Key Facts

• The yellow "lower haze" on Venus was first seen by space probes in the 1970s but remained unexplained for decades.
• Researchers at Tohoku University in Japan used a microphysical model to study Venus’ haze formation.
• The haze comes from cosmic dust left by meteorites burning up in Venus’ atmosphere, not from volcanic ash or surface dust.
• Meteorite particles act as condensation nuclei, meaning sulfuric acid droplets can form around them to create clouds.
• These droplets grow heavier and sink, eventually leaving the haze particles behind after sulfuric acid evaporates.
• Venus is the most volcanically active planet in the Solar System, but volcanic ash does not contribute to the haze.
• The discovery also helps explain why something in Venus’ atmosphere absorbs ultraviolet light.
• The process that forms Venus’ haze is similar to how clouds form on Earth, using tiny particles as centers for condensation.