Advanced extraterrestrial civilisations may be sending signals through space by "tickling" stars, new research suggests. The signalling would be the galactic equivalent of the internet.
"If it exists, it might be revealed by an analysis of already-existing stellar data," says John Learned of the University of Hawaii in Honolulu.
Learned and his colleagues have focused their attention on stars that vary regularly in brightness. Crucially, these "Cepheid variables" are so luminous they can be seen as far away as 60 million light years.
Jolting the star with a kick of energy – possibly by shooting it with a beam of high-energy particles called neutrinos – could advance the pulsation by causing its core to heat up and expand, they say.
That could shorten its brightness cycle – just as an electric stimulus to a human heart at the right time can advance a heartbeat. The normal and shortened cycles could be used to encode binary "0"s and "1"s.