July’s fireworks displays not yet over? (Planet Venus continues light spectacle)
Published 2:42 pm Friday, July 9, 2010
July 4th light shows at various locations throughout Polk County must have resonated in the heavens with special effect this year as one of the fiery projectiles seems to have made its way into outer space. This residual pyrotechnic display will be evident to anyone who takes time to look skyward after sunset every clear evening from now until the end of summer. It is Venus, the radiant planet known also as the evening star.
Though Venus in this context is called a star, in actuality it outshines every other real star in its vicinity by a factor of more than one hundred. To illustrate this point, it happens that tonight (July 9th) Venus will pass just one degree (a fingernails width at arms length) north of one of the brightest of all stars, Regulus (in the constellation of the Lion).
As you observe Venus and Regulus together, imagine there were 100 stars just like Regulus driven into its one single solitary point of light. Even then Venus would be brighter!
The reason? Venus cloud-covered surface reflects back into space 65% of the light it receives from the sun.&bsp; By comparison earth reflects 35% and the moon only 7%. The moon seems bright to us only because of its relative closeness – thousands of miles rather than millions as in the case of the planets, and trillions as in the case of the stars. If the moon were at Venus present distance (100 million miles) it would appear almost exactly the same brightness as Regulus.
During the month of July, Venus will continue to approach earth and appear even brighter. The percentage of its surface illuminated by the sun will decrease so that the planet will take the shape of a crescent just as the moon does when it is new.
Join the astronomers on the hilltop behind FENCE after sunset on Saturday, July l0th, where telescopes will be set up to view crescent-shaped Venus, as well as Mars, Saturn and many other celestial wonders.
And dont forget to bring your binoculars!