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Originally Posted by Astrobairn
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Originally Posted by Sam5
I certainly don’t know how it started. This question has been puzzling mankind for the past 50,000 years. But this “expanding space” nonsense is new and it’s designed to keep Einstein’s “speed limit of ‘c’” seem wrong. That’s all it’s for. This didn’t start until a decade or so ago, when they began finding galaxies with redshifts that suggest they are superluminal. Before that, they went with the “explosion theory”, although they didn’t like it very much. They avoid the “explosion” idea right now just by not talking about the “beginning”. That’s why Eddington invented the “balloon model” in the 1930s, to take the general public’s mind off asking questions about “the beginning” and where the "center" was located. Eddington said in a book in 1933 that we are located "in the skin of the balloon", and that was baloney too.
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OK if you want to get technical the "size" of the universe is defined by the scale factor R(t). As photons move through space towards us R(t) increases as does their wavelength. Hence the photons are redshifted. The fact is that the simplest hypersurfaces in GR have in centre on their surface. Asking where the centre is is like asking which city is at the centre of the earth. The fact is we are only able to preseve the dimensions we live in. A 1D ant living on the circumference of a circle would only know back and forward. |
The “hypersurface” part of GR theory was removed in 1932 in a paper Einstein wrote with de Sitter. The “hypersphere” or “universal curved space” part of 1916 GR theory was used only to explain a way the universe could be “static” (non-expanding and non-contracting). With the discovery of the so-called “expansion” of the universe by Lemaitre and Hubble, that part of GR theory became null and void, non-existent and obsolete. It just didn’t exist after 1932, after Einstein wrote:
“There is no direct observational evidence for the curvature, the only directly observed data being the mean density and the expansion, which latter proves that the actual universe corresponds to the non-statical case. It is therefore clear that from the direct data of observation we can derive neither the sign nor the value of the curvature, and the question arises whether it is possible to represent the observed facts without introducing a curvature at all.”
“Although, therefore, the density corresponding to the assumption of zero curvature and to the coefficient of expansion may perhaps be on the high side, it certainly is of the correct order of magnitude, and we must conclude that at the present time it is possible to represent the facts without assuming a curvature of three-dimensional space. The curvature is, however, essentially determinable, and an increase in the precision of the data derived from observations will enable us in the future to fix its sign and to determine its value.”
This paper was titled, "The Relation Between the Expansion and the Mean Density of the Universe", by A. Einstein and W. de Sitter, National Academy of Sciences 18, 213-124 (1932)