Look up this week! How and when to see 2023’s only Blue Moon as it rises in the night sky
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- The August Blue Moon will shine brightly at 02:35 BST on August 31
- Despite its name, the moon will not turn blue and will retain its usual gray hue
Skies around the world are lit up this week by a ‘Blue Moon’ in a spectacle that marks the end of August.
Stargazers are in for a treat when the third supermoon of the year rises on the eve of Aug. 30 at 9:36 p.m. EDT and at 2:35 a.m. BST (in the early hours of Aug. 31).
Despite its name, the moon will retain its usual shade of gray during the event, but may appear up to 14 percent larger and 30 percent brighter than usual.
Instead, the “blue” actually refers to it being the second Full Moon of the month, following the “Sturgeon Moon” that rose on August 1.
“Supermoons are often given names that are usually of regional or historical significance – a Supermoon is August and apparently a Sturgeon Supermoon,” explains Professor Don Pollacco from the University of Warwick.
The third Supermoon of the year will rise on the eve of August 30 at 9:36 PM EDT and at 2:35 AM BST (beginning of August 31)
‘Since the Moon’s orbital period around the Earth is 29.5 days, two Full Moons are possible in a normal month.
Since this Full Moon first occurred early in August, a second Full Moon may occur later on the same moon. This is called a Blue Moon and gives rise to the expression we use to express the rarity of events.’
A Supermoon occurs when a Full Moon nearly coincides with its perigee — the point in the Moon’s orbit at which it is closest to Earth.
“Supermoon is a popular term that indicates that a Full Moon or a New Moon occurs when our satellite is close to its perigee, ie its minimum distance from Earth,” explains astrophysicist Giana Masi.
“The term itself has no scientific value: astronomers prefer to call it perigee full moon, but ‘Supermoon’ is undoubtedly a much more charming name.”
According to NASA, there are two types of “Blue Moon” in the world of astronomy, including a calendar blue moon and a seasonal blue moon.
The latter describes the third Full Moon of four in one astronomical season, meaning that a calendar year has 13 Full Moons instead of the usual 12.
But Wednesday’s event actually falls into the “calendar” category because it’s August’s second Full Moon, following the August 1 sturgeon moon.
In general, these take place every two to three years, with the last one taking place in August 2021.
While the color won’t change this time around, many say the moon looked blue for months after Indonesia’s powerful volcanic eruption of Krakatoa in 1883.
The ash from the explosion rose as high as 50 miles (80 km) into the Earth’s atmosphere, scattering the particles blue light and making the moon appear blue as well.
A supermoon forms when a full moon nearly coincides with its perigee — the point in the moon’s orbit at which it is closest to Earth
In general, a Blue Moon occurs every two to three years, with the last occurring in August 2021
To get a good view of the moon on Wednesday, experts advise avoiding towns and cities and go to areas with clear skies.
Turning off the lights in your home can also improve visibility, although your chances depend largely on the weather and even pollution.
Professor Don Pollacco added: ‘To see the Full Moon you have to look east after sunset. If you have a clear horizon, it should be clear.
“The moon is so bright that we can see it when it’s not particularly dark or even when the weather isn’t particularly bright.
“It will be visible all night and set in the West about sunrise.”