On January 9, 1643, the Italian astronomer Giovanni Riccioli saw a weird glowing light on the night side of Venus.
He named it "The Ashen Light of Venus." Astronomers have seen it intermittently since then, while others who have looked for it have not been able to find it. To this day, no one really know what causes the Ashen Light. At first, people wanted to attribute it to the optical quality of telescopes. Today many believe that the light is associated with lightning storms on Venus. It could also be the result of solar radiation interacting with the atmosphere similar to how auroras happen on Earth. Whatever it is, it's been a scientific mystery for centuries.
