Pulsating stars could hold clues to dark matter's secrets - study

Astrophysicists from the universities of Amsterdam and Princeton lead a groundbreaking study that suggests dark matter might reveal itself through the faint additional glow emitted by pulsating stars if it consists of elusive particles known as axions.

The peer-reviewed study was published in the journal American Physical Society Sites, stated that dark matter remains one of the most enigmatic substances in the universe, constituting a staggering 85% of all matter, yet remaining undetectable by conventional means. 

Unlike the matter we're familiar with, dark matter does not interact significantly with light or other particles, making it an elusive puzzle that scientists are eager to solve.

The hypothesis proposes that dark matter is composed of axions, hypothetical particles introduced in the 1970s to address discrepancies in the behavior of subatomic particles.

Axions, if they exist, are expected to interact weakly with known particles, offering a plausible explanation for the secretive nature of dark matter.

How can the axions that potentially make up dark matter be observed?

The primary challenge in dark matter research has always been the question of detection. If axions indeed make up dark matter, how can they be observed? Recent research may have uncovered a promising solution. 

Theoretical models indicate that axions can convert into detectable light when exposed to strong electromagnetic fields.

The strongest electromagnetic fields known to exist are found around rotating neutron stars, commonly known as pulsars.

These pulsars, smaller in size but immensely dense, emit intense beams of radio waves as they spin rapidly. Scientists have likened them to cosmic lighthouses, as their beams sweep across the universe and are easily observable from Earth.

Moreover, the rapid rotation of pulsars turns them into potent electromagnets, suggesting they could serve as efficient axion factories. It is theorized that every second, a single pulsar has the potential to produce a substantial number of axions, some of which may convert into observable light.

To put this theory to the test, a team of physicists and astronomers from the Netherlands, Portugal, and the United States, collaborated to develop a comprehensive theoretical framework.

This framework aimed to understand the production of axions around pulsars, their escape from the neutron star's gravitational pull, and their subsequent conversion into low-energy radio radiation.

Utilizing cutting-edge numerical plasma simulations initially designed to explain pulsar radio wave emissions, the researchers simulated the production and propagation of axions through the pulsar's electromagnetic fields. This allowed them to quantify the additional radio signals generated by axions in comparison to the pulsar's intrinsic emissions.

To confirm these theoretical predictions, observations were conducted on 27 nearby pulsars. Unfortunately, these initial observations did not yield evidence for axions, but this outcome is not surprising. If dark matter and axions were easy to detect, scientists would have made this discovery long ago.

Despite the absence of a "smoking-gun" detection, these results remain significant. They set the most stringent limits to date on the interaction between axions and light.