constancy of light speed
The space built by dynamic horn torus coordinates is ruled by an unique topology and is equipped with an exceptional self-metrisation, what means that all measurable variables within the space are related to one fixed unalterable unit. This unit is called the 'standard dynamic horn torus', described and explained by means of interactive graphics elsewhere on this site.
There we learn that the standard dynamic horn torus contains (symbolises!) three constants: speed of light c, Planck length LP and Planck's (reduced) constant ħ. In the horn torus space Planck time is not a fundamental unit, it is identifiable but redundant and time equally not an independent variable.
Speed of light is represented by the circumferential speed of the horn torus bulge longitudes which perform the revolution around themselves, shown in an allegoric figurative visualisation with gearwheels. The animation makes different angular velocities obvious, when horn tori of different size are nested into one another and revolve with same circumferential speed, measured at their common point.
In the horn torus model all variables are defined by ratios or are closely related to ratios and not to absolute 'sizes'. The most evident ratio is that of revolution and rotation, i. e. the torsion of the torus bulge around itself and the spin around the main symmetry axis of the horn torus. In whichever size you draw the horn torus and whichever circumferential speed you choose for the longitudes, the ratios remain constant, when you always refer to the standard dynamic horn torus, characterised by the ratio 1:1, what means just one rotation per full revolution and vice versa one revolution per full rotation.
The geometrical situation, all dynamic properties and every pattern of cycloids (trajectories) remain exactly the same, on a single horn torus and within a system of dynamically nested horn tori as well, no matter which size, scale or speed you choose - we observe the most perfect self-similarity! Enlargement or scaling down of the whole system (viewed from 'outside') can not be recognized from inside, and an outside does not exist, when you describe the geometry only by terms and 'ingredients' of the system, primarily its natural unit. Existence of a maximal speed and its constancy is an intrinsic property of the horn torus space. An alteration, should it occur, can not be recognized and has no effect. (Reduction of light speed when measured along a trajectory is a different topic! Here we only describe the maximum speed on longitudes.) The standard dynamic horn torus, as unit of reference, inevitably generates, continuously maintains and reliably ensures the self-metrisation and therefore constancy. This secret, amongst many others, is disclosed by the horn torus model.