BLUE MOON AURORAS? NOAA forecasters estimate a 60% chance of polar geomagnetic storms on July 31st when a co-rotating interaction region (CIR) is expected to hit Earth's magnetic field. CIRs are transition zones
But it is the second full moon of the month of July. And the second full moon of any month is known as a "blue" moon. So how rare are they? The popular expression "once in a blue moon" may have you thinking they are quite uncommon. But in reality, they
BLUE MOON AURORAS? NOAA forecasters estimate a 60% chance of polar geomagnetic storms on July 31st when a co-rotating interaction region (CIR) is expected to hit Earth's magnetic field. CIRs are transition zones
If you happen to look up in the sky on Friday, you'll see something that only occurs "once in a blue moon." That's because it'll be a blue moon, the second full moon of the month, but this wasn't always the definition of the blue moon. Watch the video
A blue moon means it is the second full moon in a calendar month. Since the moon cycle is about 29.5 days, a blue moon doesn't happen too often, thus the phrase "once in a blue moon." The last blue moon was in 2012, the next one after this will be in 2018.