From saṃyama on the sun arises knowledge of the worlds.

Bhuvana is world, plane of existence. Sūrya is the sun. Jñāna is knowledge.

The sun represents the principle of illumination and the center of the system. By meditating deeply upon it, the yogī comes to know the structure of the cosmos.

Yogic cosmology describes multiple lokas or planes: from the lower ones (pātāla) to the celestial (svarga, mahar, etc.).

The physical sun is also a symbol of the inner sun, the center of consciousness. Saṃyama upon it reveals geography both external and internal.

Some practice it by visualizing the sun in different parts of the body, particularly in the solar plexus (which bears that name for a reason).

Knowledge of the worlds includes not only their existence but their characteristics, their inhabitants, their laws.

It is a siddhi of expansion: consciousness, centered on a luminous point, expands to encompass all of creation.