by The discovery of highly unstable and explosive “axis stars” could help scientists shed light on the Universe’s most mysterious substance: dark matter.
Despite making up an estimated 85% of the mass of the universe, dark matter is effectively invisible because it does not interact with light. That also means it cannot be made up of particles like electrons and protons that make up the atoms that come together to form stars, planets, moons and our bodies.
This has encouraged scientists to search for the elusive particles that could make up dark matter. One of the main suspects for dark matter is called “axions”, light mass particles first theorized in 1977. New research suggests that axions may be found if scientists look for regions where the particles may be clumped up. Such clumps could have formed axial stars — with explosive results.
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“Axions are one of the main candidates for dark matter. We discovered that they have the ability to heat the universe just like supernovas and normal stars have come together in dense clumps,” a said Malcolm Fairbairn, a staff member professor at King’s College London, in a statement. “With that information, we know with much greater certainty where our instruments should be pointed in the field to find them.”
The mystery of dark matter may go out with a bang
Dark matter may not interact with photons of light, the particles involved in the electromagnetic force, but it does interact with one of the other four fundamental forces of the universe: gravity.
In fact, dark matter was first discovered when scientists realized that some galaxies were rotating so fast that the gravity associated with the visible mass within them was not enough to hold them together. There had to be something else. Furthermore, in addition to discovering that dark matter is preventing galaxies from flying apart, scientists now believe that most, if not all, large galaxies are covered by dark matter halos that extend much further nor their visible disks and halos of stars, gas and dust. .
That means if dark matter is made of axes, there must be a large number of these low-mass particles to account for such observed gravitational effects. It would also suggest areas where axes are closely packed. In those regions, axes would likely start acting together as a result of the laws of quantum physics. This could cause large groups of axons in the core of galaxies to form axial stars.
These axion stars would not live as long as the dark matter haloes that surround galaxies, however, the team says.
If there were action stars, they would become unstable after reaching a certain mass. It would result in the stars exploding and releasing a burst of radiation.
The team thinks that this radiation could heat gas that once existed between galaxies during the time period between the creation of the first atoms in the universe and the formation of the first stars, about 50 million to 500 million years after the Big Bang.
Due to the bonding of electrons with protons to form the first atoms during the era of the universe known as the era of recombination, the free electrons were no longer scattering photons. Thus, the universe suddenly became transparent, and this “first light” can now be seen in the form of a cosmic fossil that uniformly fills the universe, a radiation known as the “cosmic microwave background” or “CMB.”
The team behind this research think that explosions of axial stars in the early universe may have left imprints in the CMB. Thus, the axial nature of dark matter could be confirmed by searching for this signature in radio waves known as the 21-centimeter measurement.
“Axially coherent stars, even those that are relatively compact, have the potential to explode into a halo of electromagnetism and light,” Fairbairn said. “Knowing what kind of structure axial dark matter can form and its effect on surrounding interstellar gas can lead to new ways of detecting it.
“It would probably help us to solve one of the biggest questions in science, which we have been doing for more than a century, to find the axis, and it would help to set the history of the early universe at a minimum.”
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Calculating the number of axial stars there could reveal the full explosion potential of these unstable collections of dark matter and help explain how these explosions might interact with interstellar gas. This will, in turn, give an indication of the size of the signal hidden in the CMB.
“The 21cm measurement is generally seen as the future of cosmology, and the role it plays in the search for the axiom is a big reason for that,” said King’s College London researcher David Marsh. “There are tons of action searches under way right now, including projects like Dark Matter Radio. It’s a very exciting time to be an astrophysicist right now.”
The research on axion stars was published over a series of papers in the journal Physical Review D.
