Cosmic radio waves which have puzzled astronomers for more than a decade, and even led to speculation that they were made by aliens, are probably produced by a huge neutron star, scientists have said.

Telescopes first picked up Fast Radio Bursts in 2001 and they have been recorded hitting Earth in a regular pattern ever since.

They last just a few milliseconds but seem to carry as much energy as the Sun releases in a month, suggesting they must come from a huge source of power.