Cosmic Atom Permanence Contrasts with Biological Self's Finitude

A fundamental contrast emerges when examining the constituent atoms of the human body against the expanse of cosmic time: nearly every atom comprising a person originated approximately 13.8 billion years ago and is projected to endure long after the human species concludes. The universe functions as a forge for nearly indestructible atomic matter, adhering to the conservation principle that matter is neither created nor annihilated. For instance, the hydrogen atoms circulating within an individual's bloodstream are expected to remain hydrogen across timescales that vastly exceed the lifespan of Earth.

This geological and cosmological permanence of matter stands in sharp relief against the ephemeral nature of biological life. Scientific consensus maintains that life is defined not by the enduring material itself, but by the specific, improbable organization of that matter. Living entities maintain themselves through a highly ordered arrangement of atoms, which manifests as self-replicating molecular machinery, active metabolic processes, and intricate repair systems. This delicate architecture necessitates a continuous input of free energy to counteract the universe's inherent tendency toward increasing disorder, known as entropy, a concept physicist Erwin Schrödinger later clarified as free energy rather than 'negative entropy'.

Organisms operate as dissipative structures that evolve to efficiently utilize energy, thereby increasing the universe's overall entropy while maintaining localized order. When an organism ceases function, the constituent atoms are not destroyed; instead, the specific, highly organized pattern that constituted the 'self' degrades, and the atoms are recycled into new configurations, such as geological strata or other biological forms. Astrobiologist Betül Kaçar defines life as "chemistry that has memory," suggesting that the information encoded in the arrangement, rather than the atoms themselves, is what perishes upon death. Kaçar's research, including work with the LIFE network co-led with Frank Rosenzweig, Ariel Anbar, and Mary Droser, aims to understand these co-evolutionary rules to predict life's potential in other environments.

The atoms composing humanity, including iron forged in ancient stars and dispersed via supernova explosions, represent stardust that has achieved a temporary, complex configuration. The paradox lies in the fact that this enduring matter has, through a statistically improbable sequence of events spanning billions of years, assembled into a structure capable of contemplating its own mortality and the nature of its constituents. The hydrogen atoms in our bodies are largely relics from the universe's initial moments, while heavier elements like carbon and oxygen were synthesized in earlier generations of massive stars. The atoms we host are in constant exchange; for example, oxygen atoms inhaled from the atmosphere may have been globally distributed only a few years prior, and hydrogen atoms from tap water could have resided in groundwater aquifers for millennia. This transient identity, built from near-eternal material, allows for the existence of a rare cosmic phenomenon: Big Bang atoms that have developed the capacity for self-reflection regarding universal decay and existence.