Avaliado no Reino Unido em 22 de setembro de 2018
We are living through a portion of time on the cosmic calendar called the Stelliferous Age — the Age of Stars (which began more than 13 billion years ago). Stars produce energy in the form of light, heat and warmth. They also double as chemical factories, laboratories for stirring and mixing the elements, the birthplace of life, or the place where life’s ingredients are made. So when the Stelliferous Age passes (some 100 trillion years hence), life will too. A famous book says there is a season to everything. The season for life and living is now.
Yet we inhabit a tiny portion of cosmic real estate in the visible universe, an area whose dimensions encompass only five percent of the cosmos. That portion looks boundlessly immense to us — so immense that no one can properly picture it mentally. Yet most of the universe, roughly 95 percent, is totally unknown, as we haven’t yet solved the puzzle and paradox of how to see the invisible. Even so, not knowing its composition and properties, we can gauge its impact on the visible universe through gravity, observing the effects of light as it bends through spacetime. We know this strange world is there and that it’s extremely powerful.
The laws of physics, including those of thermodynamics, say inertia in the form entropy should be slowing the speed of our expanding universe, still growing 13.8 billion years after creation in the form of the Big Bang. But it isn’t slowing down. In fact, quite the opposite: it’s accelerating. How can this be?
The answer is dark matter and dark energy, vague labels for properties or qualities of reality we do not understand. Yes, we know little about our cosmic home, yet we know more now than our ancestors who preceded us over thousands of generations. We live in a great age of discovery, or at least one great to us, although the age may look like one of ignorance and superstition thousands of years from now if our descendants and their developing technologies are still here. They will be the ones to decode the composition and properties of dark matter and dark energy, each of which respectively makes up roughly 25 and 70 percent of the universe.
These ideas and many other fascinating ones are contained in this wonderful new book (2017) produced by DK Publishing in London. “The Astronomy Book” is part of a series DK is calling “Big Ideas Simply Explained”. Many people are probably thankful for this series, myself included. As such, the volume at hand here is a collection of knowledge that can teach one much about our cosmic home.
The book is laid out chronologically, as this is probably the best way to grasp its concepts (the logical linear order of before and after). ‘Before’ of course makes up most of the book, what we knew then (in the past) compared to what we know now. It begins in a section called “From Myth to Science, 600 BCE-1550 CE”. Some sections that follow are: “The Telescope Revolution, 1550-1750”; “The Rise of Astrophysics, 1850-1915”; “Atoms, Stars and Galaxies, 1915-1950”; “New Windows on the Universe, 1950-1975”; and “The Triumph of Technology, 1975-Present”.
The final section is the most recent of course (and perhaps most fascinating). A few of its subsections are: “Most of the Universe is missing (Dark matter)”; “Stars form from the inside out (inside giant molecular clouds)”; “Wrinkles in time (Observing the CMB)” — cosmic microwave background noise, echoes of the Big Bang; “Cosmic expansion is accelerating (Dark energy)”; and “Ripples through spacetime (Gravitational waves)”.
Each section is laid out simply with an easy-to-follow, eye-pleasing design that includes “In Context” sidebars; quotations from famous astronomers; colourful graphics, diagrams, illustrations; very little math and complicated equations; brief sidebar biographies of astronomers; and a “See Also” reference guide at the bottom of many pages, directing the reader to additional, relevant material by subject heading and page numbers.
Reference sections at the end of the book include a Directory of famous or influential astronomers (laid out chronologically), a Glossary of important terms, an Index, and an Acknowledgements page for editorial assistance and photo credits.
This isn’t a book to be read in one go, just as the night sky does not invite one long, sustained glance. Instead, it’s one to return to time and again as certain ideas and questions arise in the mind. The best questions usually begin with ‘How’. This is the basis or foundation of science. Then many ‘w’ questions may follow: ‘what’, “when’, ‘where’, ‘who’, ‘why’. It’s a primer for understanding home, your place in the cosmos: what this place is, where it came from, how and why it’s here, how you and life could ever come to be. So naturally it’s philosophical as well, as many of the best questions we ask ourselves are. We want to know things. Why? Science tries to answer this question too by studying the structure and evolution of the human brain. It’s part of our Faustian pact with the universe. It made us — or allowed us to become — thinking reeds, as Pascal loved to say.
We are wanderers, nomads, explorers on a long journey out of Africa, a journey that has now taken us intellectually to the heavens and stars in our desire to emotionally go home, retracing our steps to our birthplace. In a way, life is exactly this — one long homecoming, coming to terms with who you are and where you come from. This book, a wonderful thing, will hold your hand on the journey back through time.
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