Understanding moon phasesPosted: May 3, 2011
In conjuction with today’s New Moon, this month I am going to be featuring a series from EarthSky.com on the moon’s phases. To start the month—a nice, concise, relatively clear explanation of the changing phases of our moon:
The answer is the moon is a world in space, just as Earth is. Like Earth, it’s always half illuminated by the sun. In other words, the round globe of the moon has a day side and a night side. From our earthly vantage point, as the moon orbits around Earth, we see varying fractions of its day and night sides. These are the changing phases of the moon.