By making Samyama on the sun, (comes) the knowledge of the world.
Verse 3.27
भुवज्ञानं सूर्येसंयमात् ॥२७॥
bhuva-jñānaṁ sūrye-saṁyamāt ॥27॥
By making Samyama on the sun, (comes) the knowledge of the world.
Verse 3.28
चन्द्रे तारव्यूहज्ञानम् ॥२८॥
candre tāravyūha-jñānam ॥28॥
On the moon, (comes) the knowledge of the cluster of stars.
Verse 3.29
ध्रवु तद्गणतऻानभ े ॥२९ ् ॥
dhruve tadgatijnanam
On the pole star (comes) the knowledge of the motions of the stars.
Surya, sun is pratyaksha Parabrahmam, physical manifestation of brahman, so making samyama on the sun, knows the knowledge about the world because when brahman is known, everything ( including knowledge of the world) also known.
In the last sutra,
the Sun, surya, refers to the core of one's being self, brahman.
The moon, chandra, refers to the mind.
The solar plexus ( pingala nadi) is situated in the region of the trunk;
the lunar plexus ( Ida nadi) has its seat in the cerebrum.
By samyama on that region, the yogi gains further knowledge.
The mind is equated with the moon which cools the solar system; the lunar plexus, Ida nadi maintains a steady, constant temperature in the body even
though the seasonal temperature varies. It also controls and directs the parasympathetic system and regulates the functioning of the central nervous system.
The galaxies of stars stand for galaxies of thought-waves which, like stars, twinkle, disappear, reappear and shine forth once again.
By samyama on the Pole Star (dhruva nakshatra) , a yogi knows the movements of stars and their effect on the events of the world.
Dhruva also stands for (ajna chakra) as well as the tip of the nose (nasagra). The yogi will know beforehand his own destiny as well as that of others.
King Uttanapada had two wives, Suntti and Suruchi. Though Suntti was the queen, the king was very fond of his second wife Suruchi. Each of them had a son. The elder one was Dhruva and the younger one was Uttama. One day Prince Uttama was playing sitting on his father's lap.
Dhruva too came to sit on his father's lap; but Suruchi, the mother of Uttama pulled him away, scolding him that he had to do tapas to take birth in her in order to have the privilege.
Dhruva went to his own mother, narrated the incident and begged her to permit him to go to the forest to do tapas and to gain the kingdom. It so happened that the saptarishis, the seven stars of the constellation ,Ursa Major, gave him a mantra and with that mantra, he steadfastly prayed to Lord Vishnu to bless him with the kingdom.
Lord Vishnu was pleased by his steadfast tapas at such a youthful age; He granted his wish and named a star after him, Dhruva Nakshatra, known to all of us as the Pole Star.
PATANJALI YOGA SUTRAS