The morning of May 26, a confluence of lunar events will thrill skywatchers across much of the world. Popular media is calling the event a Super Flower Blood Moon. But what do all those names mean, and will you be able to see it? Let’s break it down.
Playing the name game
Late on Tuesday, May 25, our Moon reaches perigee — the point in its orbit around Earth that brings it closest to our planet. That’s because the Moon’s orbit is an oval (or ellipse), rather than a circle. Each month, it has a closest approach (perigee) and farthest approach (apogee). On Tuesday night at 9:50 P.M. EDT, the Moon will reach perigee, coming a mere 222,023 miles (357,311 kilometers) from Earth.
Less than 12 hours later, at 7:14 A.M. EDT on Wednesday, May 26, the Moon will officially reach its Full phase. A Full Moon in May is known as a Flower Moon. So, that’s one name out of the way.
But, according to NASA, when a Full Moon occurs while the Moon is within 90 percent of perigee, the event is also called a Super Moon. That’s because a Full Moon at perigee looks slightly larger (up to 14 percent) and brighter (up to 30 percent) than a Full Moon at any other time, especially when it’s at apogee.
You might remember that last month’s Full Moon was also a Super Moon. But this month’s Full Moon is a tad more super — it occurs slightly closer to perigee than April’s Full Moon, making it appear 0.04 percent larger this month. That means Wednesday’s event will be the biggest Super Moon of 2021.
So, now we’ve taken care of two names. What about the third: Blood Moon? That’s the name bestowed upon the Moon during a lunar eclipse, which can turn our satellite from a brilliant white to a deep red.
The transformation occurs as the Moon passes through Earth’s shadow, which is not solid black because our planet has a blanket of air around it. As sunlight filters through Earth’s atmosphere and falls on the Moon, red light is bent more (into the shadow) than blue light, which gets scattered away. This puts a hint of red in Earth’s shadow, giving the Moon a ruddy hue when it passes through it.