jyotisam-in all luminous objects; api-also; tat-that; jyotih-source of light; tamasah-of the darkness; param-beyond; ucyate-is said; jnanam-knowledge; jneyam-to be known; jnana-gamyam-to be approached by knowledge; hrdi-in the heart; sarvasya-of everyone; visthitam-situated.