Variable Light Speed and Cosmic Scale Measurement

This paper rebuilds the IME account of the propagation of light on the permittivity and the permeability of the plenum, with the plenum’s density and tension as secondary readings of them. Light is the signal of the electrostatic layer, and its speed is . Three results follow. First, the fine-structure constant depends on the two constants only through the impedance , and it is constant to two parts in of the change of the solar potential in laboratory clocks, to beside the black hole candidate at the centre of the Galaxy, and to about a part in a million in the gas of a quasar at redshift 1.15. The permittivity and the permeability therefore move together, and with the locality index : an impedance lock. Read mechanically, with the magnetising field held by structure, the tension of the plenum rises as and its inertia as , so that the plenum near a dark star is both tauter and heavier, and light, reckoned from far away, slows as . Second, every rod and clock is a standing wave of the same plenum and follows the half power of , so the locally measured speed of light is everywhere. The balance tilts genuinely only in magnetic fields approaching T, where the vacuum becomes birefringent, and possibly near rapidly spinning compact bodies, a stated conjecture. Third, a static medium conserves the frequency of light in flight and cannot redden it on the way, whereas a plenum that tightens with time conserves the wavenumber of light in flight and lowers its frequency as , while atoms follow . The redshift is then . The redshift is thus a change in the medium, not an expansion of space: as a whistle heard under water keeps its pitch, a still change of medium keeps the frequency of a wave, and only a medium that changes while the light is inside it shifts the frequency. The depth of the source in the denser plenum of its galaxy and the motion of the galaxy through the plenum add a smaller gravitational and a Doppler term. The construction is exactly an expanding universe with scale factor , and it reproduces the stretching of supernova light curves, the Tolman test and the microwave background. The cosmological constant becomes the non-fading part of the tightening law. The IME reading assigns it to the magnetic and electrostatic layers, with walls pinched taut by the magnetic dipoles of galaxies, voids looser and the formatting energy of the informational layer uniform; because lensing and the smoothness of the microwave background bound any static difference between walls and voids at about , the effect works through the rate of tightening, which therefore evolves with structure, as recent surveys suggest. The dark star has no horizon: its throat opens into an inner well in which clocks slow and the cone of escaping light narrows without limit. The earlier claims of a slower void at and of a refractive Hubble constant are revised.