes, and looped or even circular shapes. The particle that includes all these kinds of shapes on its surface is the neutron. In order not to continue in shaped tension, the strings incline toward separation, and so protons, electron, and neutrinos come into existence as a result of neutron decay. Protons have straight-line strings on their surfaces, electrons have vortex or funnel-shaped strings with conical mouths on their surfaces (resulting from one free end of each string vibrating, while the other is immobile) and neutrinos have looped strings.
Nature also allows for individual strings that are not bound into any volume of matter and lack momentum. Therefore, they are not traveling at the speed of light, but are rather at rest. They can adjust themselves to interact with strings of different shapes if needed. For example, if one string spins clockwise, another string will adjust to it and spin counterclockwise; and so, the strings link together to create magnetic chains. If ordinary matter has circled or vortical strings on its surface, free strings join it and so create either magnetic field lines or electrical field lines.
Thanks to these individual strings, particles of ordinary matter interact with their neighboring particles, and so create atoms with different numbers of protons and electrons. Protons lie in the nuclei of the atoms, and electrons orbit them. Electrons on the surfaces of atoms may enter into bonds with other electrons thanks to individual strings, and so chemical bonds are created. The main types of such bonds are the covalent bond, which arises due to different spins, and the ionic bond, which arises due to the interaction of positive and negative charges.
Neutrons also exist in atomic nuclei. Since neutrons possess different shapes of strings on their surfaces, they can enter into direct bonds with strings on the surfaces of protons, generating the strong nuclear force that binds atomic nuclei together.