23Aug2013

Why Is Venus So Bright Tonight?

Venus

Venus is so much brighter than any other planet viewed in the sky. Why is it so bright? Astronomers use the term “albedo” to describe how bright a planet is, and Venus has albedo plus.

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.

Photo credit: James Jordan

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. Source: Earth and Sky

The ‘Evening Star’

Check out what’s hanging low in the western sky at sunset. That bright ‘star’ you see is in reality our sister planet Venus, also known as the “evening star.” This week it absolutely spectacular and already generating the odd UFO report or two. If you stare at it awhile it appears to move around or wobble. Try it.

Venus is so much brighter than any other planet viewed in the sky.  It reflects over 70 percent of sunlight striking it. It owes its reflective ability to the fact that  it’s blanketed with thick poisonous clouds. Sunlight bouncing from these clouds is what makes Venus so bright.

Venus is the second planet from the sun, and the brightest planet in our night sky, when it’s visible. In ancient times, the planet was thought to be two different stars, the evening star and the morning star. Venus is visible for about 9 months in the evening sky, and then alternates, spending approximately the same amount of time in the morning sky.

English: Venus orbits the Sun at an average di...

Venus orbits the Sun at an average distance of about 108 million kilometers  and completes an orbit every 224.65 days. Venus is the second planet from the Sun and it revolves round the Sun approximately 1.6 times (yellow trail) in Earth’s 365 days (blue trail 

Not many people know that Venus and Earth are the same size. Born at the same time Venus was turning into our twin sister, another Earth in fact, until something went violently wrong and volcanism took over, turning it into a fiery hell.

Venus takes about 225 Earth days to travel around the sun. The planet also spins backwards, opposite way that Earth on its axis. So on Earth, the sun rises in the east and sets in the west, but on Venus the sun rises in the west and set in the east. Weird huh?

Our closest planetary neighbour, Venus, is the third brightest light in the night sky after the Sun and the Moon. Because it lies between the Earth and the Sun, it is only partially illuminated from our vantage point and displays Moon like phases, from crescent to gibbous. A little on the fuzzy side but quite obvious.

In its crescent phase Venus is closer to Earth and thus appears much bigger than it does in its gibbous phase, when Venus is farther away. Its surface is perpetually shrouded by atmospheric clouds, so you won’t see much detail, but it’s a cool sight nonetheless. It’s also our closest planetary neighbour in space.