Venus May Have Once Been Able To Support Life

A new study into the history of Venus suggests the planet may have been suitable for life - potentially having huge oceans and green land just like Earth.

As the second planet from the sun, you may think of Venus as merely a hellish location with 900-degree surface temperatures and an atmosphere thicker than Earth.

But it turns out the planet may have had a liquid water ocean and habitable temperatures.

Climate models from NASA Goddard Institute for Space Studies in New York suggest that Venus was able to keep a source of water for 2 billion years – even though it’s a third closer to the sun than Earth.

That’s cool… How did they find this out?

Well, it’s all about the rotation of the planet and topography. These play important parts in the surface temperature and moisture - if a planet that close to the sun spins slower, it will become dryer and hotter (obvious enough).

Observations suggest Venus may have had water oceans in its distant past. A land-ocean pattern like that above was used in a climate model to show how storm clouds could have shielded ancient Venus from strong sunlight and made the planet habitable. Credits: NASA
Observations suggest Venus may have had water oceans in its distant past. A land-ocean pattern like that above was used in a climate model to show how storm clouds could have shielded ancient Venus from strong sunlight and made the planet habitable.
Credits: NASA

In its past, Venus would have spun faster. And as climate scientist, Michael Way wrote in the paper published in Geophysical Research Letters if Venus rotated slower than about 16 Earth days, temperatures could be more moderate.

And even with 46-70% more solar radiation

Today, Venus is the solar system’s slowest spinning rock, rotating once every 243 Earth days.

But even at that speed, the planet could have been liveable until at least 715 million years ago.

So what does this mean for us?

This study breathes new life into looking for life beyond Earth. Not just if there are live aliens, but for even looking for the faintest evolutionary paths of extinct species.

The results of their work suggest that warm rocky planets like this one have the capability to retain significant water, even if they are closer to the sun.

"The inner edge (of a star's habitable zone) should, therefore, be considered a transition region in which the probability of habitability gradually decreases inward rather than a strict boundary separating completely different regimes," Way and colleagues concluded.