Astronomy Smart Sparrow Lesson Notes PDF

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Astronomy Smart Sparrow Lesson Notes

Can a fully objective truth be easily discovered with a singular, or limited, perspective? 

Six Blind Men and the Elephant Video: https://www.youtube.com/watch?v=qPlJWk8-b4E  Answer: No.

Examples to explore the Greco/Roman perspective: 1. The Earth, and the humans on it, were considered the center of everything. Humans held an anthropocentric view of their place in the heavens. Gods were associated with the celestial bodies and were often thought to influence human lives. 2. Stars and planets were thought to be perfect and sacred spheres. All motion in the sky was also believed to ne uniform and circular. The concept of gravity is a modern one. Ancient philosophers conjectured that the stars and planets must be affixed to spheres to move in such an ordered fashion. 3. Celestial bodies (now known as stars and planets) appeared to be perfect and unchanging in position, motion, brightness, size, and shape. 4. It was believed the celestial bodies were relatively close to Earth. Much of the ancient lore references humans being able to reach those heavenly bodies. 5. Greco/Roman cultures ascribed objects in the sky as “supernatural” and those on land as “natural.” 6. The heavens were deemed as supernatural (with deities) because they appeared to be permanent and unchanging. 7. The Earth was viewed as natural (with humans) as there is much chaos and dynamic change.

Aristotle 384 – 322 BCE Greek philosopher (logic, metaphysics, ethics), mathematician, and scientist (physics, biology, botany, agriculture, medicine). In his Analytica Priora, his system of logic set the foundations for the Scientific Method. Aristotle is known as the Father of Zoology, and he provided empirical evidence for the spherical shape of the Earth. Aristotle’s Assumptions: 1. The Earth is the center of our universe,

Astronomy Smart Sparrow Lesson Notes

2. All motion in the night sky is uniform and circular, 3. The objects in the night sky are perfect and unchanging (e.g. brightness, size, shape, distance.) 4. The objects in the night sky were relatively close to the Earth and affixed to concentric spheres (scale).

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Geocentric Model: any theory of the structure of the solar system (or the universe) in which Earth is assumed to be at the centre of it all. The most highly developed geocentric model was that of Ptolemy of Alexandria (2nd century CE). It was generally accepted until the 16th century, after which it was superseded by heliocentric models such as that of Nicolaus Copernicus. (Source: https://www.britannica.com/science/geocentric-model )

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Anthropocentric View (Anthropocentrism): philosophical viewpoint arguing that human beings are the central or most significant entities in the world. This is a basic belief embedded in many Western religions and philosophies. Anthropocentrism regards humans as separate from and superior to nature and holds that human life has intrinsic value while other entities (including animals, plants, mineral resources, and so on) are resources that may justifiably be exploited for the benefit of humankind. (Source: https://www.britannica.com/topic/anthropocentrism )

Ptolemy 100 - 168 CE The planets in the night sky appeared to change direction and make an “S” shape, or zigzag, motion. This is called retrograde motion:

Retrograde motion was virtually ignored for centuries until Ptolemy hypothesized a modified geocentric model. Many call this modified model the Ptolemaic Geocentric Model. His model left the Earth at the center of the universe, much like Aristotle’s, but positioned planets on their own spheres of movement

Astronomy Smart Sparrow Lesson Notes (epicycles), on other spheres of movement (deferents). He proposed spheres rotating about other spheres. This explanation added more complexity (and assumptions) to the geocentric model. While it left Earth, and humankind, at the center of the universe, it added other axes and points of rotation (aka other centers).

To see Ptolemy’s model in action, take a look at the following website: https://socratic.org/questions/how-did-ptolemy-s-model-account-for-retrogrademotion

 How did Ptolemy's model account for retrograde motion?

Answer: Ptolemy included epicycles in his orbits. Explanation: Ptolomy's model of the solar system was geocentric, where the sun, moon, planets, and stars all orbit the earth in perfectly circular orbits. The problem with perfectly circular orbit around the Earth is that they do not explain the occasional backward motion, or retrograde motion, of the planets. The Greeks insisted that the motion of the planets be perfectly circular. Ptolemy modeled the planets making small circles around a point that orbited the Earth. These smaller circles were called epicycles, and they allowed the planets to move backward relative to the background stars. Ptolemy's model took epicycles even further, using them to explain the brightening and dimming of the planets as well, by having epicycles attached to epicycles. While these epicycles did not perfectly explain the motion of the planets, it was the most accurate model until Kepler's laws simplified things.

Astronomy Smart Sparrow Lesson Notes

Copernicus 1473 -1543 CE Copernicus thought Ptolemy’s model was cumbersome and required too many assumptions. He sought to simplify the model, without any new data. He simply moved the Sun to the center of the model. We now call this model the Heliocentric Model.

Moving the Sun to the center explained retrograde motion; it showed it to be an illusion. The planets do not circle back, they simply move at different speeds and are on different orbits.

Copernicus’ book, was banned from 1616-1835, as it challenged contemporary thought by putting the sun at the center of the universe AND suggesting the Universe is infinite. “On the Revolutions of Heavenly Spheres” is often credited with the start of the Scientific Revolution, which paved the way for the Enlightenment. 

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Copernicus represents the start of the Scientific Revolution, which led to the Enlightenment, or “Age of Reason.”

Heliocentric Model: the astronomical model in which the Earth and planets revolve around the Sun at the center of the Solar System. Historically, heliocentrism was opposed to geocentrism, which placed the Earth at the center. The notion that the Earth revolves around the Sun had been proposed as early as the 3rd century BC by Aristarchus of Samos,[1] but at least in the medieval world, Aristarchus's heliocentrism

Astronomy Smart Sparrow Lesson Notes

attracted little attention—possibly because of the loss of scientific works of the Hellenistic Era.[b] It was not until the 16th century that a mathematical model of a heliocentric system was presented, by the Renaissance mathematician, astronomer, and Catholic cleric Nicolaus Copernicus, leading to the Copernican Revolution. In the following century, Johannes Kepler introduced elliptical orbits, and Galileo Galilei presented supporting observations made using a telescope. With the observations of William Herschel, Friedrich Bessel, and other astronomers, it was realized that the Sun, while near the barycenter of the Solar System, was not at any center of the universe. (Source: https://en.wikipedia.org/wiki/Heliocentrism ) 

Scientific Revolution: drastic change in scientific thought that took place during the 16th and 17th centuries. A new view of nature emerged during the Scientific Revolution, replacing the Greek view that had dominated science for almost 2,000 years. Science became an autonomous discipline, distinct from both philosophy and technology, and it came to be regarded as having utilitarian goals. By the end of this period, it may not be too much to say that science had replaced Christianity as the focal point of European civilization. Out of the ferment of the Renaissance and Reformation there arose a new view of science, bringing about the following transformations: the reeducation of common sense in favour of abstract reasoning; the substitution of a quantitative for a qualitative view of nature; the view of nature as a machine rather than as an organism; the development of an experimental method that sought definite answers to certain limited questions couched in the framework of specific theories; and the acceptance of new criteria for explanation, stressing the “how” rather than the “why” that had characterized the Aristotelian search for final causes. (Source:

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Enlightenment: French siècle des Lumières (literally “century of the Enlightened”), German Aufklärung, a European intellectual movement of the 17th and 18th centuries in which ideas concerning God, reason, nature, and humanity were synthesized into a worldview that gained wide assent in the West and that instigated revolutionary developments in art, philosophy, and politics. Central to Enlightenment thought were the use and celebration of reason, the power by which humans understand the universe and improve their own condition. The goals of rational humanity were considered to be knowledge, freedom, and happiness. (Source:

https://www.britannica.com/science/Scientific-Revolution)

https://www.britannica.com/event/Enlightenment-European-history )

Check out this website to visualize the differences in the geocentric and heliocentric models: https://www.khanacademy.org/partnercontent/nasa/measuringuniverse/spacemath1/p/interact-models-of-the-solar-system

Astronomy Smart Sparrow Lesson Notes

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Why might Copernicus’s book, which promoted heliocentrism, have been banned by authorities (church/monarchy)?  To increase dissonance. The idea of putting the Sun at the center of the Solar System was challenging. It perceivably shifted the center of the Universe away from humans. By banning the book, the authorities (at the time) were reducing dissonance by eliminating conflicting ideas.

Paradigm Shift: A paradigm shif, a concept identified by the American physicist and philosopher Thomas Kuhn, is a fundamental change in the basic concepts and experimental practices of a scientific discipline. Kuhn presented his notion of a paradigm shift in his influential book The Structure of Scientific Revolutions (1962). Kuhn contrasts paradigm shifts, which characterize a scientific revolution, to the activity of normal science, which he describes as scientific work done within a prevailing framework, or, paradigm. Paradigm shifts arise when the dominant paradigm under which normal science operates is rendered incompatible with new phenomena, facilitating the adoption of a new theory or paradigm.[1] (Source: https://en.wikipedia.org/wiki/Paradigm_shift )

Watch this video about the Scientific Revolution and the Enlightenment. What ideals are representative of the Enlightenment? 1. 2. 3. 4.

Democratic ideals (liberty, tolerance, fraternity) Checks & balances system in government Separation of Church & State Reliance on science

Tycho Brahe 1546 - 1601 CE Tycho Brahe spent his days meticulously observing the night sky. In his search, he discovered a new light, or “Stella nova,” in 1572. He was also able to discern the relative distances of objects in the night sky using parallactic shift. With parallax, Tycho discerned that his newly discovered “stella nova” was farther away than our own Sun.

Astronomy Smart Sparrow Lesson Notes

Tycho Brahe was not a dull person. Tycho lost the tip of his nose in a duel, with a colleague, over who was the better mathematician. He purportedly wore a gold and silver nose prosthesis for the rest of his life. He liked to party as well. Tycho employed, and worked closely, with Johannes Kepler. It is purported the two did not get along, as Kepler was a serious and melancholy individual. One account has it that he died from a ruptured bladder because he didn’t want to violate protocol and relieve himself during the party. Though incorrect, he also combined the Ptolemaic and Copernican models of the solar system.

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Parallax: (from Ancient Greek παράλλαξις (parallaxis), meaning 'alternation') is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.[1][2] Due to foreshortening, nearby objects show a larger parallax than farther objects when observed from different positions, so parallax can be used to determine distances. (Source: https://en.wikipedia.org/wiki/Parallax )  Hold your thumb out and close each eye independently - it looks like your thumb   

moves - this is parallax. Try this at home! Parallax is the difference in the apparent position of an object when viewed from 2 positions. It is measured by the angle between those two positions. Think of when an image location appears to change when looking with either eye.

You can learn more about parallax and the thumb demonstration by watching this video.

What assumption(s) did the discovery of a “stella nova” challenge? 1. The objects in the night sky were relatively close to the Earth and affixed to concentric spheres. 2. The objects in the night sky are perfect and unchanging (i.e. brightness, size, shape). 3.

Johannes Kepler 1571-1630 CE Kepler was a German mathematician, astronomer, and astrologer, and a very religious individual. He tragically lost his Aunt to accusations of witchcraft (she was burned at the stake), and his wife was also accused and temporarily imprisoned.

Astronomy Smart Sparrow Lesson Notes Kepler meticulously measured (empiricism) the skies. He ultimately described the motion of the planets as being elliptical (instead of circular) around the sun. This moved away from the perfect circle, which had been the ideal. He, too, discovered his very own “Stella nova” in 1604. This was before the invention of the telescope. Kepler is best known for his laws of planetary motion, based on his findings reported in Astronomia nova, Harmonices Mundi, and Epitome of Copernican Astronomy. These works provided some foundation for Isaac Newton's theory of universal gravitation.

You can learn more about Kepler’s Laws in this video.

Galileo Galilei 1564 - 1642 CE Galileo is known as a "Father of Science”, especially observational astronomy, modern physics, and the scientific method. Galileo supported heliocentrism and was found guilty of heresy. He then spent his life under house arrest, and wrote one of his best-known works, Two New Sciences. Galileo proposed that facts and evidence hold truth over assumption. With improved technology (telescope), Galileo found moons orbiting Jupiter. This discovery was challenging, as these celestial bodies did not orbit Earth. Additionally, with his telescope, Galileo discovered the Earth’s moon had “blemishes” - what we now call craters. Discovering such imperfections challenged dogma at the time. Galileo’s findings angered the Church. According to some accounts, some refused to look through the telescope for fear they would be bewitched. Galileo was put on trial and placed under house arrest for the rest of his life.

Giordano Bruno 1548 AD - 1600 AD Galileo’s friend, Giordano Bruno - friar, philosopher, mathematician, poet, and cosmologist - did not fare so well. Bruno proposed an infinite universe that reflected the majesty of God. He was ultimately burned at the stake for heresy. It is unclear whether this was over his “infinite universe” concept or other philosophical or theological perspectives... Galileo suffered an easier fate of house arrest for his teachings.

Astronomy Smart Sparrow Lesson Notes

Isaac Newton 1643 - 1727 CE Newton discovered the mathematical discipline of calculus and studied spectroscopy. Spectroscopy is the study of the relation of matter and electromagnetic radiation- often through studying light through a prism. Newton did work on falling bodies and acceleration with apple tree studies- leading to the Law of Gravitation, where all bodies exert gravitational force on other bodies. Newton concluded that gravity accounted for the motion of the planets, and that God had created the universe and its laws. Newton published the Principia Mathematica, one of the most important books in the history of Science.

•Given all the galaxies in the universe, (and with only our knowledge of gravity) what would happen if galaxies were initially stationary in space? →They would be pulled together.

Watch this mini-biography on Sir Isaac Newton. Match the philosopher/scientist with their discoveries. 1. Kepler: 3 Laws of Elliptical Planetary Motion 2. Ptolemy: Ptolemaic Geocentric Model (Spheres on spheres) 3. Copernicus: Heliocentric model (An example of Occam’s Razor) 4. Brahe: Discovered parallax to discover distant changes. 5. Galileo: Used a telescope to discover Jupiter’s moons and blemishes on Earth’s moon. 6. Newton: Described the active force of gravity.

Edwin Hubble 1889 - 1953 CE Hubble initially studied Law, due to his father’s wishes, then ultimately turned to Astronomy, his passion. With the aid of powerful telescopes, Hubble observed distant galaxies. He noticed the light coming from these galaxies shifted to the red end of the spectrum-due to the Doppler effectindicating movement away from our vantage point, Earth. This is called red-shift. Hubble introduced “Hubble’s Law”, which indicates that the universe is expanding!

Astronomy Smart Sparrow Lesson Notes

The further away, the faster the galaxies are moving away. This does not imply that Earth is the center of the universe! All galaxies will observe other galaxies moving away from them in an expanding universe unless those galaxies are part of the same gravitationally-bound cluster of galaxies.

Physics Discoveries On the left is a ray of light from the sun, and on the right, light from a distant galaxy. The lines shift toward the red end of the spectrum, due to redshift.

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Light travels through space in the form of electromagnetic waves with varied wavelengths. When a star moves away, wavelengths lengthen and shift towards the red end of the spectrum. When a star moves closer, wavelengths decrease in length and shift to the blue end of the spectrum.

Galaxies are not moving through space, they are embedded in space. Space is expanding at phenomenal speeds! The raisins in the bread dough represent galaxies. As the bread dough bakes, it expands in size causing the raisins to move apart. The raisins aren’t moving through the bread dough, they are being carried away from one another by the expansion of the dough. Watch this video on perspective and scale. Is there a center in an infinite universe? NO. If you can see light from a galaxy 13 billion light years away, what does this tell you about the age of the universe? The universe is at least 13 billion years old.

Astronomy Smart Sparrow Lesson Notes

You can learn more about how Doppler Radar works here.

Georges Lemaitre 1894 - 1966 CE Georges Lemaitre was a Catholic priest, astronomer, and professor of physics. He proposed the theory of the expansion of the universe and introduced the Big Bang theory for the origin of the universe (originally called the “Cosmic Egg”). He coined the beginning point of our universe as the “primeval atom.” It has been proposed that Lemaitre introduced the theory of the expansion of the universe prior to Hubble. Also, it was Lemaitre who first suggested that the red-shift of distant galaxies was due to the expansion of space. His idea was originally ignored – even Einstein originally rejected it. It was later confirmed.

You can learn more about the Big Bang in this video.

Big Bang     

Keep in mind that the the Big Bang was not an explosion,...