More Signs Point to Venus as Habitable in its Distant Past


Looking for a quick weekend getaway? If you were to hop on a flight to Venus today, you'd arrive at a place particularly ill-suited for a vacation — or for most life as we know it. Upon your arrival to the second planet from the sun, you'd be greeted by surface temperatures comparable to those in a pizza oven, and a carbon-dioxide atmosphere more than 90 times denser than ours here on Earth. You'd die quickly. But as existence is a constant state of change, things now aren't the way they always were, and early in its life Venus may have been significantly more hospitable.

These days, humanity looks to Mars and beyond for the potential for life, but it's worth looking inward in our solar system, too. New research from NASA provides further investigation into whether Venus, a planet strikingly similar in size and mass to our own, could have ever harbored life. The conclusion reached was that, yes, for up to 2 billion years of its 4.5-billion-year life span, the planet could have had conditions favorable to life as we know it.

The research from NASA's Goddard Institute for Space Studies (GISS), published this week in the journal Geophysical Research Letters, used topographical and atmospheric data collected by the Pioneer and Magellan space probes to create 3-D climate simulations, filling in lowlands with water and accounting for an ancient sun 30 percent dimmer than it is today.

The scientists also examined Venus' rotation as a key factor in habitability. That's because research from 2014 indicates a strong link between a planet's rotation and whether it could develop clouds and atmospheric circulation necessary to be habitable. One day on Venus is comparable to months here at home, and these days it takes Venus 117 Earth days to complete one rotation. This slow rotation could actually help foster cloud development. In fact, the scientists found that as long as Venus rotated more slowly than once every 16 Earth days, a moderate enough climate could have existed.

NASA used topographical data and a land-ocean pattern similar to this artist's rendition to illustrate storm clouds, oceans and land masses in Venus's distant past.
NASA used topographical data and a land-ocean pattern similar to this artist's rendition to illustrate storm clouds, oceans and land masses in Venus's distant past.
NASA

"In the GISS model's simulation, Venus' slow spin exposes its dayside to the sun for almost two months at a time," co-author Anthony Del Genio said in a NASA press release. "This warms the surface and produces rain that creates a thick layer of clouds, which acts like an umbrella to shield the surface from much of the solar heating. The result is mean climate temperatures that are actually a few degrees cooler than Earth's today."

This new finding builds upon previous research into Venus' environment. For instance, during the decade it orbited Venus, the European Space Agency (ESA) probe Venus Express helped show the potential for surface water and uncovered more data about the significant amounts of evaporated water lost to space, something discovered by earlier probes.

Now all you'll need for that pleasant weekend beach trip to Venus looks to be... a time machine.