New evidence shows that the key assumption made in the discovery of dark energy is in error
The most direct and strongest evidence for the accelerating universe with dark energy is provided by the distance measurements using type Ia supernovae (SN Ia) for the galaxies at high redshift.
This result is based on the assumption that the corrected luminosity of SN Ia through the empirical standardization would not evolve with redshift.
New observations and analysis made by a team of astronomers at Yonsei University (Seoul, South Korea), together with their collaborators at Lyon University and KASI, show, however, that this key assumption is most likely in error.
The team has performed very high-quality (signal-to-noise ratio ‾175) spectroscopic observations to cover most of the reported nearby early-type host galaxies of SN Ia, from which they obtained the most direct and reliable measurements of population ages for these host galaxies.
They find a significant correlation between SN luminosity and stellar population age at a 99.5 percent confidence level.
As such, this is the most direct and stringent test ever made for the luminosity evolution of SN Ia.
Since SN progenitors in host galaxies are getting younger with redshift (look-back time), this result inevitably indicates a serious systematic bias with redshift in SN cosmology.
Taken at face values, the luminosity evolution of SN is significant enough to question the very existence of dark energy.
When the luminosity evolution of SN is properly taken into account, the team found that the evidence for the existence of dark energy simply goes away (see Figure 1).
Figure 1. Luminosity evolution mimicking dark energy in supernova (SN) cosmology.
The Hubble residual is the difference in SN luminosity with respect to the cosmological model without dark energy (the black dotted line).
The cyan circles are the binned SN data from Betoule et al. (2014). The red line is the evolution curve based on our age dating of early-type host galaxies.
The comparison of our evolution curve with SN data shows that the luminosity evolution can mimic Hubble residuals used in the discovery and inference of the dark energy (the black solid line). Credit: Yonsei University