https://cdn.steemitimages.com/DQmf3QKmvQG9CtXP9daUgMj3u2Scwcg9bosZEngjjGQV3AY/astronaut-1784245_1280.jpg

Many years ago, **_man_** that existed, let's say somewhere around the equator felt there were no beings existing aside himself and his fellow, in fact he probably believed the horizon he saw from his small settlement was the edge of the world. Then he found with time, there were also humans - of probably same or different color and cultural norms - living around the poles maybe, when he made bold to travel beyond that _"horizon"_; it wasn't the _edge_ after all. Some elites and scholars of different civilizations in the earth's history, had propounded **the flat earth concept** which was accepted by the people, until the emergence of **the spherical earth concept**. Though debates about the earth's shape still remain, _the early belief in a flat earth was relegated by the spherical earth concept which, was first proven by the voyage of Ferdinand Magellan and Juan Sebastián; **_The Circumnavigation_**(1519 - 1522)._

https://cdn.steemitimages.com/DQmPNNDEPyeAf55m7EBS7BdntytEfrcHjj9EDRNjsWCTUfF/solar-system-11111_640.jpg

Man out of his full blown sense of predominance, at one time believed his earth to be the center of the universe and, himself its foreman. Soon came Copernicus and the Copernican revolution with the concept of a solar system, then the theories of planetary formation, the space telescopes, the vostok 1 space mission and a series of other successful space missions. >The USSR launched the first human in space, Yuri Gagarin, into a single orbit in Vostok 1 on a Vostok 3KA rocket, on 12 April 1961. The US launched its first astronaut, Alan Shepard, on a suborbital flight aboard Freedom 7 on a Mercury-Redstone rocket, on 5 May 1961. [Wikipedia](https://en.m.wikipedia.org/wiki/Human_spaceflight) Years after embracing the existence of a solar system, planetary bodies other than our own and, other galaxies light years away from ours, we still wonder if, there are other life forms aside the ones we know. _So we make up fictitious green extraterrestrial beings, that shape-shift or wear human skins in movies._

Does Life Exist Outside The Earth?

>Home to millions of species including humans, Earth is the only place in the universe known to harbor life.

https://cdn.steemitimages.com/DQmVTQfi3tidRDajtBK93An2W9i4ABYwtomn1LmMui1C2Sg/germ-59159_640.jpg

This statement was excerpted from a good article captioned [Earth](https://www.sciencedaily.com/terms/earth.htm). The statement is undeniably right, but I'd like to make a little change to it, which I believe, with a closer look, will make it undeniably true. >Home to millions of species including humans, Earth is the only place in the universe known to harbor life as you know it. _What do you think? Alright, hold that thought for a while as we move on._

Let's look at the living system and its preservation.

A good argument would be; >the earth is made inhabitable by the gases in it's atmosphere and living organisms are sustained by its resources and nutrients... >most planetary bodies that we know of, have gases we consider toxic in their atmosphere and, are exposed to high degrees of heat and radiation due to there closeness to the sun... _**If these two premises be true, then what are the possibilities of existence of other life forms in these planets?**_

https://cdn.steemitimages.com/DQmUaTHvJ2kacHwXm2iCGHhbXhYaqacogcz4wVxbo1dooHT/mars-2051748_640.png

Biologically, the systemic and anatomical development of a primal organism would greatly depend on its environment. The organism develops in such a way that it is best adapted to its environment. Let's look at it from a picturesque point of view for a while; the ability of oxygen to act as a biological fuel does not depend on it's property alone but also on the nature of the system utilizing it, which means oxygen would only be relevant for cellular oxidation in aerobic systems. The same way some automobile engines are designed to run on gasoline and others on diesel. _That being said, is there a law that states that methane gas can not be a biological fuel in a living system developed for it?_ Life as we know it might, actually be more vast than being human, beyond carbon, nitrogen, hydrogen and oxygen compositions, DNA, or even cell... _The cell as we know it, may be the basic funtional and structural unit of life in earth biology._ **_Thanks for stopping by today; hope it was a good read?_** **_Please be sure to visit again for the second part of this content and make sure to drop your comments._** **_Aloha!!_**

REFERENCES

[Spherical Earth](https://en.m.wikipedia.org/wiki/Spherical_Earth) Retrieved on 17th August, 2019. [History of Solar System Formation and Evolution Hypotheses](https://en.m.wikipedia.org/wiki/History_of_Solar_System_formation_and_evolution_hypotheses) from Wikipedia.org [Human Spaceflight](https://en.m.wikipedia.org/wiki/Human_spaceflight) [Earth](https://www.sciencedaily.com/terms/earth.htm) from sciencedaily.com **Images Sources** _Images are from pixabay all licensed under creative commons and eligible for commercial use_