The discovery of life outside of our planet could start with a pungent whiff of chemicals on the whimsical planet of Venus.
Just yesterday, a team of astronomers from the University of Washington found a Venusian "fingerprint of phosphine", much like we've found on Mars and some select distant moons.
Why is that important?
Phosphine can be attributed to microbial life, and while its no guarantee that life is present on Venus, the bait of sensationalising it proves too tempting to resist. More testing and experimentation vis missions to the gassy planet need to happen before the jump to the life conclusion.
Researchers at the Massachusetts Institute of Technology surmised earlier this year that finding phosphine on other terrestrial planets might indicate the presence of alien metabolisms at work. In theory, the microbial forms of life expel the gas as a digestive function and this is used as a potential biosignature.
In short, they found potential alien microfarts.
Victoria Meadows, an astrobiologist on the discovery team at the University of Washington concurs, saying: "The interpretation that it's potentially due to life, I think, is probably not the first thing I would go for. We have some explaining to do. This discovery especially is just another reminder about how much more we have to learn about Venus."
While still a stretch to commit that life exists on Venus, it does add weight to the theory that while it's is a harsh and unforgiving environment for life, its clouds harbour the right conditions for microbial life.
Above the extreme temperatures and pressure of the planet's surface is a Goldilocks zone where the aforementioned conditions ease before the atmosphere gradually becomes more Earth-like. Researchers have discovered that microbial life exists in our atmosphere, independent of industrial means.
And after all, Venus does have oxygen-rich layers similar to ours in its atmosphere.
Why Is It Debatable?
Phosphine by nature is harmful to oxygen reliant lifeforms, and yet, can only be created by lifeforms - human or microbe - that we know of.
Phosphine was used as a chemical weapon in World War I and is still widely used as a fumigant for crops. Plus its a side-effect of meth.
The conundrum is that if the phosphine is there not by lifeform means, it could mean that there's no possibility of life as it would kill it.
But the phosphine itself could be a sign of life but is limited to our understanding and experience with phosphine.
But the search for life isn't constrained to what we aren't sure of yet.
In truth, phosphine by all rights should not exist on Venus, is only created by lifeforms (as far as we know) and deserves a harder look with more dedicated missions.
Could there be oxygen based lifeforms in the more stable atmospheric conditions of Venus that are expelling phosphine?
Sure, but we don't understand how yet and subscribing to that way of thinking is a surefire way to negate the many alternative avenues of scientific truth.
And to assume this means the presence of life is bordering on confirmation bias and misuse of the scientific method.
Using phosphine as a biosignature simply hones our search for extraterrestrial life. Much like the"where there's smoke, there's fire analogy". However, we aren't exactly sure if there's a metaphorical fire on Venus just yet.
It is certainly interesting.
And can be fun to optimistically leap to exciting conclusions, but never at the expense of good science. The search for life deserves us to put on or scientific detective hats and do the legwork before we give life on Venus the green light.