Astronomy Chapter 3 – Flashcards
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Scientific Thinking
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based on everyday ideas of observation and trial and error experiments
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Ways people used science in the past
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keeping track of time/seasons agriculture religious purposes aiding navigation
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What did ancient civilizations achieve in astronomy?
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daily timekeeping seasons and calendars lunar cycles planets and stars predicting eclipses
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Ancient greek science
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math and science originated in middle East Babylonia-time and circles Greeks first known to make scientific models of nature.. geocentric model
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Pluto and Aristotle
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Earth-center of the universe Heavens must be "perfect" Perfect spheres in perfect circles difficult to explain retrograde motino
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Ptolemy (AD 100-700)
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Ptolemaic model... sufficiently accurate Planets go backward in the model circle on a circle
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How did Islamic scientists preserve/extend Greek science?
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Baghdad- holds Astronomy info Europe- middle/Dark ages... Knowledge went back to Europe in the renaissance. Renaissance: rediscovered what Greeks had learned
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Copernicus (1473-1543)
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proposed sun centered model something going around something else determine layout of the solar system correct planetary distances in AU incorrect-still used perfect circles
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Tycho Brahe (1546-1601)
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complied the most accurate naked eye measurements couldn't detect stellar parallax geocentric other planets go around the sun
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Johannes Kepler (1571-1630)
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tried to match Tycho's observation with circular orbits eventually led to ellipses ellipse: elongated circle.. focus points
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Kepler's 1st law of planetary motion
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the orbit of every planet around the sun is an ellipse with the sun at one focus
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Kepler's 2nd law of planetary motino
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as a planet moves around its orbit, it sweeps out equal areas in equal times
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Kepler's third law of planetary motino
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more distant planets orbit the sun at slower average speeds
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Galileo's object to Copernican view
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1. Earth could not be moving because objects in air would be left behind 2. Noncircular orbits are not "perfect" as heavens should be 3. If Earth were really orbiting the Sun, we'd detect stellar paralax
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Overcoming the first objection
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Aristotle- all objects naturally come to rest Galileo- an object that will stay in motion unless a force acts to slow them down Newton's 1st law of motion
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Overcoming the second objection
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Tycho- comet and supernova challenged idea of perfection Using telescopes, Galileo saw: sunspots on sun mountains an valleys on the moon, not a perfect sphere
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Overcoming the third objection
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Galileo looked at Milky Way with telescope made out of stars.. considered that stars are really far Galileo didn't measure parallax with telescope
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Galileo saw four moons orbiting Jupiter
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shocking... moons move around moving planet
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Phases of Venus
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prove that it orbits Sun not Earth
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What practical value did astronomy offer to ancient civilizations?
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It helped them keep track of time and seasons, and it was used by some cultures for navigation
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Scientific Thinking is _________.
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based on everyday ideas of observation and trial and error experiments
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The names of the seven days of the week are based on __________.
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the seven naked eye objects that appear to move along the constellations
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The metonic cycle is _________.
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used to keep lunar calendars approximately synchronized with solar calendars
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Ptolemy was important to the history of astronomy because he __________.
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developed a model of the solar system that made sufficiently accurate predictions of planetary positions to remain in use for many centuries.
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The ancient Greeks get a lot of attention for their contribution to science because ________.
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they were the first people known to try to explain nature with models based on reason and mathematics, without resort to supernatural
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What do we mean by a geocentric model of the universe?
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a model designed to explain why we see in the sky while having Earth at the center of the universe
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What was the Ptolemaic model?
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An Earth centered model of planetary motion published by Ptolemy
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The great contribution of Nicholas Copernicus was to _________.
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create a detailed model of our solar system with the Sun rather than the Earth at the center
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The great contribution of Tycho Brahe was to ___________.
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observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion
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Stellar paralax was ____ observed by Galileo
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NOT
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The focus of an ellipse is ______ located precisely at the center of the ellipse
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NOT
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Not one of direct consequence of Kepler's laws
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the force of attraction between only 2 objects decreases with the square of the distance between their centers
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Scientific models are used to ________.
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make specific predictions that can be tested through observations or experiments
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In science, a broad idea that has been repeatedly verified so as to give scientists great confidence that it represents reality is called a __________.
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theory
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Suppose the planet uranus were much brighter in the sky, so that it was easily visible to the naked eye what would most likely be true in this case?
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A week would eight days instead of 7.
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How does a 12 month lunar calendar differ from our 12 month solar calendar?
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It was 11 fewer days
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What best describes a set of conditions under which archaeoastronomers would conclude that an ancient structure was used for astronomical purposes?
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the structure has holes in the ceiling that allow viewing the passage of constellations that figure prominently in the cultures folklore
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How did the Ptolemaic model explain apparent retrograde motion?
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the planets moved along small circles that moved on larger circles around the Earth
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When Copernicus first created his sun-centered model of the universe, it did not lead to substantially better predictions of planetary positions than the ptolemaic model..why not?
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Copernicus used perfect circles for orbits of the planets
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Earth is farthest from the Sun in July and closest to the sun in January. During which season is Earth moving fastest in its orbit?
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Winter
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According to Kepler's 3rd law, how does a planet's mass affect its orbit around the Sun?
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mass has no effect on orbit around the Sun
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All statements are true.. which deals with Kepler's 3rd law?
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Venus orbits the Sun at a slower average speed than Mercury
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Suppose a comet orbits the Sun on a highly eccentric orbit with an average (semimajor axis) distance of 1 AU. How long does it take to complete each orbit?
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1 year which we know from Kepler's 3rd law
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Galileo challenged the idea that objects in heaven were perfect by__________.
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observing sunspots on the sun/and mountains on the moon
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Galileo observed all of the following... which observation offered direct proof of a planet orbiting the sun?
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phases of Venus
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Which of the following is not with the major hallmarks of science?
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Science consists of proven theories that are understood to be true explanations of reality
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Which of the following is not a good scientific theory?
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A scientific theory cannot be accepted until it has been proven true beyond all doubt
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Which one uses the word "theory" correctly?
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Einstein's theory of relativity has been tested and verified thousands of times
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Imagine that despite all the evidence, Earth actually is not rotating and orbiting the Sun. Which hypothetical observation would be inconsistent with Sun centered view of the Solar System?
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We discover a small planet beyond Saturn that rises in the west and sets in the East each day.
