Relativists always keep telling us that General Relativity (GR) has passed every test with flying colors. More precisely, they always tell us that every ‘prediction’ of GR has come true. Here we choose to accept that OK every test within the dynamical boundaries of Solar System was passed.
We also choose to not question the failure of GR at galactic and clusters of galaxies scale where they had to balance out their equations with ghost object of dark matter. We prefer to not raise question on this failure of GR because, as will be explained in upcoming posts, the dark matter was not the failure of theory but was the result of incorrect application of theory. Therefore, to the extent of galactic dynamics, we choose not to raise objection on GR.
But in definite terms, GR has failed the test at Cosmological Scales with more than flying colors.
In famous 1917 Cosmology paper where Einstein introduced Cosmological Constant, he writes following:
Before introducing Cosmological Constant, Einstein (1917) is saying that space (on cosmological scale) must have constant curvature i.e. whole cosmos is a huge sphere.
Now please see how Einstein has concluded this 1917 paper:
In starting lines of this page, Einstein is saying that introduction of cosmological constant has also given the result that space on cosmological scale is spherical. At the end, he is explaining that curvature of space is positive even if cosmological constant is not considered or taken into account.
Therefore, by all means, ‘prediction’ of GR for Cosmology was that Space (or Universe) is curved or spherical etc.
Now the latest observations and measurements have actually shown that space is not curved at cosmological scale. Universe (or space) is flat at cosmological scales, as a famous website explains it here.
The so-called Standard Model of Cosmology i.e. Lambda-CDM (nickname Big Bang Theory) is actually based on wrong assumption that GR is true for Cosmic Scales. Fact is that GR has terribly failed the test of Cosmos.