One of the most fascinating aspects of astronomy is the potential for life outside of Earth. And this is amongst stardust, black holes, and beautifully unique planets. Discussions on life outside our planet can be more than scientific, philosophical even. Here, we chew over a recent study presenting real scientific evidence for the potential of biological life on Venus.

Firstly, why have we pushed Venus to the side in terms of biological presence? This planet is often known as the scorching wonder that is named after the Roman goddess of love and beauty. Anyone into horoscopes will tell you that the movement of this particular planet can impact earthly romances. Whether Venus’ astrological traits are true or not, the planet has always been viewed as inhabitable. Its proximity to the sun makes it burn at around 462 °C (863 °F); this combined with an atmospheric pressure 90 times that of Earth makes water-based life unlikely here. 

Venus: A hostile environment presumably unsuitable for water-based life. Image by NASA/JPL

That is why a study conducted by Greaves et al. 2020 shocked the space community with news of potential life on a planet other than Mars. These researchers sought the presence of a “biosignature” gas, which means a gaseous substance that is a sign of life; it is only known from biological organisms or agents. When scientists search for the presence of extraterrestrial life, it goes beyond looking for movement or any organisms themselves. Life leaves marks that alter soil and air composition among others. It is these biological footprints that scientists seek when looking for the possibility of life in space. 

Through a series of deductions, the study chose to focus on phosphine gas (PH₃), a colorless, flammable, and highly toxic substance. The researchers justified this choice by describing why this may be an indicator for life on Venus; PH₃ on Earth is a result of microbial activity, by anaerobic bacteria (organisms that don’t require oxygen to live). On gaseous planets, PH₃ is a result of the packets of gaseous atmospheric layers and gas circulation. On Venus, a non-gaseous planet, PH₃ would be quickly destroyed by the type of crusty surface the planet is made of. So the presence of PH₃ here could possibly mean life… just like the microbial presence on Earth.

Phosphine gas (PH₃) as a molecular figure. Could this simple substance indicate life on Venus? Image by Massachusetts Institute of Technology (MIT).

Utilizing chemical and physical lab techniques, the scientists were able to absorb atmospheric gas samples from Venus to be analyzed. Excitingly, the isolation and identification process yielded the presence of PH₃! This was groundbreaking. The study attributed three potential sources of the gas; a photochemical process we don’t know about, a geochemical process we don’t know about, or…life.


There is still SO much we don’t know about space. In fact, we don’t even know more than 7% of our own planet’s oceans. In fact, NASA recently reported the discovery of water in sunlit parts of the moon; this challenges what we thought we knew about the moon, perhaps life may exist here as well? Going back to Venus, who truly knows the capabilities of such an extraterrestrial environment; there could be a completely novel and unique process that generates phosphine gas without its degradation. But as of now, the unexplainable presence of PH₃ could be attributed to life.

“The study attributed three potential sources of the gas; a photochemical process we don’t know about, a geochemical process we don’t know about, or…life.”

If you clicked on the link that would take you to this exciting study, you might have noticed an Editor’s Note stating that there have been recalibrations of the data. Science magazine explains that this reanalysis now depicts that the phosphine gas is 7 times lower than what was originally proposed. While this definitely takes a hit at some of the study’s credibility, the researchers still firmly believe that there is an unexplainable presence of PH₃ on Venus, despite its low quantity. Hopefully, this aspect of astrobiology is explored further to give us a better picture of potential life on Venus. Until then, turn up the song “Life on Mars” by David Bowie and wonder if Venus is the dark horse all along.

At certain moments of dawn and dusk, Venus can be seen from Earth as a larger, brighter star. Image by NASA.

What do you think about this discovery? How many more studies would we need to corroborate this novel information? Let us know what you think in the comments below!


References

Greaves, J. S., Richards, A. M., Bains, W., Rimmer, P. B., Sagawa, H., Clements, D. L., … & Drabek-Maunder, E. (2020). Phosphine gas in the cloud decks of Venus. Nature Astronomy, 1-10.

Strickland, A. (2020, October 26). NASA mission finds water on the sunlit surface of the moon. CNN. Retrieved from https://www.cnn.com/2020/10/26/world/moon-water-nasa-announcement-scn-trnd/index.html

Voosen, P. (2020, November). Potential signs of life on Venus are fading as astronomers downgrade their original claims. Science. Retrieved from https://www.sciencemag.org/news/2020/11/potential-signs-life-venus-are-fading-astronomers-downgrade-their-original-claims

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