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43.6667° N 70.2667° W
Founded January 1970
2022-2023: XXVII
Sunrise: 6:59 a.m.
Sunset: 5:53 p.m.
Civil twilight ends: 6:22 p.m.
Sun's host constellation: Virgo the Maiden
Moon phase: Waning Gibbous (43% illuminated)
Moonrise: 12:22 a.m. (10/19/22)
Moonset: 3:43 p.m (10/19/22)
Julian date: 2459871.21
"Logic will get you from A to B. Imagination will take you everywhere."
-Albert Einstein
THE DAILY ASTRONOMER
Tuesday, October 19, 2022
No Laughing Matter
5204!*
As of today, October 18, 2022, that is the number of exoplanets -planets in orbit around other stars- that planet-seeking astronomers have so far detected. Based on these findings alone, scientists estimate that approximately 1- 2 trillion exoplanets remain undiscovered in the Milky Way Galaxy. While astronomers do not anticipate being able to find them all -unless they happen upon the Encyclopedia Galactica- they are optimistic that tens of thousands more exoplanets will be found within the next couple of decades.
Naturally, as the exoplanet hunt continues, so, too, will the earnest search for alien life. Presuming that no extraterrestrial arrives to announce its presence, we shall have to resort to indirect means of detection. Such means involve analysis of exoplanet atmospheres: to identify what we believe would be biosignatures of metabolic activity: molecular oxygen, methane, water vapor and laughing gas.
Yes, you read that sentence correctly: laughing gas, known chemically as nitrous oxide.** A team of scientists from the University of California Riverside recently published an article pertaining to the possible detection of nitrous oxide in the atmospheres of speciated planets.
Astrobiologist Eddie Schwieterman and his colleagues produced computer models related to the possible emission of nitrous oxide by living beings. They determined that this gas could be released in sufficient quantity so as to be detectable by the recently launched -and already wildly successful- James Webb Space Telescope.
Schwieterman noted that most exoplanet researchers had ignored nitrous oxide as a gas indicative of metabolic activity. Despite the UC-Riverside models, many researchers remain skeptical. First, some phenomena unrelated to biological processes produce nitrous oxide, such as lightning strikes. Schwieterman counters this objection by noting that lightning discharges also produce nitrous dioxide. Detection of that latter gas could lead to a planet being eliminated as a possible location of life.
A more serious objection pertains to Earth's atmosphere, where one cannot detect much nitrous oxide despite the widespread proliferation of life. To this argument, Schwieterman stated that "this conclusion doesn't account for periods in Earth's history when ocean conditions would have allowed for much greater biological release of nitrous oxide." Despite the skepticism, many exoplanet research teams will likely include nitrous oxide on the list of chemicals they'll attempt to detect as they search for life elsewhere in the galaxy.
One must add that the simple detection of such biosignatures will not provide conclusive evidence of extraterrestrial life. Instead, the presence of these chemicals would indicate that a given planet might be inhabited by beings whose forms and functions might remain unknown to us. Of course, such planets would become the focus of intensive study, particularly by SETI (the Search for Extraterrestrial Intelligence), which would attempt to detect manipulated EM emissions produced by any life forms, presuming, of course, that they are sufficiently advanced to have developed radio communication capabilities.
The search will continue and will remain difficult and fraught with uncertainty. However,the detection of nitrous oxide might eventually lead to the true discovery of alien life in the Milky Way. Who will have the last laugh, then?
*No, mathematicians. We don't mean 5204 factorial, the integer value of which is so unfathomably long as to be terrifying. In this instance, we're using the exclamation point simply for emphasis.
**Discovered by Joseph Priestly in 1772, nitrous oxide contains two atoms of nitrogen to one atom of oxygen. In 1844, dentist Horace Wells discovered that nitrous oxide was quite effective as an anaesthesia. Known colloquially as "laughing gas," this substance has also been used to treat some psychotic disorders and, naturally, by many people seeking a rapid high.
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