“Amateur astronomers and idiom lovers will both have reason to rejoice this week: It’s the once in a blue moon when an actual blue moon will rise in the sky.
“And it’s not just any blue moon. It’s a rare blue supermoon. The Earth’s lunar sidekick will seem extra big and bright as it reaches its fullest stage on Wednesday.
“We won’t see this particular lunar twofer again until 2037, so here’s what you need to know to make the most of it.”
Read more at NPR