By Amruth Chinnappa
A decades-old hypothesis has been validated with the discovery of missing matter, now found to be present in filaments which link together various galaxies. The finding answers a major question plaguing scientists about the elusiveness of a huge number of baryons and is attributed to two teams lead by Hideki Tanimura from the Institute Of Space Astrophysics, France and Anne de Graaf from the University of Edinburgh, United Kingdom.
Baryons and the Big Bang
Baryons are subatomic particles which make up nearly all the matter of the visible universe. Scientists have used resultant energy from the Big Bang to postulate about the total number of existing baryons for long, yet the observed quantity accounted for just 10% of the entirety. The remaining, assumed to be present in the interlinking region of galaxies, were unable to be detected by X-rays because of their tenuous and cold nature.
The researchers made use of the Sunyaev-Zeldovich effect according to which, low energy photons from the Big Bang scatter off the electrons in gases to reveal a dim patch in the microwave background. In 2015, the Planck satellite was used to map this effect throughout the universe but was unable to pick up any clear impressions of the missing particles in these 15 megaparsec long filaments (Around 49 light years).
The missing matter: Revealing the baryons
The study used The Sloan Digital Sky Survey which provides the most detailed spectroscopic maps of the Universe, to locate pairs of ‘Luminous Red Galaxies’. The Planck satellite was used on the separation between these pairs with the data stacked to reveal a clear presence of the baryons. The team lead by Hideki Tanimura considered 260,000 pairs and found that the matter present in these regions was three times denser than that of the mean particle density of the universe.
The Anne de Graff team worked with over a million pairs and observed a density six times greater than the mean. Tanimura explained the variation saying, “We expect differences because we are looking at filaments at different distances. If this factor is included, our findings are very consistent with the other group“, thereby reasserting the findings.
What it means for the scientific community
The observable universe accounts for just 4% of the total estimable universe, where dark matter exists in the vast majority.
The validation of previously contemplated theories count for a step in the right direction to the scientific community at large and provides a stronger foundation in our efforts to unravel the secrets of the cosmos.
Featured Image Source: NASA Goddard Photo and Video via VisualHunt.com / CC BY