The subject of speculation for many years, this was the subject of a question by the Kerala High Court in mid-January. The answer was that this was indeed man-made, and following a tradition begun in the past by tribals in the area. However, the people involved also mention the brightness of Sirius on the day. What?
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The Makarajyothi phenomenon. Each year, a bright light is observed on Makaravillaku day on a hill near Sabarimalai, and is the highlight of the Ayyapa pilgrimage season. Popular belief has it that this is a mysterious phenomenon, but in the aftermath of the recent stampede on that day, the HC asked for details on this. The priests involved have conceded that the actual light on the hill is a man-made fire, but claim that the jyothi alludes to Sirius which is brightest that day. See these Hindu articles for more:
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