A Blue Moon

The saying is "Once in a Blue Moon" and I always understood that a blue moon never happened.

But I was wrong! About a month ago, I was reading on a forum that there was going to be two moons in the month of July.

Last week in Science, the question was asked of the students "What is a Blue Moon?" I thought to myself, there's going to be some interesting answers here and yes there was a couple before some one  said something about an extra moon. We/they are studying (I forget sometimes that its them that are learning, not supposed to be me) planets and the solar system.

Moon rotates once every 28 days and ever so often if there is a new moon very early in the month then there is time for a second new moon in that same month, the second one is called a Blue Moon. The second or blue moon will be on Friday night.