Astronomers uncover what might have existed earlier than the Big Bang

Dark matter has puzzled physicists for almost a century, remaining one in all fashionable science’s best mysteries. Although invisible, its gravitational results are essential to explaining the construction and dynamics of galaxies.

Approximately 85% of the universe’s matter is undetectable by even essentially the most superior instruments. This unseen mass, referred to as darkish matter, might have predated the Big Bang.

Dark matter was first proposed within the Thirties to clarify discrepancies between galactic motions and their seen mass. Later, observations of the cosmic microwave background (CMB)—the faint afterglow of the Big Bang—solidified its function in cosmology.

According to the 2018 Planck Collaboration, darkish matter accounts for 27% of the universe’s complete power, far surpassing the 5% comprised of unusual matter.

Since its discovery, researchers have sought to uncover darkish matter’s nature. Supersymmetry (SUSY), an extension of the Standard Model of particle physics, presents probably the most promising frameworks by proposing associate particles for each recognized particle.

Within this framework, weakly interacting large particles (WIMPs) emerged as prime candidates for darkish matter. WIMPs, in the event that they exist, would work together weakly with unusual matter and could possibly be produced in particle accelerators just like the Large Hadron Collider (LHC) or detected straight via underground experiments.

However, the seek for WIMPs has up to now come up empty. Experiments like DAMA, which reported an annual modulation sign probably linked to darkish matter, stay contentious. Efforts to breed such alerts via tasks like COSINE-100 have but to yield conclusive outcomes.

Similarly, the LHC has didn’t detect any SUSY particles, casting doubt on the best WIMP fashions. As a end result, scientists have begun to discover extra unique potentialities for darkish matter’s origin and habits.

One such groundbreaking concept is the “Dark Big Bang” (DBB) concept, proposed in 2023 by Katherine Freese and Martin Winkler from the University of Texas at Austin. Unlike the traditional Big Bang, which explains the beginning of unusual matter, the DBB means that darkish matter arose from a separate occasion.

This second Big Bang, occurring someday after the primary, would have generated darkish matter via the decay of a quantum subject trapped in a false vacuum state.

In this mannequin, the early universe consisted of two sectors: the seen sector, stuffed with the acquainted particles and forces, and a darkish sector, which remained chilly and decoupled. Eventually, the darkish sector underwent its personal section transition, analogous to the seen sector’s sizzling Big Bang.

This transition produced a thermal bathtub of darkish particles, ruled by a novel set of bodily legal guidelines. The DBB mannequin is especially versatile, as it will possibly accommodate a variety of darkish matter particle lots, from as gentle as a couple of keV to as heavy as 101210^{12}1012 GeV.

What units the DBB mannequin aside is its potential to depart observable traces. The section transition at nighttime sector might generate gravitational waves (GWs), ripples within the cloth of spacetime. These GWs could be distinct from these produced by black gap mergers or neutron star collisions and could possibly be detected by next-generation observatories.

In specific, low-frequency GWs detectable by pulsar timing arrays (PTAs) such because the International Pulsar Timing Array (IPTA) and the Square Kilometer Array (SKA) might present essential proof for the DBB.

Recent work by Cosmin Ilie, an Assistant Professor of Physics and Astronomy at Colgate University, and Richard Casey, a senior physics pupil, has additional refined the DBB concept. Their research explores new parameter areas for the darkish sector’s tunneling subject, figuring out eventualities that align with current cosmological observations.

These eventualities predict not solely the right abundance of darkish matter but in addition GW alerts that might quickly be inside attain of PTA experiments.

“Detecting gravitational waves generated by the Dark Big Bang might present essential proof for this new concept of darkish matter,” says Ilie. Such detection could be groundbreaking, providing the primary direct proof of darkish matter’s distinct origin.

The 2023 detection of background GWs by the NANOGrav collaboration, part of IPTA, provides an intriguing dimension to this analysis. While the precise supply of those waves stays unsure, they may probably align with the DBB mannequin’s predictions.

Beyond its implications for darkish matter, the DBB concept presents a contemporary perspective on the early universe. Traditionally, cosmology has operated below the belief that every one matter, darkish or in any other case, emerged from the identical occasion.

The concept of a dual-origin universe challenges this notion, suggesting a extra complicated interaction of forces and fields within the universe’s infancy. If confirmed, the DBB mannequin might reshape our understanding of cosmic evolution, from the formation of the primary galaxies to the large-scale construction of the universe.

The seek for darkish matter is a central pillar of recent physics, driving developments in expertise and concept. Direct detection experiments, equivalent to these performed deep underground, proceed to push the boundaries of sensitivity, aiming to seize fleeting interactions between darkish matter particles and unusual matter.

Meanwhile, astrophysical observations, from the CMB to galactic rotation curves, present oblique however compelling proof for darkish matter’s gravitational affect. The DBB mannequin, with its distinctive predictions and testable penalties, provides a robust new instrument to this arsenal.

As observational capabilities advance, the prospect of detecting GWs from a DBB turns into more and more believable. Projects like SKA, anticipated to come back on-line within the subsequent decade, promise unprecedented sensitivity to low-frequency GWs. These efforts might lastly raise the veil on darkish matter’s mysterious origins, answering questions which have puzzled scientists for generations.

In the broader context, understanding darkish matter is not only a scientific pursuit however a quest to grasp the elemental nature of the universe. Whether via conventional particle physics or novel cosmological theories just like the DBB, every discovery brings us nearer to unveiling the total tapestry of existence.