A rare blue moon will appear on Halloween night.

2020 may not have been the ideal year for travel and fun, but it was a year with many amazing astronomical events. These included the blood moon in April and major meteor showers in July and August.

And on this list, astronomy enthusiasts will be even more eagerly anticipating the blue moon phenomenon, as it is even rarer since it occurs on Halloween night.

Contrary to popular belief, a blue moon isn't actually a phenomenon where the moon is blue; it's the name given to the second full moon in a month. Normally, the moon is only full on the 15th day of the lunar month, but if it's full a second time, it's called a blue moon. Blue moons usually recur every 2-3 years due to the difference in the lunar and solar calendar cycles. However, in 2020, the blue moon appeared on Halloween night, making the event even more special. This was also the first time a blue moon appeared on Halloween night worldwide since 1944.

Of course, there are instances where the moon actually turns blue due to weather conditions or natural influences. For example, volcanic eruptions can cause the moon to shift to a pale blue hue.

According to meteorologist Brian Lada, if people miss this year's blue moon, they will have to wait until 2039 to witness a similar phenomenon on Halloween. Therefore, astronomy enthusiasts should carefully note the calendar to be able to admire this event.

If you can't go out on Halloween night, staying home and admiring the super rare blue moon is also very interesting. In Vietnam, if the weather is clear, you can also observe the blue moon with the naked eye. If you are a fan or simply curious about astronomical events, don't miss this year's blue moon!

Huong Thao