"What is curious about Venus’ clouds – other than that they are unlike anything on Earth – is that in those clouds are mysterious dark patches, dubbed “unknown

"What is curious about Venus’ clouds – other than that they are unlike anything on Earth – is that in those clouds are mysterious dark patches, dubbed “unknown absorbers” by scientists as the tiny particles that make up the patches soak up most of the ultraviolet and some of the visible light from the sun and thus affect the planet’s albedo and energy budget. The patches were first observed by ground-based telescopes more than a century ago. They ebb and flow over time, changing their distributions and contrasts. “The particles that make up the dark splotches, have been suggested to be ferric chloride, allotropes of sulfur, disulfur dioxide and so on, but none of these, so far, are able to satisfactorily explain their formation and absorption properties,” explains Yeon Joo Lee, the senior author of the new report. On the other hand, Limaye notes observations that the particles are about the same size and have the same light-absorbing properties as microorganisms found in Earth’s atmosphere, and scientists, beginning with the noted biophysicist Harold Morowitz and astronomer Carl Sagan, have long speculated about the possibility that the shadowy patches in the clouds of Venus are, in fact, microscopic life." https://news.wisc.edu/mysterious-cloud-absorbers-seen-to-drive-venusian-albedo-climate/#:~:text=What%20is%20curious%20about%20Venus,from%20the%20sun%20and%20thus https://news.wisc.edu/mysterious-cloud-absorbers-seen-to-dri...