Scientists have been searching for extraterrestrial life for quite a while now. This is not just a science fiction phenomenon anymore that predicts the existence of extraterrestrial beings on some faraway planet.

Up till now, scientists have tried observing distant planets using spacecraft and powerful telescopes expecting to find signs of life. This time around scientists are trying to predict the existence of extraterrestrial life based on how long life has existed on planet Earth. In a study published in the Astrophysical Journal, scientists have tried to predict the existence of extraterrestrial beings using the Astrobiological Copernican Limit.

Earth came into being when the gravitational forces of the universe hardened the surrounding disc of gas and dust into a planet. Scientists predict this happened 4.5 billion years ago. It took another billion years for life to appear. This life existed on a micro-scale and it was a long wait before life evolved into civilized humans. And only 100 years ago intelligent humans came into being. Considering this timescale, and assuming that other civilizations in the universe took the same time to appear and evolve, there could be 36 other extraterrestrial civilizations in the milky-way galaxy.

If extraterrestrial life exists, it could be located as far as 17,000 light-years away, making it nearly impossible to make any contact with them. however, if that extraterrestrial life does not exist in the universe, then our time in the universe is quite limited.

The study, “The Astrobiological Copernican Weak and Strong Limits for Intelligent Life”, was authored by Tom Westby and Christopher J. Conselice.