Venus is so much brighter than any other planet viewed in the sky. Why is it so bright?
See the best Venus-Jupiter conjunction in years in mid-March 2012
Photo credit: James Jordan
Astronomers use the term “albedo” to describe how bright a planet is. When light strikes a planet, some is absorbed by the planet’s surface or atmosphere – and some is reflected. Albedo is a comparison between how much light strikes an object – and how much is reflected.
Venus has the highest albedo of any planet in our solar system. Venus is so bright partly because it reflects over 70 percent of sunlight striking it. It owes its reflective ability to the fact that it’s blanketed with clouds. Sunlight bouncing from these clouds is what makes Venus so bright.
When the moon is close to full, it can look a lot brighter than Venus, but the moon reflects only about 10 percent of the light that hits it. The moon has a low albedo of around .1, meaning that it reflects about 10% of the light that it receives. Venus, on the other hand, is the most reflective object in our solar system, with an albedo of close to .7. The moon has a low albedo because it’s made of volcanic rock. It appears bright to us only because it’s so nearby.
The clouds in the atmosphere of Venus contain droplets of sulfuric acid – one of the eye-stinging ingredients in our urban smog – as well as acidic crystals suspended in a mixture of gases. Light bounces easily off the smooth surfaces of these spheres and crystals. That’s one reason the clouds of Venus are so good at reflecting light.
Does the outer atmosphere of Venus really contain sulfuric acid or is it sulfurous acid? Absorption of sulfur dioxide in water forms sulfurous acid, not sulfuric. Does ultraviolet radiation from the Sun contribute to the additional oxidation of sulfur dioxide to sulfur trioxide, which does form sulfuric acid?
How should I know Frederic
Venus is so bright on a clear night sky…I’ve been seeing Venus and Jupiter for a weeks now…stunning!
[...] the Moon hidden from direct sunlight by the sun-reflecting Earth. Also captured in the image is the bright planet Venus on the right. Venus and Jupiter passed only three degrees from each other last week during a [...]
Two other factors causing Venus to be the brightest planet are 1) Venus is so near to us and 2) being an “inferior” planet it receives more sunlight than planets farther out.
The burning gases i.e sulphuric acid and carbon di oxide a lot of light is produced making it appear very bright.
Venus displays crescent phases like the Moon.
This accounts for much of the brightness change observed from Earth with the naked eye.