Aliens will bear-sized believe cosmologists

LONDON: Aliens, if they exist, will weigh about 300 kilogrammes - roughly of the size of a bear, according to a cosmologist.

The analysis by Fergus Simpson, from the University of Barcelona, also found that a habitable extraterrestrial planet would hold about 50 million aliens.

Simpson's findings are based on a model called Bayes' theorem and a branch of mathematics called Bayesian statistics.

The purpose of such techniques is to estimate the probabilities that change depending on the information available.

Simpson started his calculation with the number of individuals who would most likely live in a given alien civilisation, and came up with about 50 million or fewer individuals, 'Live Science' reported.

Simpson's analysis, on the prepublished site arXiv, also focused on the size of other life forms.

He noted that animals on Earth have a widely known relation between size and the number of individuals - the smaller the species is, the more individuals of that species tend to exist.

For example, an alien seeking life on Earth would be far likelier to run into a mosquito than a blue whale.

However, the relation between size and population can also be plotted on a curve against probability, which predicts that the median weight of an alien would be about 314 kg - about the size of a bear or an elk.

Based on the results of this model, about half of extraterrestrial creatures would weigh more than that and half would weigh less, Simpson said.

However, some scientists say this mathematical prediction has some serious limitations.

Michael Kopp, a professor at Aix-Marseille University in France, said he is not sure about the statistical argument because it is not clear if humans are a random sample of intelligent beings.