So when we speak, as Kṛṣṇa is saying, that imaṁ vivasvate yogaṁ proktavān aham avyayam (BG 4.1), that means this Bhagavad-gītā was spoken long, long before. It is not that Arjuna is the first man who heard Bhagavad-gītā from Kṛṣṇa. Kṛṣṇa said that "This yoga system I spoke to Vivasvān, sun-god." And vivasvān manave prāha. "And the sun-god explained this science to his son, Manu." Manu is the forefather of the mankind. In Sanskrit, from Manu, it has come manuṣya or mānava. Mānava-jāti, in Sanskrit. So Manu from "man." And similarly, in English also, from Manu the mankind or the man. The original word is Manu. Here it is said that vivasvān manave prāha. Formerly, there were transportation service from one planet to another. That transportation service is still existing, but not with this planet. But higher planetary system there is transportation service from one planet to another by different kinds of airplanes. And in the Siddhaloka... There is another planet, which is called Siddhaloka. In the Siddhaloka the living entities or human beings are so advanced in yogic practice that they can travel with this body from one planet to another. This description are there in the Śrīmad-Bhāgavatam, Second Canto. And in this planet also there are many yogis even still existing, they can travel in this planet very swiftly by yogic power. There are many yogis who daily take bath in four places: in Prayāga, in Rāmeśvaram, in Jagannātha Purī, and in Hardwar. Still there are some yogis in India. So they can transfer themselves, transport themselves, from one place to another very quickly. So there was no difficulty in communicating with Manu or Manu's son, Ikṣvāku. The communication was there, or the radio system was so nice that communication could be transferred from one planet to another.
So here it is said that vivasvān manave prāha manur ikṣvākave 'bravīt. First of all, this was spoken to sun-god Vivasvān, and Vivasvān spoke to his son Manu, and Manu spoke to his son Ikṣvāku. This Mahārāja Ikṣvāku happened to be an ancient emperor on this planet, and in his dynasty Lord Rāmacandra appeared, Mahārāja Ikṣvāku. He is kṣatriya. These are all kṣatriya. Sūrya, Vivasvān is also kṣatriya. There are two kṣatriya families, one from the sun and one from the moon, candra-vaṁśa and sūrya-vaṁśa. They're existing. And the Indo-European stock, they are also coming from the kṣatriyas. From the history of Mahābhārata, we can understand the Aryan families who migrated to Europe, they also belonged to this sūrya-vaṁśa or candra-vaṁśa. Anyway, that is another department of knowledge.