Blue Supermoon: UK Sky to Host Rare Lunar Phenomenon

The UK has been treated to a weekend of captivating sunsets and sunrises, with the moon appearing an unusual shade of orange. This captivating celestial display has been attributed to smoke from North American wildfires drifting across the Atlantic.

The Met Office explains that these dramatic hues occur when dust and particles become trapped in the atmosphere due to high pressure. This phenomenon scatters blue light, leaving only red light to paint the sky in its distinct colour.

Meanwhile, the moon's orange appearance when low in the sky is a result of its light passing through a denser portion of the Earth's atmosphere, as explained by BBC Sky at Night magazine. During the summer months, the full or nearly full moon remains below the celestial equator, preventing it from rising high enough above the horizon to lose its orange hue.

Adding to this spectacle, Monday night promises the relatively rare occurrence of a blue supermoon, a celestial event where a blue moon coincides with a supermoon.

What is a supermoon?

According to NASA, a supermoon occurs when a full moon aligns with the moon's closest approach to Earth in its elliptical orbit, a point known as perigee. This celestial dance happens around three to four times a year.

At its closest point, the full moon can appear up to 14% larger and 30% brighter than the faintest moon of the year, which occurs when it is furthest from Earth in its orbit. While visually detecting a supermoon can be tricky, its influence on Earth is undeniable. Due to its closer proximity, the moon can cause higher tides than usual.

This supermoon will be visible in the sky for three days, beginning on Monday evening.

What is a blue moon?

The term "blue moon" carries a touch of ambiguity. While we often associate the term with a rare celestial occurrence, there are two distinct definitions:

Firstly, a blue moon occurs when two full moons fall within a single calendar month, a phenomenon that happens every two to three years.

Secondly, a blue moon can also refer to the third full moon in an astronomical season when there are four full moons. These astronomical seasons are marked by equinoxes and solstices.

Monday night's blue supermoon falls under the seasonal definition, with the last blue supermoon under the monthly definition occurring in August of last year.

It's crucial to note that the moon will not actually appear blue. In fact, it will likely appear more red or yellow at dusk as its light refracts through the atmosphere at the horizon.

How rare is a blue supermoon?

While the combination of a full moon, a supermoon, and a blue moon is considered "irregular" by NASA, it's important to acknowledge that the terms "blue moon" and "supermoon" lack scientific precision. As a result, definitions can vary, leading to differing estimations on the timing of the next blue supermoon.

Can you see the blue supermoon in the UK?

The full blue supermoon will reach its peak at 7:25 PM on Monday evening. The moon is expected to rise around 8:50 PM in the eastern sky and set on Tuesday morning at approximately 6:35 AM in the western sky.

However, according to BBC weather presenter Simon King, cloud cover and patchy rain spreading eastward across the UK might pose a challenge for viewing. While there will be opportunities for clear skies at different points throughout the night, viewing conditions may be limited.

Despite the moon not being technically full on Tuesday night, it will remain near-full, offering a second chance for viewing with potentially clearer skies.

So, grab your binoculars, find a spot with minimal light pollution, and hope for a break in the clouds to witness this captivating celestial spectacle.