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New Distance Measurements Bolster Challenge to Basic Model of Universe:
A new set of precision distance measurements made with an international collection of radio telescopes have greatly increased the likelihood that theorists need to revise the “standard model” that describes the fundamental nature of the Universe.
The new distance measurements allowed astronomers to refine their calculation of the Hubble Constant, the expansion rate of the Universe, a value important for testing the theoretical model describing the composition and evolution of the Universe. The problem is that the new measurements exacerbate a discrepancy between previously measured values of the Hubble Constant and the value predicted by the model when applied to measurements of the cosmic microwave background made by the Planck satellite.
"We find that galaxies are nearer than predicted by the standard model of cosmology, corroborating a problem identified in other types of distance measurements. There has been debate over whether this problem lies in the model itself or in the measurements used to test it. Our work uses a distance measurement technique completely independent of all others, and we reinforce the disparity between measured and predicted values. It is likely that the basic cosmological model involved in the predictions is the problem," said James Braatz, of the National Radio Astronomy Observatory (NRAO).
[...] "The maser method of measuring the expansion rate of the universe is elegant, and, unlike the others, based on geometry. By measuring extremely precise positions and dynamics of maser spots in the accretion disk surrounding a distant black hole, we can determine the distance to the host galaxies and then the expansion rate. Our result from this unique technique strengthens the case for a key problem in observational cosmology." said Mark Reid of the Center for Astrophysics | Harvard and Smithsonian, and a member of the Megamaser Cosmology Project team.
"Our measurement of the Hubble Constant is very close to other recent measurements, and statistically very different from the predictions based on the CMB and the standard cosmological model. All indications are that the standard model needs revision," said Braatz.
Journal Reference:
D. W. Pesce, J. A. Braatz, M. J. Reid, et al. The Megamaser Cosmology Project. XIII. Combined Hubble Constant Constraints - IOPscience, The Astrophysical Journal Letters (DOI: 10.3847/2041-8213/ab75f0)
(Score: 3, Interesting) by Snotnose on Saturday June 13 2020, @11:59PM (2 children)
Just a month or two ago I was reading there might be more than 1 way for a type 1a Supernova to happen. If true, the 1a can no longer be considered a standard candle and as such, stuff like the universe is expanding is no longer valid.
When the dust settled America realized it was saved by a porn star.
(Score: 2) by HiThere on Sunday June 14 2020, @01:04AM
While there are three proposed ways for a type 1a supernova to happen, they all have the same brightness. So they are still good as "standard candles".
https://www.sciencemag.org/news/2020/06/galaxy-s-brightest-explosions-go-nuclear-unexpected-trigger-pairs-dead-stars [sciencemag.org]
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by PiMuNu on Sunday June 14 2020, @07:08PM
> the universe is expanding is no longer valid.
That's a big statement. More plausible would be the measured rate of universal expansion has a larger-than-expected systematic uncertainty (or even correction)
i..e. the universe is expanding, but maybe at a different speed.