Astronomers have proposed a new experiment that involves the use of super-dense stars to study how dark matter interacts with standard matter.
Dark matter has not yet been observed directly but its presence is inferred from astronomical observations. It is theorized that dark matter accounts for about 80 percent of the matter in the universe but its actual nature remains a mystery.
Scientists have been studying galaxies without dark matter to better understand this mysterious entity. Besides questions on the true nature of dark matter, there are also questions regarding a hypothetical force between normal and dark matter.
Astronomers want to know if there is another force that pulls or pushes standard matter away from dark matter. This hypothetical force is sometimes called the fifth force.
Researchers, now propose a new experiment that uses super-dense stars to learn more about the interaction between dark matter and normal matter and see if this fifth force does exist.
Lijing Shao, from the Max Planck Institute for Radio Astronomy, said that binary pulsars provide a new way of testing the fifth force between normal matter and dark matter.
By using radio telescopes, scientists can measure neutron stars by tracking the timing of their radio pulses. In a study published in the journal Physical Review Letters, Shao and colleagues proposed a test that uses the neutron star PSR J1713+0747.
PSR J1713+0747, which lies about 3,800 light-years from Earth, has one of the most stable and predictable rotations in space.
Researchers would be able to measure an interference with the binary orbit over time if a fifth force exists, and the neutron star accelerates towards dark matter in a way that is different from its acceleration towards its white dwarf companion. There should be a deformation of the binary orbit or change in the orbit's eccentricity.
"Here we propose a novel celestial experiment using the orbital dynamics from radio timing of binary pulsars, and obtain a competing limit on ηDM from a neutron-star-white-dwarf (NS-WD) system, PSR J1713+0747," the researchers wrote in their study.
"The result benefits from the large material difference between the NS and the WD and the large gravitational binding energy of the NS. "