Just like we are studying the outer space, so many scientists are studying. But still they cannot give any perfect information of all the planets. Although we see, actually, we are seeing daily. Take for example the sun planet. We see every morning the sun is there. But actually we do not know what is the sun planet. There are, may be so many theories, but actually, we do not know what is the sun planet. But we can understand from the Vedic literature. The sun planet is as good as this planet. There are also cities, towns, houses, and population, and it is very big. This information we get from the Vedic knowledge. Just like in the Bhagavad-gītā it is said, Kṛṣṇa says that, imaṁ vivasvate yogaṁ proktavān aham avyayam (BG 4.1). "This knowledge of Bhagavad-gītā, I spoke first to the sun-god. His name is Vivasvān." Vivasvān manave prāha. "And that Vivasvān explained this knowledge to his son Manu." Manur ikṣvākave 'bravīt. "And Manu also explained the same knowledge to his son, Mahārāja Ikṣvāku, King Ikṣvāku." He's the forefather of the kṣatriya dynasty in which Lord Rāmacandra appeared. So we get this knowledge from the Vedas, perfectly.
There are so many things, just like the forms of life, how many form of life are there. That is stated in the Vedic knowledge. 8,400.000 species. Jalajā nava-lakṣāni. In the water, there are 900,000 forms of life. It does not say one million or eleven hundred or, no, exactly. Nine hundred. Jalajā nava-lakṣāni sthāvarā lakṣa-viṁśati. Sthāvarā means the living entities which cannot move. Just like the trees, plants, they are also living entities, but they cannot move. They are called sthāvarā. Two millions. Now where is the botanist who can give exact information how many plants and trees are there? But you get fully, full information. Sthāvarā lakṣa-viṁśati kṛmayo rudra-saṅkhyakāḥ. This is the evolutionary process, from aquatics to the plant life, then insect life, kṛmayo. Rudra-saṅkhyakāḥ. Rudra-saṅkhyakāḥ means eleven hundred thousand. Pakṣiṇāṁ daśa-lakṣaṇam. The birds, after insects, the next evolution is to the bird species. So there are one million different species of birds. Pakśiṇāṁ daśa-lakṣaṇam. Paśavaḥ triṁśal-lakṣāni. Then beast, four-legged beast, animals. There are three millions. And mānuṣāḥ catur-lakṣāṇi. And then we come to the form of the human being; there are also four hundred thousand species. In this way, altogether there are 8,400,000 species, forms of life.