A composite image of the planet Venus as seen by the Japanese probe Akatsuki. The clouds of Venus could have environmental conditions conducive to microbial life, some researchers say.

The hot, hellish world of Venus is shrouded in a thick layer of clouds, but in those drifting clouds could be a niche for extraterrestrial microbial life, new research suggests.

An international team of researchers led by planetary scientist Sanjay Limaye of the University of Wisconsin–Madison's Space Science and Engineering Center lays out a case that the hunt for life beyond Earth should also include the clouds of Venus.

Limaye carries out his research as a NASA participating scientist in the Japan Aerospace Exploration Agency's Akatsuki mission to Venus.

Dark patches

"Venus shows some episodic dark, sulfuric rich patches, with contrasts up to 30-40 percent in the ultraviolet, and muted in longer wavelengths. These patches persist for days, changing their shape and contrasts continuously, and appear to be scale-dependent," Limaye said in a university statement.

The particles that make up the dark patches have almost the same dimensions as some bacteria on Earth, although the instruments that have sampled Venus' atmosphere to date are incapable of distinguishing between materials of an organic or inorganic nature.

The patches could be something akin to the algae blooms that occur routinely in the lakes and oceans of Earth, only these would need to be sustained in the Venusian atmosphere.

The proposed Venus Atmospheric Maneuverable Platform craft would fly like a plane but float like a blimp and could stay aloft in the planet’s cloud layer for up to a year gathering data and samples. (Image credit: Northrop Grumman)

Russian mission

The Wisconsin scientist and his colleagues are hopeful that an exobiological research chapter can be opened at Venus. There are ongoing discussions about possible NASA participation in Russia's Roscosmos Venera-D mission, now scheduled to launch in the late 2020s. (Venera is the Russian name for Venus.)

Current plans for Venera-D might include an orbiter, a lander and a NASA-contributed surface station and maneuverable aerial platform.

This new research and speculation can be found in a paper published online March 29 in the journal Astrobiology.

Leonard David is author of "Mars: Our Future on the Red Planet," published by National Geographic. The book is a companion to the National Geographic Channel series "Mars." A longtime writer for Space.com, David has been reporting on the space industry for more than five decades. Follow us @Spacedotcom, Facebook or Google+. This version of the story published on Space.com.