TORONTO – Trick-or-treaters around the world will receive more than just candy this Halloween, as a rare blue moon should light up the sky on Saturday night.
The show takes place when two full moons coincide in the same calendar month, and this year will be visible in all time zones.
WHY IS IT CALLED BLUE MOON?
Despite the name, the color of the moon is not really blue. Instead, a blue moon is a common way of referring to the second full moon in October, since the first is usually called a full moon.
However, there is also an alternative definition of a blue moon that says it is the third full moon of four occurring in a single season, according to NASA.
HOW RARE IS A BLUE MOON?
Contrary to what is said, blue moons are not so unusual, as they occur every 2.5 years in different time zones.
What makes this blue moon so rare is that it will be seen in all time zones. The last time this happened was in 1944, according to Farmer’s Almanac.
Also, it’s happening on Halloween, making the phenomenon even more rare.
On average, blue moons appear on Halloween once every 19 years and are visible only to those who live in certain time zones. The last full moon that appeared on Halloween was on October 31, 2001 and was only seen by people in the central and Pacific time zones.
“Whenever the moon is technically full on October 31, it will also have to be a blue moon because the lunar cycle lasts only 29.5 days,” says the Farmer’s Almanac website.
People living east of the international date line will see this full moon on November 1st and will have a blue moon at the end of November as it will be their second full moon in the lunar cycle.
The blue moons are a direct result of the lunar cycle. Since the cycle is shorter than most months on the calendar – lasting only 29.5 days – the blue moons are likely to occur in October.
The next blue moon is expected to fall on Halloween in 2039.