Venus never had oceans

Washington: The planet Venus can be seen as the Earth’s evil twin. At first sight, it is of comparable mass and size as our home planet, similarly consists mostly of rocky material, holds some water, and has an atmosphere.

A team of astrophysicists led by the University of Geneva (UNIGE) and the National Centre of Competence in Research (NCCR) PlanetS, Switzerland, investigated whether our planet’s twin did indeed have milder periods. The results, published in the journal Nature, suggest that this is not the case.

Yet, a closer look reveals striking differences between them: Venus’ thick CO2 atmosphere, extreme surface temperature, and pressure, and sulphuric acid clouds are indeed a stark contrast to the conditions needed for life on Earth.

This may, however, have not always been the case. Previous studies have suggested that Venus may have been a much more hospitable place in the past, with its own liquid water oceans.
Astrophysicists led by Martin Turbet, a researcher at the Department of Astronomy of the Faculty of Science of the UNIGE and member of the NCCR PlanetS, have tried to answer this question with the tools available on Earth.

Martin added, “The associated high temperatures meant that any water would have been present in the form of steam, as in a gigantic pressure cooker.” Using sophisticated three-dimensional models of the atmosphere, similar to those scientists use to simulate the Earth’s current climate and future evolution, the team studied how the atmospheres of the two planets would evolve over time and whether oceans could form in the process.

“Thanks to our simulations, we were able to show that the climatic conditions did not allow water vapour to condense in the atmosphere of Venus,” said Martin Turbet.

This means that the temperatures never got low enough for the water in its atmosphere to form raindrops that could fall on its surface.