So I've got a new Fermi paradox solution. Once we build a large enough radio telescope we will start receiving a lot of chatter from around the universe. Buried in this will be a "high energy physics challenge" involving a powerful particle accelerator, a superconductor, and some synthetic elements with very large nuclei. After performing this challenge there will be another asteroid belt where Earth used to be, and someone somewhere will get some LULZ when they detect a certain kind of characteristic gamma ray pulse followed by silence.