CH.3 Mastering Astronomy

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, and how do we know? It depends on the eccentricity of the orbit, as described by Kepler's second law. It depends on the eccentricity of the orbit, as described by Kepler's first law. 1 year, which we know from Kepler's third law. Each orbit should take about 2 years because the eccentricity is so large.

1 year, which we know from Kepler's third law

What do we mean by a geocentric model of the universe? A model of the Milky Way Galaxy that has our solar system located at its center. A model designed to explain what we see in the sky while having the Earth orbit the Sun. A model designed to explain what we see in the sky while having the Earth located in the center of the universe. It is the name given to sphere-shaped models that show all the constellations as they appear in our sky on the celestial sphere.

A model designed to explain what we see in the sky while having the Earth located in the center of the universe.

According to Kepler's third law (p2 = a3), how does a planet's mass affect its orbit around the Sun? More massive planets orbit the Sun at higher average speed. More massive planets must have more circular orbits. A more massive planet must have a larger semimajor axis. A planet's mass has no effect on its orbit around the Sun.

A planet's mass has no effect on its orbit around the Sun.

Which of the following is not part of a good scientific theory? A scientific theory cannot be accepted until it has been proven true beyond all doubt. A scientific theory must make testable predictions that, if found to be incorrect, could lead to its own modification or demise. A scientific theory must explain a wide variety of phenomena observed in the natural world. A scientific theory should be based on natural processes and should not invoke the supernatural or divine.

A scientific theory cannot be accepted until it has been proven true beyond all doubt.

Suppose the planet Uranus were much brighter in the sky, so that it was as easily visible to the naked eye as Jupiter or Saturn. Which one of the following statements would most likely be true in that case? Its slow motion through the sky would have led it to be named after the Goddess of Procrastination. The discovery that the Earth is a planet going around the Sun would have come hundreds of years earlier. A week would have 8 days instead of 7. Its brightness would make it possible to read by starlight at night. Its gravity would cause the tides to be much higher than they actually are.

A week would have 8 days instead of 7.

What was the Ptolemaic model? An Earth-centered model of planetary motion published by Ptolemy A Sun-centered model of planetary motion published by Ptolemy The Earth-centered model of the cosmos in which the Earth was surrounded by seven perfect spheres, one each for the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn The first scientific model to successfully predict solar and lunar eclipses

An Earth-centered model of planetary motion published by Ptolemy

Which of the following best describes how modern astronomers view astrology? Astrology was a great idea until it was disprove by the work of Copernicus, Tycho, Kepler, and Galileo. Astrology played an important part in the development of astronomy in ancient times, but it is not a science by modern standards. Astrology is new age mumbo-jumbo that was a waste of time when it was invented thousands of years ago and remains a waste of time today. Astrology is a synonym for astronomy.

Astrology played an important part in the development of astronomy in ancient times, but it is not a science by modern standards.

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? Copernicus placed the planets in the wrong order going outward from the Sun. Copernicus placed the Sun at the center but did not realize that the Moon orbits the Earth. Copernicus used perfect circles for the orbits of the planets. Copernicus misjudged the distances between the planets.

Copernicus used perfect circles for the orbits of the planets.

Only one of the statements that follow uses the term theory in its correct, scientific sense. Which one? Evolution is only a theory, so there's no reason to think it really happened. I have a new theory about the cause of earthquakes, and I plan to start testing it soon. Einstein's theory of relativity has been tested and verified thousands of times. I wrote a theory that is 152 pages long.

Einstein's theory of relativity has been tested and verified thousands of times.

How does a 12-month lunar calendar differ from our 12-month solar calendar? It has about 11 fewer days. It does not have seasons. Its new year always occurs in February instead of on January 1. It uses a 23-hour rather than a 24-hour day.

It has about 11 fewer days.

What practical value did astronomy offer to ancient civilizations? It helped them keep track of time and seasons, and it was used by some cultures for navigation. It helped them find uses for ancient structures like Stonehenge. It helped them understand our cosmic origins. It allowed them to predict eclipses with great accuracy.

It helped them keep track of time and seasons, and it was used by some cultures for navigation.

Galileo observed all of the following. Which observation offered direct proof of a planet orbiting the Sun? Patterns of shadow and sunlight near the dividing line between the light and dark portions of the Moon's face Phases of Venus Four moons of Jupiter. The Milky Way is composed of many individual stars.

Phases of Venus

Which of the following is not consistent with the major hallmarks of science? A scientific model must make testable predictions. Science progresses through the creation and testing of models that explain observation as simply as possible. Science consists of proven theories that are understood to be true explanations of reality. Scientific explanations should be based solely on natural causes.

Science consists of proven theories that are understood to be true explanations of reality.

Which of the following was not observed by Galileo? Four moons orbiting Jupiter Phases of Venus Stellar parallax Mountains and valleys on the Moon

Stellar parallax

Which of the following statements about an ellipse is not true? The focus of an ellipse is always located precisely at the center of the ellipse. A circle is considered to be a special type of ellipse. The semimajor axis of an ellipse is half the length of the longest line that you can draw across an ellipse. An ellipse with a large eccentricity looks much more elongated (stretched out) than an ellipse with a small eccentricity.

The focus of an ellipse is always located precisely at the center of the ellipse.

Which of the following is not one of, nor a direct consequence of, Kepler's Laws? More distant planets orbit the Sun at slower speeds. A planet or comet in a noncircular orbit travels faster when it is nearer to the Sun and slower when it is farther from the Sun. As a planet moves around its orbit, it sweeps out equal areas in equal times. The orbit of each planet about the Sun is an ellipse with the Sun at one focus. The force of attraction between any two objects decreases with the square of the distance between their centers.

The force of attraction between any two objects decreases with the square of the distance between their centers.

How did the Ptolemaic model explain the apparent retrograde motion of the planets? The planets resided on giant spheres that sometimes turned clockwise and sometimes turned counterclockwise. The planets sometimes stopped moving and then reversed to move backward along their circular orbits. The planets moved along small circles that moved on larger circles around the Earth. The model showed that apparent retrograde motion occurs as Earth passes by another planet in its orbit of the Sun.

The planets moved along small circles that moved on larger circles around the Earth.

Which of the following best describes a set of conditions under which archaeoastronomers would conclude that an ancient structure was used for astronomical purposes? They find that, looking out from the center of the building, there are two windows that align with the rise and set points of two bright stars. The structure has the same dome shape as modern astronomical observatories. The structure consists of lines in the desert that make patterns visible only from high above. The structure has holes in the ceiling that allow viewing the passage of constellations that figure prominently in the culture's folklore, and many other structures built by the same culture have ceiling holes placed in the same way.

The structure has holes in the ceiling that allow viewing the passage of constellations that figure prominently in the culture's folklore, and many other structures built by the same culture have ceiling holes placed in the same way.

All the following statements are true. Which one follows directly from Kepler's third law (p2 = a3)? Venus has a thicker atmosphere than Mercury. Venus takes longer to rotate than it does to orbit the Sun. Venus is more massive than Mercury. Venus orbits the Sun at a slower average speed than Mercury.

Venus orbits the Sun at a slower average speed than Mercury.

Which of these hypothetical observations (none of them are real) would force us to reconsider our modern, Sun-centered view of the solar system? We discover that the universe is actually contracting, not expanding. We discover an Earth-sized planet orbiting the Sun beyond the orbit of Pluto. We discover a small planet beyond Saturn that rises in the west and sets in the east each day. We find that we are unable to measure any parallax for a distant galaxy.

We discover a small planet beyond Saturn that rises in the west and sets in the east each day.

Earth is farthest from the Sun in July and closest to the Sun in January. During which Northern Hemisphere season is Earth moving fastest in its orbit? Summer Fall Spring Winter

Winter

In science, a broad idea that has been repeatedly verified so as to give scientists great confidence that it represents reality is called _________. a paradigm a Ptolemaic model a hypothesis a theory

a theory

Scientific thinking is _________. an ancient mode of thinking first invented in Egypt a difficult process that only a handful of people can do well completely different from any other type of thinking based on everyday ideas of observation and trial-and-error experiment

based on everyday ideas of observation and trial-and-error experiments

The astrology practiced by those who cast predictive horoscopes can be tested by __________ asking astrologers if it works. polling people to find out what percentage believe their horoscopes to be accurate. comparing how often the predictions come true to what would be expected by pure chance. counting how many times the predictions come true.

comparing how often the predictions come true to what would be expected by pure chance.

The great contribution of Nicholas Copernicus was to _________. discover the law of gravity discover the laws of planetary motion create a detailed model of our solar system with the Sun rather than Earth at the center prove that the Earth is not the center of the universe

create a detailed model of our solar system with the Sun rather than Earth at the center

Ptolemy was important in the history of astronomy because he _________. was the first to create a model of the solar system that placed the Sun rather than the Earth at the center was the first to believe that all orbits are perfect circles developed a model of the solar system that made sufficiently accurate predictions of planetary positions to remain in use for many centuries developed the first scientific model of the universe

developed a model of the solar system that made sufficiently accurate predictions of planetary positions to remain in use for many centuries

Scientific models are used to _________. present the scale of the solar system to the general public prove that past paradigms no longer hold true make specific predictions that can be tested through observations or experiments make miniature representations of the universe

make specific predictions that can be tested through observations or experiments

The great contribution of Tycho Brahe was to _________. discover four moons orbiting Jupiter, thereby lending strong support to the idea that the Earth is not the center of the universe discover that planets orbit the Sun in elliptical orbits with varying speed offer the first detailed model of a Sun-centered solar system, thereby beginning the process of overturning the Earth-centered model of the Greeks observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion

observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion

Galileo challenged the idea that objects in the heavens were perfect by _________. observing sunspots on the Sun and mountains on the Moon proving Kepler's laws were correct inventing the telescope showing that heavy objects fall at the same rate as lighter objects

observing sunspots on the Sun and mountains on the Moon

The names of the 7 days of the week are based on _________. the names of prophets in the Bible the seven naked-eye objects that appear to move among the constellations the seven most prominent constellations in the summer sky the names of the seven planets closest to the Sun

the seven naked-eye objects that appear to move among the constellations

The ancient Greeks get a lot of attention for their contributions to science because _________. they were the only ancient culture that kept written records of their astronomical observations the books of every other culture were lost in the destruction of the library of Alexandria they were the first people to realize that Earth is a planet orbiting the Sun they were the first people known to try to explain nature with models based on reason and mathematics, without resort to the supernatural

they were the first people known to try to explain nature with models based on reason and mathematics, without resort to the supernatural

The Metonic cycle is used to predict the future orientation of the Earth's axis in space. the ancient Greek name for the cycle of lunar phases that repeats every 29 1/2 days. the 18-year, 11-day period over which the pattern of eclipses repeats. used to keep lunar calendars approximately synchronized with solar calendars.

used to keep lunar calendars approximately synchronized with solar calendars.