The bond albedo of Venus is 0.75.
Albedo is a measurement of the reflectivity of an object. A theoretically perfect reflecting object would have an albedo of 1, and reflect 100% of the electromagnetic radiation that falls upon it. While an object that was perfectly black and doesn’t reflect any light would have an albedo of 0. In real life, objects in the Solar System have albedo values between 0 and 1. And in the case of Venus, the albedo is 0.75.
Just for comparison, the bond albedo of the Moon is only 0.12. That’s actually pretty dark. The brightest albedo in the Solar System is Saturn’s moon Enceladus, with an albedo of 0.99. It reflects almost all of the light that falls onto it.
One of the reasons that Venus is so bright in the sky is because of its high albedo. This albedo comes from the permanent cloud layer that surround the planet. These clouds are made up of sulfuric acid that reflect much of the radiation that falls upon them.
We have written many articles about Venus for Universe Today. Here’s an article about Venus’ wet, volcanic past, and here’s an article about how Venus might have had continents and oceans in the ancient past.
We have recorded a whole episode of Astronomy Cast that’s only about planet Venus. Listen to it here, Episode 50: Venus.