Chapter 4 Flashcards
The diagram below shows a view of the eastern horizon (horizontal line ——–) with the direct eastern horizon point labeled B. The direction to points northeast of the direct east point is labeled with an A and an arrow. The point southeast of the direct east point is labeled with a C and an arrow.
A B C
——————EAST——————
For a mid-latitude northern hemisphere observer, what point corresponds to the rising point of the sun on the date of the vernal equinox?
B
The diagram below shows a view of the eastern horizon (horizontal line ——–) with the direct eastern horizon point labeled B. The direction to points northeast of the direct east point is labeled with an A and an arrow. The point southeast of the direct east point is labeled with a C and an arrow.
A B C
——————EAST——————
For a mid-latitude northern hemisphere observer, what point corresponds to the rising point of the sun on the date of the autumnal equinox?
B
If you lived on Mars, which planets would exhibit retrograde motion?
All of these choices are correct.
If you lived on Mars, which planet would be visible as a crescent phase?
Venus
Galileo’s telescope showed him that Venus has a large angular diameter of 61 seconds of arc when it is a crescent; a small angular diameter of 10 seconds of arc when it is nearly full and, finally, when Venus is “half full,” an angular size of 59 seconds of arc. At which point described below is Venus closest to the Earth?
a large angular diameter of 61 seconds of arc when it is a crescent
Galileo’s telescope showed him that Venus has a large angular diameter (61 seconds of arc) when it is a crescent and a small angular diameter (10 seconds of arc) when it is nearly full. When Venus is “half full,” its angular size is about 59 seconds of arc.
This sequence of phases and angular sizes indicates that Venus:
circles the sun.
Why is Stonehenge thought to be an ancient astronomical observatory?
Stones are aligned with significant rising and setting positions.
Plato proposed that all heavenly motion is which of the following?
both circular and uniform
How did Claudius Ptolemy account for the retrograde motion of the planets?
Each planet moves on an epicycle that in turn moves on a deferent that circles around Earth.
Who accurately determined the size of Earth by considering sun angles at Syene and Alexandria?
Eratosthenes (c. 200 BC)
One of the first principles of ancient astronomy is that the heavens beyond _____ are perfect, and the Earth is corrupt.
the moon
Who taught that the Earth is stationary and at the center of the universe with the sun, the moon, and the planets moving around Earth in perfect circles?
Aristotle (384-322 BC)
How did Nicolaus Copernicus account for the retrograde motion of the planets?
Inner planets orbit the sun faster and pass outer planets as they orbit around the sun.
What feature of Aristotle’s model of the universe was included in the model proposed by Copernicus?
uniform circular motion
Why did the model of the universe proposed by Copernicus gain support soon after its publication?
It was a more elegant explanation of retrograde motion.
When Tycho observed the new star of 1572, he could detect no parallax. Why did that result undermine belief in the Ptolemaic system?
This star is farther away than the moon and thus the heavens are not perfect and unchanging.
What was the most important contribution of Tycho Brahe to modern astronomy?
twenty years of accurate measurements of planetary positions
How was Tycho Brahe able to make more accurate astronomical measurements than had been made before his time?
He designed and used large devices to measure small angles.
How did Kepler’s first law of planetary motion alter the Copernican system?
It changed the perfect circles to ellipses and it placed the sun at one focus of each orbit.
Which of the “First Principles of Ancient Astronomy” did Kepler’s laws contradict?
Earth is at the center of the universe and all heavenly motion is uniform and circular.
What does Kepler’s second law indicate about the orbital speed of a planet?
A planet moves at its fastest when it is closest to the sun.
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 whom of the following?
Nicolaus Copernicus
What phases of Venus are predicted by the Ptolemaic system?
new and crescent phases only
What phases of Venus were observed by Galileo?
new, crescent, quarter, gibbous, and full phases
The phases of Venus observed by Galileo support the model of the universe presented by which of the following?
Nicolaus Copernicus
Evidence of early prehistoric human cultures observing astronomical phenomena exists in which of the following?
archaeoastronomical sites
Which is not an archaeoastronomical site?
the island of Hveen
What did Plato propose about all heavenly motion?
The motion is in circular paths.
Why did Plato propose what he did about heavenly motion and the shape of heavenly objects?
because he believed the sphere to be the most perfect geometrical form
What effect did Plato’s proposal have on future astronomers?
His idea of a sphere being the most perfect geometric form influenced astronomical theories for literally hundreds of years.
In Ptolemy’s mathematical model of planetary motion, a planet was on a circular path, known as an epicycle, whose center was on another circular path, a deferent, that was centered on Earth.
Which planets’ motions were described with epicycles in the Ptolemaic system?
all of the known planets
In Ptolemy’s mathematical model of planetary motion, a planet was on a circular path, known as an epicycle, whose center was on another circular path, a deferent, that was centered on Earth.
What were epicycles used to describe?
the retrograde motion of planets
In Ptolemy’s mathematical model of planetary motion, a planet was on a circular path, known as an epicycle, whose center was on another circular path, a deferent, that was centered on Earth.
How did the epicycles of Mercury and Venus differ from those of Mars, Jupiter, and Saturn?
Their centers had to always be on the line between Earth and the sun.
In Ptolemy’s mathematical model of planetary motion, a planet was on a circular path, known as an epicycle, whose center was on another circular path, a deferent, that was centered on Earth.
Why did the centers of the epicycles of Mercury and Venus have to remain on the line between Earth and the sun?
because they were never seen very far from the sun in the sky
Why didn’t Copernicus’s system predict the positions of planets any better than Ptolemy’s?
because he used circular orbits
Galileo made several important telescopic discoveries.
How did Galileo’s telescopic discovery of craters on the moon contradict Ptolemaic theory?
It showed that a heavenly body was not perfect
Galileo made several important telescopic discoveries.
How did Galileo’s telescopic discovery of the moons of Jupiter contradict Ptolemaic theory?
It showed that not everything orbited Earth.
Galileo made several important telescopic discoveries.
How did Galileo’s telescopic discovery of sunspots contradict Ptolemaic theory?
It showed that a heavenly body was not perfect.
Which of the following scientists was condemned by the Catholic Church?
Galileo
In 1572, Tycho observed a brilliant “new star,” now called Tycho’s supernova.
Which is true about Tycho’s “Tychonic” system?
Planets orbited the sun, which orbited Earth.
Which is an assertion or conjecture that must be tested?
a hypothesis
Which is a system of rules and principles that can be applied to a wide variety of circumstances?
a theory
Which is a theory that has been refined, tested, and confirmed so often that scientists have great confidence in it?
a natural law
Which represents an unchangeable truth?
None of these choices are correct.
Which set of astronomical tables was developed most recently?
the Rudolphine tables
Which set of astronomical tables is based on Ptolemy’s model?
the Alfonsine tables
Which set of astronomical tables is based on the Copernican model?
the Prutenic tables
Which set of astronomical tables were worked on by Tycho and Kepler?
the Rudolphine tables
Which set of astronomical tables were considered most accurate?
the Rudolphine tables
Which list below has the life and work of the following scientists in chronological order, from left to right?
Copernicus, Galileo, Tycho, Ptolemy
Ptolemy, Copernicus, Tycho, Galileo
The quantitative numerical result of Kepler’s research was
a set of tables giving future positions of the planets.
Below is a postage stamp with a picture of a scientist holding an astronomical model.
Which object is the central figure in the model?
sun
Below is a postage stamp with a picture of a scientist holding an astronomical model.
Who developed this theoretical model?
Copernicus
Below is a postage stamp with a picture of a scientist holding an astronomical model.
What is the larger circle in his model?
a deferent
Below is a postage stamp with a picture of a scientist holding an astronomical model.
What is the smaller circle in his model?
an epicycle
Whose observatory is shown in the figure below?
Tycho’s
