There is an expression that reads: in this world nothing can be said to be certain, except death and taxes (alleged to have been said by Benjamin Franklin). Leaving aside the notion that taxes are a 1 certainty for another discussion, it is certain that all organic beings — from the most primitive single-celled organisms to complex plants and animals, have ﬁnite lifetimes.
Any being [human] reading this, now and for the inﬁnite future, clearly is alive. All things alive are the byproduct of chemical and electrical interactions between a very, very large number of nonliving atoms! An atom is the smallest unit of matter that retains all of the chemical properties of an element. There are 118 known elements, 92 of which are naturally occurring [the rest are laboratory creations and unstable]. Each element has a unique atomic structure: a one-of-a-kind combination of sub-atomic particles [protons, neutrons, and electrons].
Matter refers to anything that occupies space and has mass, and is made up of one or more elements. “Almost 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. The remaining 0.85% is composed of another ﬁve elements: potassium, sulfur, sodium, chlorine, and magnesium” (wikipedia).
The life expectancy of the human species varies in different parts of the world. In the US, human lifespans have steadily increased — averaging around 80 years today. The US has had human (aboriginal) occupation for some 10,000 years, following the end of the last Ice Age. Since the arrival of a handful of Pilgrims ho came to stay about 400 years ago, its population has now grown to over 3 billion. At the rate of 80 years each, therefore, any one individual is one out of 375 billion discrete lifetimes ever lived in this country. While many people live longer — a rare few to as many as 120 years, the certainty of eventual death for us all is ever present.
The planet Earth is 4.5 billion years old. For the ﬁrst billion years, there were no living organisms. Sexually reproducing organisms appeared about 1 billion years ago; mammals 200 million years ago; the great apes 14 million years ago; and homo sapiens 200 thousand years ago. Currently, there are nearly 9 million species of living things, with the vast majority belonging to the animal kingdom. The remaining kingdoms include plants, fungi, single-celled protozoa, and chromista [algae].
Of all the 5 billion living species that have ever existed, 99% disappeared through mass extinction events. Today, scientists estimate that upwards of 200 species are disappearing every 24 hours.
Where did all these species come from? Six theories focus on events occurring during the earth’s formation. These range from lightening striking water containing methane, ammonia, and hydrogen, and generating the building blocks of life called amino acids and sugars. Other ideas suggest these building blocks were organized in the mineral crystals of naturally occurring clay, or in deep-sea vent sites, or under ice-covered oceans, or through unique molecular formations.
The most interesting theory to me is that life’s building blocks (elements) didn’t originate on Earth at all, but came to the planet from the cosmos. Of course, this begs the question: if there were no elements on earth until their arrival from the cosmos, where did they form? A 1952 article called The Creation of the Universe, by Dr.s Ralph Alpher, George Gamow and Hans Bethe, posited that within three minutes after the Big Bang, the formation of such light elements as hydrogen and helium began — some of which eventually found their way to Earth. This inter stellar transfer is known as panspermia, the hypothesis that life-elements exist throughout the Universe and are distributed by meteoroids, asteroids, comets, and planetoids.
The late Dr. Carl Sagan once said, “The surface of the Earth is the shore of the cosmic ocean. We’re made of star stuff.” More recently, Dr. Jennifer Johnson, at Ohio State University, produced a periodic table of all the elements coded to illustrate one of six cosmic origins: the Big Bang, cosmic rays, merging neutron stars, and three different classes of exploding stars. “So right after the Big Bang — no planets, no life until stars had time to enrich the Universe,” she said.
We know that during the Earth’s formation (eventually ending with an iron core, surrounded by liquid magma, and all contained within a rocky crust), uncounted millions of impacts by interstellar objects took place. It is thought that one such event was so massive as to split off enough solid material from Earth to create what we call our moon. Subsequently, Earth’s crust morphed into massive plates, and through a process called gravitational subduction, produced mountains and realigned whole continents. The phenomenon called plate tectonics continues to this day, evidenced by earthquakes and tsunamis across the globe.
While rarely occurring over the recent past, sizable meteorites continue to occasionally strike the Earth, and uncounted asteroids and planetoids threaten to approach (and perhaps make contact) in the distant future. The presence of cosmic dust particles penetrating our atmosphere, however, is a daily event: as much as 60 tons fall to earth every day. Whatever the source, and no matter whether life did originate elsewhere ﬁrst, everything that is alive on this planet Earth will eventually die. It should be noted that, in the context of geologic time, to be alive on this planet Earth is to be but a momentary visitor. And now comes the question: what happens after the life of a living organism ceases? In physical terms, for a short period — at the time of death, the atoms in the elements making up any individual living organism — a fallen tree, a squashed ant, or a human body in a grave, remain in place. At some point, however, those elements and atoms will be reclaimed and recycled by the natural world. A fallen tree may disappear in the smoke of a forest ﬁre; the ant remains may dry up and be absorbed by rainwater runoff; and the human body will eventually return to dust [within minutes in the case of cremation].
Remembering that atoms and energy cannot be destroyed, and that once on Earth does not leave, it might be best stated this way: “They [atoms] will slowly fall away from each other, disperse and be recycled into the planet. The atoms that make up your body right now have existed for billions of years and have been part of many things. In fact over your lifetime your body has recycled many atoms as you breathed in, ate, cut your hair, trimmed your nails, breathed out, shed skin and gone to the bathroom. When you are through with your atoms they will continue to exist and be part of many more things, living and non living, for billions of more years (John Catallier, former Police Officer, Quora).
If this is so, then any John or Mary that we knew in the 21st Century could have been a cat on the streets of Paris in the 1520’s; or will be a monarch butterﬂy heading south for the winter in the year 2265; or even once have lived as the person we remember as Aristotle, or perhaps Cleopatra.
So far as we know, there is no connection from one such atom formation to another. When any such transformation occurs, over wildly varying time spans, it is a necessary and a good thing. It can be argued, of course, whether this all happens randomly or by design. Perhaps one day, the mystery of reincarnation will be resolved, just as evolution, the generation of atomic energy, and powered ﬂight and space travel once were. Whatever is happening, it can’t be seen. Atoms remain invisible to the human eye.
What we do know is that the atom, itself, consists largely [99%] of open space. We also know that when combined into cells and tissue and organs according to gene-directed DNA, all living things use energy for nutrition, excretion and respiration, grow and develop, reproduce, and adapt to their surroundings. And then die.
The idea of the atom is credited to the Greek Philosopher Democritus, who in 400 BC was the ﬁrst to use the term. Since then, we have learned that particular combinations of atoms can be at once the most peaceful and beautiful thing imaginable. Conversely, we know they retain the power to combine into a form that could destroy every living thing on the planet in an instant.
If there is a moral to this story, it might be this: because alive-time on this planet Earth is but a momentary speck in the grand scheme of things, it behooves us to live every conscious moment to the full. And, when in real-time you or someone you love ceases to exist, know you and they are never literally gone forever.