We may finally have the answer to the long-standing question: “Are we alone in the galaxy?”. According to the calculations by a group of scientists at the University of Nottingham, we are not.
These scientists believe they have created a “cosmic evolution” based calculation or estimation, which suggests the possible existence of about 36 intelligent alien civilisations in the Milky Way, according to Forbes.
The number 36 is based on an assumption that the way life has evolved on Earth is relatively the same way that it evolves everywhere else in the universe. Of course, that is provided that we are referring to a planet (not Earth) which is the correct distance away from a star, after approximately 5 billion years, according to Live Science.
“Basically, we made the assumption that intelligent life would form on other [Earth-like] planets like it has on Earth, so within a few billion years life would automatically form as a natural part of evolution,” said Christopher Conselice, a professor of astrophysics at the University of Nottingham and a co-author of the research to The Guardian.
The calculation used to arrive at the number 36 is called the “Astrobiological Copernican Limit”. It takes star formation history, how many metal-rich stars are in existence and how likely it would be for stars to host planets similar to Earth in their habitable zones.
“The classic method for estimating the number of intelligent civilizations relies on making guesses of values relating to life, but opinions about such matters vary quite substantially,” said Tom Westby, Assistant Professor, Faculty of Engineering at the University of Nottingham, and lead author on the paper to Forbes. “Our new study simplifies these assumptions using new data, giving us a solid estimate of the number of civilizations in our galaxy.”
“I think it is extremely important and exciting because for the first time we really have an estimate for this number of active intelligent, communicating civilisations that we potentially could contact and find out there is other life in the universe – something that has been a question for thousands of years and is still not answered,” said Conselice.
Read the paper here.