VENUS was once a planet capable of life, boasting a shallow liquid-water ocean and habitable surface temperatures for up to two billion years, according to NASA scientists.
New modelling done by the space agency’s Goddard Institute for Space Studies (GISS) indicated the planet could have enjoyed a vastly different past to its current form.
Michael Way is a researcher at GISS and the lead author of the report which was published in the journal Geophysical Research Letters.
He said the systems we use to monitor climate change on Earth can be employed to give us unprecedented insight into the former climatological life of other planets.
“Many of the same tools we use to model climate change on Earth can be adapted to study climates on other planets, both past and present,” he said in a statement released by NASA. “These results show ancient Venus may have been a very different place than it is today.”
Venus as we know it is a hellish place with surface temperatures as high as 462C. It has a carbon dioxide atmosphere 90 times as thick as Earth’s and almost no water vapour.
However scientists have long theorised that the planet was once made up of similar elements to Earth but given its proximity to the Sun took a different evolutionary path.
Evidence from a pioneering mission in the 1980s suggested that Venus may have once had an ocean.
Working on that assumption, NASA used a land-ocean pattern like the one pictured above in a climate model to show how storm clouds could have shielded ancient Venus from strong sunlight and made the planet’s environment habitable.
Venus is the second closest planet to the Sun and thus receives a far greater amount of the Sun’s rays which researchers believe caused its early oceans to evaporate and later produced its heavy carbon dioxide atmosphere.
NASA also worked off the assumption found in new research that a slower planet rotation doesn’t necessarily mean a thicker atmosphere.
Venus’s rotation is very slow, taking 117 Earth days to complete but scientists no longer believe that excludes it from have a habitable environment.
“In the GISS model’s simulation, Venus’ slow spin exposes its dayside to the Sun for almost two months at a time,” co-author and fellow GISS scientist Anthony Del Genio said. “This warms the surface and produces rain that creates a thick layer of clouds, which acts like an umbrella to shield the surface from much of the solar heating.”
He said such a scenario would mean climate temperatures that were “actually a few degrees cooler than Earth’s today”.