Ear105 2:16

Ear105 2:16 - EAR1052/16 15:43 AbsolutetimeHowoldarethings?

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EAR 105 2/16 15:43 Absolute time…How old are things? The earth is 4.56 billion years old 4560 million years 4,560,000,000 years 4.56 ga early understandings 1. Ancient mythological/religious traditions Bishop james usher 17 century scholar calculated- 600 year old earth Early understanding based on scientific calculations and observations of natural  phenomena 1. Ocean salinity 2. Rate of sediment deposition 3. Cooling of earth Often yielded ages that many scientists believed were too young.  Cooling earth Lord Kelvin Calculated the age of the earth based on cooling. Neglected 1. Hear production 2. Internal structure of the earth. The discovery of radioactivity Radioactivity was discovered in the late 1800s Earth scientists quickly realized that this might be the key to answering the question,  “how old is the earth?”
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Why? What is Radioactivity? Not all atoms are stable. Some undergo the process of radioactive decay and change 
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Ear105 2:16 - EAR1052/16 15:43 AbsolutetimeHowoldarethings?

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