New study says universe expands at constant rate
A new study challenges the idea that dark energy is causing the universe to expand at an accelerating rate.
Tech Times reports that a group of researchers studying supernovae found evidence that the universe is expanding at a constant rate.
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CrazyNeutrino said:
New study says universe expands at constant rateA new study challenges the idea that dark energy is causing the universe to expand at an accelerating rate.
Tech Times reports that a group of researchers studying supernovae found evidence that the universe is expanding at a constant rate.
More…
It will be interesting to see if this survives the test of time.
If so, I wonder what else will need adjustment.
CrazyNeutrino said:
New study says universe expands at constant rateA new study challenges the idea that dark energy is causing the universe to expand at an accelerating rate.
Tech Times reports that a group of researchers studying supernovae found evidence that the universe is expanding at a constant rate.
More…
I wonder if they’re misunderstanding the technical article, confusing “constant rate” with “cosmological constant”. I’d have to read the technical article to be sure. The discovery of dark energy independently by two groups has already won the Nobel Prize.
So it can’t be retracted ;-)
Went looking for the technical article on Arxiv. Um, which one?
There are at least thirty six scientific papers on Arxiv this year by independent authors that extract cosmological data from the exact same set of 740 type 1a supernovae.
mollwollfumble said:
Went looking for the technical article on Arxiv. Um, which one?There are at least thirty six scientific papers on Arxiv this year by independent authors that extract cosmological data from the exact same set of 740 type 1a supernovae.
The 740 Type 1a supernovae are known as the JLA dataset. The set contains 11 “problematic” supernovae. JLA sample (Betoule, Kessler et al. 2014).
The original preprint on which all others are based is
Improved cosmological constraints from a joint analysis of the
SDSS-II and SNLS supernova samples.
M. Betoule, R. Kessler et al.
Preprint online version: June 5, 2014
ABSTRACT
Aims. We present cosmological constraints from a joint analysis of type Ia supernova (SN Ia) observations obtained by the SDSS-II and SNLS
collaborations. The data set includes several low-redshift samples (z < 0.1), all three seasons from the SDSS-II (0.05 < z < 0.4), and three years
from SNLS (0.2 < z < 1), and it totals 740 spectroscopically confirmed type Ia supernovae with high quality light curves.
Methods. We followed the methods and assumptions of the SNLS three-year data analysis except for the following important improvements:
1) the addition of the full SDSS-II spectroscopically-confirmed SN Ia sample in both the training of the SALT2 light-curve model and in the
Hubble diagram analysis (374 SNe), 2) intercalibration of the SNLS and SDSS surveys and reduced systematic uncertainties in the photometric
calibration, performed blindly with respect to the cosmology analysis, and 3) a thorough investigation of systematic errors associated with the
SALT2 modeling of SN Ia light curves.
Results. We produce recalibrated SN Ia light curves and associated distances for the SDSS-II and SNLS samples.? The large SDSS-II sample
provides an effective, independent, low-z anchor for the Hubble diagram and reduces the systematic error from calibration systematics in the low-z
SN sample. For a flat ΛCDM cosmology, we find Ωm =0.295 ± 0.034 (stat+sys), a value consistent with the most recent CMB measurement
from the Planck and WMAP experiments. Our result is 1.8σ (stat+sys) different than the previously published result of SNLS three-year data. The
change is due primarily to improvements in the SNLS photometric calibration. When combined with CMB constraints, we measure a constant
dark-energy equation of state parameter w =−1.018 ± 0.057 (stat+sys) for a flat universe. Adding BAO distance measurements gives similar
constraints: w =−1.027 ± 0.055. Our supernova measurements provide the most stringent constraints to date on the nature of dark energy.
After the OPERA neutrino experiment announced “faster than light” , then recanted, I’ll wait until repeat experiments confirm this one.
> Ωm =0.295 ± 0.034 (stat+sys), a value consistent with the most recent CMB measurement from the Planck and WMAP experiments. We measure a constant
dark-energy equation of state parameter w =−1.018 ± 0.057.
In other words, the standard model of the universe expansion from 70% dark energy and constant cosmological constant (ie w=-1) is totally confirmed by the latest set of 740 supernovae.
Have a look at this diagram. If the claim “universe expands at a constant rate” had any validity then the line in the top part of the diagram would be a straight line and the best fit cosmology would be the solid line (0,1) at the top and bottom of the chart. This clearly does not fit the data. The best fit (0.7, 0.3) is the bog standard Lambda Cold Dark Matter model of dark energy and dark matter as derived from sources such as the Planck measurement of the Cosmic Microwave Radiation and the Baryon Acoustic Oscillation measurements. This is the exact same data (JLA 740 Type 1a supernovae) referred to in the news article of the OP.
In other words, the hyped claim that “New study says universe expands at a constant rate” is pure BS. It was proved false two years before the OP was written.
Some more facts for you information, JLA stands for “joint light-curve analysis”, because the supernovae are found from multiple sources all the way from observations of nearby galaxies (Low z supernovae) all the way out to supernovae observed by the Hubble Space
Telescope in deep field observations of the most distant visible universe.(redshift > 1).
mollwollfumble said:
Have a look at this diagram. If the claim “universe expands at a constant rate” had any validity then the line in the top part of the diagram would be a straight line and the best fit cosmology would be the solid line (0,1) at the top and bottom of the chart. This clearly does not fit the data. The best fit (0.7, 0.3) is the bog standard Lambda Cold Dark Matter model of dark energy and dark matter as derived from sources such as the Planck measurement of the Cosmic Microwave Radiation and the Baryon Acoustic Oscillation measurements. This is the exact same data (JLA 740 Type 1a supernovae) referred to in the news article of the OP.In other words, the hyped claim that “New study says universe expands at a constant rate” is pure BS. It was proved false two years before the OP was written.
Some more facts for you information, JLA stands for “joint light-curve analysis”, because the supernovae are found from multiple sources all the way from observations of nearby galaxies (Low z supernovae) all the way out to supernovae observed by the Hubble Space
Telescope in deep field observations of the most distant visible universe.(redshift > 1).
For world’s best cosmology, see Figure 16 of https://arxiv.org/format/1401.4064