By Henry Moore An “interstellar” signal experts believed could have been aliens was actually just a nearby lorry, new research has revealed. “Alien” sound waves recorded north of Papua New Guinea were likely just vibrations from a truck on a local road, scientists have said. This undermines the theory debris found near the location contained “alien materials”, as had been widely reported at the time. “The signal changed directions over time, exactly matching a road that runs past the seismometer,” Research leader Dr Benjamin Fernando said. “It’s really difficult to take a signal and confirm it…