Scientists get the measure of life on other planets

Alien life forms are out there – and there could be thousands of them, according to a new scientific analysis.

Researchers at the University of Edinburgh refined existing research to work out that there could be at least 361 life forms in our Galaxy - and possibly as many as 38,000.

The scientists arrived at their findings using the latest information on the conditions needed for life to emerge on other planets. This included looking at the combination of stars and planets needed to form a solar system which can support life, and the likelihood of life
surviving long enough to develop into an intelligent civilisation – creatures which are biologically complex and are potentially able to communicate across the stars.

The factors affecting the possibility of life on other planets are complicated, but in recent times there have been many advances in astronomy that allow improved estimates and better understanding of these factors. The team used these advances to construct a computer model of the galaxy, and studied how life evolved within.

The study, funded by the Science and Technology Facilities Council and Scottish Universities Physics Alliance, is published in the International Journal of Astrobiology.

The researchers looked at three scenarios of how life could develop. The first of these assumes that it is difficult for life to be formed but easy for it to evolve, and suggests there are 361 intelligent civilisations in the galaxy.

A second scenario assumes that life is easily formed, but it struggles to develop intelligence, then as many as 31,513 other forms of life are estimated to exist.

Finally, they examined the possibility that life could be passed from one planet to another during asteroid collisions, which gave a result of 37,964 intelligent civilisations in existence.

Duncan Forgan, who carried out the research, said: “It is important to realise that the picture we've built up is still incomplete, and even if alien life forms do exist, we may not necessarily be able to make contact with them, and we have no idea what form they would take. Life on other planets may be as varied as life on earth and we cannot predict what intelligent life on other planets would look like or how they might behave.”


Galaxy used in simulations
An image of the galaxy reproduced in the simulations. 



For further information:

Duncan Forgan,
School of Physics and Astronomy,
tel 0131 668 8359;

Catriona Kelly,
Press and PR Office,
tel 0131 651 4401;