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CH 3 - The Size & Age of our Universe2

CH 3 - The Size & Age of our Universe2 - CHAPTER 3...

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CHAPTER 3 THE SIZE AND AGE OF OUR UNIVERSE We know that materials in the Solar System condensed as long ago as 4.567 × 10 9 years ago. We also know that our Solar System comprises elements that must have been formed in earlier phases of solar evolution. How have we actually measured the age, and hence size, of our universe? 3.1 MEASURING ASTRONOMICAL DISTANCES AND TIME We require a methodology for determining the scale of the universe. Later, we will see how this scale relates to the age of the universe. We shall bootstrap a scaling method for measuring distance. 3.1.1 A BREIF HISTORY OF ASTRONOMICAL MEASUREMENT Our current understanding of the universe is importantly dependent upon our models and our understanding of the scales inherent in those models. Astronomy is an old science in that astronomical measurements were being made at the dawn of recorded civilization. Signs of the Zodiac were thought to be ways of remembering which groups of stars are in the sky during which seasons = helps you navigate (particularly around Mediterranean & Middle East) It is known that the ancient Sumerians studied the heavens; the Sumerian Animal Round may be the first known astronomical instrument. The earliest scientific enquiry focused on the heavens. That science that evolved into contemporary astronomy had already established its roots by the time of the earliest historical records . En Hedu’anna 45 (circa 2354 BCE ), high priestess of the Moon Goddess of Babylon is one of the first known names in the science. She is also regarded as the first poet! En Hedu’anna = meaning ornament of heaven The ancient Druids of Britain, the Inca of Peru, the Mayans of Central America, the Aztecs of Mexico and all the peoples of the Middle East looked to the sky for order and predictability... Stonehenge Druids = Stone Henge – built to predict Winter Solstace so they can determine when to start planting seeds again
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The ancient Babylonians were keen observers of the stars and planets. The Phonecians, the Greeks, the Indians, the Chinese, the Persians, the Mesopotamians ... navigation (the astrological signs) The Polynesians almost surely navigated by the stars, Sun, Moon and planets as they sailed the Paci c Ocean a thousand years ago. fi It is arrogant of us to want to believe that the ancients were astronomically ignorant: 2000 years BC, the Babylonians already had obtained an accurate measurement of the length of the year Our western thread of astronomical science is based in the early Greek civilization. It is remarkable how much the early Greeks actually knew about the Earth and Solar System. Thales (624-527 BC) ... the Ionian school of thought promoted the possibility of understanding rather than simply describing nature.
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CH 3 - The Size & Age of our Universe2 - CHAPTER 3...

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