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Cosmic Evolution

“Cosmic evolution” names the history of the whole universe told as one sequence, from radiation and particles through galaxies, stars and planets to life and society, with each stage building on the last. It is the arrow reading of the unfolding sense at its widest: one irreversible history with a direction. It also includes the sharpest crossing to the other sense, a cosmology that carries the whole Darwinian mechanism.

The sequence

Harlow Shapley’s Harvard course of 1952–53 combined the sciences in a single history of the universe, and his popular Of Stars and Men (1958) treated the sciences as studying one set of processes of origin, growth and decay. Erich Jantsch’s The Self-Organizing Universe: Scientific and Human Implications of the Emerging Paradigm of Evolution (1980) told the history from the cosmos through life to culture as a sequence of self-organising systems far from equilibrium, drawing on Prigogine. Eric Chaisson’s Cosmic Dawn (1981) belongs with the cosmic histories of those years, and his later work gave the subject its definition: cosmic evolution is “the study of the many varied developmental and generational changes in the assembly and composition of radiation, matter, and life throughout all space and across all time”. He divided it into seven epochs, particulate, galactic, stellar, planetary, chemical, biological and cultural, and proposed energy rate density, the flow of free energy through a system per unit of its mass, as a single measure of the complexity that rises across them. The metric is the part most pressed: critics argue that its criteria admit systems not complex by usual standards, and Chaisson has acknowledged that the correlation with complexity is approximate.

Widening selection

Chaisson uses “evolution” in the broad sense on purpose, and widens selection with it: “selection can be generally taken to mean preferential interaction of any object with its environment”, so that “selection occurs in the inanimate world as well as among animate objects”. Biological evolution becomes “just one, albeit important, subset of broader evolutionary action”. The direction he describes has no goal: cosmic evolution “is an aimless, meandering process”. The mineralogists who coined mineral evolution placed their subject as “a fascinating specific example of the more general process of cosmic evolution”, while insisting that it is not Darwinian (see Mineral evolution).

Big history

Big history took the sequence into teaching history. David Christian’s Maps of Time: An Introduction to Big History (2004) set human history inside the history of the universe, and the field organises the story as a series of thresholds of increasing complexity, from the Big Bang and the first stars to life, humans, agriculture and the modern world. Chaisson’s epochs and energy metric are among its scientific sources.

Cosmological natural selection

Lee Smolin’s cosmological natural selection, proposed in “Did the Universe Evolve?” (1992) and set out in The Life of the Cosmos (1997), crosses to the descent sense without widening anything. Each black hole gives rise to a new universe, whose physical constants differ slightly from those of its parent; universes whose constants favour black holes leave more offspring, so that over many generations the constants are tuned for black-hole production. Smolin presents it as natural selection among universes, with variation, heredity and differential reproduction, and uses the word in Darwin’s sense. The step from black hole to new universe cannot be observed, and Smolin offered an indirect test instead: if the constants are tuned for black holes, neutron stars should have a low maximum mass, and a heavy neutron star would count against the hypothesis. Pulsars of about two solar masses, measured from 2010, have been read by some as counting against it and by others as falling within the range the prediction allows.

See also: Evolution (the subject landing) · Mineral evolution · Thermodynamics · Chaisson · Smolin · Prigogine