Hellish Venus may have lost its water quickly
By JONATHAN O’CALLAGHAN , Science. Excerpt: With surface temperatures hot enough to melt lead, Venus today is a veritable hellhole, despite being similar in size to Earth and orbiting in the habitable zone of the Sun. Yet studies suggest the planet may have once hosted oceans and even conditions suitable for life. Explaining how all that water disappeared has been a problem. A study published today in Nature offers a solution, identifying a new water-loss mechanism operating high in Venus’s atmosphere that could have doubled the rate of water loss. Speedier drying could have allowed oceans to exist until later in Venus’s history—implying the planet might have been habitable for longer. ...At 96% carbon dioxide, its atmosphere traps so much heat that surface temperatures reach more than 450°C. Yet spacecraft and telescopes have seen faint hints of water vapor in the atmosphere, and in the late 1970s, NASA’s Pioneer Venus orbiter detected a sign of long-vanishe...