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Confirmed the enigmatic variation of the Hubble constant.
A new measurement of the Hubble constant, which expresses the expansion rate of the universe, confirming the discrepancy between his early universe value, determined by the Planck satellite, and the current one in the universe. This discrepancy might suggest a “new physics” beyond the standard model of cosmology. A new measurement of the Hubble constant confirmation that the expansion rate of the universe is accelerating, suggesting that our current picture of the cosmos can “missing something fundamental”.
The Planck satellite had obtained an expansion speed of about 66.9 kilometers per second for megaparsecs (a parsec corresponds to 3.3 light years approximately), while the other measurements it showed about 73.
The image of the quasar RXJ1131-1231 quadrupled from the gravitational lens formed by a galaxy on his line of sight. Under these measures, however, there is a basic difference: by observing the cosmic microwave background radiation, Planck has measured the Hubble constant for the early universe, while the other approach, which considers the part the most “near space” to us, measuring the value of the recent Universe constant. The difference observed so opens the door to the possibility that the Hubble constant is not so constant and has instead had an evolution, maybe in connection with some strange properties of the already strange and enigmatic dark energy that should support the expansion of the cosmos. Unless, as it is still possible, the discrepancy between the values is not due to a statistical fluctuation linked to inaccuracies in the measurements, in which case, however, should disappear with the increase and improvement of the measurements. The new result – of particular importance because it was obtained by a different method from the previous and independent – not however in this direction: the 71.9 ± 2.7 kilometers per second per megaparsec estimated by H0LiCOW are substantially in line with those obtained with the methods Cepheid / supernovae and in clear contrast to Planck. This difference may suggest a “new physics” beyond the standard model of cosmology.
The H0LiCOW astronomers measured the Hubble constant using the effect of gravitational lensing of distant massive galaxies on light from quasars – unbelievably bright cores of galaxies – even more distant. The gravitational lens is the phenomenon by which the trajectory of a ray of light that passes beside an extremely massive object is deflected due to the influence exerted by the object gravitational, which behaves so much like a lens. Since in massive galaxies the mass is not evenly distributed, they do not create perfectly spherical distortions, or the light of the different background quasar follows paths of slightly different lengths. Furthermore, the brightness of the quasar varies in time. Researchers can thus see different images with delays that depend on different paths and are directly linked to the value of the Hubble constant. Our method is the simplest and most direct way to measure the Hubble constant, since it only uses the geometry and general relativity, no other assumptions. The study examined five quasars, but the H0LiCOW partnership plans to improve the measurement and significantly reduce the possible statistical errors by performing the same measurements over a hundred quasars observed by gravitational lenses.
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