The moon is Earth's most constant companion and the easiest celestial object to find in the night sky.



The rhythm of the phases of the moon has guided humanity for millennia; for instance, calendar months are roughly equal to the time it takes to go from one full moon to the next. But the moon's orbit and phases can seem mysterious. for example, the moon always shows us the same face, but it's always changing size as how much of it we see depends on the moon's position in relation to… Continue