Not of This Earth

In the interest of peace on earth, Scott McLemee reviews some of the metrics that attempt to gauge the existence of other forms of life in the universe.

December 22, 2017
Theatrical poster of film "Close Encounters of the Third Kind"

It’s been a very long year, and unrelievedly peculiar. So much so that the revelation of a Pentagon research program on unidentified flying objects (with an annual budget, at one point, of $22 million) hardly registers except as a return to old, familiar modes of strangeness.

The New York Times story about the program ran Dec. 16. On a hunch, I checked IMDB and confirmed that the 40th anniversary of Close Encounters of the Third Kind’s release was just a couple of days before that -- a coincidence, but also a reminder that public interest in the matter tends to be cyclical. As are sightings: the French scientist in Close Encounters is based on Jacques Vallée, whose computer analysis of UFO reports from around the world established that they typically come in waves.

Here the skeptic is prone to think in terms of the extraordinary popular delusions and madness of crowds. The cynic will be impressed, though not surprised, by the elasticity of the Pentagon’s budget. On the other hand, the holiday season is the best possible time for headlines about UFOs. Of any topic in the news likely to come up during a family gathering, it’s the one where disagreement is most likely to remain friendly.

In the interest of peace on earth, let’s end the year with a look at the Rio scale and the London scale -- two 21st-century metrics for assessing the impact of solid evidence, should it ever arrive, that We Are Not Alone.

While similar in important ways, the scales cover different phenomena. They take as a model the Torino scale for rating the threat posed by an asteroid or comet passing through earth’s orbit. Based on the estimated diameter, mass and probability of hitting our planet, the Torino formula generates an index ranging from zero (no likelihood of collision or significant impact) to 10 (certain collision with catastrophic global effect on climate) with the intervening values expressing varying levels of risk and possible destructiveness.

The “impacts” registered by the other two scales are less apocalyptic, at least in their immediate implications. The Rio scale is designed to rate the potential significance of any announcement claiming the discovery of extraterrestrial intelligence. It was proposed in a paper given at the International Academy of Astronautics conference in Rio de Janeiro in 2000 and adopted by the organization’s standing committee on the Search for Extra-Terrestrial Intelligence two years later.

Most SETI research involves looking for electromagnetic signals produced by civilizations elsewhere in the universe. The Rio scale defines three parameters for a purported discovery based on the type of phenomenon, the circumstances through which it was identified and the distance from which it originated. An ongoing transmission from within our solar system, detected by a number of SETI researchers and assessed as meant to establish contact, would be assigned a high value in each parameter. At the other extreme would be a short-lived phenomenon found in an archival data set, judged to be the equivalent of machine noise from a device outside this galaxy. Finally, a reliability factor is assigned to the claimed discovery, based, in part, on whether verification has been carried out. The various weightings are combined to generate a Rio scale value ranking the claim between zero (meaningless or fraudulent) and 10 (extraordinary).

In 2010, one of the scale's creators, Iván Almár of the Konkoly Observatory of the Hungarian Academy of Sciences, collaborated on a similar index for research concerning extraterrestrial but nonintelligent life forms. The London scale (presented at a meeting of the Royal Society in London) would rate claimed discoveries of microbes on Mars, or of whatever may be swimming in the oceans on Saturn's moons.

"In addition to ranking the discoveries," says the paper proposing the scale, it "is useful to highlight and understand the types or categories of information that may be needed for further validation or dismissal of a claim." Both the Rio and the London metrics are, ultimately, a kind of peer review expressed in quantitative form, and not widely known; they lack the sensational simplicity of J. Allen Hynek's three kinds of close encounter. To knock Homo sapiens out of any lingering belief in Earth as the center of the universe wouldn't really take a Steven Spielberg light-and-sound extravaganza or the air force shooting down a flying Tic-Tac -- just a fossil skeleton in a meteorite or two.


Be the first to know.
Get our free daily newsletter.


Back to Top