The Invisible Force: Shedding Light on the Mystery of Dark Matter

It is without a doubt that the existence of dark matter (DM) in the universe is one of the most intriguing mysteries of modern cosmology, especially because of the good agreement between observations and the theoretical framework of the so-called concordance model ΛCDM. The simple assumption that DM is a pressure-less component known as cold dark matter seems to be sufficient to explain, in particular, the formation of large-scale structures in the cosmos.

Figure-1: A map of different explanations for the dark matter phenomenon that are currently being investigated. (Image: G. Bertone and T. Tait, (https://www.nature.com/articles/s41586-018-0542-z))

Figure-2: Current energy composition of our universe (image credit: http://hep.ucsb.edu/people/hugh/research/)

Today, the scientific community generally accepts that 95% of the universe is made up of stuff that we’ve never seen before and do not understand. In the figure-2, the energy composition of our universe in the present day is shown.

1. Dark energy: 70%
2. Dark matter: 25%
3. Ordinary matter: 5%

5% of the total ordinary matter is distributed in the stars, galaxies, clusters, hot intergalactic gas, warm intergalactic gas, etc. The truth is, even though dark matter is 85% of the total matter in the universe, we don’t know what it is because we’ve never seen it directly.

Ever since astronomers reached a consensus in the 1980s that most of the mass in the universe is invisible — that “dark matter” must glue galaxies together and gravitationally sculpt the cosmos as a whole — experimentalists have hunted for the nonluminous particles.

Samuel Velasco/Quanta MagazineSamuel Velasco/Quanta Magazine

Reference

https://sites.google.com/view/aruncosmo/Mathematica-Codes#h.9i8puamboxix