Cosmic Evolution

By Eric J. Chaisson

galaxy


Adapted from Cosmic Evolution: The Rise of Complexity in Nature, published by Harvard University Press, 2001

It is perhaps a sobering thought that we seem so inconsequential in the Universe. It is even more humbling at first--but then wonderfully enlightening--to recognize that evolutionary changes, operating over almost incomprehensible space and nearly inconceivable time, have given birth to everything seen around us. Scientists are now beginning to decipher how all known objects--from atoms to galaxies, from cells to brains, from people to society--are interrelated. We are attempting to sketch the unifying scenario of cosmic evolution, a powerful new epic for the new millennium.

Simply defined, cosmic evolution is the study of change--the vast number of developmental and generative changes that have accumulated during all time and across all space, from big bang to humankind. To quote some long-forgotten wit, "Hydrogen is a light, odorless gas which, given enough time, changes into people." More seriously, cosmic evolution comprises the sum total of all the many varied changes in the assembly and composition of radiation, matter, and life throughout the history of the Universe. These are the changes that have produced our Galaxy, our Sun, our Earth, and ourselves.

As such, the most familiar kind of evolution--biological evolution, or neo-Darwinism--is just one subset of a much broader evolutionary scheme encompassing much more than mere life on Earth. In short, what Darwinism does for plants and animals, cosmic evolution aspires to do for all things.

Of central importance, we can now trace a chain of knowledge--a loose continuity along an impressive hierarchy—sequentially linking:

  • the evolution of primal energy into elementary particles and atoms
  • the evolution of those atoms into galaxies and stars
  • the evolution of stars into heavy elements
  • the evolution of those elements into the molecular building blocks of life
  • the evolution of those molecules into life itself
  • the evolution of advanced life forms into intelligence
  • the evolution of intelligent life into a cultured and technological civilization.

Metaphorically (at least), cosmic evolution aims to frame a heritage--a cosmic heritage--a grand structure of understanding rooted in events of the past, a sweeping intellectual map embraced by humans of the present, a virtual blueprint for survival along the arrow of time. The objective, boldly stated, is nothing less than an interdisciplinary cosmology in which life has not merely a place in the Universe, but also perhaps a role to play as well.

Who are we? Where did we come from? How did everything around us, on Earth and in the heavens, originate? What is the source of order, form, and structure characterizing all material things? Even more fundamentally, why is there something rather than nothing?

With cosmic evolution as an intellectual framework, we can begin to understand the environmental conditions needed for matter to have become increasingly ordered, organized, and intricately structured, and not merely among biological systems. This trend toward increased complexity throughout Nature writ large violates no laws of physics, and certainly not those of thermodynamics. Indeed, it is modern thermodynamics that perhaps best helps to explain the rise in order, form, and complexity among all animate and inanimate objects.

Nor is the idea of ubiquitous change novel to our rapidly increasing knowledge of the world, the Universe, and ourselves. What is new and exciting is the way that frontier, non-equilibrium science now helps us mold an integrated cosmology, from quark to quasar, from microbe to mind--indeed one wherein life does play an integral role.

Cosmic evolution is the study of many varied changes on a universal scale, a subject that seeks to synthesize the reductionistic posture of specialized science with a holistic view of systems science. It is a story about the awe and majesty of twirling galaxies and shining stars, of redwood trees and buzzing bees, of a Universe that has come to know itself. But it is also a story about our human selves--our origin, our existence, and perhaps our destiny.

Eric J. Chaisson is Research Professor of Physics at Tufts University, where he also directs the Wright Center for Science Education. He has twice won the Science Writing Award from the American Institute of Physics--for Cosmic Dawn (1981) and for The Hubble Wars (1995). This article is adapted from a new book, Cosmic Evolution: The Rise of Complexity in Nature, published by Harvard University Press, 2001.