Cosmic Evolution
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Cosmic evolution is the scientific study of universal change. It is an intellectual framework that offers a grand synthesis of the many varied changes in the assembly and composition of radiation, matter, and life throughout the history of the universe. While engaging the time-honored queries of who we are and whence we came, this interdisciplinary subject attempts to unify the sciences within the entirety of natural history—a single broad scientific narrative of the origin and evolution of all material things, from big bang to humankind. (Closely related subjects include epic of evolution, big history, and astrobiology).
The roots of cosmic evolution extend back millennia. Early Greek philosophers of the fifth century BCE, most notably Heraclitus, are celebrated for their reasoned claims that all things change. Its modern history began more than a century ago, including the wide insights of Robert Chambers, Herbert Spencer, and Lawrence Henderson. Only in the mid-20th century was the cosmic-evolutionary scenario articulated as a research paradigm to include empirical studies of galaxies, stars, planets, and life—in short, an expansive agenda that combines physical, biological, and cultural evolution. Harlow Shapley articulated the idea to the public at mid-century, and NASA embraced it in the late 20th century as part of its more limited astrobiology program. Carl Sagan, Eric Chaisson, Hubert Reeves, and Steven Dick, among others, became dedicated proponents of cosmic evolution in its current form writ large, and it now continues to be more intricately formulated as both a technical research program and a scientific worldview for the 21st century.
The arrow of time provides a convenient archetypical symbol for cosmic evolution. Seven major epochs are arrayed across 14 billion years of time—a compact collection of salient features of cosmic history from its fiery origins to the here and now. The arrow captures the sequence of events based on a large body of post-Renaissance observational and experimental data—a continuous thread of change from simplicity to complexity, from inorganic to organic, from chaos in the early universe to order more recently. Evolution, broadly considered, has become a powerful unifying factor in all of science, bridging numerous academic disciplines—including physics, astronomy, geology, chemistry, biology, and anthropology, among others—thus forging an interdisciplinary scientific story of epic proportions that includes every known class of structured object in our richly endowed universe.
Notable among quantitative efforts to describe cosmic evolution is the concept of energy flow through open, thermodynamic systems, including galaxies, stars, planets, and life forms. Information content is another potential metric to model the subject, though informational bits and bytes might be akin to energy acquired, stored, and expressed within ordered systems. The observed increase of energy rate density (energy/time/mass) among a whole host of ordered systems is one useful way to address the rise of complexity in an expanding universe that still obeys the cherished 2nd law of thermodynamics and thus continues to accumulate net entropy. As such, material systems—from buzzing bees and redwood trees to shining stars and thinking beings—are viewed as temporary, local islands of order in a vast, global sea of disorder.
Accordingly, biological evolution (or neo-Darwinism via natural selection) is a small, albeit important, subset of a more extensive evolutionary scheme stretching across all of space and all of time. Nothing entirely random pertains, as systems are “non-randomly eliminated” as unfit for their environments by dynamically mixing chance with necessity, or randomness with determinism, thereby deciding the winners and losers throughout Nature regardless of whether those systems are quarks or quasars, microbes or minds. Most contemporary researchers consider the term cosmic evolution as all-encompassing, thereby incorporating different types of evolutionary change within and among many temporal epochs:
- Cosmic Evolution
- Eras: physical evolution-->biological evolution-->cultural evolution
- Epochs: particulate-->galactic-->stellar-->planetary-->chemical-->biological-->cultural.
- Eras: physical evolution-->biological evolution-->cultural evolution
By contrast, some researchers (notably astrophysicists) restrict their view of cosmic evolution to change within stars and galaxies, confining the adjective “cosmic” to only astronomical objects during mostly the first several billion years of the universe. Others (astrobiologists) also limit their study of this subject, working among more specialized venues such as planets and moons suitable for life during the most recent few billion years. But those who study the entire subject of cosmic evolution in its most general scope over 14 billion years (including both astrophysics and astrobiology) address all changes ubiquitously and indefinitely, as diagramed above.
Although by no means the culmination or pinnacle of the evolutionary process, technologically intelligent humans, as a quintessential expression of cultural evolution, now reflect back upon the profound series of changes that brought us forth. Considering culture’s possible logical outcome, we may already exist in a postbiological universe—one that has evolved beyond flesh and blood intelligence to artificial intelligence. Such proposals help to inform the search for extraterrestrial life, asserting the importance of biological and cultural evolution as key elements of cosmic evolution and not separate from it. Whether humankind is alone in the universe or among many other sentient beings, cosmic evolution remains a viable explanation of our material origins.
This subject can elicit controversy, for several reasons: Evolution of any kind inherently attracts detractors, especially among religious fundamentalists; cosmic evolution addresses universal and human origins, which often cause emotion; it challenges age-old ideas about life’s sense of place in the cosmos; it champions change, which many people dislike or distrust; it welcomes a broad interpretation of the concept of evolution, which some biologists prefer as their exclusive purview pertinent only to life; it proposes a grand, sweeping, interdisciplinary worldview based on rationality and empiricism, which, despite its experimental tests, some find intellectually arrogant.
Some mystics subjectively embrace cosmic evolution for religious purposes (both western and eastern), given its highly inclusive big-bang-to-humankind narrative and its spiritual overtones. However, this is not the intent of main-stream scientific researchers who ply the trade; rather, the effort described herein is a decidedly objective, empirical, and quantitative science driven by naturalists who adhere, liberally and broadly, to the modern scientific method. Ultimately, if people of all cultures and persuasions find cosmic evolution religiously or philosophically attractive, then all the more intellectually powerful is this transdisciplinary scenario of rich natural history for the new millennium.
Modern References
- Chaisson, E., Cosmic Evolution, Harvard Univ. Press, 2001. ISBN 0-674-00987-8
- Chaisson, E., Epic of Evolution, Columbia Univ. Press, 2006. ISBN 0-231-13560-2
- Christian, D., Maps of Time, Univ. of California Press, 2004. ISBN 0-520-23500-2
- Dick, S. The Biological Universe, Cambridge Univ. Press, 1996. 0-521-66361-X
- Dick, S. and Strick, J., The Living Universe, Rutgers Univ. Press, 2004. ISBN 0-8135-3733-9
- Reeves, H, Patience dans l’azur: L’evolution cosmique, Editions du Seuil, 1981.
- Sagan, C., Cosmos, Random House, 1980. ISBN 0-394-50294-9
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