If you look up at the Moon on Thursday, March 6, you might catch a glimpse of something strange—two letters ... shadows along the lunar terminator, the line that separates the Moon’s ...

Known as the 'Lunar X' or the 'Werner X,' this optical illusion appears on the terminator line between the light and dark side of the moon every four hours when it's in its first quarter phase.

James is a published author with four pop-history and science books to his name. He specializes in history, strange science, and anything out of the ordinary.

When we can only see part of the illuminated surface of the Moon, the line between the light and dark sides is called the "terminator line". Just like during sunset on Earth, the surface features ...