According to a new research paper accepted for publication in the Journal of the British Interplanetary Society, extraterrestrials are sleeping while they wait. In the paper, authors from Oxford’s Future of Humanity Institute and the Astronomical Observatory of Belgrade Anders Sandberg, Stuart Armstrong, and Milan Cirkovic argue that the universe is too hot right now for advanced, digital civilizations to make the most efficient use of their resources. The solution: Sleep and wait for the universe to cool down, a process known as aestivating (like hibernation but sleeping until it’s colder).

Understanding the new hypothesis first requires wrapping your head around the idea that the universe’s most sophisticated life may elect to leave biology behind and live digitally. Having essentially uploaded their minds onto powerful computers, the civilizations choosing to do this could enhance their intellectual capacities or inhabit some of the harshest environments in the universe with ease.