UCLA SETI Group newsletter 2016-09-25

View this email in your browser

September 25, 2016

Dear friends,

Last week marked the end of the summer and the beginning of classes at UCLA. This quarter I am teaching a course titled "EPSS 3 Astrobiology" in which we describe the origin, evolution, and search for life in the universe. The course is at capacity with 425 students. One of my favorite lectures is devoted to the search for extraterrestrial intelligence. I am updating this lecture to include a description of UCLA SETI efforts during the past year.

EPSS 3 Astrobiology course contents.

This week I will be attending the International Astronautical Congress (IAC) in Guadalajara, Mexico. Two scientific sessions are of particular interest to me: SETI Science and Technology and SETI and Society. I will present the results of the UCLA SETI observations in the first session. In preparation for the meeting, the Spring 2016 SETI course students and I wrote an article that outlines the results of our search at the Green Bank Telescope this past April.

Over the summer there was an unfortunate SETI false alarm in connection with this year's IAC. One of the SETI session speakers sent an advance copy of his team's presentation to the other speakers. The presentation described a candidate signal observed with the RATAN-600 radio telescope in Zelenchukskaya, Russia. The researchers scanned a specific direction on the sky at 11 GHz (2.7 cm wavelength) on 39 separate occasions. Each scan lasted about 2 seconds. In 1 out of the 39 observations, a strong signal was detected. In some sense, the SETI researchers were following protocol, alerting other SETI researchers to the existence of a candidate signal and prompting additional observations. Most of us suspected, however, that a brief signal observed only once at a single telescope was almost certainly due to terrestrial radio frequency interference (RFI).

On the Rio Scale that quantifies the importance of a SETI candidate detection, the RATAN-600 signal receives a score of 1 (insignificant) or 2 (low). Unfortunately, the heading "candidate SETI signal detected" in the presentation proved too hard to resist. A blogger described the detection without spelling out all the caveats, the mainstream media got a hold of the blog post, and a brouhaha ensued. It took much effort (including additional observations by other teams) to set the record straight and convey that the signal was most probably of terrestrial origin.

The Rio Scale quantifies the importance of a SETI candidate detection.

The RATAN-600 false alarm is somewhat reminiscent of asteroid impact scares that have peppered news reports over the years. These episodes generally have a common synopsis: trajectory calculations following initial observations suggest that an asteroid may impact Earth; additional observations decrease the size of the uncertainty region, often increasing the initial impact probability assessment; finally, further observations shrink the uncertainty region even more, this time eliminating the possibility of an impact. This sequence of events is expected on the basis of a scientific analysis of the data, but it is often misunderstood by the public. There is an inherent difficulty in communicating the concept of impact probability (or SETI detection probability) to a general audience, especially when these probabilities evolve with time as a result of additional observations. Scientists must make announcements to encourage the necessary additional observations. If the announcements are not transparent, conspiracy theories arise. If the announcements are transparent, impatient bloggers or journalists rush to write a story before all the necessary verification observations are obtained. To avoid this problem, students of the UCLA SETI course were instructed to exercise self-restraint and abide by the principles outlined in the International Academy of Astronautics's Declaration of Principles Concerning the Conduct of the Search for Extraterrestrial Intelligence. Many of our candidate signals have more significance than the RATAN-600 signal, having been observed twice in the same direction on the sky and for longer durations, but so far none of the detections have prompted us to request additional observations or follow-up observations by other teams with other telescopes.

I am looking forward to interacting with other SETI researchers at the IAC meeting in Guadalajara. I will report on these interactions and the SETI sessions in a future newsletter.

Warm regards,

Jean-Luc Margot