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Saturday, June 15, 2013

A brief history of the universe and its inhabitants (Cosmos)

This book has not been revised since its first publications in 1980, but in the meantime our understanding of physics and biology has advanced significantly. Although the book is dated, the physical principle on which the universe is founded remains unchanged. The author is a brilliant physicist & philosopher, a cosmologist, a sociologist and a humanist who is at ease when he is describing the physics of spacetime and matter from which this cosmos evolved or formation of life on this planet or the scientific, political and sociological issues surrounding the space exploration. The author quotes extensively from the history of physics and biology, religious literature, world history, media and numerous other sources with which he is familiar, and discusses our responsibilities and commitment for the preservation of the planet and the universe. He not only touches on diverse topics with deep understanding but also communicates with his readers equally well.

The author describes his experiences with the American space program and NASA. He briefed the Apollo astronauts before their flights to the moon, and his wok with missions that explored the solar system. He is responsible for the universal message from earth (on a plaque) on spacecrafts Pioneer 10, Pioneer 11, and the Golden Record (voice message) on Voyager mission. Many space missions he was associated with have left solar system; Voyager 1, Voyager 2, Pioneer 10, and Pioneer 11. These spacecrafts will probably survive in interstellar space lot longer than human race. He gives reasonable amount of information about voyager missions and the possible problems it could have faced while entering the Jupiter's outer shell of high-energy charged particles or the need for small nuclear power plant for energy for its long flight farther away from sun. The geological wonders of Jovian moons Io, and his optimism of Voyager spacecraft entering the heliopause, the outer boundary of solar system in the middle of 21st century.

While discussing the personal and professional conflicts faced by German mathematician Johannes Kepler with the local Roman Catholic Church, and challenges he faced with the imperial mathematician, Tyco Brahe, to get access to his experimental data, the author makes it all come alive. Kepler and Newton represent critical transition in human history and their discovery that fairly simple mathematical laws pervade all of nature. Their accurate predictions of planetary motions based on experimental data are the first step in understanding of our interaction with the rest of the cosmos. The city of Alexandria, Egypt was a home for learning and culture and how it tragically ended life of a brilliant woman scientist known by the name of Hypatia. She stood at the epicenter of social forces that were manipulating free thinking and intellectual pursuit. The slavery sapped classical civilization of its vitality. The growing Christian church was consolidating power and attempting to eradicate scientific thought that it claimed to be paganism. She continued to teach and publish until 415 A.D., when local Cyril parishioners murdered her and her remains burned. Her name was long forgotten while Cyril became a saint.

Does our cosmos expand indefinitely or at some stage it starts contracting? The author draws an interesting analogy with Hindu scriptures of Upanishads and Puranas, which predicts that the universe undergoes the cycles of birth and death every one hundred Brahma years, where one day and a night of Brahma are about 8.64 billion years, approximately half the age of our universe. It is supposed that a universe is a dream of God who after one hundred Brahma years dissolves himself into a dreamless sleep, and the universe dissolves with him. After another Brahma century, he recomposes himself to another great cosmic dream.

The author concludes this book by stating that since consciousness arose on this planet and our immediate concern is our own survival, but our own survival is balanced by numerous cosmic forces. We owe our obligations to this planet and the universe and not just ourselves.

Reference: Cosmos by Carl Sagan

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