Super Blue Moon  

01 Sep 2023 Super Blue Moon  

This article covers “Daily Current Affairs” and the topic details “Super Blue Moon”. The topic “Super Blue Moon” has relevance in the “Geography” section of the UPSC CSE exam.

For Prelims:

What is the Super Blue Moon ?
What is apogee and perigee? 

For Mains:

GS1:  Geography

Why in the news?

The full moon during Raksha Bandhan on August 30-31 is attracting attention for its uniqueness as it will be both a “blue moon” and a “super moon.” 

What is a Supermoon? 

• The moon’s orbit around the Earth is not a perfect circle but an elongated or elliptical shape. 
  • It takes the moon 27.3 days to complete one orbit around the Earth, but 29.5 days from one new moon to the next. 
  • This slight difference arises because both the Earth and the moon are in motion around the sun. 
  • Consequently, it takes extra time for the sun to illuminate the moon the same way it does at the start of every Earth orbit. 
  • A full moon occurs when the moon is directly opposite the sun from Earth’s perspective, resulting in the entire illuminated side facing Earth. 
• A super moon happens when the moon is passing through or is close to its perigee, the point closest to Earth in its elliptical orbit, and it’s also a full moon. While this also happens with new moons, they remain invisible. 
• A full moon at perigee, or a super moon, appears approximately 14% larger and 30% brighter than a full moon at apogee, known as a “micro moon,” according to NASA.

Additional Information: 

• Perigee is used to describe the point in an object’s orbit around a celestial body, such as a planet or a moon, where it is closest to that body. 
  • In simpler terms, it is the lowest point or the closest distance an object reaches in its orbit to the celestial body it is orbiting.
• Apogee is used to describe the point in an object’s orbit around a celestial body, such as a planet or a moon, where it is farthest from that body. 
  • In simpler terms, it is the highest point or the greatest distance an object reaches in its orbit away from the celestial body it is circling.

What is a Blue Moon? 

• A blue moon is a term used when two full moons occur in a single calendar month. 
  • Since the time between new moons is about 29.5 days, there are occasions when the first full moon of a month happens at the beginning, leaving days for another full cycle to be completed in the same month. 
• Consequently, a month featuring a full moon on the 1st or 2nd day will also have a second full moon on the 30th or 31st. NASA notes that this phenomenon occurs every two or three years. 
• Importantly, the term “Blue Moon” has no relation to the moon’s actual colour, as the moon can appear differently hued due to atmospheric conditions. 

How Rare is a Blue Supermoon? 

• According to NASA, blue supermoons are exceedingly rare events. They typically occur only once every ten years due to specific astronomical conditions. 
• On occasion, the gap between blue supermoons can extend to as long as twenty years. The next pair of super blue moons is expected in 2037, appearing in January and March.

Sources:
In pictures | Rare blue supermoon dazzles stargazers around the globe – The Hindu 

Yojna daily current affairs eng med 1st Sep 2023

Q1. With reference to Supermoon, consider the following statements: 

1. A super moon happens when the moon is passing through or is close to its apogee. 
2. According to NASA, a full moon at perigee is known as a micro moon.
3. The term “Blue Moon” is related to the actual colour of the moon, as atmospheric conditions can cause the moon to exhibit a blue colour.

Which of the statements given above is/are correct?

(a) 1 and 2 only

(b) 2 and 3 only

(c) 3 only 

(d) None 

Answer: (d) 

Q2. Consider the following: 

1. Perigee is the point in an object’s orbit where it is at its closest distance to the celestial body it is orbiting.
2. The apogee is the point where it reaches its greatest distance away from that celestial body.
3. A full moon at perigee appears approximately 14% larger and 30% brighter than a full moon at apogee.

How many of the abovementioned statements are correct ?

(a) Only one 

(b) Only two 

(c) All three 

(d) None 

Answer: (c)

Q3. Discuss the scientific phenomena behind a Super Blue Moon and its occurrence. How does it differ from a regular full moon?

Gaurav N