Theory:

The lesson "The comet II" is a continuation of "The comet I" written by Jayant Narlikar. The story of comet II focuses on Duttada's superstitious family and the precautions taken by global conference participants to avert the predicted destruction of the Earth due to Comet Dutta's impact.
 
After conversing with Mr. James Forsyth about stopping Comet Dutta from colliding with the Earth, Mr. John Macpherson, Defence Science Advisor, had scheduled a world conference. At that conference, scientists and experts worldwide, including Manoj Dutta (the discoverer of Comet Dutta), confirmed James' prediction regarding Comet Duttada's effects on Earth. When they (conference members) confirmed James' prediction, they discussed and suggested a solution to the Comet Dutta problem; that is, the conference had agreed to take a deflective measure against Comet Dutta.
 
The conference attendees proposed sending a spacecraft with a nuclear payload to encounter Comet Dutta and then remotely exploding the spacecraft at the precise moment they (Comet Dutta and the spacecraft) meet. The operation against Comet Dutta was called the 'Project Light Brigade'. It was set to begin on October 9th to deflect Comet Dutta and prevent it from attacking the Earth on December 15th. The specifics of the conference were determined to be kept secret.
 
During that period, Duttada and Sir John became good friends, and Sir John told Duttada that he would buy Christmas gifts only after December 15th, as it was the day Comet Dutta was predicted to collide with the Earth and he was not sure of the Light Brigade's success.
 
After a three-week stay in London, Duttada returned to Kolkata to find his family members planning a yajna to pacify Comet Dutta. Duttada's family believed that conducting such a yajna would calm down the comet and protect the Earth from its harmful effects. Duttada was furious with his family and refused to do yajna. His thoughts were entirely focused on the Project Light Brigade's outcomes. Playing with his grandson, Khoka, was his only form of relief.
 
Since his return from London, Duttada has been in contact with Sir John regularly. In the middle of October, he received a reply from Sir John stating that he felt confident in purchasing his Christmas gifts, indicating the Project Light Brigade's success.
 
And, as predicted, Comet Dutta passed close to the Earth on December 15th, but it went away without striking. Indrani Debi told Duttada that Comet Dutta had passed by without causing any harm to the Earth because of the yajna they had done. The story concludes with Duttada's perplexity over the wide gap between superstition and science.