Scientists at the University of Nottingham have found that there could be dozens of intelligent life forms beyond our Earth and within our Milky Way galaxy. Scientists point out that there are at least 36 active intelligent civilizations in our own galaxy, based on calculations from "cosmic evolution." The study paper has been published in the Astrophysical Journal.
The paper further claims that extra-terrestrial communications are happening. It highlights that life, as it began on Earth, can begin elsewhere - on other planets - where conditions were conducive to form life.
However, many assumptions on extra-terrestrial life have been made in the study. One of them is that about 5 billion years are required for intelligent life to form on other planets. To put it this way, it took about 4.5 billion years for a technological civilization to appear on Earth. The paper says that a technical civilization will at least last one hundred years.
The calculation of existing civilizations depends on the time span and how actively other civilizations would try to communicate by sending out signals to space in different ways, like radio transmissions from satellites.
How Did They Find It?
Researchers calculated this on the basis of something called as the "Astrobiological Copernican Limit," relying itself on various parameters such as star formation histories and its time taken, the commonness of metal-rich stars like the Sun and also the probability of stars hosting Earth-like planets and the presence of such planets in the habitable zones.
Overall, the number was assumed to be 36 but it comes with a margin of error and so many related assumptions. There could be more than 36 alien civilizations, or it may even be zero.
Can We Communicate With Them?
Detecting and communicating with one such civilization is close to impossible, for now at least. Because the average distance to one such civilization is about 17,000 light-years. Which means, information sent now would reach them after 17,000 years.
Christopher Conselice, Professor of Astrophysics at the University of Nottingham told Forbes, said: "Searches for extraterrestrial intelligent civilizations not only reveals the existence of how life itself forms, but also gives us clues about how long our own civilization will last."
Finding intelligent life elsewhere would reveal to us that our civilization might exist for much longer than a few hundred years, he added.