For decades, humans have been scanning for signals of alien technology emanating from the galaxy. The search highlights the contradiction between the abundance of planets and stars spanning space and time and the lack of intelligent life, also known as the Fermi Paradox.

A group of physicists from the Sharif University of Technology in Tehran, Iran, plans to resolve the convergence between the high probability of alien civilizations and the complete lack of evidence that one exists. A new one studyavailable on the preprint website arXiv, examines a harsh reality: if we have not yet made contact with a technologically advanced civilization, that may be because intelligent life is short-lived. In fact, the scientists behind the new paper, Sohrab Rahvar and Shahin Rouhani, estimate that advanced civilizations will last no more than roughly 5,000 years.

Where is everyone?

Physicist Enrico Fermi first proposed the question in 1950, suggesting that life is common throughout the universe but our search for extraterrestrial intelligence continues to come up empty. The Fermi Paradox prompts several explanations for the lack of evidence: either space is too big to detect alien signals, intelligent civilizations deliberately protect themselves from detection, or perhaps we are alone in the universe, among many other proposed resolutions of the paradox.

A new study provides a different explanation. The authors used the Drake equationa formula used to estimate the number of active extraterrestrial civilizations in the Milky Way, and matches it with the electromagnetic reach of our current technology. Today’s radio telescopes are capable of listening to a region of space spanning nearly 100,000 years of galactic history (it takes about 100,000 years for light to travel across the galaxy). Therefore, our technology should have allowed us to identify any civilization that existed during that time, according to the study.

Figures show that technologically advanced civilizations last about 5,000 years. That would explain why we don’t detect radio signals from another planet; any advanced civilizations that may have existed in the Milky Way have died, or their short life in the universe has yet to come.

The clock is ticking

Earth has been an advanced civilization for about 300 years. Over the past 100 years or so, we have been able to emit technosignatures that could be detected by intelligent life on another planet. As our modern world continues to grow, our doom is getting closer, new research seems to suggest.

The authors of the new paper list several threats that could spell doom for advanced civilizations: a large asteroid impacting the planet, volcanic eruptions, climate change, pandemics, nuclear war, and artificial intelligence.

Although the study doesn’t necessarily mean that civilizations will die out once they hit their 5,000-year mark, it does suggest that it’s highly unlikely that it will last much longer than that given time. Sooner or later, civilizations tend to bring about their own demise.