Computer Simulations might solve one of the most debated questions in astrophysics, is the dark matter real?

Baryonic matter accounts for only 5% of our universe. Scientists have no clue from where the remaining 95% came but they do believe that nearly 80% of the universe is filled with a form of matter, called Dark Matter, which cannot be detected by visible light or any other electromagnetic radiation. Similarly, it doesn’t react with any form of baryonic matter. Due to these properties, its direct observation is not possible, at least for now, but a number of Astrophysical Observations have suggested that it surely exists. The fact that it is invisible to the entire Electromagnetic Spectrum is the reason why it is called ‘Dark’. It has always been a massive debate whether it exists or not and a recent study suggests that scientists have a found a way to put an end to this argument once and for all.

Fritz Zwicky, a Swiss Astronomer, was the first man who indicated in 1933 that an invisible substance must be present to keep galaxies on their specified orbits. He argued that the speed of their motion is so much that they should drift apart if not for the mass of that material which creates sufficient gravitational pull to keep things in order. Vera Rubin concreted his idea as he found that the Centrifugal Force created by the rotation of galaxies like ours should tear them apart if we consider that only visible matter is available.

As the existence of Dark Matter provides an excellent explanation for several observations like the distribution of background radiations, many scientists are certain that it constitutes the majority of our universe. Similarly, it offers a great understanding of the arrangement and formation rates of galaxies. Although we have so many positives attached to it, humanity has failed to find a direct proof of its existence. Having said that, things may change quite dramatically if the latest efforts deliver as much as they promise.

According to a recent study, published in the Physical Review Letters, the answer to this long-lasting question lies in the movement of the stars of the small galaxies around Milky Way. The researchers of the University of California joined forces with the scientists of the University of Bonn and used computer simulations to figure out the matter distribution of the Satellite Dwarf Galaxies that surround humungous galaxies like Andromeda and Milky Way. Their main focus was on ‘Radial Acceleration Relation (RAR)’, a relationship which is responsible for the movement of stars in the circular galaxies.

As stars revolve around a galactic center, a continuous acceleration ensures that their direction is changing constantly. According to scientists, the attraction of matter in the galaxy is responsible for this and RAR is used to provide the details about the matter distribution and structure of the galaxies. In other words, it describes the relationship between this acceleration and the one caused by the visible light only. Dr. Cristiano Porciani, a Professor at the Argelander Institute for Astronomy, was delighted as he told the world about their work and said,

“We have now simulated, for the first time, the RAR of dwarf galaxies on the assumption that dark matter exists. It turned out that they behave as scaled-down versions of larger galaxies.”

There is another side of the picture of as well which says that Newton’s perception of gravity was not accurate and there is no substance like Dark Matter in our universe. This is where the role of satellites creep in as they are a powerful tool to deduce an answer. The European Space Agency launched the Gaia spacecraft in 2013 with the aim of extracting in-depth information about the stars of the Milky Way and its satellite galaxies. Despite the fact that it has collected heaps of data, we are quite far from solving this puzzle. Enrico Garaldi, a Doctoral Student, emphasized that in the following words:

“Individual measurements are not enough to test the small differences we have found in our simulations. But repeatedly taking a close look at the same stars improves the measurements every time. Sooner or later it should be possible to determine whether the dwarf galaxies behave like in a universe with dark matter — or not.”