Final proof may soon be found, proof that we are not alone in this universe. What proof? A biosignature gas? The problem with many proofs is that they depend on a negative: we must find a substance that only
life can produce in the spectra of exoplanet atmospheres, i.e. something not produced by any other natural process. What would that be?
Oxygen is the most likely biosignature gas, since we know our flora on Earth produces lots of it. Geology and photochemistry can’t produce it in abundance. However, a simulated world by Damagel-Goldman found that extreme solar radiation could release oxygen from carbon dioxide.
Victoria Meadows of the University of Washington’s virtual Planetary Laboratory has initiated a search for other “oxygen false positives.” Meanwhile, Sara Seager at MIT has invented the spectral technique for
analyzing exoplanet atmospheres. She looks at the ring of starlight around an exoplanet as she finds it in front of the star it orbits. On Earth, photosynthesis requires only sunlight, water and carbon dioxide to produce oxygen. Seager has suggested to her team that they consider all possible chemical possibilities outside of those familiar on Earth.
Some possibilities: Sunlight can boil down a planet’s ocean. At high altitudes UV radiation can snip the hydrogen off water, leaving a dense oxygen atmosphere. Ammonia might accumulate if critters harvest carbon from methanol. In general, if two gases that react with each other are both found in an exoplanet’s atmosphere, a third process could be producing them.
Many gas molecules accumulate on Earth, produced by life forms, but carbon monoxide can be a false positive for life, as could the inability to detect any oxygen, since it probably took hundreds of thousands of
years for Earth to accumulate detectable oxygen in our atmosphere.
It’s good to know that astrobiologists are alert to all biochemical possibilities as they react to recent surprises. They realize the importance of watching Earth’s life emissivity, while also thinking
outside the box. (“Scientists Debate signatures of Alien Life,”
www.quantamagzine.org)
—
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. coming in 2016)
Excerpts, Synopses, Reviews, On Writing, Characters and More-
ArchivesofVarok.com
Reviews of significant books- www.goodreads.com/Cary_Neeper
How the Hen House Turns- www.ladailypost.com
Complexity, Bio, Bibliography and Links- caryneeper.com
Astrobiology– astronaut.wpengine.comsearch:Who’s Out There
