The ‘super’ part of the phrase refers to a super moon, which occurs when the moon is closer to the earth than usual. Because the moon doesn’t orbit earth in a perfect circle, its distance from earth varies. A super moon occurs when a full moon is closest to earth on its orbit, making it about 14 percent bigger and 30 percent brighter than a normal full moon.
The ‘blue’ part of the description has nothing to do with the moon’s colour. A moon is considered a ‘blue moon’ when it’s the second full moon in a month, which is rare since full moons happen roughly every 29.5 days, hence the saying “once in a blue moon.”
The term ‘blood moon’ is used to describe a lunar eclipse, which is when the earth passes directly between the sun and moon, and the moon falls in earth’s shadow. The moon doesn’t go completely dark, as the the sun’s light still shines onto the moon’s surface, but it appears a reddish-orange colour.
Greg Stevens captured this incredible photo of the blood moon last week. He says he had set up his gear and was waiting for the cloud cover to clear before he snapped this picture around 2.15am on Thursday morning. “I was hoping to get a time lapse, but that didn’t happen. However, I’m pretty happy I got this shot.”