14 DAY TRIAL // The orbit-based Fermi Gamma Ray Space Telescope may have discovered signs of dark matter colliding with its antiparticles at the core of our galaxy, the Milky Way, its science team reports. Dark matter is a proposed form of matter that was introduced in calculations to try to make sense of the way our Universe behaved. It is believed to be permeating everything and also to be the scaffolding on which galaxies lie and interact with each other, although no clear, direct evidence of its existence was ever discovered, Nature News reports.
Fermi recently captured very bright flashes of high-energy gamma-rays coming in from the galactic core, and two experts believe they may have been produced by dark matter interacting with other exotic particles. In a scientific paper published on the arXiv pre-print server, New York University expert Lisa Goodenough and Fermi National Accelerator Laboratory scientist Dan Hooper report that they were surprised by how well the dark matter model seemed to accommodate these observations, and mention that no assumptions had to be made when taking this possibility into account.
Not everyone agrees with the two researchers, however. Some experts say that the flashes may be explained by ordinary astronomical phenomena, and add that previous studies have established that dark matter particles weigh in at around 30 gigaelectronvolts (GeV). Such an energy is incompatible with the new measurement, critics say. Stockholm University physicist Ian Conrad believes that the pieces of evidence Goodenough and Hooper brought to the table are “pretty shaky.”
In spite of the fact that dark matter is believed to be unable to interact with ordinary matter, except through the force of gravity, some scientists believe that, when dark matter collides with its antiparticles, radiation (such as gamma-rays) and ordinary particles may be generated. The new Fermi observations are not the first to hint at dark matter. In August 2008, data from the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) satellite showed that there was an excess of electrons and positrons (their antiparticles) around our planet, which could mean that we live in a blob of dark matter.
“The galactic center is a very challenging region,” Goddard Space Flight Center Fermi telescope mission project scientist Julie McEnery says. She believes that the new Fermi readings may, indeed, point at “real gamma-rays.” She adds, however, that remnants of exploding stars and pulsars may also be a potent source of this high-energy radiation, and that more studies are needed before a final conclusion on the existence of dark matter in the galactic core is drawn.