Behold the Blue Supermoon

Aug 28, 2023

What is a Supermoon?

Some astronomical events only happen once in a blue moon — like, for instance, blue moons. And a blue SUPERmoon? That’s a once-in-a-decade occurrence. Fortunately for lunar-lovers the world over, the evening of August 30 will feature the sky-filling phenomenon.

To break down what will make Wednesday night’s moon so magnificent requires an understanding of two key concepts: "blue moons" and "perigee.” A “blue” moon doesn’t refer to our nearest celestial neighbor suddenly turning teal. Rather, it indicates that the moon will be full for the second time in a month. The moon takes almost a month to cycle through its phases. It takes 29.53 days, to be precise. Because of this, seeing two full moons in a 31-day month like August is rare. And it can never happen in February.

The last blue moon rose in August 2021. The next will not grace the skies until May 2026. Neither will be supermoons, though. That requires the moon to be at perigee. The perigee phase is when the moon is at its closest point to Earth in its orbit. The moon’s path around our planet resembles a gentle wave as much as it does a circle. It draws closer and pulls away even as it revolves around us. At perigee, or “supermoon” status, the moon appears 7% larger and 14% brighter than it does at apogee. Apogee status is when the moon is at its farthest point from Earth.

According to NASA, the best time to view the blue supermoon will be 9:35pm on Wednesday. At this time, it will just be cresting above the horizon. You can bring binoculars if you want. But the spectacle should be big enough and bright enough to enjoy with the naked eye.

Reflect: Think about something rare or special that you've experienced. How did it make you feel? How can we appreciate and enjoy moments that don't happen very often?

According to the infographic, how does the moon in the perigee phase compare to the moon in the apogee phase? (Common Core RI.5.7; RI.6.7)
a. A perigee moon is closer to Earth than an apogee moon.
b. A perigee moon is farther away from Earth than an apogee moon.
c. A perigee moon is the same distance away from earth as an apogee moon.
d. A perigee moon appears smaller in the sky than an apogee moon.
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