when the Sun changes the apparent direction of travel in the sky, caused by the precession of the equinox.

January 14th is the usual date for the Sankranti and it is believed that a bath in a river or the sea is very purifying on that day. Ganga Sagar, the place where the river Ganges (Ganga) meets the Sagar, Bay of Bengal is especially popular since it is believed that the place became holy because of the penance performed by sage Kapila there and because the sons of Sagara got sadgati (went to heaven) after Ganga flowed over their ashes. Let us learn more about sage Kapila this month.
King Sagara, an ancestor of Rama, had performed the Aswamedha yagna (Horse-sacrifice) ninety-nine times. When the horse was sent around the earth the hundredth time, Indra, the King of Heaven, grew jealous and kidnapped the horse, hiding it in the hermitage of Kapila. Sagara's sons, numbering 60000 dug out all the quarters of earth and when they entered northeast to find the horse thief, they found Sage Kapila, i.e., Vishnu in the semblance of a sage. When they tried to attack sage Kapila believing him to be the thief, he burnt them to heaps of ashes by his yogic powers. Anshuman, a grandson of King Sagara, came to sage Kapila begging him to redeem the souls of Sagara's 60,000 sons. Kapila replied that only if the Ganges descended from heaven and touched the ashes of the 60,000 would they be redeemed. Ganges was eventually brought to earth, , through the tapasya of King Bhagiratha, son of Dilipa, and grandson of Anshuman thereby redeeming the 60,000 sons of Sagara.

Kapila is the son of Kardama Prajapati and Devahuti. Many of the details about sage Kapila's life are described in Book 3 of the Bhagavata Purana, where it is mentioned that his parents are Kardama Muni (Kardama Prajapati)and Devahuti. After his father left home, Kapila instructed his mother, Devahuti in the philosophy of yoga and devotional worship of Lord Vishnu, enabling her to achieve liberation (moksha). Kapila's Sankhya is also given by Krishna to Uddhava in Book 11 of the Bhagavata Purana, a passage also known as the "Uddhava Gita". Kapila is considered as one of the minor incarnations of Lord Vishnu. In Sri Suktam, we get a passage, “Kardamena Praja bhuta mayi sambhava Kardama Sriyam Vaasaya me kule Mataram Padmamalineem…”
Kapila said, "Acts (Karma) only cleanse the body. Knowledge, however, is the highest end (for which one strives). When all faults of the heart are cured (by acts), and when the felicity of Brahma becomes established in knowledge, benevolence, forgiveness, tranquility, compassion, truthfulness and candor, abstention from injury, absence of pride, modesty, renunciation, and abstention from work are attained.
Kapila is also mentioned by Krishna in the Bhagavad Gita:
Of all trees I am the banyan tree, and of the sages among the demigods I am Narada. Of the Gandharvas I am Chitraratha, and among perfected beings I am the sage Kapila.(10.26)
Kapila comes in the 16 names of Ganesha (Kapilo Gajakarnakah…). Kapila Govu (Dark tanned cow) is considered very auspicious.
Thus even if we can’t go to Ganga Sagar (there was a big stampede in the recent mela resulting in a few deaths and injuries), remembering sage Kapila is purifying.