With surface temperatures approaching 900 degrees Fahrenheit and an atmosphere 90 times thicker than Earth's, Venus is a hellish place, hot enough to melt lead. But earlier in its history, the second planet from the sun may have had a liquid water ocean and temperatures suitable for life, a new study shows.
Assuming that Earth and Venus started off with roughly the same ingredients, NASA climate models suggest that Venus was able to hold on to its water for about 2 billion years, despite its orbital perch roughly one-third closer to the sun than Earth.
Even with 46 to 70 percent more solar radiation, if Venus rotated more slowly than about 16 Earth days, it could have had moderate temperatures, climate scientist Michael Way, with the NASA Goddard Institute for Space Studies in New York, and colleagues write in a paper published in Geophysical Research Letters.
RELATED: Why Haven't we Returned to Venus' Hellish Surface?
Venus today is the solar system's slowest spinner, rotating once every 243 Earth days. Even at that rate, Venus' climate could have remained habitable until at least 715 million years ago, Way and colleagues concluded.
Still unknown is if Venus could have maintained its warm climate long enough for life to evolve.
"The rotation rate and topography of Venus play crucial roles in its surface temperature and moisture," the study said.
Nevertheless, the study has implications for looking for life beyond Earth, the authors noted.
WATCH: Can We Mathematically Prove Aliens Exist?