What is a blue moon?

Posted: 11:26 AM EDT Jul 28, 2011

The term is used when a full moon occurs twice in the same calendar month.

It happens every 2.7 years and never in the month of February since there are not enough days.

Is the moon really blue, though?

It depends, most moons are not blue!

However, if there is a volcanic eruption or even a forest fire the smoke in the sky can turn the moon a blue color.