A recently published statistical analysis has argued that alients, if they exist, will be the size of bears.
Fergus Simpson, of the University of Barcelona, has used Bayes’ theorem and Bayesian statistics to argue that, based on estimated population sizes and distributions, an alien would have a median weight of 692lbs, or 314kg. As Biological Natural Scientists will know, body size on Earth roughly inversely correlates with the frequency of a species. Finding a mosquito is more likely than finding a blue whale, for example.
Simpson used this idea to posit that the median weight of a widely distributed alien species would be 692lbs, and aliens were likely to live on planets with a radius of 1.4 times that of Earth or less. This assumption was based on Earth’s ability to retain an atmosphere and water, and the ease of sustaining life at larger sizes.
While Simpson’s analysis gives us a good indicator as to what an alien could look like, Mathematicians and Staticians have found flaws in his arguments. Simpson’s argument was based on an assumption of civilizations of less than 50 million people, but there are no reasons to believe this to be true. It is also possible that humans are the median of all civilizations, and so rather than using humans as a ‘lower bound’ from which to gauge intelligent life might be incorrect.
A researcher at the STEI Institute has also argued that anything that large is likely to be in the water. Earth Sciences applicants should consider the connection between bodies of water and the biodiversity of creatures there to assess the validity of this claim.