Prepare for the grand spectacle of the year: the magnificent “blue supermoon” is set to grace the skies on August 30, 2023. But don’t let the name mislead you – this lunar marvel won’t actually be blue. Rather, its name is derived from a fascinating interplay of lunar events that converge in a captivating display.
The label “blue” supermoon doesn’t pertain to the moon’s color, but rather to its timing as the second full moon of August. This uncommon occurrence earns it the “blue” moniker, as it is the second full moon within the same month.
However, there exists another kind of blue moon called the “seasonal blue moon.” This phenomenon arises when four full moons transpire within a single astronomical season, a rare happening due to the mismatch between the lunar and solar years (354 days vs. 365 days). The next of these seasonal blue moons will grace the night skies on August 19, 2024.
Now, onto the “super” element of the moon’s name. A supermoon arises when the full moon comes closest to Earth in its elliptical orbit. The moon’s path around Earth isn’t a perfect circle; it’s more elliptical, resulting in its proximity to Earth fluctuating. A supermoon is deemed such when it comes within 90% of its closest approach to Earth, known as perigee. Notably, this specific lunar event is the third of four supermoons anticipated in 2023.
On August 30, this particular supermoon will shine at a mere 222,043 miles (357,344 kilometers) away from our planet, rendering it the most substantial and most luminous supermoon of the year. Despite being only 20 miles (33 kilometers) closer than the full moon on August 1, the August 30 spectacle is poised to be the showstopper.
This captivating phenomenon is rooted in the category of blue moons that stem from two full moons occurring in the same calendar month. This alignment is a natural outcome considering a new full moon appears approximately every 29.5 days. Given that the Sturgeon Moon illuminated the sky on August 1, the upcoming August 30 full moon satisfies the criteria for a blue moon. Referred to as “calendar blue moons,” this phenomenon arises approximately every two to three years, with the following occurrence anticipated on May 31, 2026.
As the stage is set for this celestial spectacle, let’s delve deeper into the science behind this unique convergence of events.
Why the Moon Isn’t Actually Blue
Despite its name, the “blue supermoon” will not cast a blue hue upon the night sky. The term “blue moon” has nothing to do with the moon’s color. Instead, it’s a product of our calendrical system’s interaction with lunar phases.
The Dance of Earth, Moon, and Sun
Understanding the occurrence of a blue moon involves the intricate interplay of Earth, the Moon, and the Sun. The Moon orbits our planet approximately every 29.5 days, a period known as a synodic month. However, Earth’s calendar months don’t align perfectly with lunar months, which results in occasional double full moons in a single calendar month.
Varieties of Blue Moons
There are two distinct types of blue moons:
- Calendar Blue Moon: This is the more common type and occurs when two full moons happen within the same calendar month. Given the slightly shorter lunar month, this phenomenon typically transpires every two to three years.
- Seasonal Blue Moon: Less frequent but equally intriguing, a seasonal blue moon transpires when four full moons occur within a single astronomical season. This unusual event arises due to the discrepancy between the lunar year (approximately 354 days) and the solar year (365 days).
The Supermoon Phenomenon
Adding another layer of fascination to this celestial event is the concept of a supermoon. When the Moon reaches its perigee, the point in its orbit closest to Earth, it appears significantly larger and brighter in the night sky. Supermoons, therefore, offer a breathtaking visual spectacle.
2023: A Year of Supermoons
The blue supermoon of August 30, 2023, is a noteworthy one among a series of supermoons in the same year. To qualify as a supermoon, the moon must come within 90% of its perigee in a given month. This August’s full moon is the third out of four such supermoons in 2023, making it a standout celestial occurrence.
Witnessing the Wonder
As the moon rises on the night of August 30, don’t be surprised if it appears larger and brighter than usual. This astronomical convergence, where a blue moon aligns with a supermoon, offers a unique opportunity to observe and appreciate the cosmic wonders that grace our night skies.
So, prepare your telescopes, cameras, or simply your own eyes for a captivating night of lunar brilliance. The “blue supermoon” of 2023 is a reminder of the beauty and complexity of our celestial neighborhood, inviting us to look up in wonder and admiration.