On a hot November day in the tropical forest of Arecibo, Puerto Rico, amongst the croaking of coquís, the message went out. Warbling audio crackled over loudspeakers—the audible result of the work of ...

“I have no clue if there are aliens out there,” concedes Douglas Vakoch, director of METI International, an organization committed to contacting extraterrestrial intelligence. But he is certain that ...

Orbits of the G objects at the center of our galaxy, with the supermassive black hole indicated with a white cross. Stars, gas and dust are in the background. Credit - Anna Ciurlo, Tuan Do/UCLA ...