Rutuja M. Borawke, M.E.S. Abasaheb Garware College, Pune
Scientists from Physical Research Laboratory (PRL), Ahmedabad & IISc Bangalore have compiled research that focuses on examining the driving force for expanding the universe & the nature of dark energy. Mohanty from PRL clears the fact that only 5% of the universe is understood. The remaining is hence known as dark energy & dark matter. They are responsible for the rotational speeds of galaxies & the formation of cosmic structure; also accelerating the expansion of the universe.
Recent studies have put forward precise data and conclusions leading to discrepancies in defining the ‘dark universe’. The astronomical observations and standard model of cosmology deliver a much smaller rate of acceleration than the standard model of particle physics. Mohanty suggests changing the most favored standard model of cosmology if the discrepancy between theoretical & practical data is not resolved. It might be the case that some interactions between different sectors of dark matter and dark energy have not yet been recognized. He also adds by saying that there are two domains of this study; one being the interpretation of data observed for studying the existence of dark energy and the second is about understanding the microscopic nature of dark energy that has negative pressure.
Researchers identify to revise the tool for measuring cosmological distance using the spectroscopic redshift and the use of standard candles like Type-1a supernovae or Cepheid variables- stars whose luminosity varies periodically with time. Although dark energy is unlike any other particle or field so far studied, practical observations might help us get into the deep roots of the science of the universe. The only way to do this is to continuously measure and examine the accelerating universe. This is now possible due to advancements in cosmological studies involving precision experiments and particle physics.
Several theories explain the mechanism of expanding universe, e.g. zero-point energy and renormalization, dark energy scalar field, string relics, supergravity, quantum gravity, etc. Despite these, no solid facts are stating the present state of observations is true to these theories. Mazumdar et al have presented pieces of evidence for dark energy from type 1a supernovae, CMB, galaxy surveys, and observations from clusters. They have also indicated anomalies in the standard CDM (cosmological constant and cold dark matter) model of cosmology and discuss the discrepancy in values H0 and σ8 in large-scale structural observations of the CDM model.
Mohayee et al. have presented experimental evidence that our universe is homogenous. According to their data, Quasars show dipolar distribution which is contrary to the standard model and is similar to the Hubble expansion rate. Newell discusses the key point here, stating that symmetry considerations account for the distribution of matter in the galaxy, and not the energy minimization hypothesis. Pomeau suggested screening of fermions when scattered by a gravity field, where it produces an effect that modifies Newton’s constant at large distances. As a result, no such dark matter candidate is required for practical observations and this can, hence, become a possibility to analyze the expansion of our universe.
Also read: Unravelling the rare case of Kikuchi Fujimoto disease
References:
- Ananthanarayan, B., & Mohanty, S. (2021). The accelerating universe: Evidence and theories. The European Physical Journal Special Topics, 230(9), 2051–2053. https://doi.org/10.1140/epjs/s11734-021-00259-x
- Mazumdar, A., Mohanty, S., & Parashari, P. (2021). Evidence of dark energy in different cosmological observations. The European Physical Journal Special Topics, 230(9), 2055–2066. https://doi.org/10.1140/epjs/s11734-021-00212-y
- Mohayaee, R., Rameez, M., & Sarkar, S. (2021). Do supernovae indicate an accelerating universe? The European Physical Journal Special Topics, 230(9), 2067–2076. https://doi.org/10.1140/epjs/s11734-021-00199-6
One thought on “The universe expansion: New theories proposed!”