Astronomy Chapter 3
Which of the following are the three key hallmarks of science?
1) science progresses through the creation and testing of models of nature that explain the observations as simply as possible. 2) models must make testable predictions that will force us to revise or abandon the model if they do not agree with observations. 3) modern science seeks explanations for observed phenomena that rely solely on natural causes
Jupiter orbits the Sun at an average distance of 5.203 AU and takes 11.86years to complete each orbit. Based on these facts, which statement is true?
11.86^2=5.203^3
Ellipse
A elongated circle, or oval shape, the shape of the planets orbit.
Kepler's Second Law
A planet moves faster in the part of its orbit nearer the Sun and slower when farther from the Sun, sweeping out equal areas in equal times.
During the Dark Ages in Europe, the scientific work of the ancient Greeks was preserved and further developed primarily by scholars in
Baghdad.
Earth is slightly closer to the Sun in January than in July. How does the area swept out by Earth's orbit around the Sun during the 31 days of January compare to the area swept out during the 31 days of July?
Both areas are the same.
The controversial book of this famous person, published in 1543 (the year of his death), suggested that Earth and other planets orbit the Sun.
Copernicus
He discovered that Jupiter has moons.
Galileo
He discovered what we now call Newton's first law of motion.
Galileo
One of the "nails in the coffin" for Earth-centered universe was
Galileo's observations of the moons of Jupiter.
How did the Ptolemaic model explain the apparent retrograde motion of the planets?
It held that the planets moved along small circles that moved on larger circles, also known as epicycles, around Earth.
Why wasn't the Sun-centered model of Copernicus immediately adopted after he proposed it?
It was not noticeably more accurate than the old Ptolemaic model
He discovered that the orbits of planets are ellipses.
Kepler
All of the following statements are true. Which one can be explained by Kepler's second law?
Mars moves faster in its orbit when it is closer to the Sun than when it is farther from the Sun.
Kepler's Third Law
More distant planets orbit the sun at slower average speeds, obeying a precise mathematical relationship. (p^2=a^3
You discover an asteroid that orbits the Sun with the same 1-year orbital period as Earth. Which of the following statements must be true?
The asteroid's average (semimajor axis) distance from the Sun is 1AU.
Which of the following is not one of, nor follows directly from, Kepler's laws?
The force of attraction between any two objects decreases with the square of the distance between their centers.
Process of Science: What is Occam's razor?
The idea that scientists should prefer the simpler of two models that agree equally well with observations.
Kepler's First Law
The orbit of each planet around the Sun is an ellipse with the Sun at one focus.
An original observation of Galileo's that helped to overturn the ancient Earth-centered model was
The phases of Venus
Which of the following statements about scientific theories is false?
Theories are not taken seriously if they contradict older, more developed, theories.
What do the structures of Stonehenge, the Templo Mayor, and the Sun Dagger all have in common?
They were all used by ancient peoples for astronomical observations
Kepler's Laws of Planetary Motion
Three laws discovered by Kepler that describe the motion of the planets around the Sun.
He was the first to prove that comets lie beyond Earth's atmosphere.
Tycho Brahe
All the following statements are true. Which one follows directly from Kepler's
Venus orbits the Sun at a slower average speed than Mercury.
Which of the following can you observe about Venus with the naked eye? Select all that apply.
Venus sometimes shines brightly in the western sky shortly after sunset Venus sometimes shines brightly in the eastern sky shortly before dawn
As you learned in the video, Galileo's observations of Venus in gibbous (nearly full) phase showed conclusively that Venus orbits the Sun, not Earth. Which figure shows Venus's position when Galileo saw it in gibbous phase?
Venus to the top left of the Sun (farther from the Earth than from the Sun)
What do we mean by a geocentric model of the universe?
a model designed to explain what we see in the sky while having Earth located in the center of the universe
Part complete Kepler's second law, which states that as a planet moves around its orbit it sweeps out equal areas in equal times, means that
a planet travels faster when it is nearer to the Sun and slower when it is farther from the Sun.
Part complete When did Ptolemy live?
about 2,000 yrs ago
When did Copernicus live?
about 500 years ago
Kepler's third law, p2 = a3, means that
all orbits with the same semimajor axis have the same period. a planet's period does not depend on the eccentricity of its orbit. planets that are farther from the Sun move at slower average speeds than nearer planets. the period of a planet does not depend on its mass.
At the Sun Dagger in New Mexico, a dagger-shaped beam of sunlight pierces a spiral
at noon on the summer solstice.
Scientific thinking is _________.
based on everyday ideas of observation and trial-and-error experiments
Where was the Sun in Ptolemy's model of the universe?
between the orbits of Venus and Mars
How did Eratosthenes estimate the size of Earth in 240 B.C.?
by comparing the maximum altitude of the Sun in two cities at different latitudes on the summer solstice
epicycle
circle within a circle
model
conceptual representation created to explain and predict observed phenomena
Ptolemy was important in the history of astronomy because he
developed a model of the solar system that made sufficiently accurate predictions of planetary positions to remain in use for many centuries.
Copernicus was the first person to suggest a Sun-centered solar system. t/f
false
Process of Science: I am doing science when I already know the answer to my scientific question and I am searching for evidence in the natural world strictly to support what I know. t/f
false
Based on the video, which Venus phase would be impossible to see (from Earth) if Venus orbited Earth as described in Ptolemy's Earth-centered model?
gibbous (nearly full)
semi-major axis
half of the major axis
In Ptolemy's Earth-centered model, when would Venus appear directly behind the Sun as viewed from Earth?
never
The great contribution of Tycho Brahe was to _________.
observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion
Aphelion
point in a planet's orbit that is farthest from the sun
Perihelion
point nearest point to the sun
The names of the seven days of the week are based on the
seven naked-eye objects that appear to move among the constellations.
The shadow cast by a simple stick or obelisk allowed ancient people to
tell the time of day
The path that led to modern science emerged from ancient civilizations in which part of the world?
the Mediterranean and the Middle East
Deferent
the circle around the earth in which a celestial body or the center of the epicycle of its orbit was thought to move
minor axis
the shorter axis of an ellipse
The ancient Greeks get a lot of attention for their contributions to science because _________.
they were the first people known to try to explain nature with models based on reason and mathematics, without resort to the supernatural
Why did Ptolemy have the planets orbiting Earth on "circles upon circles" in his model of the universe?
to explain the fact that planets sometimes appear to move westward, rather than eastward, relative to the stars in our sky
A scientific model must make a testable prediction. t/f
true
Process of Science: If any single test of a scientific hypothesis contradicts it, the hypothesis must be revised. (Assume that you've ruled out errors in the testing process; that is, the test result really does contradict the hypothesis.) t/f
true
