Yōga Sūtra 3.27

भुवनज्ञानं सूर्ये संयमात्।

bhuvanajñānaṁ sūryē saṁyamāt।

[भुवन ज्ञानं सूर्ये संयमात्।
bhuvana = world; jñānaṁ = knowledge; sūryē = the sun; saṁyamāt = by samyama;]

By practicing samyama on the Sun, one gains the knowledge of the world.