With the help of the European Space Agency's Venus Express, scientists are investigating whether Venus had an ocean and was habitable in the past.
Venus is often referred to as Earth's sister planet even though they are very different in so many ways. Venus is hellishly hot, while Earth is full of life with relatively mild temperatures overall.
The two planets have their similarities, though, such as their size, composition and mountainous terrains, and now there could be even be some more.
ESA's Venus Express orbiter has found some interesting facts about the hot planet's water. The orbiter has confirmed that Venus has lost large quantities of water into space. Because of the Sun's ultraviolet radiation streaming into the atmosphere of Venus, the water molecules are broken into atoms (one oxygen and two hydrogens) and then they escape to space.
The Venus Express measured the escape rate of the atoms and confirmed that about twice as much hydrogen than oxygen is escaping. So scientists believe that the source of the escaping ions is water. A heavy form of hydrogen, called deutirium, is also seen to be progressively enriched in the echelons of the upper Venusian atmosphere. This is because it is harder for deutirium to escape the grip of the planet.
Colin Wilson from UK's Oxford University said, "Everything points to there being large amounts of water on Venus in the past," However, this doesn't mean that there were oceans on Venus in the past.
A computer model designed by Eric Chassefière of the Université Paris-Sud in France suggests that the water was mostly on the atmosphere and present only in the early times of Venus when its surface was molten. When the water molecules were split by sunlight and escaped to space, the temperature drop probably aided in the solidifying of the planet's surface, which means there were no oceans.
This is just a hypothesis and it remains an important question. If Venus did have surface water at some point, it could have had an early habitable phase. Even if Chassefière's model is true, it does not nullify that colliding comets brought more water to Venus after the surface hardened and created bodies of standing water that could have allowed life to form.
"Much more extensive modelling of the magma ocean-atmosphere system and of its evolution is required to better understand the evolution of the young Venus," Said Chassefière.
The data provided by the ESA's Venus Express will be very crucial when creating computer models such as Chassefière's, which will further explain what Venus's past water situation was like.
Information for this article was gathered from the European Space Agency.