Stormy atmospheres of exoplanets hint at high probability of life

As astronomers are hunting down Earth-sized worlds orbiting their stars in Earth-like orbits, other factors influence whether or not a given extrasolar planet has the "right stuff" for life to thrive.

In research presented at the Meeting of the Royal Astronomical Society in London, astronomers discussed the dusty, stormy atmospheres of exoplanets and brown dwarfs and how they could be hothouses for the formation of prebiotic molecules.

These are organic molecules that are known to form the building blocks for life as we know it.

"The atmospheres around exoplanets and brown dwarfs form exotic clouds that, instead of being composed of water droplets, are made of dust particles made of minerals," astronomer Craig Stark, of the University of St. Andrews, Scotland, said.

The idea is that lightning storms generate copious amounts of highly charged ions and electrons, which then get stuck to dust particles, using them as miniature prebiotic chemistry factories.

Of particular interest is the formation of formaldehyde, ammonia, hydrogen cyanide and the amino acid glycine, all of which underpin Earth's biosphere.

Although we can't currently detect lightning storms in alien atmospheres, the churning (and often violent) atmospheric conditions of exoplanets and brown dwarfs certainly appear to be conducive to some pretty dramatic lightning bolts - events that have been observed on other planets in the solar system.

And should there be a healthy mix of dusty clouds, who knows? Organic chemistry may thrive, only boosting the already high probability for life on other worlds in our galaxy.

The research is set to be published in The International Journal of Astrobiology.