Everywhere within the universe there are unlimited numbers of living entities in 8,400,000 different forms.

Śrī Caitanya Caritāmṛta Madhya 19.138-

"In this universe there are limitless living entities in 8,400,000 species, and all are wandering within this universe.

Purport

This is a challenge to so-called scientists and philosophers who presume that there are living entities on this planet only. So-called scientists are going to the moon, and they say that there is no life there. This does not tally with Śrī Caitanya Mahāprabhu's version. 

He says that everywhere within the universe there are unlimited numbers of living entities in 8,400,000 different forms. 

In the Bhagavad-gītā (2.24) we find that the living entities are sarva-gata, which means that they can go anywhere. 

This indicates that there are living entities everywhere. They exist on land, in water, in air, in fire and in ether. Thus there are living entities in all types of material elements. Since the entire material universe is composed of five elements — earth, water, fire, air and ether — why should there be living entities on one planet and not others? 

Such a foolish version can never be accepted by Vedic students. From the Vedic literatures we understand that there are living entities on each and every planet, regardless of whether the planet is composed of earth, water, fire or air. 

These living entities may not have the same forms that are found on this planet earth, but they have different forms composed of different elements. Even on this earth we can see that the forms of land animals are different from the forms of aquatics. According to the circumstance, living conditions differ, but undoubtedly there are living entities everywhere. 

Why should we deny the existence of living entities on this or that planet? Those who have claimed to have gone to the moon have not gone there, or else with their imperfect vision they cannot actually perceive the particular type of living entities there.

The living entities are described as ananta, or unlimited; nonetheless, they are said to belong to 8,400,000 species. As stated in the Viṣṇu Purāṇa:

jala-jā nava-lakṣāṇi sthāvarā lakṣa-viḿśati

kṛmayo rudra-sańkhyakāḥ pakṣiṇāḿ daśa-lakṣaṇam

triḿśal-lakṣāṇi paśavaḥ catur-lakṣāṇi mānuṣāḥ

"There are 900,000 species living in the water. There are also 2,000,000 nonmoving living entities (sthāvara), such as trees and plants. There are also 1,100,000 species of insects and reptiles, and there are 1,000,000 species of birds. 

As far as quadrupeds are concerned, there are 3,000,000 varieties, and there are 400,000 human species." Some of these species may exist on one planet and not on another, but in any case within all the planets of the universe — and even in the sun — there are living entities. This is the verdict of the Vedic literatures. As the Bhagavad-gītā (2.20) confirms:

na jāyate mriyate vā kadācin

nāyaḿ bhūtvā bhavitā vā na bhūyaḥ

ajo nityaḥ śāśvato 'yaḿ purāṇo

na hanyate hanyamāne śarīre

"For the soul there is neither birth nor death at any time. He has not come into being, does not come into being, and will not come into being. He is unborn, eternal, ever-existing and primeval. He is not slain when the body is slain."

Since the living entities are never annihilated, they simply transmigrate from one life form to another. Thus there is an evolution of forms according to the degree of developed consciousness. One experiences different degrees of consciousness in different forms. A dog's consciousness is different from a man's. 

Even within a species we find that a father's consciousness is different from his son's and that a child's consciousness is different from a youth's. Just as we find different forms, we find different states of consciousness. When we see different states of consciousness, we may take it for granted that the bodies are different. In other words, different types of bodies depend on different states of consciousness. This is also confirmed in the Bhagavad-gītā (8.6):

yaḿ yaḿ vāpi smaran bhāvaḿ tyajanty ante kalevaram

taḿ tam evaiti kaunteya sadā tad bhāva-bhāvitaḥ

"One's consciousness at the time of death determines one's type of body in the next life." 

This is the process of transmigration of the soul. A variety of bodies is already there; we change from one body to another in terms of our consciousness.

"There are 900,000 species living in the water. There are also 2,000,000 nonmoving living entities (sthāvara), such as trees and plants. There are also 1,100,000 species of insects and reptiles, and there are 1,000,000 species of birds. 

As far as quadrupeds are concerned, there are 3,000,000 varieties, and there are 400,000 human species." Some of these species may exist on one planet and not on another, but in any case within all the planets of the universe — and even in the sun — there are living entities. This is the verdict of the Vedic literatures. As the Bhagavad-gītā (2.20) confirms:

na jāyate mriyate vā kadācin

nāyaḿ bhūtvā bhavitā vā na bhūyaḥ

ajo nityaḥ śāśvato 'yaḿ purāṇo

na hanyate hanyamāne śarīre

"For the soul there is neither birth nor death at any time. He has not come into being, does not come into being, and will not come into being. He is unborn, eternal, ever-existing and primeval. He is not slain when the body is slain."

Since the living entities are never annihilated, they simply transmigrate from one life form to another. Thus there is an evolution of forms according to the degree of developed consciousness. 

One experiences different degrees of consciousness in different forms. A dog's consciousness is different from a man's.

From the Vedic literatures we understand that there are living entities on each and every planet, regardless of whether the planet is composed of earth, water, fire or air. 

These living entities may not have the same forms that are found on this planet earth, but they have different forms composed of different elements. Even on this earth we can see that the forms of land animals are different from the forms of aquatics. 

According to the circumstance, living conditions differ, but undoubtedly there are living entities everywhere (Sarva-gatah)