Origins of Existence: How Life Emerged in the Universe
272
Origins of Existence: How Life Emerged in the Universe
272eBook
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Overview
Adams suggests that life was not merely some lucky break, but rather a natural outcome of the ascending ladder of complexity supported by our universe. Since our galaxy seems to harbor millions of planets with the same basic elements of habitability as Earth, the emergence of life is probably not a rare event. If life emerges deep inside planets and moons, as new research suggests happened on our planet, the number of viable habitats is truly enormous. Seven chronological chapters take the reader from the laws of physics and birth of the universe to the origins of life on Earth -- showing how energy flowed, exploded, and was repeatedly harnessed in replicating structures and organisms.
In his groundbreaking first book, Fred Adams established the five eras of the universe with a focus on its long-term future. It is perhaps not surprising that he now turns his attention to the mystery of our astronomical origins. Here is a stunning new perspective, a book of genesis for our time, revealing how the laws of physics created galaxies, stars, planets, and even life in the universe.
Product Details
| ISBN-13: | 9781439138205 |
|---|---|
| Publisher: | Free Press |
| Publication date: | 05/11/2010 |
| Sold by: | SIMON & SCHUSTER |
| Format: | eBook |
| Pages: | 272 |
| File size: | 5 MB |
About the Author
Fred Adams received his Ph.D. from the University of California. Recipient of the Helen B. Warner Prize, Adams is a professor of physics at the University of Michigan and lives in Ann Arbor, Michigan.
Read an Excerpt
Chapter 0: Beginnings
firm physical laws
sculpt our changing universe
cosmic creation
4,500,000,000 b.c., Earth:
A long time ago, when Earth was quite young, the night skies were much busier than the seemingly quiescent heavens of today. The solar system was brimming with large asteroids and comets, which provided an unrelenting supply of ammunition for planetary bombardment. Nightly meteor showers were spectacular. Rocky intruders more than ten kilometers across — like the one that would much later enforce the untimely demise of the dinosaurs — were commonplace. The planet's fragile surface experienced catastrophic change on a regular basis.
Against this violent and destructive backdrop, warm pools of water on the surface teemed with organic chemicals, which continually tried to organize themselves into larger structures. But the task proved to be a Sisyphean nightmare. Every time a milestone of molecular complexity was attained, abrupt changes in the background environment undermined the achievement. Hard-won complexity was immediately compromised, and the tortuously slow chemical processes were forced to start over from their simple beginnings.
Meanwhile, deep beneath the planetary surface, chemical processes of greater import were quietly taking place. Far removed from the ever-changing surface of the planet, the hot and hellish regions of the deep interior proved to be remarkably stable. With fiery heat, molten rock, and toxic sulfurous gases in great abundance, this subterranean setting more closely resembled a mythical inferno than a garden of Eden. Yet it was this extreme environment that supported the slow and steady progression of chemical processes of ever greater complexity. The evolution of simple physical systems into more complex ones continued unabated. In a relatively short time, from a geological perspective, these molecular systems increased their complexity to the point of self-replication and became biological systems. For the first time on Earth, life emerged.
As the twentieth century fades into history, we understand our physical universe with unprecedented clarity. Astronomers have developed viable creation paradigms for the formation of virtually everything in the universe, from moons and planets within our solar system to the birth of the entire cosmos. In a beautiful display of consilience, these diverse instances of cosmic genesis are all driven by the same underlying laws of physics. Such theories are continually tested against new observations and experimental data, which verify and modify our working understanding of these creation phenomena. A remarkable quality of our universe emerges from this study: These physical laws, and the astronomical structures they create, are apparently not only necessary but are also sufficient for the genesis of life itself.
Our description of the cosmos can be organized into four scales of astronomical inquiry — the whole universe, galaxies, stars, and planets. Each of these scales provides a window through which we may view the operations of nature. And each of these astronomical entities experiences a life cycle, beginning with a birth event and ultimately ending with a deathlike closure. Birth sometimes comes rapidly and violently, as when our universe first burst into existence at the big bang, or when the Moon was forged from the rocky shrapnel of a cosmic collision. But in other instances astronomical birth comes tortuously slowly, as when stars condense from their parental molecular clouds, or when microscopic dust grains accumulate into moons and planets.
This book is a quest to understand how our universe and its astronomical structures provide the basic ingredients for biological genesis. To see how life fits into the greater context of the cosmos, we must understand the relationships among the windows of astronomy — especially how the same underlying laws of physics produce such diverse astronomical entities. These physical laws, in turn, determine which environments have the potential for biological creation and its subsequent development. Given the recent advances in our understanding of planet formation, star formation, galaxy formation, and even the creation of the universe, these connections can be made at a higher level of clarity and confidence then ever before.
In the beginning the universe had no planets, no stars, and no galaxies. No life of any kind could possibly have gained a foothold in its tumultuous environment. In the earliest epochs even the universe itself did not exist, at least not as a distinct identifiable entity. In this primordial chaotic void, the underlying laws of physics were of fundamental importance — they held the power to enforce all of creation. Later these same physical laws drove the formation and evolution of all the astronomical bodies and biological organisms in the cosmos. But before the universe was graced with galaxies, stars, planets, and atoms, it simply could not carry out the operations of chemistry, biology, geology, or astronomy. In the stark simplicity of the beginning, there was only physics.
Some 12 billion years ago these laws of physics compelled our universe to spring into existence as a distinct region of the space-time continuum. Understanding this moment of creation is blurred by both the quantum mechanical nature of space and time at this distant beginning, and by our current inability to apply physical laws to the extreme conditions of cosmic birth. In spite of this murkiness, however, astrophysicists can describe the evolution of the universe from an early age of 10-43 seconds onward, albeit with some uncertainty, but with ever-increasing confidence as we vicariously travel toward the present epoch. This detailed description of the physical universe is the providence of big bang theory, which has been bolstered by a wealth of observational data. Astronomers have precisely measured the abundance of the lightest elements, the existence and properties of a cosmic background radiation field, and the expansion of the universe itself. Standing firmly on these three pillars of experimental confirmation, the big bang theory provides a solid framework to explore the evolution of our universe and the production of the galaxies, stars, and planets living within it.
As the universe expands, the force of gravity acts in relentless opposition and endeavors to pull it back together. But current observational data strongly indicate that gravity has already lost this war — our universe seems destined to expand forever. Although its current 12-billion-year age is utterly insignificant compared with the upcoming future vistas of time, the cosmos has lived long enough to forge some remarkable structures.
Within the universe, to be sure, the force of gravity has won significant battles on small scales. As a direct result of gravity's influence, galaxies and clusters have coalesced. When a local region of intergalactic space succumbs to the organizational efforts of gravity, the matter condenses, in about one billion years, into a whirlpool galactic structure. After separating from the intergalactic background, galaxies organize themselves into central bulges, massive dark halos, and spinning disks sporting beautiful spiral patterns. Young galaxies are powered by enormous central engines — supermassive black holes swallowing nearby matter — driven by the gravitational force. These active galactic nuclei grow less dominant with time and leave more quiescent black holes in their wake. After their formation galaxies endure for vast expanses of time and are expected to last perhaps ten billion times longer than the current age of the universe. These stable structures provide ideal environments for the genesis of smaller entities such as stars, planets, and, within our galaxy, people.
The lifeblood of galaxies, and indeed the present-day universe, is the energy provided by stars. These stellar power plants are wrung from interstellar molecular clouds, where they spend their first few million years of life. Most stars live far longer — some much longer than the current age of the universe — and spend their lives wandering through the disk of their galaxy. In addition to supplying most of the cosmic energy budget, the stellar population plays a vital role in biological development: The short-lived massive stars explode as they die and enrich the galaxy with life-giving heavy elements, including carbon, oxygen, nitrogen, and calcium; the longer-lived smaller stars provide stable energy sources for potential biospheres.
Along with the stars, smaller planetary bodies are forged in great abundance. Out of the swirling nebulae that accompany forming stars, massive gaseous giants and smaller rocky orbs condense. Many planets are graced with an orbiting entourage of rocky moons — their own miniature solar systems. Under favorable conditions, both planets and moons can harbor ample supplies of water. Our own Moon has traces of water. Europa, a moon of Jupiter, is covered with frozen oceans and is likely to maintain liquid water below. Solar systems are crowded with astronomical petri dishes, ripe with possibility for life to gain a foothold.
In the next act of this unfolding drama, biology takes center stage. The stars, in collaboration with the early universe, produce the basic raw material in the form of heavy elements. The cosmos forms galaxies to organize this raw material, massive stars to synthesize further element production, smaller stars to supply power, and planets to provide shelter. The laws of physics are graced with the proper form to allow intricate chemical reactions to occur. Although the next developmental step is more uncertain, chemical reactions of increasing complexity take place and build molecules of ever greater size. These physical systems eventually pass through a threshold of sufficient complexity and become self-replicating biological systems. Life begins.
The cosmos must grind through a long sequence of specific constructions to produce living planets like our Earth. This miraculous chain of events is sometimes described as a grand design, which implies an active designer. One opposing view describes the ascent of life as a series of purely random events, as if biological emergence is akin to winning a lottery. From an astronomical perspective, however, the formation of galaxies, stars, and planets is neither random nor designed. Instead, these events of cosmic genesis result directly from the action of physics, whose laws naturally foster the development of such complex structures against the cold background of deep space.
This book tells the story of global cosmic ecology, from the smallest asteroids to the almost unfathomable scale of the whole universe, and even beyond. It is a history of the cosmos, from before the big bang to the formation of galaxies, stars, planets, and moons. It is the story of microscopic particles organizing themselves into ever-larger molecular structures, with ever-increasing levels of complexity, and culminating in the everyday miracle that we call life. It is a scientific glimpse at the face of creation.
Copyright © 2002 by Fred C. Adams