A group of astronomers has concluded that Venus never had enough water to form oceans. In their opinion, the planet was a hot, inhospitable world throughout its history.
Venus is sometimes called Earth’s sister, because they are almost identical in size. However, the similarities end there. Venus’ atmosphere is two orders of magnitude denser than Earth’s and consists almost entirely of carbon dioxide, creating a powerful greenhouse effect. Because of it, the planet’s surface is heated to a temperature of 500 °C.
However, in the distant past, when the Sun emitted less energy, the situation might have been different. Many astronomers have long explored the possibility that Venus used to have oceans capable of supporting life.
Researchers from the University of Cambridge decided to test this possibility by studying the Venusian atmosphere. They assumed that the gas envelope of the planet must be in equilibrium. Any chemicals removed from the atmosphere must then be recovered in the atmosphere because the interior and exterior of the planet are in constant chemical interaction with each other.
This recovery occurs through volcanism. When magma rises from the mantle to the surface, it releases gases from deep within the planet, making up for the losses. On Earth, volcanic eruptions are mostly steam because the interior of our planet is rich in water. But on Venus, it’s different.
The scientists first calculated the rate of breakdown of water, carbon dioxide and carbonyl sulfide molecules in Venus’ atmosphere. Further, based on the composition of the volcanic gases needed for their reimbursement, they found that those consisted of no more than six percent water. These dry eruptions suggest that Venus’ interior, the source of magma that releases volcanic gases, is also dehydrated. This meant there was never enough water on the planet to form oceans.
Whether this is true or not, NASA and ESA missions, which will be launched to Venus early next decade, will help to check. One of them, called DAVINCI, will drop a probe on the planet that will analyze its atmosphere in detail to find the answer to the question of whether it could have possessed an ocean.
Provided by Phys.org
