Secondo un nuovo studio, Venere potrebbe non aver mai ospitato oceani:
To study the water history of Venus, Constantinou and her colleagues looked at water, carbon dioxide, and carbonyl sulfide in the planet’s atmosphere, and how fast they are broken apart. These molecules need to be constantly replenished by volcanic outgassing to maintain a stable atmosphere.
On Earth, volcanic gasses that enter the atmosphere are dominated by steam because our planet’s interior is so wet. The researchers found that volcanic gasses on Venus are made up of just 6 percent steam, at a maximum. From this, they inferred that Venus’ interior is very dry, and the planet was never able to maintain a liquid ocean.
This is consistent with observations of the surface, which show a lack of water erosion compared to places like Earth and Mars.
[…] “If Venus once had a large water reservoir, our work suggests that it was never able to condense out as water oceans. Instead, an early Venus would have had an atmosphere with lots of steam,” Constantinou explained.
“Over billions of years, this atmospheric steam would have undergone photodissociation, breaking water molecules into hydrogen and oxygen, with the lighter hydrogen gradually escaping into space. This process ultimately left Venus with the arid atmosphere we observe today.”