Number of alien worlds quantified
Intelligent civilisations are out there and there could be thousands of them, according to an Edinburgh scientist.
The discovery of more than 330 planets outside our solar system in recent years has helped refine the number of life forms that are likely to exist.
The current research estimates that there are at least 361 intelligent civilisations in our Galaxy and possibly as many as 38,000.
The work is reported in the International Journal of Astrobiology.