Astronomy Notes PDF

The scientific method as we understand it today was not fully in place until quite recently. We have to keep this in mind when we examine things from a historical perspective. Archeoastronomy is the study of how people in the ancient past have understood the phenomena in the sky, how they used thes...

The scientific method as we understand it today was not fully in place until quite recently. We have to keep this in mind when we examine things from a historical perspective. Archeoastronomy is the study of how people in the ancient past have understood the phenomena in the sky, how they used these phenomena, and what role the sky played in their cultures. These ancient people were not scientists! Stonehenge Megalithic ruin near Amesbury in Wiltshire UK, built during the Bronze Age. Main structure dates to -2500 BC Roughly circular area with -90 stones The largest stones(25 tons) called Sarsen stones, were carried from as far as 32 km away A lot of stones have fallen but they know where they were so they have made replicas **Unit 0:** ### **Page 17-19: Impact of Scientific Questions** - - - - - ### **Page 21-24: Scientific Method and Theories** - - - ### **Page 26-27: Science vs. Pseudoscience** - - - - - ### **Page 29-30: Importance of Astronomy** - - ### **Page 31-32: Quantitative Nature of Astronomy** - - ### **Page 44: Understanding Distances** - - ### **Page 41-60: The Milky Way and Beyond** - - - ### **Archeoastronomy Overview:** - - - - - ### **Seasons, Solstices, and Equinoxes:** - - - ### **Stonehenge Overview:** - - - - - ### **Astronomical Significance of Stonehenge:** - - ### **Other Notable Points:** - - Archeoastronomy is the study of how people in the ancient past have understood the phenomena in the sky, how they used these phenomena, and what role the sky played in their cultures. These ancient people were not scientists The Sun appears to rise and set at different locations: Winter: toward the south Summer: toward the north Fall and Spring: due east and west Also note the elevation of the Sun -- it gets higher up in the sky in the summer. The Sun rises and sets at different points on the horizon throughout the year. In the Northern Hemisphere: on June 21 (called the summer solstice), the Sun rises at the northernmost point. on December 21 (called the winter solstice), the Sun rises at the southernmost point. Newgrange (\~3200 BC): tomb (passage-grave) in Ireland, set in a 76 m mound (reconstructed). A narrow slit illuminates the central tomb at sunrise on the winter solstice. Megalithic ruin near Amesbury, in Wiltshire, UK, built during the Bronze Age. Main structure dates to \~2500 BC. Roughly circular area with \~90 stones of various shapes and sizes. The tallest stand 7.3 m (24 ft) above ground. Earth and timber structures also form part of the complex. Was not built as a single structure, but expanded and remodeled over a period of 2000 years. The Horseshoe of trilithons point to sunrise on the summer solstice (June 21st). The sun rises just to the left of the Heel Stone and shines into the largest trilithon. The Avenue leads into Stonehenge from the opposite direction, towards sunset on the winter solstice. This was perhaps the more important alignment. The bluestones are arranged with the 'altar' stone at their focus, and in this direction. Analysis of pig bones nearby shows that slaughtering and feasting took place as part of winter -- rather than summer -- festivities. Archeoastronomy: Summary Knowledge of astronomy was crucial for ancient civilizations. Marking the beginning and end of the seasons allowed people to plan for sowing and harvesting, among other things. Ancient civilizations took great pains to build astronomical sites like Stonehenge. There are many things we don\'t know about these sites, but they had no scientific motivation. The origins of astronomy are intertwined with superstition, myth, and arcane rituals. **Unit 2** ### **Learning Objectives:** - - - ### **Historical Context:** - - - - - ### **Why Greece?** - - ### **Significance of the Greeks:** - - ### **Key Greek Thinkers:** 1. - - - 2. - - - 3. - - - 4. - - 5. - 6. - ### **Philosophical and Cosmological Models:** 1. - - 2. - - 3. - - - ### **Key Astronomers:** 1. - - 2. - - 3. - - 4. - ### **Eclipses and Phases of the Moon:** - - - ### **Legacy:** - - This slideshow provides a comprehensive look at how Greek thinkers transitioned from mythology to rational thought, creating the foundations of modern astronomy and science. Practical astronomy was quite advanced by the beginning of the Iron Age (Archeoastronomy, Babylon, Egypt, \...), but **Greek philosophers were the first to try to understand the Universe** from a scientific point of view. **Thales** (\~600 BC) introduced the idea of an orderly Universe that can be understood through observation and theory. His student **Anaximander** performed the first experiments, introduced the idea of infinity, and conceived the first model of the Universe. **Pythagoras** (\~550 BC) greatly advanced mathematics (discovered irrational numbers and the five regular solids), and proposed a spherical Earth. **Anaxagoras** (\~450 BC) proposed that the Moon and the Sun were very far away, and made of ordinary matter. **Empedocles** (\~450 BC) introduced the four elements (earth, water, air, and fire). **Leucippus** and **Democritus** (\~400 BC) introduced the idea of the atom and proposed geocentric (=centered on Earth) models of the Universe. The **scientific tradition** started by Thales and Anaximander **culminated in Aristarchus and Hipparchus**, who made the first **realistic estimates of the size of the Sun and the Moon, and their distances from Earth. Eratosthenes measured the size of the Earth.** **Aristarchus proposed a heliocentric (Sun-centered) Universe**, and Hipparchus made the most accurate astronomical measurements of his time. Unfortunately, **Plato and Aristotle broke away from the scientific tradition and started a school of thought where ideas were not questioned and theories were not tested with data**. Fundamental tenets of this philosophy were that the Earth is at the center of the Universe, that the heavens are perfect and immutable, and that all celestial movement must be uniform, circular, and eternal. This view would hold sway for 18 centuries. **Ptolemy systematized the knowledge of Astronomy around 150 AD into a geocentric system with hundreds of spheres**. His model could reproduce the observations of planetary motion available at the time, but at the cost of incredible complexity. **Unit 3:** ### **Nicolaus Copernicus and His Context:** 1. - - - 2. - - ### **Nicolaus Copernicus:** 1. - - 2. - - ### **Key Work - The Commentariolus (c. 1512):** - 1. 2. 3. 4. 5. 6. 7. 3. - - 4. - 5. - ### **Major Work - De Revolutionibus Orbium Coelestium (1543):** - - ### **Advantages and Disadvantages of Heliocentrism:** 1. - - 2. - - ### **After Copernicus:** 1. - - 2. - - ### **Summary of Copernican Revolution:** - **Unit 4:** #### **Early Life:** - - - - #### **Stella Nova of 1572:** - - - #### **Personal Life:** - - - - - - #### **Observations and Contributions:** - - - - - #### **Tychonic System:** - - #### **Astrology and Astronomy:** - - #### **Uraniborg:** - **Unit 5:** ### **1. Kepler's Background:** - - - - - - ### **2. Kepler's Model of the Solar System (Mysterium Cosmographicum, 1596):** - - - ### **3. Collaboration with Tycho Brahe:** - - - ### **4. Kepler's Scientific Philosophy:** - - ### **5. Kepler's Three Laws of Planetary Motion:** 1. 2. 3. ### **6. Ellipses and Eccentricity:** - - ### **7. Kepler's Third Law and Orbital Periods:** - - ### **8. Reception of Kepler's Laws:** - - - **Unit 6** ### **1. Galileo Galilei\'s Life and Influence** - - - - - ### **2. The Birth of Experimental Physics** - - ### **3. Galileo's Law of Inertia** - - ### **4. Heliocentrism** - - ### **5. The Telescope and Galileo's Discoveries** - - ### **6. Galileo's Major Discoveries** - - - - - - ### **7. Conflict with the Catholic Church** - - - - ### **8. Impact and Legacy** - - **Unit 7:** ### **Scientific Revolution and Enlightenment** - - - ### **Isaac Newton** - - - ### **Key Achievements of Newton** 1. 2. 3. 4. ### **Newton's Annus Mirabilis (1666)** - - - - - ### **Newton\'s Laws of Motion** 1. 2. 3. ### **Newton\'s Universal Law of Gravitation** - - - ### **Gravity and Weight** - - - ### **Orbits and Escape Velocity** - - ### **Newton's Influence on Kepler's Laws** - - - ### **Newton\'s Legacy** - - - ### **Key Takeaways** - - -