Rio scale

{{Short description|Measure for extraterrestrial intelligence events}}

The Rio scale was proposed in 2000 as a means of quantifying the significance of a SETI detection.{{Cite web |title=The Rio Scale |url=https://iaaspace.org/wp-content/uploads/iaa/Scientific%20Activity/setirio.pdf}}{{Cite magazine |last=Arbesman |first=Samuel |title=Quantifying Alien Encounters: The Rio Scale |language=en-US |magazine=Wired |url=https://www.wired.com/2012/02/quantifying-alien-encounters-the-rio-scale/ |access-date=2022-05-30 |issn=1059-1028}} The scale was designed by Iván Almár and Jill Tarter to help tell policy-makers how likely, from 0 to 10, it is that an extraterrestrial radio signal has been produced by an intelligent civilization.{{Cite web |last=Bartels, SPACE.com |first=Meghan |title=To Fight Fake News, SETI Researchers Update Alien-Detection Scale |url=https://www.scientificamerican.com/article/to-fight-fake-news-seti-researchers-update-alien-detection-scale/ |access-date=2022-05-30 |website=Scientific American |language=en}}

The scale is inspired by the Torino scale, which is used to determine the impact risk associated with near-Earth objects. Just as the Torino scale takes into account how significant an object's impact on the planet would be, the Rio scale takes into account how much a public announcement of the discovery of extraterrestrial intelligence would probably impact society.

The IAA SETI Permanent Study Group officially adopted the Rio scale as a way of bringing perspective to claims of extraterrestrial intelligence (ETI) detection, and as an acknowledgement that even false ETI detections may have disastrous consequences.{{Cite web |title=How can you tell if that ET story is real? St Andrews scientists revise the Rio Scale for alien encounters |url=https://www.seti.org/press-release/how-can-you-tell-if-et-story-real-st-andrews-scientists-revise-rio-scale-alien-encounters}}{{Cite web |last=Hall |first=Shannon |title=Strange signals from 234 stars could be ET - or human error |url=https://www.newscientist.com/article/2109139-strange-signals-from-234-stars-could-be-et-or-human-error/ |access-date=2022-05-30 |website=New Scientist |language=en-US}}

The scale was modified in 2011 to include a consideration of whether contact was achieved through an interstellar message or a physical extraterrestrial artifact, including all indications of intelligent extraterrestrial life such as technosignatures.{{Cite web |author1=Mike Wall |date=2016-10-28 |title=Mysterious Star Pulses May Be Alien Signals, Study Claims |url=https://www.space.com/34541-alien-life-search-possible-seti-signals.html |access-date=2022-05-30 |website=Space.com |language=en}} A 2.0 version of the scale was proposed in 2018.{{cite news |last1=Tudhope |first1=Christine |title=Scientists revise the Rio Scale for reported alien encounters |url=https://phys.org/news/2018-07-scientists-rio-scale-alien-encounters.html |access-date=18 September 2022 |work=phys.org |ref=phys-20 |language=en}}{{cite news |last1=Bartels |first1=Meghan |title=SETI Researchers Want to End the Alien-Detection Hype |url=https://www.space.com/41327-seti-alien-signals-hype-richter-scale.html |access-date=18 September 2022 |work=Space.com |date=31 July 2018 |ref=spacecom-20 |language=en}}