• Post category:Space Exploration
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Today we will discuss one hot topic which gave a hope that we are not alone in this universe as life forms. Recently, British scientists revealed they had uncovered strong evidence that phosphine – a toxic, rancid gas produced by microbes – exists in the burning, acid-drenched atmosphere of Venus.

The atmosphere of Venus as viewed in ultraviolet by the Pioneer Venus Orbiter in 1979.
The atmosphere of Venus as viewed in ultraviolet by the Pioneer Venus Orbiter in 1979.

Venus’ location closer to the Sun than Earth and the extreme greenhouse effect raising temperatures on the surface to nearly 462 °C (863 °F), and the atmospheric pressure 90 times that of Earth, make water-based life as we know it unlikely on the surface of the planet.

However, a few scientists have speculated that thermoacidophilic extremophile microorganisms might exist in the temperate, acidic upper layers of the Venusian atmosphere. The presence of phosphine in the planet’s atmosphere, a potential biosignature supports this speculation.

(A thermoacidophile is an extremophilic microorganism that is both thermophilic and acidophilic; i.e., it can grow under conditions of high temperature and low pH).

Venus’s Atmosphere

In 1962, Mariner 2, the first successful mission to Venus, measured the planet’s temperature for the first time, and found it to be “about 500 °C (900 °F). Since then, evidence from various space probes showed Venus has an extreme climate, with a greenhouse effect and the atmosphere contains sulfuric acid clouds.

Why Phosphine?

Phosphine is shaped like a pyramid with three atoms of hydrogen bonded to a single atom of phosphorus.
Phosphine is shaped like a pyramid with three atoms of hydrogen-bonded to a single atom of phosphorus.

Detection of phosphine (PH3) in Venus’s atmosphere is not linked to any known abiotic method of production present or possible under Venusian conditions. It is not expected for a molecule like phosphine to persist in the Venusian atmosphere, since under the ultraviolet radiation, it will eventually react with water and carbon dioxide. PH3 is associated with anaerobic ecosystems on Earth and may indicate life on anoxic exoplanets. As of 2019, no known abiotic process generates phosphine gas on terrestrial planets (as opposed to gas giants) in appreciable quantities, so detectable amounts of phosphine could indicate life.

(Here on Earth, phosphine is found in our intestines, in the feces of badgers and penguins, and in some deep sea worms, as well as other biological environments associated with anaerobic organisms)

So, what do you think we should shift our focus from Mars to Venus in search of life or possibility of deeper exploration of Venus? Do let us know your views.

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