Why the Full Moon Never Rises at Midnight The sun always
illuminates half of the moon. The phase of the moon that we see
depends on how much of the illuminated surface is visible from
earth. When the sun illuminates the same half of the moon that
we see, the moon looks full. That happens when the sun, earth,
and moon are approximately lined up, with the earth between the
sun and moon. So the moon and the sun are on opposite sides of
our sky. When the moon is coming up, the sun is going down. At
midnight, the sun is approximately straight down, shining on the
opposite side of the earth. If the moon is full, then at
midnight it is straight up. It's not just starting to rise over
the horizon. According to H. D. Hoover, principal author of the
Iowa Test of Basic Skills for 40 years, this question would not
work in a high school standardized test because so few students
would get it. About 25 percent of those who picked their answer
randomly would make the right choice, and the total percentage
right would probabl