Source: here.
Upon the great snake shesha sleeps the great god viShNu, even as the the kalpa wears out. He stirs only when the waters rise and threaten to sink the world plane. This shesha is time and hence he is called ananta. Thus, when viShNu sleeps on the coils of the great world snake he is experiencing the cyclic passage of time.
Once the great god vAyu and the world snake ananta had a contest of strength. shesha wound around the mount meru around which the world revolves and vAyu was supposed to dislodge the snake from the great mountain. The efforts of mAtarishvan to dislodge the great snake proved futile for a long time eventhough the world shook with his terrible gusts. Then in fury he uprooted the mount meru snake and all and hurled the mountain with great ferocity. Under the impact of vAyu’s blow, meru shattered and ananta lost his grip and surrendered. With meru shattered the world shook and had no axis. The deva viShNu then stabilized the shattered meru it with his foot.
Versions of this tale are persistantly narrated in the local puraNas associated with viShNu shrines and also the garuDa purANa. This is remarkable example of the fact of precession being preserved in the language of myth. viShNu is a predominantly precessional deity. All his five early incarnations contain the precessional motifs that were uncovered by Santillana and von Dechend in The Hamlet’s Mill.
1) matsya. The deluge represents the sinking of the old equinoctical constellations below the equatorial plane- that is sinking of the world plane below water. It is revived by the viShNu as the fish which provides the new world axis in the form of its immense horn.
2) kurma. The meru is used as a churning rod by the devas and the asuras and the same snake ananta or vAsuki as the churning rope. The rod meru, is the classic world axis of Hindu myth and the snake is the cyclic time. The great rod slips, much to the consternation of the devas, when viShNu assuming the form of a turtle stabilizes the meru mountain and allows the cosmic churn to continue. This again represents the slipping of the axis by precession.
3) varAha. The world plane sinks again below water (that is the equinoctical plane sinking due to precession) and is restored by viShNu as varAha. The boar brings back a new equinoctical plane.
4) nR^isiMha. The world axis is called the skambha, as praised in the great hymn of the atharvans. nR^isiMha emerges from the shattered pillar at the end of the kalpa. It occurs at the twilight zone (neither day nor night) between the inner and outer zones of the palace of hiraNyakashipu (neither in nor out). This again represents the loss of the world axis (the pillar) and the transitional zone between two equinoctical constellation during precession.
5) vAmana. Here viShNu with the 3 steps secures the 3 scaffolds with which the ancients concieved the world axis: 1) the zenith segment 2) the nadir segment and 3) the zone formed by the tilt in the axis- the celestial tropics.
Thus, the snake shesha coiled around meru represents the path of cyclic time around the around the world axis, and the shaking of the axis by vAyu the precessional shifts of the axis. Likewise the Hindu mythic image of vAsuki supporting the earth is a symbolic representation of the cyclic time around the world axis.
The language of myth has indeed preserved one of the most primal astronomical discoveries of the ancient humans and Hindus verily retain the most vivid memories of it. It is, hence, not surprising that the Vedic astronomers were able to carry out successful calendrical reform stretching from punarvasu in the hazy past to bharaNi-ashvayuja in the late vedic period. In face of this it is certain that those Indologists who doubt the antiquity of the Vedic texts are afflicted by an incurable mental ailment.