CC Madhya 21.84
ati kṣudra, tāte tomāra cāri vadana
Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura, one of the greatest astrologers of his time, gives information from the Siddhānta-śiromaṇi that this universe measures 18,712,069,200,000,000 × 8 miles. This is the circumference of this universe. According to some, this is only half the circumference.