Fully understanding how a rocky planet becomes habitable and remains so is a fundamental challenge for planetary scientists and astrobiologists, given the diversity and complexity of intrinsic and extrinsic processes that contribute to sustain habitable conditions over geological and biological time scales. In the face of this challenge, it is imperative that the full range of rocky planet atmospheric evolution data within our Solar System be exploited. Although Venus represents a clear end-member of planetary habitability, its contributions to understanding the prevalence of long-term temperate surface conditions on large rocky worlds have yet to be fully realized. Upcoming missions to Venus, including NASA’s VERITAS and DAVINCI, and ESA’s EnVision mission, will begin to flesh out this understanding.
“We often assume that Earth is the model of habitability, but if you consider this planet in isolation, we don’t know where the boundaries and limitations are. Venus gives us that,” said Dr. Stephen Kane, an astrophysicist at the University of California, Riverside.
“Though it also features a pressure cooker-like atmosphere that would instantly flatten a human, Earth and Venus share some similarities.”
“They have roughly the same mass and radius. Given the proximity to that planet, it’s natural to wonder why Earth turned out so differently.”
Many scientists assume that insolation flux, the amount of energy Venus receives from the Sun, caused a runaway greenhouse situation that ruined the planet.
“If you consider the solar energy received by Earth as 100%, Venus collects 191%. A lot of people think that’s why Venus turned out differently,” Dr. Kane said.
“But hold on a second. Venus doesn’t have a moon, which is what gives Earth things like ocean tides and influenced the amount of water here.”
In addition to some of the known differences, more NASA missions to Venus would help clear up some of the unknowns.
Planetary scientists…
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