- The clouds on Venus are comprised of unusual dark patches made of tiny particles.
- Astronomers like Carl Sagan have long speculated that these patches could be extraterrestrial microorganisms.
- Whatever these patches are made of, they are greatly affecting weather on Venus.
Something mysterious is going on in the Venus’ clouds. It is the hottest planet in our solar system (460 degrees Celsius at the surface) with a harsh, thick atmosphere filled with sulfuric acid and carbon dioxide.
The surface of the Venus has never been observed by the human eye as it is densely obscured by reflective clouds. Atmospheric gases are spread over the cloud layers in patterns that astronomers don’t fully understand. The clouds also comprised of unusual dark patches dubbed ‘unknown absorbers’.
The small particles that make up the patches absorb large amounts of solar radiations, affecting Venus’ albedo and energy budget. These patches were first discovered more than 100 years ago. Their contrast and distribution change over time.
So far, scientists haven’t been able to figure out what these dark patches are, but some observations show that they could be allotropes of sulfur, disulfur dioxide, and ferric chloride. Though none of them provides a satisfactory explanation of the formation and behavior of patches.
The famous astronomer Carl Sagan and biologist Harold Morowitz have long speculated that the shadowy patches could be extraterrestrial microorganisms. The particles that make up the patches in the clouds of Venus have similar size and properties as microorganisms found in the atmosphere of Earth.
A few species can evolve independently on Venus, as long as their chemical, spectral and physical characteristics are consistent with the composition of the planet’s clouds. Sagan also mentioned the possibility of liquid water on Venus which may have survived there for as long as 2 billion years.
Nevertheless, whatever these dark patches are made of, the new study conducted by researchers at the Technical University of Berlin shows that unknown absorbers are affecting the weather on Venus.
The study is based on more than 10 years of data obtained from Akatsuki (Japan’s Venus Climate Orbiter that studied planet’s atmosphere), Venus Express (Venus exploration mission of the ESA), and Hubble Space Telescope.
Infrared Image of Venus showing clouds mostly on the night side of the planet | Credit: Akatsuki/JAXA
Venus’ albedo — part of the energy from the sunlight reflected back to space — changed drastically between 2006 and 2017. Due to these changes, Venus clouds absorbed different amounts of solar energy, which affected the circulation of the planet’s atmosphere.
More specifically, these alterations vigorously influenced the activity of the Venus’ upper atmosphere where winds exceed 360 kilometers per hours, a phenomenon called super-rotation.
The changes in Venus’ albedo show that there is a connection between solar heating and strong gusts that underpin the planet’s upper atmosphere dynamics. It’s quite astonishing that the Venus’ climate oscillations are much more powerful than the Earth’s long-term variations.
Overall, the findings present dynamics of Venue’s albedo and mysterious dark patches at the top of the planet’s clouds that play a major role in changing the weather on Venus.