A long time ago, Venus may have had flowing liquid water and may have featured temperatures similar to the temperatures found on Earth. If so, we can add Venus to the list of planets within our galaxy that may have been capable of sustaining life at some point. Now, Venus features storms of acid and has bone-crushing atmospheric pressure. It’s a hellish planet to consider ever living on, but scientists have been studying the planet for years, and now believe that that very situation was possible around the same time when life was beginning to evolve on our own home planet.
— Phys.org (@physorg_com) August 9, 2016
David Grinspoon at the Planetary Science Institute in Arizona told New Scientist that Venus probably once featured warm liquid water oceans that was in contact with rock and organic molecules. Grinspoon says that those are the requirements for life, and so it is possible that Venus once was the home for life.
“As far as we understand at present, those are the requirements for the origin of life.”
In 2010, researchers noted that Venus shared surprisingly similar sizes, densities, and composition. It’s probable that they were formed using the same base materials, research from this decade suggests. The research team says that Venus also has a high ratio of deuterium to hydrogen atoms. This reportedly points to having once homed a vast amount of water.
— Newser (@Newser) August 8, 2016
New climate models support the theory even further. Michael Way of the NASA Goddard Institute for Space Studies led the team of researchers that conducted the simulations. Depending on the rotation of Venus and the amount of energy the planet was receiving from the sun, the theory that Venus could have housed life is plausible, the team says. They even showed that in at least one simulation, Venus could have remained habitable as recently as 715 million years ago.
It all hinges on whether or not Venus was spinning as slowly as it is today.
“If Venus was spinning more rapidly, all bets are off,” Way said.
“We have created a suite of 3D climate simulations using topographic data from the Magellan mission, solar spectral irradiance estimates for 2.9 and 0.715 billion years ago, present day Venus orbital parameters, an ocean volume consistent with current theory and measurements, and an atmospheric composition estimated for early Venus. Using these parameters we find that such a world could have had moderate temperatures if Venus had a rotation period slower than about 16 Earth days, despite an incident solar flux 46-70% higher than modern Earth receives. At its current rotation period of 243 days, Venus’s climate could have remained habitable until at least 715 million years ago if it hosted a shallow primordial ocean.”
The team said that it might have been habitable for a couple of billion years, which would make it so that life could have potentially evolved quite a bit, just as it has on our own planet.
— New Scientist (@newscientist) August 8, 2016
If it ever was similar to earth in climate, what happened to it?
“It’s one of the big mysteries about Venus. How did it get so different from Earth when it seems likely to have started so similarly?” Grinspoon mentioned to New Scientist. “The question becomes richer when you consider astrobiology, the possibility that Venus and Earth were very similar during the time of the origin of life on Earth.”
We’d have to actually go to Venus to really figure that out, but according to Business Insider, NASA is already considering it.
The team’s report about the possibility that Venus may have been compatible to life has been accepted for publication by Geophysical Research Letters.
— Fraser Cain (@fcain) August 8, 2016