An international team of scientists has discovered that pulsars are not the source of an excess of positrons (antiparticles for electrons) arriving at Earth from outside the solar system. The study is published in Science, according to the University of Maryland (USA).
Observations carried out at the HAWC (High Altitude Water Cherenkov Observatory) gamma observatory in Mexico showed that a sufficient number of positrons did not reach the Earth from the Geminga and PSR B0656 + 14 pulsars. Previously, these objects were considered the most likely source of the excess positrons in the upper atmosphere, first discovered in 2008.
Scientists believe Geminga and PSR B0656 + 14 are surrounded by a cloud of matter that absorbs radiation from pulsars, in particular positrons. Experts do not know what could be the source of the excess number of positrons reaching Earth. It is possible that antielectrons owe their origin to dark matter.
Hypothetical dark matter participates in gravitational, but not electromagnetic, interaction. It accounts for about a quarter of the mass-energy of the universe. The nature of the particles that make up dark matter is unknown to scientists.