In Atom: An Odyssey from the Big Bang to Life on Earth . . . and Beyond, Lawrence Krauss tackles an enormous task in describing the life of an oxygen atom from its beginnings to its end. On a number of occasions, Krauss abandons the atom to relate scientific ideas, principles, and stories of exploration that are relevant to that time in the atom’s life. Although parts of the book are quite speculative, Atom is a marvelous work that records a possible history of the cosmos from beginning to end. Even though it is written with an approach similar to that taken by David Darling in Deep Time: The Journey of a Subatomic Particle from the Moment of Creation to the Death of the Universe—and Beyond (1989), this work by Krauss is much more complete, drawing upon many new advances in scientific knowledge. Atom also contains similarities to a chapter inThe Periodic Table (1975), by Primo Levi, in which Levi traces the life of a carbon atom for some 235 years after a carbonate rock in which it resides is discovered in 1740.
Although the reader must be willing to exert frequent intellectual effort when reading Atom, the reward is well worth it. Krauss clearly explains the modern ideas of physics, astronomy, geology, and biology and integrates them into the development of stars, planets, and the origin of life. The book is entertaining and easy to read, particularly after the atom reaches Earth. The book generates awe and wonderment about the universe.
Since it would require a quantum theory of spacetime not yet formulated to explain what happened prior to the Big Bang, Krauss starts with that event. At the onset of the Big Bang, which is believed by most scientists to have generated the universe, there were no atoms or elements. Krauss suggests that the entire visible universe would then fit into a volume about the size of a baseball. The energy and density of mass inside that space were inexplicably high. Under those conditions, the four fundamental forces in nature—gravitational, electromagnetic, strong nuclear, and weak nuclear—were all unified, acting as one underlying force for all particles. A battle had been waging between matter and antimatter prior to the Big Bang to determine which one would provide the building blocks of the universe. Although the reason is rather obscure, Krauss points out that a minuscule imbalance occurred in the favor of matter, most likely due to a microscopic asymmetry associated with the fact that time moves forward, not backward.
After the Big Bang, there was an extremely hot primordial soup of elementary particles, consisting of free quarks, electrons, photons, neutrinos, gluons, and their antiparticles. Within a fraction of a second after the Big Bang, the resulting expansion of matter produced some cooling. Quarks were then subjected to the strong nuclear force. Some were attracted together to form the eight protons and eight neutrons that would eventually be involved in the formation of the oxygen atom tracked by Krauss. However, since free neutrons decay into protons, the only neutrons in existence ten minutes after the Big Bang were those that had bonded with protons to form helium nuclei. Based on statistical probabilities, Krauss believes that the building blocks that would ultimately combine to form his oxygen atom had now become twelve key hydrogen nuclei and one key helium nucleus.
Approximately 330,000 years after the Big Bang, as the universe continued to expand and cool, temperatures finally declined enough for atoms to begin forming. Due to localized spatial density variations, gravity began assembling clumps of matter at various locations in the universe. The struggle between gravity pulling inward and gas pressure pushing outward generated interactions that spread the eventual building blocks of the oxygen atom far apart, unlikely to ever get together again. As temperatures continued to drop, molecules began forming and protostars evolved from the gaseous matter.
Of the particles that would finally join to produce the key oxygen atom, Krauss suggests that four of the key hydrogen atoms traveled to a distant pregalactic gas cloud, where they remain unheard from until very late in the story. The other eight key hydrogen atoms and the key helium nucleus take up residence in a huge, pregalactic gas cloud that becomes the breeding ground for new stars. As the battle between gravity and gas pressure finally reaches a state of equilibrium in one of the protostars, a star is born. Four of the key hydrogen atoms and the key helium atom are components of this star. Krauss notes that they are probably kilometers apart. The other four key hydrogen atoms in this galactic cloud are light years away from the new star.
At this juncture, Krauss diverts to discuss the astrophysics associated with the life of a massive star. At times like these, the...
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