May's full Blue Moon put on a dazzling display over the weekend, flooding the night sky with moonlight as the red supergiant star Antares glowed nearby.
A Blue Moon is the name given to the second full moon in a single calendar month — a rare occurrence that only takes place about once every 2.5 years, because the moon's 29.5-day cycle doesn't neatly align with the calendar. It's also the name given to the third full moon in a single season containing four full moons — though this original meaning doesn't apply for the May 31 lunar event.
