People/Edwin Powell Hubble: Difference between revisions

"Such a condition would imply that we occupy a unique position in the universe, analogous, in a sense, to the ancient conception of a central earth. '''The hypothesis cannot be disproved but it is unwelcome and would be accepted only as a last resort in order to save the phenomena. Therefore, we disregard this possibility''' and consider the alternative, namely, a distribution which thins out with distance. A thinning out would be readily explained in either of two ways. The first is space absorption. If the nebulae were seen through a tenuous haze, they would fade away faster than could be accounted for by distance and red-shifts alone, and the distribution, even if it were uniform, would appear to thin out. The second explanation is a super-system of nebulae, isolated in a larger world, with our own nebula somewhere near the centre. In this case the real distribution would thin out after all the proper corrections had been applied. Both explanations seem plausible, but neither is permitted by the observations. The apparent departures from uniformity in the World Picture are fully compensated by the minimum possible corrections for redshifts on any interpretation. No margin is left for a thinning out. The true distribution must either be uniform or increase outward, leaving the observer in a unique position. '''But the unwelcome supposition of a favoured location must be avoided at all costs.... Such a favoured position, of course, is intolerable … Therefore, in order to restore homogeneity, and to escape the horror of a unique position''', the departures from uniformity, which are introduced by the recession factors, must be compensated by the second term representing effects of spatial curvature. There seems to be no other escape." <ref name=ObservationalApproachToCosmolog></ref></blockquote>