I like to imagine that time when there was nothing alive on this planet. The whole earth was a place where the only interactions were between rocks and wind, water and shores. The only chemistry present was in its simple form with electrons moving from atom to atom or being shared. The energy in matter had not yet pushed for anything I now call organic.
Forces and particles from distance galaxies buffeted the stuff of this small blue planet. Chunks from other worlds sometimes rained down from the sky. Perhaps there was some level of awareness in this young world, a kind of intelligence. But there was more to come.
If I could go to this ancient, lifeless place, if I could go back 4 billion years, I would be entering a sterile environment. There would be a total absence of life as I an encased in it now. Every thing I would touch, every breath I took (if I could breathe) would leave a living signature behind. I would be trailing a cascade of life in an otherwise lifeless world.
Cells from my body, organisms that live in and on me would be invaders in this world previously untouched by life. A living cloud of thousands of kinds of organisms would travel around with me and descend on everything in my wake.
Of course, I could not survive in this setting without the presence of the oxygen made so abundantly by plants. I could not continue to live, nor could the organisms that accompany me live, without nourishment from our fellow creatures. We have all evolved together and rely on one another to stay alive.
We have come jointly from the same lifeless past. Where once there was nothing at all alive, I now cannot move without bumping into my fellow creatures. Every where inside me and around me, I am immersed in and flooded with living creatures. My world is wholly alive.