Astronomy Chapter 4 Study guide – Flashcards
Unlock all answers in this set
Unlock answersquestion
Why are Stonehenge and The Big Horn Medicine Wheel thought to be ancient astronomical observatories?
answer
For the way it aligned with the sun.
question
What was Plato's idea about the motion of heavenly bodies?
answer
He thought they were makers of time
question
How did Ptolemaeus account for the retrograde motion of the planets?
answer
epicycles
question
Who accurately determined the size of the Earth by considering sun angles at Syene and Alexandria?
answer
Eratosthenes around 200 B.C
question
Who taught that the Earth is stationary and the center of the universe with the sun
answer
the moon, and the planets moving around Earth in perfect circles?,Aristotle
question
How did Nicolaus Copernicus account for the retrograde motion of the planets?
answer
inner planets orbit the sun faster and pass after planets as they orbit around the sun
question
What feature of Aristotle's model of the universe was included in the model proposed by Copernicus?
answer
uniform circular motion
question
Why did the model of the universe proposed by Copernicus gain support soon after its publication?
answer
It has a better explanation than retrograde motion
question
When Tycho observed the new star of 1572, he could detect no parallax. Why did that result undermine belief in the Ptolemaic system?
answer
It proved the Heavens weren't perfect
question
What was the most important contribution of Tycho Brahe to modern astronomy?
answer
He had very accurate measurements of planets positions
question
How was Tycho Brahe able to make more accurate astronomical measurements than had been made before his time?
answer
He made an instrument to measure small angles
question
How did Kepler's first law of planetary motion after the Copernican system?
answer
He said it was ellipses
question
Which of the "First Principles of Ancient Astronomy" did Kepler's laws contradict?
answer
The Heavens weren't perfect and the Earth is not in the center of the universe
question
What does Kepler's second law indicate about the orbital speed of a planet?
answer
It moves fast when close to the sun, moves slower when its away from the sun
question
If the semimajor axis of a planet is 4 AU what is its orbital period?
answer
8 years
question
Galileo's discovery of four moons orbiting Jupiter showed that planetary bodies could move and carry moons. This supports the model of the universe presented by which astronomer?
answer
Copernicus
question
What phases of Venus were observed by Galileo?
answer
a complete cycle
question
The phases of Venus observed by Galileo support the model of the universe presented by which astronomer?
answer
Copernicus
question
Why is the Copernican system no more accurate than the Ptolemaic system in predicting the positions of the planets?
answer
the orbits were in a perfect cycle
question
What was the main idea of Ptolemy's model of planetary motion?
answer
The Earth was at the center of the universe
question
Why were the telescopic discoveries of mountains on the moon and spots on the sun so controversial?
answer
It proved that they weren't perfect
question
Why was Galileo's telescopic discovery of moons orbiting Jupiter important?
answer
There could be other centers that caused Planetary motion
question
What was the biggest difference between Brahe's universe and Copernican universe?
answer
Tycho believed Earth was the center of the universe and Copernican belived the sun was the center of the universe
question
What was Tycho Brahe's greatest contribution to astronomy?
answer
Precise measurement
question
What is the significance of the two stone cairns in the Big Horn Medicine Wheel?
answer
They're aligned with the summer solstice
question
What were the three major contributions of Hipparchus to astronomy and math?
answer
Trigonometry, star catalog, precision
question
Be able to work orbital period problems
answer
page 71.
