Some neutron stars only appear as radio blips (Image: NASA/NRAO/AUI/NSF)

Mysterious radio blips that come from apparently empty regions of space may be the voices of long-dead stars.

Thirteen unexplained radio blips have turned up in radio telescope observations since the 1980s. They emerged in spots where there are no stars or galaxies to be seen, last anywhere from hours to days, and do not seem to repeat. The blips could be traces of a vast population of stellar corpses – neutron stars that roam the universe largely unseen, suggests a team led by Eran Ofek of the California Institute …