From saṃyama on the pole star arises knowledge of their movements.

Dhruva is the pole star, the fixed, the immovable. Gati is movement. Tad refers to the stars.

The pole star (Dhruva) is the apparently fixed point around which all other stars revolve. By meditating upon it, one comes to know the movement of the celestial bodies.

Dhruva also has symbolic meaning: it is the point of stability amid change. Everything revolves except the center.

Knowing the movement of the stars implies understanding cosmic cycles, ages, astrological influences.

In the body, dhruva corresponds to the ājñā chakra, the point between the eyebrows, the stable command center.

There is a story in the Purāṇas about a child named Dhruva who, through intense meditation, achieved a permanent place in the sky as the pole star.

The message: what is truly stable is not physical but consciential. The yogī finds their own inner dhruva.