There could be more than 30 alien civilisations in our galaxy, researchers have found in a major study.
A new paper looked to understand how many planets in our neighbourhood could be home to alien life, by assuming that life develops on other planets in a similar way to how it develops on Earth, and matching that to planets that could be home to similar evolution.
It found that there could be dozens of active civilisations waiting to be found in our Milky Way. But it could also shed light on our own fate, and suggest our prospects for long-term survival are lower than we may have thought.
“There should be at least a few dozen active civilizations in our Galaxy under the assumption that it takes 5 billion years for intelligent life to form on other planets, as on Earth,” Christopher Conselice of the University of Nottingham said in a statement.
“The idea is looking at evolution, but on a cosmic scale. We call this calculation the Astrobiological Copernican Limit.”
The Astrobiological Copernican limits come in two forms.
One is the ‘weak’ limit, which suggests that intelligent life forms on a planet any time after 5 billion years. The other is the ‘Strong’ limit where life formed between 4.5 billion and 5 billion years years ago.
The new research used the latter, and also assumed that these new species would need to develop in metal-rich environments.
This is because human beings developed near a metal-rich environment, due to the metal present in the Sun.