New observations by the astronomers have disclosed that something is missing from the process of how the dark matter behaves. Our universe is formed by 85% of the dark matter. It cannot be experienced directly but the presence of it can be surmised through the gravitational pull into the visible matter in space. It does not emit, absorb, or reflect light.
NASA’s Hubble’s Space Telescope and the European Southern Observatory’s Very Large Telescope (VLT) in Chile have reported a missing additive to the current dark matter theories. It has been found that small scale concentrations of the dark matter produce a gravitational lensing effect which is ten times more than expected.
Galaxy clusters are the most enormous structure in the universe which are made up of individual member galaxies and it is the biggest repository of the dark matter. They are held together by the dark matter’s gravity and the individual galaxies themselves replete with dark matter. Therefore dark matter is distributed in both small and large scopes.
“Galaxy clusters are ideal laboratories to understand if computer simulations of the universe reliably reproduce what we can infer about dark matter and its interplay with luminous matter,” said Massimo Meneghetti of the INAF (National Institute for Astrophysics)-Observatory of Astrophysics and Space Science of Bologna in Italy, the study’s lead author.
“We have done a lot of careful testing in comparing the simulations and data in this study, and our finding of the mismatch persists,” Meneghetti continued. “One possible origin for this discrepancy is that we may be missing some key physics in the simulations.”
Priyamvada Natarajan of Yale University in New Haven, Connecticut, one of the senior theorists on the team, added, “There’s a feature of the real universe that we are simply not capturing in our current theoretical models. This could signal a gap in our current understanding of the nature of dark matter and its properties, as these exquisite data have permitted us to probe the detailed distribution of dark matter on the smallest scales.”
The measurement of the bending of the light helped to map the distribution of dark matter in clusters. Dark matter gravity magnifies and warps the light from far away background objects. In the cluster the higher the concentration of the dark matter, the light bends more dramatically.
Both Hubble and spectra from VLT helped the team of the astronomers to make a detailed dark- matter map. Dozens of multiply imaged, lensed, background galaxies were identified. With the help of the lensing distortions, the astronomers were able to track the amount and dissemination of the dark matter.
The 3 galaxy clusters used during the study are –
They were distributed into two Hubble surveys –
The images of Hubble also exposed an amazing number of smaller-scale arcs and images twisted out of shapes nested near every cluster’s core, where the most substantial galaxies settle. Astronomers believe that the nested lenses are produced due to the gravity of the heavy combination of matter inside the individual cluster galaxies. Spectroscopic inspection calculated the velocity of the stars orbiting inside various cluster galaxies to find the exact count of their masses.
The complete research is published in the journal Science.