View Full Version : Christmas Sunset.

December 10th, 2003, 03:50 PM
As evening approaches on Christmas, Dec. 25th, step outside and look west toward the setting sun. Even before the sky turns completely dark you can see them: brilliant Venus and the crescent moon hanging together not far above the horizon--a beautiful sight.

Venus is so bright it's often mistaken for an airplane or a UFO. Onlookers have been known to call 911 when they see it. And when lots of people notice Venus, police phones can ring off the hook. Dec. 25th could be such a night because together the moon and Venus are unusually eye-catching.

Here's something to think about while you're gazing at Venus: Its pearly-white light looks icy and cold, but with a surface temperature of 860 F (460 C) Venus is the hottest world in the solar system. A block of lead placed on the ground there would quickly melt. Venus is so hot because it has a dense atmosphere (90 times more so than Earth's) made of 96% carbon dioxide--a planet-warming greenhouse gas. Also, Venus is thoroughly blanketed by clouds, leaden-grey and laced with sulfuric acid. These oppressive clouds, ironically, are what make the planet seem from a distance so bright and lovely. They're excellent reflectors of sunlight.

The crescent moon beside Venus on Dec. 25th will be equally lovely--a slender arc of bright light cradling the dark lunar disk. Look closely. Can you see a ghostly glow across the whole moon? Leonardo DaVinci first understood this phenomenon some 500 years ago. It is sunlight reflected from Earth onto the moon. Astronomers call it "Earthshine."

Side-by-side with Venus, a crescent moon with Earthshine is regarded as one of the prettiest sights in the heavens. And the ensemble is bright enough to see even from light-polluted cities.

Merry Christmas!


December 10th, 2003, 04:20 PM
Gorgeous photo! Yours?

December 10th, 2003, 04:32 PM
oh that's amazing! thanks for the info!

Phoenix Blue
December 10th, 2003, 06:22 PM
Probably not, it's hosted on NASA's website. :)

December 11th, 2003, 10:28 AM
Oh well, the info was interesting anyway. :)

December 12th, 2003, 03:38 AM
Does it apply to the southern emisphere as well?