Scientists reclassify ranking for alien life

The scale for ranking possible extraterrestrial life has been redefined by a team led by St Andrews scientists.

For years the Rio Scale has been used, but this is to be replaced by the Rio Scale 2.0 after a collaboration between St Andrews University and the SETI Institute in Mountain View, California.

Lead researcher, Dr Duncan Forgan from the university’s Centre for Exoplanet Science, explained: “It’s absolutely crucial that when we talk about something so hugely significant as the discovery of intelligent life beyond the Earth, we do it clearly and carefully.

“Having Rio 2.0 allows us to rank a signal quickly in a way that the general public can easily understand, and helps us keep their trust in a world filled with fake news.”

The Rio Scale is a tool used by astronomers searching for extraterrestrial intelligence to help communicate to the public “how excited” they should be about what has been observed.

The scale measures the probability a signal really is from aliens, as well as the consequences for humans. A score is given between zero and 10, so that the public can quickly see how important a signal really is.

Jill Tarter, co-founder of the SETI Institute, said: “Rio 2.0 is an attempt to update the scale to make it more useful and compatible with current modes of information dissemination, as well as providing means for the public to become familiar with the scale.”