A study by researchers at Britain’s University of Nottingham published this week suggests there could be more than 30 intelligent civilizations in our galaxy.
The study, published Monday in the Astrophysical Journal, uses a calculation based on how long it took advanced life to develop on Earth – about five billion years ago - and applied it to the known galaxy.
Lead researcher on the study, University of Nottingham Astrophysics Professor Christopher Conselice, says they came by their number assuming it would take just as long for life to develop on other planets. “The idea is looking at evolution, but on a cosmic scale. We call this calculation the Astrobiological Copernican Limit.”
First author on the study and Assistant Engineering Professor Tom Westby says previous methods for estimating the number of intelligent civilizations relied on the guessing of values relating to life, opinions about which “vary quite substantially. Our new study simplifies these assumptions using new data, giving us a solid estimate of the number of civilizations in our galaxy.”
Westby says based on the assumption that advanced life – a technologically capable civilization that sends out communications – takes up to five billion years to form, and to make of the planets and stars in the galaxy, they calculated there are about 36 advanced civilizations in the Milky Way.
They caution, however that communication with these civilizations could be difficult, as the average distance to them would be about 17,000 light-years. They also say whether or not we are currently alone in the galaxy depends on how long the civilizations survive.