Life on Venus
An announcement by an international team of astronomers about the discovery of phosphine gas in the atmosphere of Venus has triggered global excitement about the possibility of the presence of lifeforms on the neighbouring planet.
- Apart from being produced in industrial processes, phosphine, a colourless but smelly gas, is known to be made only by some species of bacteria that survive in the absence of oxygen.
How can we say that there is life on Venus?
- The scientists have discovered the presence of a chemical which is known to be produced only through biological process, and not through any naturally occurring chemical process.
- There are some other ways in which this chemical might be produced, for example, in the underbelly of volcanoes or meteorite activity, but that would have shown in much lower concentrations.
- In fact, this discovery was made in 2017, and the scientists checked and re-checked their data over the last three years before deciding to make it public.
- The paper in Nature Astronomy says this presence of phosphine is “unexplained” after an exhaustive study of all the possible other sources and “production routes in Venus’s atmosphere, clouds, surface and subsurface, or from lightning, volcanic or meteorite delivery”.
- So, the only possible explanation for the origin of this phosphine, based on our current knowledge, could be in the biological processes, the way it is produced on Earth, by some microbes.
- During the announcement, scientists were very careful to emphasise, repeatedly, that this was not a confirmation of the presence of life on Venus.
Can Venus support life?
- There are several things that we know of about Venus that make life, as we know it, unsustainable on that planet. The temperature of Venus is too high, and its atmosphere is highly acidic, just two of the things that would make life impossible.
- But it is suggested that this phosphine could be remnants from a time when Venus was a much more hospitable place.
Missions to Venus
- Missions to Venus are not new. Spacecraft have been going near the planet since the 1960s, and some of them have even made a landing.
- The Indian Space Research Organisation (ISRO) is also planning a mission to Venus, tentatively called Shukrayaan, in the near future. As of now, the plan is still on the drawing board. All future missions to Venus would now be attuned to investigating further evidence of the presence of life.
- Phosphine is a colourless, flammable, and explosive gas at ambient temperature that has the odour of garlic or decaying fish. Small amounts occur naturally from the break down of organic matter. It is slightly soluble in water.
- Phosphine is used in the semiconductor industry to introduce phosphorus into silicon crystals . It is also used as a fumigant, a polymerisation initiator and as an intermediate for the preparation of several flame retardants.
- Phosphine has an odour of garlic or decaying fish but is odourless when pure.