What is it about? It is logical that since the earth and the sun are already moving around the Milky Way that the speed of light in a vacuum depends on our speed at rest (which is already quite fast). That is to say, the limit of the speed of light moves with us and therefore the minimum limits such as Planck's constant do move as well. If we reached half the speed of light; Would the speed of light in a vacuum be half? This would be quite absurd. What would happen is that the frequency of the light will change so the matter will change its frequency as well and also the magnetic fields etc. our reality will change. Planck's constant (minimum energy, minimum time, minimum space, etc.) also requires the constant of the speed of light in a vacuum. That Planck's constant applies to everything that exists also indicates that everything that exists is the same: energy, but we still do not have a correct concept of energy, which is everything. Particles don't make much sense