Dark matter is what the universe is mostly made up of—almost 80% of the universe’s mass is made up of dark matter. Nevertheless, dark matter remains mostly elusive for astrophysicists. What exactly is dark matter and how did it come into being is something physicists and astrophysicists have been striving to decipher for many years.
For a long time, scientists have believed that dark matter is a left-over substance from the Big Bang. Researchers have long sought this kind of matter, but so far, all experimental searches have remained unsuccessful.
A new research published very recently in Physical Review Letters has proposed that dark matter might have been produced even before the Big Bang during the era known as cosmic inflation, the time when space was undergoing rapid expansion. This rapid expansion has been believed to have produced certain types of particles that are known as scalars. The famous Higgs Boson has been the only scalar particle to be discovered till date.
This study has revealed a new relationship between particle physics and astronomy. “If dark matter consists of new particles that were born before the Big Bang, they affect the way galaxies are distributed in the sky in a unique way. This connection may be used to reveal their identity and make conclusions about the times before the Big Bang too," says Tommi Tenkanen, of the Johns Hopkins University and the author of the study.
Even if not much is known of its origin, dark matter plays an important role in the formation of galaxies and galaxy clusters. It exists by the effect of its gravitation on how visible matter moves and is distributed in space.
The new study developed a simple mathematical framework with the help of which it was possible to find out that dark matter might have been produced even before Big Bang took place. "We do not know what dark matter is, but if it has anything to do with any scalar particles, it may be older than the Big Bang. With the proposed mathematical scenario, we don't have to assume new types of interactions between visible and dark matter beyond gravity, which we already know is there," comments Tenkanen.
It is to be noted here that the idea of dark matter’s existence before the Big Bang is not entirely new. Actually, scientists could not have come out with calculations or mathematical formulations that could support the idea. The new study breaks that and also showed that simple mathematical framework can actually explain the origin of dark matter. It also shows that theorists have always overlooked the simple mathematical possibilities that could have explained the origin of dark matter.
The mathematical framework developed in the study would also be helpful in testing the origin of dark matter by an analysis of the signatures that have been left by dark matter on the distribution of matter in the universe.
"While this type of dark matter is too elusive to be found in particle experiments, it can reveal its presence in astronomical observations. We will soon learn more about the origin of dark matter when the Euclid satellite is launched in 2022. It's going to be very exciting to see what it will reveal about dark matter and if its findings can be used to peak into the times before the Big Bang”—Tenkanen hoped.