August 2024 Blue Supermoon: When will it be seen and why is this astronomical event called that?

The blue supermoon will appear slightly larger and brighter, but not necessarily blue. (Unsplash)

An unusual astronomical event lights up the cold night, characteristic of the month of August in Peru and other countries in the southern hemisphere. It is the blue supermoon, a name that refers to the increase in size and brightness of the full moon, and a rarity that goes beyond the apparent color of the natural satellite.

The blue supermoon is visible on the night of August 19, 2024. After sunset, starting at 6:30 p.m., the star emerged in the eastern part of the sky, the side opposite the horizon where the sun sets. As the hours pass, the moon rises in the sky.

Although this is the main date of the astronomical event, it should be noted that the satellite will have the appearance of a full moon until the following night.

Astronomer Gianluca Masi broadcast live the observation of the blue supermoon from Rome, Italy, starting at 4:30 pm (Peruvian time).

For a supermoon to occur, the Moon must be in its full moon phase, which occurs when it is located behind the Earth with respect to the Sun, so that it reflects the light of the star towards our planet. In addition, the satellite must be at least 90% of its perigee, which is the point in its orbit closest to Earth.

This coincidence makes it appear 7% larger and 15% brighter than an average full moon.

The term ‘blue moon’, on the other hand, does not refer to its physical appearance. The term came into use at the beginning of the 20th century: it was used to refer to the third full moon in a season of four full moons.

A season (summer, autumn, winter or spring) lasts three months, while lunar phases repeat every 29.5 days, so there are usually only three full moons per season. However, winter 2024 has four full moons: July 21, June 21, August 19 and September 17.

For these reasons, the full moon on August 19 is a super blue moon.

The second full moon in a month is also known as a blue moon, an equally rare event. Both types of blue moon occur approximately every two and a half years.

Full moon. (AP)

The reason these rare full moons were named this way is unclear, though NASA says it “may be a comparison to rare events such as when dust in the atmosphere makes the moon appear really blue.” That’s because these particles filter out longer wavelengths of light, such as red and yellow, while allowing blue to pass through to our eyes.

“During the two years following the eruption of the Krakatoa volcano in Indonesia in 1883, people around the world reported seeing strangely colored sunsets and a Moon that appeared blue,” notes the Encyclopedia Britannica.

Regardless of astronomical coincidences, the August full moon is always called the ‘sturgeon moon’, a name given by North American tribes because at this time of year (summer in the northern hemisphere), a greater number of sturgeon fish were observed in the lakes.

Unlike blue moons, supermoons occur more frequently. In 2024 alone, we will have four of them on the following dates:

• August 19 – Super Blue Sturgeon Moon.
• September 17 – Super Corn Moon.
• October 17 – Super Hunter’s Moon (the biggest and brightest full moon of 2024).
• November 15 – Super Beaver Moon.