It is not commonly realized how many esoteric assumptions enter into even
such apparently simple concepts as the speed of light and the geometric
nature of the universe. To illustrate, a recent theory rather vigorously
advocated by some astrophysicists strongly questions the constancy of the
velocity of light in space and time, as well as the generally accepted
Einsteinian nature of the universe. These writers regard the universe much
more realistically as a Euclidian universe (3-dimensional, as in our
everyday experience) and the velocity of light as constant with respect to
its source, rather than with respect to any observer as Einstein does.
'In essence, therefore, the method of this paper leaves astronomical space
unchanged but reduces the time required for light to travel from a star to
the earth.'
[Parry Moon and Domina Eberle Spencer: 'Binary Stars and the Velocity of
Light,' Journal of the Optical Society of America, Vol. 43, August 1953, p.
639]
Or, more specifically, and rather surprisingly:
'The acceptance of Riemannian space allows us to reject Einstein's
relativity and to keep all the ordinary ideas of time and all the ideas of
Euclidean space out to a distance of a few light years. Astronomical space
remains Euclidean for material bodies, but light is considered to travel in
Riemannian space. In this way the time required for light to reach us from
the most distant stars is only 15 years.'
[Ibid., p. 635]