Earth-like tectonic plates on ancient Venus may explain its carbon dioxide- & nitrogen-rich atmosphere

Subject : Science and Tech

Section: Space technology

Context:

Venus, often referred to as Earth’s sister planet, may have experienced tectonic activity about 4.5 billion to 3.5 billion years ago, according to a new study.

Venus planet:

Venus and Earth are about the same size, mass, density and volume. Still, Venus is the least understood of the terrestrial planets.
It appears in Earth’s sky always close to the Sun, as either a “morning star” or an “evening star”.
It is the third brightest object in Earth’s sky after the Moon and the Sun.
It has a weak induced magnetosphere and an especially thick carbon dioxide atmosphere, which creates, together with its global sulfuric acid cloud cover, an extreme greenhouse effect.
This results at the surface in a mean temperature of 737 K (464 °C; 867 °F) and a crushing pressure of 92 times that of Earth’s at sea level, turning the air into a supercritical fluid.

Study findings:

The planet’s atmospheric composition is mainly composed of carbon dioxide (96.5 per cent) and nitrogen (less than 3.5 per cent). Plate tectonics may have been instrumental in creating its carbon dioxide– and nitrogen-rich atmosphere on Venus.
The new findings suggest that ancient Venus may have been home to microbial life. That means Earth and Venus may have been even more alike than thought.

Outcome from new findings:

We very likely had two planets at the same time in the same solar system operating in a plate tectonic regime.
Plate tectonics would have likely ended on Venus after it lost water and its atmosphere got too hot and thick. This process may have dried up the necessary ingredients that make tectonic movements possible.
Only early plate tectonics could explain Venus’ current atmosphere and surface pressure. This early tectonic movement would have been happening on Earth and Venus simultaneously.
Venus may have transitioned from limited tectonic movement early in its history to the stagnant lid model that exists today. A stagnant lid means its surface has only a single plate with minimal amounts of movement to release gases into the atmosphere.
We might have planets that transition in and out of habitability rather than just being continuously habitable.
DAVINCI is National Aeronautics and Space Administration’s (NASA) upcoming mission to Venus.
Shukrayaan-1 will be India’s mission on Venus.

Plate tectonics theory (PTT):

Suggested by McKenzie and Parker in 1957 and propounded in 1967 by Morgan.
Both conventional current theory and seafloor spreading theory paved the way for the theory of plate tectonics.
It explains the movement of the Earth’s lithospheric plates, which make up the Earth’s outermost shell.
It describes how Earth’s thin outer shell is broken into big pieces called tectonic plates, which float on the planet’s mantle. Plate tectonics gave rise to oceans, continents and mountains, along with playing a critical role in nourishing life on Earth.

PTT is based on 4 general geomorphological assumptions:

The slab or zone of the lithosphere is divided into several vertical columns geomorphologically known as plates drifting kinematically over a semi-molten asthenosphere called a tectonic.
The surface area of a continental plate is also extended over the oceanic lithosphere. Thus, there is no complete segregation between the continental and the oceanic lithosphere.
The movement or tectonics of the respective plates depends on the direction and the impulse action of the thermal Convection currents. Consequently, the plates are converging and also divergent away from each other.
The process of convergence and divergence further creates a new crust over the Earth’s surface and also disintegrates the crust apart. The rate of formation and disintegration of the crust has acquired a profile of equilibrium by which the surface area of the earth remains constant.

Source: DownToEarth