Clouds.
One of the most unique aspects of clouds is that they’re an organic phenomenon that doesn’t exist only on Earth.
In fact, they almost certainly exist on other planets. For example, planets in our own solar system that likely have water clouds include Jupiter and Saturn. While water clouds aren’t immediately detectable on these gas giants, it’s believed that beneath their thick gaseous layers, they do exist.
There’s also water ice on Mars—or at least strong evidence of it. It’s highly likely that Mars once had even more liquid water, which implies the presence of clouds in its past. And then there’s Uranus and Neptune, about which there’s a lot of conjecture. Some scientists believe these planets contain supercritical water oceans.
But it’s not just our solar system. On the exoplanet K2-18b, we know there’s water vapor—that is, clouds. The same goes for Kepler-138c and Kepler-138d, which many believe to be largely composed of water.
Now, keep in mind: just because water exists doesn’t mean anything organic is present on those planets. It simply means that a critical component of organic life exists elsewhere in the universe. And there’s still so much we don’t know.
For example, if life does exist on other worlds, how is it fundamentally different from life on our own? And how does water impact life on those planets—if, in fact, life is out there?
Photo credit: artist unknown
