Friday, August 12, 2016

Venus May Have Been the First Habitable World in Our Solar System! (video)

   These days, Earth is the only known habitable planet in our Solar System, and the best candidates for potential habitability are Mars and icy moons like Europa. 
   But as it turns out, the most habitable planet in our early Solar System might have been an unexpected candidate: our scorching-hot neighbor Venus.
   Venus is sometimes called Earth's "sister planet" as a result of its similar size, mass, and distance from the Sun. But in the present day, it is completely inhospitable to life, with average surface temperatures approaching 870 degrees Fahrenheit, an extremely thick atmosphere, and an atmospheric pressure that is 92 times that of Earth. But three billion years ago, it might have been an entirely different story, and Venus might have been habitable before Earth ever was.

   The hypothesis that Venus could have been "another Earth" has been gaining traction in the scientific community for years, especially since NASA's climate modeling determined that Venus may have had habitable temperatures for up to two billion years. It still would have received 40% more heat from the Sun than Earth does now, but according to a new study, that may not have mattered if Venus had a slower rate of revolution than it does now.

  "If Venus was spinning more rapidly, all bets are off", lead author Michael Way told Gizmodo. But if it were spinning much slower than Earth, "you get temperatures almost like Earth. That's remarkable."
   For the study, the team of researchers made global climate models for Venus using a similar process as the one scientists use to model climate change on Earth. They used data from the Magellan spacecraft for current Venus data, as well as estimates for water and radiation from past Venus, and found that for two billion years, the surface temperature would have been very similar to Earth's. 2.9 billion Years ago, it would have been approximately 52 degrees Fahrenheit, and 715 million years ago, it would have increased by only four degrees, making it perfectly hospitable to human (or extraterrestrial) life. 

  "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 researchers wrote in their paper.

   Of course, this is still highly speculative, since there's so much still unknown. First, we don't know if Venus' rotation rate were as slow as it is now, and even if it were, the study found that Earth-like topography increased temperatures significantly. Further, if Venus was habitable up until 715 million years ago, then some catastrophic event must have happened to make the climate change so drastically. But still, the study presents a plausible scenario in which Venus could have been habitable, and may mean that we should look for signs of ancient Venusian life.


No comments: