1 Name________________________ Unit 2: The Copernican Revolution Vocabulary: Define each term below in a complete sentence on a separate sheet of paper. (Terms that are *, please illustrate) Cosmology Retrograde Motion* Geocentric* Epicycle* Deferent* Ptolemaic Model* Heliocentric* Copernican Revolution Ellipse* Focus* Semi-major axis* Eccentricity Perihelion* Aphelion* Sidereal orbital period Escape Velocity* Inertia Mass Newtonian Mechanics Gravitational Field Stonehenge* Acceleration Gravity* A. Ancient Astronomy 1.Where is Stonehenge? When and who built it? -Salisbury Plain, _______________ -Began 2800-finished __________ B.C. -took 1700 years 2.What was Stonehenge’s purpose? -3-dimensional ____________________, for religious and agriculture purposes -brought in large boulders (up to 50 tons) from miles away 3. What ancient cultures were accomplished in ancient astronomy? -Mayans- ____________Temple in Mexico- used for human sacrifices when the planet Venus appeared -Plains Indians- Big Horn Medicine Wheel, ____________________ -Chinese- 12th century, kept accurate records of comets, and a ‘guest star’ later known as a supernova, visible during the __________ -Muslims- a vital link between ancient Greece and the Renaissance (dark ages), saved astronomical data, developed trigonometry, names stars such as Rigel, _____________ and Vega B. The Geocentric Universe 1.What Greek word is the word planet derived from, why did they get this name? -________________—meandering wanderer, stay close to ecliptic, why? 2. Explain the difference between retrograde and prograde motion: -Prograde motion- ___________________ -Retrograde motion- _____________________ 3. What did Aristotle mean by a geocentric universe? -Geo= Earth -___________________________ 4. How was the geocentric Earth explained by epicycle and deferent? -_____________- small orbits -______________- larger orbits C. Model of the Solar System 1.Who was Nicholas Copernicus? -______________________- rediscovered heliocentric model from ancient Greece-Aristarchus 2. Describe the seven points of the Copernican Revolution in your own words: 1)Earth isn’t the center of ________________ 2)Earth is only center to ______________________________ 3)All planets revolve around the Sun 4)Stars are much further away than the Sun 5)Any motions from the stars—_____________________________ 6)Sun’s motion due to ________________________ 7)Retrograde motion can only be explained accurately through a __________________________ 3.What was Copernicus’s motivation for his geocentric model? -Wanted a simpler model to explain the motion of planets—__________________________ 2 D. The Birth of Modern Astronomy 1.Who was Galileo Galilei? -Italian mathematician/philosopher -_______________________________, saw conflict with Aristotle’s geocentric model 2. What did Galileo see with one of the first telescopes? -Moon- _____________________________________________________________ -Sun- had blemishes (sunspots)—inferred the Sun rotates -Jupiter- __________________________________________________ Strong support for Copernican model of solar system 3. What confrontation did Galileo face based on his observations? -Galileo published __________________ -Roman Catholic Church- burned ____________(astronomer) a few years before based on his strong belief in Copernican model -Same for Galileo unless he takes back what was said in his book -He denied his book and was placed under house arrest for life after the ______________ -Was obviously correct, Catholic Church only recently admitted it was wrong in the 1980’s, over 300 years later E. Kepler’s Laws of Planetary Motion 1.Who was Johannes Kepler? -______________________ 2.What did Kepler inherit? -_______________________ position as Imperial Mathematician of Holy Roman Empire and all of his observations of planets 3. How did Kepler determine the shape of a planet’s orbit? -Thru __________________ of different part of Earth’s orbit 4. What is Kepler’s first law? -All orbits of planets are ________________________________ 5. How is an ellipse different than a circle? -An elongated circle -focus- _____________________ -major axis- ________________________________ 6. What is a semi-major axis and eccentricity? -Semi-major axis- ___________________________________________ -Eccentricity- ratio of the distance between the foci to the length of the major axis -Circle- ____________________________________________________ 7. What distances can we calculate from the semi-major axis and the eccentricity? -________________- closest approach to the Sun -________________- greatest distance to the Sun 8.Define Kepler’s second law (in your own words): -As objects approaches perihelion they _______________________ 9.Define Kepler’s third law (in your own words): -________________________________________________ 10.What are major points of the front cover: Orbital Properties of Planets: -Almost all of the planets’ orbits except Pluto and Mercury are almost circles= eccentricity is close to 0 F. Dimensions of the Solar System? 1.What do Kepler’s laws not tell us about the planets? -____________________________________________________________________ 2. What are the two methods for determining the distance to the Sun? a. __________________________________________________ b. ___________________________________________________ 3 3. What is an exact A.U., how do we know? -149,597,870 km, we’ll just use 150,000,000 km, ______________________________ G. Newton’s Laws 1.Why are Kepler’s discoveries described as empirical? -Came from analysis of observational data, not derived from _____________________________ -in other words: Why did the planets orbit the Sun? __________________________ 2. Who was Isaac Newton? -________________________________________________ (same year Galileo died) -Discovered laws of gravity 3.What are Newton’s Three Laws (in your own words): 1) _________________________________________________________________________________ ___________________________________. 2) ____________________________________________________________ 3) ________________________________________________________________ 4.How is gravity different on Earth than the Moon? -The more massive an object = _______________________ -Moon- its mass is less than Earth= less gravity 5.What is the inverse-square law? -_____________________________________________________ 6. What is the formula for Newton’s law gravity? -_______________________= (Mass of object #1) x (Mass of object #2)/distance2 7.What two forces are the reason for Earth’s motion? -_______________________ 8.How fast is the Earth traveling around the Sun? -30 km/second or ________________________ 9.How do you know the Earth is traveling this fast? -Earth’s circle of radius= 1 A.U.= circumference= 2(PIE)A.U.= 940 km 10.What is the mass of the Sun and Earth? -Sun: ______________ -Earth: ______________ 11. How are the masses of the Sun and Earth calculated? -Need to know gravitational influence -Earth- need to know distance to moon and length of sidereal month -Sun- ____________________________________________________ 12. How did Newton modify Kepler’s third law, why? -Both planet and Sun orbit their common center of mass= 2 foci -Kepler= period(year)2 = semi-major axis (A.U.) 3 , / -Newton= _________________________________ 13. Define escape velocity -________________________________ 14. What is the formula for escape velocity? -Escape Velocity = 15. What is the escape velocity of Earth? -To stay in orbit = constant free fall but have inertia = 7.9 km/second or ______________________ -To escape Earth= 11.2 km/second or _________________________ .