Venus is shrouded in a veil of mystery. The yellowish “lower haze” at the bottom of its atmosphere was discovered by the Venera and Pioneer Venus probes in the 1970s. These spacecraft were some of the first to successfully send images of the planet back to Earth, but the haze they saw went unexplained for decades. Now the mystery Venus was keeping has been unveiled.

What nobody knew then was that the haze is an accumulation of particles from meteorites. “Shooting stars” that burn up in the atmosphere leave behind cosmic dust particles, and after sulfuric acid interacts with these particles, it leaves behind a haze. Planetary scientist Hiroki Karyu and his research team at Tohoku University in Sendai City, Japan, finally figured out how the haze formed using a microphysical model. This type of model involves microphysics—the micro-scale processes that create clouds and precipitation on Earth and other bodies.

“The continuous influx of cosmic dust is sufficient to sustain this lower haze layer with the particle size distribution observed by the entry probes,” Karyu said in a study published in Nature Astronomy. “These haze particles of cosmic origin act as efficient condensation nuclei, promoting cloud formation in the main cloud deck even far from their initial source.”

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About 66 million years ago, the Chicxulub asteroid smashed into Earth, kicking up tsunamis and dropping hot debris that annihilated non-avian dinosaurs and many other species. But not everything it left in its wake was destructive. This space rock hit what is now the partially submerged Yucatan Peninsula, and at the bottom of the ocean, the impact generated enough heat to create a hydrothermal system that persisted for 8 million years and may have been a hotbed of life.

When researchers drilled for samples in the impact zone in 2016, they studied the types of rock that had formed as a result of the asteroid strike. This gave more insight into what happened in the immediate and long-term aftermath of this cataclysmic event.

The collision was intense enough to cause deformation far beneath the surface. Subterranean effects reached 35 km (almost 22 miles) down, and included the melting an immense amount of rock. Exposure to seawater made that rock porous. As hot water seeped into the pores, a hydrothermal system formed. The hot water gushing into an isolated region of the freezing depths could have attracted microorganisms and possibly other life forms that were otherwise struggling to survive.

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