Phosphine, Life, and Venus
Updated: October 21, 2020
Source: Phosphine, Life, and Venus
Regarding the released report that Venus was found to “possibly harbor life” (see this Nature article)
What’s Phosphine? #
- A chemical compound found in small amounts in Earth’s atmosphere
- Used in: electronics fabrication, rodenticide
On Earth it’s primarily found in its oxidized form, generally thought to be the result of lightning strikes, where the required amount of electrons would be present. But, it’s also been noticed in anaerobic environments (low/no oxygen). Some studies have suggested that glucose’s presence is very effective at increasing its (phosphine’s) production.
Phosphine on Venus #
The detection of phosphine in the upper atmosphere of Venus is interesting because phosphine should hardly be present in a heavily-oxidized environment, as that region is. If using Earth’s phosphine production is any analog: volcanoes and lightning should only be able to produce a fraction of what was observed in the atmosphere.
The exhaustive list of models which could produce this amount of phosphine leaves scientists to believe that there are two ways in which it could be at the level it’s being observed at:
- an unknown inorganic route
- an organic route as observed on Earth (i.e. micro-organisms)
Venus’s hostile environment #
Venus has been unanimously believed to be inhospitable to life. With Venera 3 (1966), Venera 4 (1967), Mariner 5 (~1967), Venera 7 (1970), and Venera 13 (1981), independently demonstrating that:
- ~91 atm
- 876F atmosphere
- Sulfuric-acid clouds
With these above points, not only do our landers last only hours (Venera 13, ~2 hour lifetime), but life seems improbable.
Venusian Life #
Morowitz/Sagan postulated its possibility in 1967. And, to date, this paper still seems plausible. There is still the possibility of an abiotic process that we’re not aware of (yet). Or maybe we’ve incorrectly identified the phosphine levels?
Unless there is some error in the data collection at both James Clerk Maxwell telescope (Mauna Kea) and Atacama Large Millimeter Array (Chile), organic production seems non-trivially possible.
Follow-up Experiments #
The authors of the sourced paper suggest (difficult) experiments to confirm this phosphine measurement:
- ALMA (Chile) could find another phosphine band to measure (this would take days-long data collection…which is hard)
- Earth-based IR observations (which can be polluted by our atmosphere)
- Atmospheric sampling via a probe
- We may have brought the microorganisms there with our probe visits
- this article’s author finds that unlikely due to the improbable odds of an Earth-based organism being able to survive both the journey there and the atmosphere itself
- Organic life is much more resilient/adaptive than we thought. This phosphine hypothesis closely mirrors that of the methane (as an byproduct of life) hypothesis on Mars.