The mystery behind radio signals that have baffled scientists at Australia’s most famous radio telescope for 17 years has finally been solved.

The signals’ source? A microwave oven in the kitchen at the Parkes observatory used by staff members to heat up their lunch.

Simon Johnston, head of astrophysics at the CSIRO, the national science agency, said astronomers first detected the signals, called perytons, in 1998. The signals “were reasonably local, say within 5km of the telescope”.

Originally researchers assumed the signals – which appeared only once or twice a year – were coming from the atmosphere, possibly linked to lightning strikes.

Then on 1 January this year they installed a new receiver which monitored interference, and detected strong signals at 2.4 GHz, the signature of a microwave oven.

They can’t all be rocket scientists