Dark Matter May Have Originated Before the Big Bang, Scientist Says

Dark matter—the mysterious hypothetical substance that scientists have yet to identify—may have existed before the Big Bang, a scientist from Baltimore's Johns Hopkins University has suggested.

While this idea has previously been proposed by others, physicist and astronomer Tommi Tenkanen has now laid out a mathematical explanation to support the hypothesis in a study published by the journal Physical Review Letters.

The paper sheds new light on the origin of dark matter and how it may be possible to detect it with astronomical observations.

"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," Tenkanen said in a statement. "This connection may be used to reveal their identity and make conclusions about the times before the Big Bang too."

Currently, scientists cannot explain what more than 95 percent of the universe's mass consists of. As a result, they have proposed the existence of hypothetical "dark" forms of matter and energy to help explain the vast gaps in our knowledge.

Dark matter appears to make up about 27 percent of the universe's mass, whereas dark energy accounts for 68 percent. "Normal" matter—the stuff we can see and observe—makes up less than 5 percent.

Unlike normal matter, dark matter does not absorb, reflect or emit light, making it extremely difficult to observe. In fact, no one has directly detected the substance to date, despite numerous attempts. Scientists have simply inferred its existence due to its apparent gravitational effects on normal matter, according to NASA.

"Dark matter is a long-standing problem," Tenkanen told Newsweek. "We know it exists but not what it actually is nor what its origins is."

It was long thought that dark matter was produced during the Big Bang—the beginning of the universe as we know it—which occurred around 13.8 billion years ago. However, the fact that it hasn't been directly detected by experiments yet suggests that this isn't the case.

"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," Tenkanen said.

In the study, Tenkanen outlines a mathematical framework that indicates dark matter may have its origin in a "pre-Big Bang epoch" known as the cosmic inflation, which was characterized by the rapid expansion of space.

While we think of the Big Bang as the beginning of the universe, there is a good chance that the theory is incomplete. In fact, the theory only really refers to the aftermath of the "Bang."

"What cosmologists nowadays mean by the Big Bang is an epoch roughly 13.8 billion years ago when the universe was compressed into a tiny volume," Tenkanen said. "Because of the huge compression, molecules and atoms were decomposed into smaller elementary particles that formed a hot soup scientists call a heat bath. We know this because the so-called Cosmic Microwave Background (CMB) radiation that has been measured very accurately is a clear image of that state."

"However, properties of this CMB radiation suggest that before the heat bath formed, the universe was in a different state cosmologists call cosmic inflation. During inflation, the space was expanding very rapidly," he said.

Tenkanen says that the rapid expansion of space produced vast quantities of so-called "scalar" particles—which include the famous Higgs boson that was discovered by researchers at the European Organization for Nuclear Research (CERN) in 2012.

"The key finding of my study is that not only so many scalars may have formed during such a state that they constitute dark matter, but that they leave a unique imprint on the large scale structure of the universe—which formed much later, after the Big Bang," he said. "This makes the hypothesis testable with astronomical observations in the near future."

"I hope astronomers will soon discover the predicted imprint of dark matter in the large scale structure of the universe, that is in the distribution of galaxies and galaxy clusters," he said. "We will soon now more about that when the Euclid satellite is launched into space in 2022."

Some scientists were more cautious about the results of the latest study, however. Ethan Brown, an assistant professor of physics and astronomy at Rensselaer Polytechnic Institute who was not involved in the paper, told Newsweek: "The work is interesting in the sense that it gives a possible connection between cosmic inflation and dark matter, but the statement that this has anything to do with a pre Big Bang era is unfounded."

This article was updated to include additional comments from Tommi Tenkanen and Ethan Brown.

dark matter, universe, galaxies
This image shows the distribution of dark matter, galaxies, and hot gas in the core of the merging galaxy cluster Abell 520. NASA
Dark Matter May Have Originated Before the Big Bang, Scientist Says | Tech & Science