It is common knowledge that dark matter makes up about 80% of the universe's mass but what is not known is exactly what it is or how it came to be. Now, adding to its mystery, a new study is revealing the elusive matter may have existed before the Big Bang.
A new connection between particle physics and astronomy
"The study revealed a new connection 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," said Tommi Tenkanen, a postdoctoral fellow in Physics and Astronomy at the Johns Hopkins University and the study's author.
Dark matter is difficult to grasp as its not directly observable. Rather its presence is known by its gravitation effects on how visible matter moves and is distributed in space.
Now, the new findings are in direct opposition to a long-held belief that dark matter must be a leftover substance from the Big Bang.
"If dark matter were truly a remnant of the Big Bang, then in many cases researchers should have seen a direct signal of dark matter in different particle physics experiments already," said Tenkanen.
A simple mathematical framework
The novel study employs a simple mathematical framework to illustrate that dark matter may have been produced before the Big Bang. More specifically, it would have come into existence during an era known as the cosmic inflation when space was expanding very quickly. This expansion is believed to lead to the introduction of certain types of particles called scalars such as the Higgs boson.
"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," explained Tenkanen.
Although the notion that dark matter may have predated the big bang is not new, there have been no calculations to support the idea so far. Tenkanen says this is because researchers have overlooked the simplest possible mathematical scenario for dark matter's origins.
His new method not only offers a glimpse into that scenario it may also lead to a new way to test the origin of dark matter by observing the signatures dark matter leaves 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 peek into the times before the Big Bang."
The study is published in Physical Review Letters.