Could seasonal variations in atmospheric content provide evidence for life on exoplanets? Sounds better than just a sniff of methane. However, noting seasonal variations requires sniffing at different times during a planet’s year, which may be tricky but possible, given the talents of the new TESS telescope (and later the Webs.)
According to a 15 May 2018 article in Physics Today, Carles Resling noted a sinusoidal “seasonal variation” in trees of Earth’s Northern Hemisphere measurements of carbon dioxide. Stephanie Olson of UC Riverside “…identified three gases.…” She confirmed the seasonal variation but decided CO2 was likely to have saturated absorption lines
during the entire exoplanet year. Methane would show a photochemical variation occuring “…regardless of the presence of life.” A seasonal variation of oxygen would be more promising since it is not soluble in water and can be indicated by measuring ozone in the near-ultraviolet with a “large-aperture space telescope with a UV spectrometer.” (S.L.
Olson et al, Astrophysics J. Lett 858, L14, 2018.)
Future missions that promise to search for evidence of life on exoplanets include ESA’s PLATO, a six-year mission scheduled for a 2024 launch. It will look at one million stars, for planetary transit and oscillations, building on Kepler’s work to understand their dynamics and habitability with twenty four 12-centimeter-diameter telescopes. It should be able to see small planets, ring moons and asteroids.
We will soon be hearing from the TESS mission, which will cover 85% of the sky looking for nearby exoplanets, first the Southern Hemisphere sky then the Northern. An EOS.org favorite, its mission will be to directly detect and analyze giant planet atmospheres with its spectrography “…working in concert with its coronograph, revealing the structure and
chemical composition of the atmosphere.
TESS’s launch was successful, and it is now in its“commissioning period,” its functions checked for accuracy. NASA’s May 18 report notes a lunar flyby, a first test image taken, and a successful final “science orbit” attained.
(https://www.nasa.gov/feature/goddard/2018/nasa-s-tess-spacecraft-continues-testing-prior-to-first-observations). Under the direction of Dr. George Ricker, more than 12 universities, research institutes, and observatories are involved, and first observations should be coming in near the end of July.
Author of The Archives of Varok
The View Beyond Earth (Book 1.)
The Webs of Varok (Book 2.)
Nautilus Silver Award 2013 YA
ForeWord IBPA finalist 2012 adult SF
The Alien Effect (Book 3.)
An Alien’s Quest (Book 4. Released Nov.21, 2016)
Excerpts, Synopses, Reviews, On Writing, Characters and More-
Reviews of significant books- http://www.goodreads.com/Cary_Neeper
How the Hen House Turns- http://www.ladailypost.com
Complexity, Bio, Bibliography and Links- http://caryneeper.com
Astrobiology- https://astronaut.com search:Who’s Out There