By the end of this unit, a successful student will be able to:
- be able to describe the Ptolemaic, geocentric view of the universe including the use of such terms as epicycle and deferent, prograde and retrograde motion, superior and inferior planets, conjunction and opposition.
- recognize the motivations that led to the Copernican heliocentric view of the universe - particularly in simplifying the motions of the Moon and planets
- see how the Copernican revolution challenged the prevailing world view of the time and moved the Earth from a special, central place to a more average place
- identify Galileo’s early contributions to astronomy and describe how they supported the Copernican heliocentric view.
- Note the flaws in Copernican theory (continued use of epicycles, no aberration of starlight or stellar parallax visible at the time) and how they were addressed by Kepler and other later astronomers
- Identify the postions of the inferior and superior planets as they appear in heliocentric theory, and how those positions correspond to where they appear in the evening and morning skys. (Maximum elongation, conjunction, opposition, quadrature)
- Understand how geometry was used to determine the relative distances to the planets and be able to solve a right angle trigonometry problem to determine the distances to inferior planets.
- explain how triangulation (parallax) and radar have been used to determine absolute distances in the solar system.
- Describe Tycho Brahe’s contributions to Kepler’s research
- Describe Kepler’s three laws of planetary motion
- identify the features of an ellipse and elliptical orbit including the semi-major axis, eccentricity, perihelion and aphelion
- describe how eccentricity relates to the shape of an ellipse
- explain the consequences of the 2nd law on how a planet changes speed in its orbit
- Use the third law to determine either the period or the semi-major axis of an object orbiting the Sun
- Use the third law and ratio reasoning to describe how an object’s period would change if its semi-major axis would change by a simple factor (or vice versa)
- describe what a force is according to Newton’s laws of motion
- describe the meaning of Newton’s law of gravity ( ) and use ratio reasoning to identify how much the force would change if the distance or mass were to change by an integer factor (i.e. mass or distance were doubled, tripled, cut in half, etc. )
- explain how Newton’s laws modify Kepler’s laws.
- describe how Newton’s version of Kepler’s 3rd law can be used to determine the masses of distant objects (stars with companions, planets with moons, galaxies, etc.)
All assignments are due on the date listed. That is not the date they are assigned.
Due date Day Assignment
9/28 Thu Read: 2.1, 2.2 (Ptolemaic, geocentric universe)
Do: R&D: 1, 2, 3
CST: 3
Define: retrograde, prograde, inferior planets, superior planets,
inferior conjunction, superior conjuction, opposition
9/29 Fri Read: 2.3, 2.4 (Copernicus & Galileo – heliocentric universe)
Do: R&D: 4, 6, 7, 8
T/F& MC: 3,4,12,13
10/2 Mon Read 2.5, 2.6 (Brahe, Kepler, elliptical oribits)
Do: R&D: 9, 10, 11, 12
T/F & MC: 5, 6, 7, 8,
10/3 Tue Do: T/F & MC: 15, 16, 17
Problems: 3,4 (skip eccentricity), 5, 6,8
Term 3 Progress Reports
10/4 Wed Do: Kepler activity – ellipse lab
10/5 Thu Read: 2.7
Do: R&D: 14, 18, 19,20
TF & MC: 10, 18, 19, 20
10/6 Fri Kepler’s 3rd Law problems
10/9 Mon Test Ch 2
Observations TBA
Observing targets: Evening: Saturn (very low west)
Andromeda Galaxy
Early Morning: Venus, Mars, Jupiter (low East, Venus highest, Jupiter lowest)
Orion Nebula
Online Labs & simulations: Solar Systems Model Lab UNL: http://astro.unl.edu/naap/ssm/ssm.html
Planetary Orbits - UNL: http://astro.unl.edu/naap/pos/pos.html
Links - Ancient Astronomy, The Copernican Revolution & Kepler's Orbits
Ancient Astronomy
- The Babylonians have left us the earliest written records of astronomy. A map illustrating their view of the world and heavens, including their zodiac can be found in thisMonograph from the British Library
- To their east, the ancestors of the Indians were developing their study of the stars and planets as well. The Antiquity and Astronomy of the Vedic Culture page covers their enterprises. (Broken Link 8/24)
- After the Babylonians and Egyptians, the early Greeks wrestled with problems of astronomy and cosmology.
- Eratosthenes is the earliest recorded person to scientifically estimate the size of the Earth to relative accuracy. Carl Sagan explains this discovery in this youtube clip from his 1980 mini-series Cosmos: Episode I - The Shores of the Cosmic Ocean: Eratosthenes measures the size of the Earth, 6 min 58 s
- In the Americas, Mayan Astronomy reached its heights independent of the cultures on the other side of the Atlantic.
- For further information, Wolfgang Dick maintains an extensive set of links related to The History of Astronomy (Broken Link 8/24)
- Between Ptolomey and Copernicus, much of the advances in astronomy were made by Muslim Mathemeticians, Astronomers, and Scientists.
- Carl Sagan details Kepler's life and the scientific method in the third episode of his 1980 mini-series Cosmos. This YouTube clip ends and summarizes the episode while relating Kepler's dream of a trip to the Moon. Episode III - The Harmony of the Worlds: Kepler's tale of a trip to the moon and his mother's arrest, summary of Kepler's acceptance of facts; 3 min 45 s