The Sun has an invisible companion as it moves across the sky today: the new Moon. We can't see the Moon because it's passing between Sun and Earth, so it's immersed in the Sun's intense glare. And even if we could pick it out, there's nothing to see -- it's nighttime on the side of the Moon that's facing our way.
That makes the near side of the Moon -- the same hemisphere that always faces our way "“"“ the dark side. So the side that faces away from us -- what's often called the dark side -- is basking in sunshine.
That side of the Moon gets just as much sunlight as the front. It made sense to call it the "dark" side before the Space Age, when no one had seen it. But astronauts and robotic craft have photographed the farside in detail. We even have good maps of it -- good enough to get you from the Sea of Moscow to the Apollo Basin with a side trip to Jules Verne crater. So while we can still call it the farside, it's not quite right to call it the dark side of the Moon.
There is one way in which it's darker than the side that faces our way, though. Nights on the front side of the Moon are bathed in earthshine -- sunlight reflected off of Earth. In fact, if you were standing on that side of the Moon today, you'd see a full Earth shining dozens of times brighter than a full Moon.
But since the farside faces away from Earth, there's no earthshine to soften the night. So when it's dark on the far side of the Moon, it's really dark.
Script by Damond Benningfield, Copyright 2008
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