English physicist Brian Cox, who is also an Advanced Fellow of particle physics in the University of Manchester, says he knows why we have not found aliens yet. Cox claims that they likely destroyed themselves long ago because intelligent life destroys itself not long after it evolves.

Brian Cox adds that the advances in technology and science necessary to contact other life forms in the universe would destroy the development of political institutions able to manage them. Subsequently, this leads the civilizations to destroy themselves.

The technology that emits greenhouse gases such as carbon dioxide and the nuclear weapons created could ultimately destroy civilizations. The same can happen to our planet.

This problem was actually first pointed out by Enrico Fermi, the physicist who built the first nuclear reactor, in 1950.  Fermi said that any civilizations with rocket technology, even a simple one, can colonize the galaxy in a few million years. However, since no one accomplished this, he concluded that we were alone in the Milky Way.

“One solution to the Fermi paradox is that it is not possible to run a world that has the power to destroy itself and that needs global collaborative solutions to prevent that,” says Cox. “It may be that the growth of science and engineering inevitably outstrips the development of political expertise, leading to disaster.”

A study published in January also reveals that we have not discovered aliens because they are dead. Astrobiologists from the Australian National University say that it is very likely that the universe is filled with habitable planets like Earth but evolution does not happen fast enough for aliens to adapt to them.

The team suggests that microbial life populated planets before but they are too fragile to survive those harsh and unstable conditions of the planets. Subsequently, early microbial life in the planets died out too soon.