astronomy 5
The difference between speed and velocity is that _________.
velocity also includes a direction. Velocity describes speed in a particular direction
Absolute zero is _________.
0 Kelvin The Kelvin scale starts from absolute zero
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
Imagine another solar system, with a star of the same mass as the Sun. Suppose a planet with a mass twice that of Earth (2MEarth) orbits at a distance of 1 AU from the star. What is the orbital period of this planet?
1 year. The planet's mass is so small compared to the star's mass that it has essentially no effect on the planet's orbit. (W know this from Newton's version of Kepler's third law.) The fact that the planet has the same orbital distance as Earth therefore means it must have the same orbital period as Earth.
When space probe Voyager 2 passed by Saturn, its speed increased (but not due to firing its engines). What must have happened?
Saturn must have lost a very tiny bit of its orbital energy.
The acceleration of gravity on Earth is approximately 10 m/s2 (more precisely, 9.8 m/s2). If you drop a rock from a tall building, about how fast will it be falling after 3 seconds?
30 m/s. To find this answer, remember that the acceleration of gravity means that each second, an object's downward speed increases by 10 m/s. Therefore, if it starts from rest (speed = 0), after 1 second it is falling at 10 m/s, after 2 seconds it is falling at 20 m/s, and after 3 seconds it is falling at 30 m/s.
At latitude 50 degrees North, the celestial equator crosses the meridian at altitude:
40 degrees in the South
What do astronomers mean by a constellation? A constellation is a group of stars that are all located in about the same place in space. A constellation is a region in the sky as seen from Earth. A constellation is any random grouping of stars in the sky. A constellation is a group of stars related through an ancient story.
A constellation is a region in the sky as seen from Earth.
You observe a full Moon rising at sunset. What will you see at midnight? A full moon high in the sky A third-quarter moon A waning gibbous moon A first-quarter moon
A full moon high in the sky
Which of the following correctly describes the meridian in your local sky? The point directly over your head A half-circle extending from your horizon due east, through the north celestial pole, to your horizon due west A half-circle extending from your horizon due east, through your zenith, to your horizon due west A half-circle extending from your horizon due north, through your zenith, to your horizon due south
A half-circle extending from your horizon due north, through your zenith, to your horizon due south
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.
You observe a full moon rising at sunset. What will you see at midnight? a. A waning gibbous moon b. A full moon high in the sky c. A first quarter moon d. A third quarter moon
b.
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.
Which of the following scenarios involves energy that we would typically calculate with Einstein's formula E=mc2?
A small amount of the hydrogen in of a nuclear bomb becomes energy as fusion converts the hydrogen to helium. Gravitational potential energy is not described by Einstein's formula.
Which of the following is not true about a scientific theory?
A theory is essentially an educated guess.
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 is the difference between a bound orbit and an unbound orbit around the Sun?
An object on a bound orbit follows the same path around the Sun over and over, whereas an object on an unbound orbit approaches the Sun just once and then never returns. This is the definition of bound and unbound orbits (around the Sun).
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.
Which of the following represents a case in which you are not accelerating?
Driving in a straight line at 60 miles per hour You are accelerating because your speed is decreasing.
Why are astronauts weightless in the Space Station?
Because the Space Station is constantly in free-fall around the Earth Gravity is everywhere - the strength of Earth's gravity is only slightly lower in low-Earth orbit than on the surface.
At which lunar phase(s) are tides most pronounced (for example, the highest high tides)?
Both new and full moons These are the spring tides, when the tidal forces of the Sun and Moon work together.
Suppose you drop a 10-pound weight and a 5-pound weight on the Moon, both from the same height at the same time. What will happen?
Both will hit the ground at the same time.
Each of the following lists two facts. Which pair of facts can be used with Newton's version of Kepler's third law to determine the mass of the Sun?
Earth is 150 million km from the Sun and orbits the Sun in one year.
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.
During the period each year when we see Mars undergoing apparent retrograde motion in our sky, what is really going on in space? Earth is catching up with and passing by Mars in their respective orbits. Mars is moving around the Sun in the opposite direction from which Earth is moving around the Sun. Earth and Mars are getting closer together. Earth and Mars are on opposite sides of the Sun.
Earth is catching up with and passing by Mars in their respective orbits
For most of history, the lack of observable stellar parallax was interpreted to mean that _________. Earth is stationary at the center of the universe stars must all lie at the same distance from Earth, on the celestial sphere Galileo's theories of the universe were essentially correct stars were too far away for parallax to be measured with available technology
Earth is stationary at the center of the universe
Earth is closer to the Sun in January than in July. Therefore, in accord with Kepler's second law:
Earth travels faster in its orbit around the Sun in January than in July.
Suppose that the Sun shrank in size but that its mass remained the same. What would happen to the orbit of the Earth?
Earth's orbit would be unaffected. For Earth to be pulled into a closer orbit, the force of gravity between Earth and the Sun would have to become stronger. Does changing the Sun's size (but not mass) change the force of gravity?
Each choice describes how a few astronomical phenomena are related to time periods. Which list is entirely correct? (Careful: some lists are partially correct.) Earth's rotation defines a day. The cycle of the Moon's phases takes about a week. Earth's orbit defines a year. Earth's cycle of axis precession defines a month. Earth's rotation defines a day. The saros cycle of eclipses defines a month. Earth's orbit defines a year. Earth's cycle of axis precession takes 26,000 years. Earth's rotation defines a day. The cycle of the Moon's phases takes about a month. Earth's orbit defines a year. Earth's cycle of axis precession takes 26,000 years. Earth's rotation defines a day. The Sun's rotation defines a week. The Moon's rotation defines a month. Earth's orbit defines a year.
Earth's rotation defines a day. The cycle of the Moon's phases takes about a month. Earth's orbit defines a year. Earth's cycle of axis precession takes 26,000 years.
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.
If we have a new moon today, when we will have the next full moon? In about two weeks In about a month In about one week In about six months
In about two weeks
Why is Newton's version of Kepler's third law so useful to astronomers?
It can be used to determine the masses of many distant objects. We can apply Newton's version of Kepler's third law whenever we observe one object orbiting another; this is the primary way that we measure masses throughout the universe.
How does Earth's varying distance from the Sun affect our seasons? It doesn't; Earth's orbital distance plays no significant role in the seasons. It causes the seasons to be more extreme than they would be if the Earth's distance from the Sun were always the same. It makes summer warmer in the Northern Hemisphere than in the Southern Hemisphere. It is responsible for the fact that the seasons are opposite in the Northern and Southern hemispheres.
It doesn't; Earth's orbital distance plays no significant role in the seasons.
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.
Suppose you are in an elevator that is traveling upward at constant speed. How does your weight compare to your normal weight on the ground?
It is the same. As long as the elevator is not accelerating, your weight on a scale in the elevator will be the same whether the elevator is on the ground or rising (or falling) at constant speed.
What is stellar parallax? It is the slight back-and-forth shifting of star positions that occurs as we view the stars from different positions in Earth's orbit of the Sun. It is the change in the set of constellations that we see at different times of year in the evening sky. It describes the fact that stars are actually moving relative to one another, even though to our eyes the stars appear fixed in the constellations. It is the daily rise and set of the stars.
It is the slight back-and-forth shifting of star positions that occurs as we view the stars from different positions in Earth's orbit of the Sun.
Which of the following was not a major advantage of Copernicus's Sun-centered model over the Ptolemaic model?
It made significantly better predictions of planetary positions in our sky
Which statement must be true for a rocket to travel from Earth to another planet? It must have large engines. It must be launched from space, rather than from the ground. It must carry a lot of extra fuel. It must attain escape velocity from Earth.
It must attain escape velocity from Earth. If it does not have escape velocity, it will either fall back down or orbit Earth.
According to Kepler's third law:
Jupiter orbits the Sun at a faster speed than Saturn.
What do we mean by the orbital energy of an orbiting object (such as a planet, moon, or satellite)?
Orbital energy is the sum of the object's kinetic energy and its gravitational potential energy as it moves through its orbit. Therefore, the object's orbital energy is conserved, even though its kinetic energy and gravitational potential energy may both vary along the orbit.
Two stars that are in the same constellation:
May actually be very far from each other
Right now, where would you find a tidal bulge on Earth?
On the portion of Earth facing directly toward the Moon and on the portion of Earth facing directly away from the Moon. These are the approximate locations of the two tidal bulges. (Approximate because Earth's rotation pulls the bulge slightly ahead of the Earth-Moon line.)
During the time that a planet is in its period of apparent retrograde motion: _________ The planet is getting closer to the Sun in its orbit. The planet appears to rise in the west and set in the east, rather than the usual rising in the east and setting in the west. Over many days or weeks, the planet moves westward relative to the stars, rather than the usual eastward relative to the stars The planet moves backwards (clockwise as viewed from above Earth's north pole) in its orbit of the Sun.
Over many days or weeks, the planet moves westward relative to the stars, rather than the usual eastward relative to the stars
A newly discovered planet orbits a distant star with the same mass as the Sun at an average distance of 106 million kilometers. Its orbital eccentricity is 0.4. Part A: Find the planet's orbital period. Part B: Find the planets nearest orbital distance from its star Part C: Find the planet's farthest orbital distance from its star
Part A: 7.16 months Part B: 0.43 AU Part C: 0.99 AU
Part A: The dwarf planet Eris orbits the Sun every 557 years. What its average distance (semi major axis) from the Sun? Part B: How does its average distance compare to that of Pluto?
Part A: Eris's semi major axis = 67.7 AU Part B: aEris/aPluto = 1.72
Halley's comet orbits the Sun every 76.0 years and has an orbital eccentricity of 0.97 . Part A: Find its semi major axis distance. Part B: Find its perihelion distance. Part C: Find its aphelion distance. Part D: Does Halley's comet spend most of its time near its perihelion distance, its aphelion distance, or halfway between?
Part A: Semi major axis distance = 17.9 AU Part B: 0.537 AU Part C: 35.3 AU Part D: Near its aphelion distance
Part A: The Shadow cast by a simple stick or obelisk allowed ancient people to: Part B: Why wasn't the sun-centered model of Copernicus immediately adopted after he proposed it? Part C: An original observation of Galileo's that helped to overturn the ancient Earth-centered model was: Part D: Which of the following are the three key hallmarks of science? (3)
Part A: Tell the time of day Part B: It was not noticeably more accurate than the old Ptolemaic model Part C: The phases of Venus Part D: 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
Part A: Choose the correct description of the path of the Sun at a latitude of 40 degrees North for the March and September equinoxes. Part B: Choose the correct description of the path of the Sun at a latitude of 40 degrees North for the summer (June) solstice. Part C: Choose the correct description of the path of the Sun at a latitude of 40 degrees North for the winter (December) solstice
Part A: The sun rises due east, reaches an altitude of 50 degrees South on the meridian, and sets due west Part B: On the June solstice, the Sun rises more than 23.5 degrees north of due east, reaches an altitude of 73.5 degrees on the meridian in the south, and sets more than 23.5 degrees north of due west. Part C: On the December solstice, the Sun rises more than 23.5 degrees south of due east, reaches an altitude of 26.5 degrees on the meridian in the south, and sets more than 23.5 south of due west.
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
In winter, Earth's axis points toward the star Polaris. In spring, the axis points toward...
Polaris
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 best explains why the Moon's orbital period and rotation period are the same?
The Moon once rotated faster, but tidal friction slowed the rotation period until it matched the orbital period. The law of conservation of angular momentum does not say that the orbital and rotational angular momentum must be equal.
What does the fact that we always see the same face of the Moon tells us about?
The Moon rotates with the same period that it orbits Earth
Summarize the development of the Greek geocentric model through Ptolemy. How did the Ptolemaic model account for apparent retrograde motion?
The Ptolemaic model was able to explain retrograde motion by having the planets move backward on their circular orbits on which they went around Earth
Suppose the Sun were suddenly to shrink in size but that its mass remained the same. According to the law of conservation of angular momentum, what would happen?
The Sun would rotate faster than it does now. Angular momentum is the product mass ( velocity (of rotation) ( radius. Shrinking the Sun's radius does not affect its mass, so the rotational velocity must increase in order to keep angular momentum constant.
If you are located in the Northern Hemisphere, which of the following correctly describes a relationship between the sky and your location? The altitude of the north celestial pole equals your longitude. The longitude of the north celestial pole is circumpolar, and therefore crosses your zenith at the meridian. The altitude of the north celestial pole equals your latitude. The altitude of the celestial equator equals your latitude.
The altitude of the north celestial pole equals your latitude.
Which of the following statements does not use the term angular size or angular distance correctly? The angular size of the Sun is about the same as that of the Moon. You can use your outstretched hand against the sky to estimate angular sizes and angular distances. The angular distance between those two bright stars in the sky is about 2 meters. The angular distance between those two houses in the distance is 30 degrees.
The angular distance between those two bright stars in the sky is about 2 meters.
Suppose that a lone asteroid happens to be passing Jupiter on an unbound orbit (well above Jupiter's atmosphere and far from all of Jupiter's moons.) Which of the following statements would be true?
The asteroid's orbit around Jupiter would not change, and it would go out on the same unbound orbit that it came in on. "Sucking" is not one of the allowed orbits under the universal law of gravitation.
What does the term temperature measure?
The average kinetic energy of particles in a substance. Thus, for example, air molecules are moving faster on average on a hot day than on a cool day
Suppose you kick a soccer ball straight up to a height of 10 meters. Which of the following is true about the gravitational potential energy of the ball during its flight?
The ball's gravitational potential energy is greatest at the instant when the ball is at its highest point. The ball has different amounts of kinetic and gravitational potential energy at different points in its flight, although the total energy is the same at all times (neglecting energy lost to air resistance).
What is the celestial sphere? The celestial sphere is a model of how the stars are arranged in the sky relative to our Sun, which is in the middle of the sphere. The celestial sphere is a model that shows the true locations in space of the Sun and a few thousand of the nearest stars. It represents a belief in an Earth-centered universe, and hence is no longer considered to have any use. The celestial sphere is a representation of how the entire sky looks as seen from Earth.
The celestial sphere is a representation of how the entire sky looks as seen from Earth.
Which of the following statements about the celestial sphere is not true? When we look in the sky, the stars all appear to be located on the celestial sphere. The Earth is placed at the center of the celestial sphere. The celestial sphere does not exist physically. The celestial sphere is another name for our universe.
The celestial sphere is another name for our universe.
A rock held above the ground has potential energy. As the rock falls, this potential energy is converted to kinetic energy. Finally, the rock hits the ground and stays there. What has happened to the energy?
The energy goes to producing sound and to heating the ground, rock, and surrounding air. The rock lost gravitational potential energy as it fell and cannot get it back unless it returns to its original height.
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.
Suppose Earth's axis tilt was significantly greater than its current 23.5 degrees, but Earth's rotation period and orbital period were unchanged. Which statement below would not be true? The region of Earth where the Sun does not rise on the winter solstice would be larger (extending farther south) than it is now. The length of each season (for example, the number of days from the summer solstice to the fall equinox) would be significantly longer than it is now. Summers and winters would be more severe (for example, hotter and colder, respectively) than they are now. Polaris would not be our North star.
The length of each season (for example, the number of days from the summer solstice to the fall equinox) would be significantly longer than it is now.
In the formula E = mc2, what does E represent?
The mass-energy, or potential energy stored in an object's mass. Notice that c2 is a large number, so this formula tells us that a small amount of mass contains a large amount of energy.
All the following statements are true. Which one explains the reason that there is not a solar eclipse at every new moon? The nodes of the moon's orbit precess with an 18-year period. The Moon is only about one fourth as large as Earth in diameter. The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane. The Moon goes through a complete cycle of phases about every 29 1/2 days.
The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane.
What do we mean when we talk about the Milky Way in our sky? The spiral-shaped galaxy in which we live. The whitish patch of light we see when we look toward the center of the Milky Way Galaxy. The patchy band of light that outlines the plane of the Milky Way Galaxy as seen from Earth. The bright stars of the constellations that lie along the ecliptic in our sky.
The patchy band of light that outlines the plane of the Milky Way Galaxy as seen from Earth.
What is the ecliptic? The Sun's daily path from east to west in our sky A half-circle extending from your horizon due north, through your zenith, to your horizon due south The path the Sun appears to trace around the celestial sphere each year The path traced by the Moon's shadow on Earth during a solar eclipse
The path the Sun appears to trace around the celestial sphere each year
In the Greek geocentric model, the retrograde motion of a planet occurs when:
The planet actually goes backward in its orbit around Earth
Imagine another solar system, with a star more massive than the Sun. Suppose a planet with the same mass as Earth orbits at a distance of 1 AU from the star. How would the planet's year (orbital period) compare to Earth's year?
The planet's year would be shorter than Earth's. This would be the case only if the force of gravity was weaker than it is between Earth and the Sun.
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.
What is the saros cycle? The roughly one-month cycle of lunar phases in the sky The 26,000-year cycle of the Earth's precession The roughly 18-year cycle over which the pattern of eclipses repeats The annual cycle of the seasons
The roughly 18-year cycle over which the pattern of eclipses repeats
Beijing and Philly have about the same latitude but different longitudes. What can be said about the tonight's night sky in these two places?
The sky will look about the same.
Last night I saw Jupiter right in the middle of the Big Dipper. (Hint: Is the Big Dipper part of the Zodiac?) Choose the correct explanation why the statement makes sense (or is clearly true) or does not make sense (or is clearly false)
The statement does NOT make sense because Jupiter, like all the planets, is always found very close to the ecliptic in the sky. The ecliptic passes through the constellations of the zodiac, so Jupiter can only appear to be in one of the zodiac constellations - and the Big Dipper is not part of the zodiac.
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.
Which of the following best describes why we have seasons on Earth? The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year. The varying speed of Earth in its orbit around the Sun gives us summer when we are moving fastest and winter when we are moving slowest. Earth's elliptical orbit means we are closer to the Sun and therefore receive more intense sunlight at some times of year than at others. The tilt of Earth's axis causes the Northern Hemisphere to be closer to the Sun than the Southern Hemisphere in summer, and visa versa in winter.
The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year.
Suppose that two objects collide. Which of the following things is not the same both before and after the collision? The total temperature of the objects The total energy of the objects The total momentum of the objects The total angular momentum of the objects
The total temperature of the objects. To understand why temperature is not a conserved quantity, remember that temperature is a measure of only one type of energy (thermal energy, which is the kinetic energy of moving particles) and this energy can be converted into other types of energy.
Suppose you heat an oven to 400°F and boil a pot of water. Which of the following explains why you would be burned by sticking your hand briefly in the pot but not by sticking your hand briefly in the oven?
The water can transfer heat to your arm more quickly than the air. The boiling water has a lower temperature (212°F) than the air in the hot oven (400°F), but because it is much more dense, heat is transferred to your arm at a higher rate due to the more frequent collisions between your arm and the water molecules.
I live in the United States, and during my first trip to Argentina I saw many constellations that I'd never seen before. Choose the correct explanation why the statement makes sense (or is clearly true) or does not make sense (or is clearly false)
This statement makes sense, because the constellations visible in the sky depend on latitude. Since Argentina is in the Southern Hemisphere, the constellations visible there include many that are not visible from the U.S.
Which of the following best describes the origin of ocean tides on Earth?
Tides are caused by the difference in the force of gravity exerted by the Moon across the sphere of the Earth. This is an accurate statement; be sure you understand it.
Suppose you are facing north and you see the Big Dipper close to your northern horizon, with Polaris (and the Little Dipper) above it. Where will you see the Big Dipper in six hours? To the right of Polaris; that is, 90 degrees counterclockwise from its current position To the left of Polaris; that is, 90 degrees clockwise from its current position Still in the same place, below Polaris Directly above Polaris
To the right of Polaris; that is, 90 degrees counterclockwise from its current position
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.
The Andromeda Galaxy is faintly visible to the naked eye in the constellation Andromeda. Suppose instead it were located in the same direction in space as the center of the Milky Way Galaxy (but still at its current distance). How would it appear to the eye in that case? It would look about the same, but it would be harder to pick out because its cloud-like appearance would make it blend in with the cloud-like appearance of the Milky Way in our sky. It would be much brighter because it would be illuminated by the many stars in the center of our galaxy. We could not see it at all. It would look about the same but would be in the constellation Sagittarius instead of Andromeda.
We could not see it at all.
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.
Which of the following statements is not one of Newton's Laws of Motion? The rate of change of momentum of an object is equal to the net force applied to the object. For any force, there always is an equal and opposite reaction force. In the absence of a net force acting on it, an object moves with constant velocity. What goes up must come down.
What goes up must come down. his is not one of Newton's laws, and it's not even true. Objects with escape velocity can go up without coming back down.
In which of the following cases would you feel weightless? While falling from a roof While accelerating downward in an elevator While parachuting from an airplane While walking on the Moon
While falling from a roof. You are in free-fall when falling off a roof, so you are weightless (until you hit the ground)
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
When it is summer in Australia, the season in the United States is...
Winter
The South Celestial pole is 40 degrees above your Southern Horizon. What does it tell you?
You're at latitude 40 degrees South
Suppose you live in the United States and you see a crescent moon in your evening sky tonight. What will a friend in South America see tonight? Your friend will see a first-quarter moon. Your friend will also see a crescent moon. Your friend will see a gibbous moon. Your friend won't see the Moon tonight because it is up only in the morning.
Your friend will also see a crescent moon.
Suppose you lived on the Moon. Which of the following would be true? Both your weight and your mass would be the same as they are on Earth. Both your weight and your mass would be less than they are on Earth. Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth. Your mass would be less than your mass on Earth, but your weight would be the same as it is on Earth.
Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth. You would weigh only about 1/6 as much on the Moon as you do on Earth, but your mass would still be the same.
About how many stars are visible to the naked eye on a clear, dark night away from city lights? a few hundred billion a few dozen several million a couple thousand
a couple thousand
The planets never travel in a straight line as they orbit the Sun. According to Newton's second law of motion, this must mean that _________.
a force is acting on the planets
We cannot see a new moon in our sky because _________. a new moon is quite near the Sun in the sky it is above the horizon during the daytime no sunlight is illuminating the Moon it is obscured by Earth's shadow
a new moon is quite near the Sun in the sky
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
In any particular place on Earth, certain constellations are visible in the evening only at certain times of the year because __________. a. our evening view of space depends on where Earth is located in its orbit around the Sun b. during some times of year, some constellations drop below the southern horizon c. some constellations are circumpolar d. on any particular night, we can only see stars that are directly opposite (180 degrees away from) the Sun in the sky
a.
Suppose Earth's axis tilt was significantly greater than its current 23.5 degrees, but Earth's rotation period and orbital period were unchanged. Which statement below would not be true? a. The length of each season (for example, the number of days from the summer solstice to the fall equinox) would be significantly longer than it is now. b. Polaris would not be our North star. c. Summers and winters would be more severe (for example, hotter and colder, respectively) than they are now. d. The region of Earth where the Sun does not rise on the winter solstice would be larger (extending farther south) than it is now.
a.
Suppose you use the Southern Cross to determine that the south celestial pole appears 40 degrees above your horizon. Then you must be located at _________. latitude 40 degrees south longitude 40 degrees latitude 40 degrees north latitude 50 degrees south
atitude 40 degrees south
During the period each year when we see Mars undergoing apparent retrograde motion in our sky, what is really going on in space? a. Earth and Mars are getting closer together. b. Earth is catching up with and passing by Mars in their respective orbits. c. Mars is moving around the Sun in the opposite direction from which Earth is moving around the Sun. d. Earth and Mars are on opposite sides of the Sun.
b.
For most of history, the lack of observable stellar parallax was interpreted to mean that __________. a. stars must all lie at the same distance from Earth, on the celestial sphere b. Earth is stationary at the center of the universe c. Galileo's theories of the universe were essentially correct d. stars were too far away for parallax to be measured with available technology
b.
If our year were twice as long (that is, if Earth took twice as many days to complete each orbit around the Sun), but Earth's rotation period and axis tilt were unchanged, then __________. a. the Earth would not have seasons b. the four seasons would each be twice as long as they are now c. the cycle of precession would take 13,000 years instead of 26,000 years d. stars would take twice as long to rise and set
b.
Suppose you live in the United States and you see a crescent moon in your evening sky tonight. What will a friend in South America see tonight? a. Your friend will see a first quarter moon. b. Your friend will also see a crescent moon. c. Your friend will see a gibbous moon. d. Your friend won't see the Moon tonight, because it is up only in the morning.
b.
The Andromeda Galaxy is faintly visible to the naked eye in the constellation Andromeda. Suppose instead it were located in the same direction in space as the center of the Milky Way Galaxy (but still at its current distance). How would it appear to the eye in that case? a. It would be much brighter, because it would be illuminated by the many stars in the center of our galaxy. b. We could not see it at all. c. It would look about the same, but would be in the constellation Sagittarius instead of Andromeda. d. It would look about the same, but it would be harder to pick out because its cloud-like appearance would make it blend in with the cloud-like appearance of the Milky Way in our sky.
b.
When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting __________. a. dimmer b. higher in the sky c. brighter d. lower in the sky
b.
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
It's 6 am and the Moon is at its highest point in your sky (crossing the meridian). What is the Moon's phase? a. new b. full c. third quarter d. first quarter
c.
Suppose you see a photo showing Jupiter half in sunlight and half in shadow (that is, a first quarter Jupiter). This photo might have been taken by _________. a. the Arecibo radio telescope in Puerto Rico b. the Hubble Space Telescope (which orbits Earth) c. the Galileo spacecraft that orbited Jupiter in the 1990s d. the Keck telescope on Mauna Kea, Hawaii
c.
The Sun's path, as viewed from the equator, is highest in the sky on __________. a. the day when Earth is closest to the Sun b. the summer solstice c. the spring and fall equinoxes d. the winter solstice
c.
At the North Pole on the summer solstice, the Sun:
circles the horizon at altitude 23 1/2 degrees
Stars that are visible in the local sky on any clear night of the year, at any time of the night, are called _________. celestial circumpolar seasonal bright
circumpolar
Tycho Brahe's contribution to astronomy included:
collecting data that enabled Kepler to discover the laws of planetary motion.
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
All the following statements are true. Which one explains the reason that there is not a solar eclipse at every new moon? a. The Moon is only about 1/4 as large as Earth in diameter. b. The Moon goes through a complete cycle of phases about every 29 1/2 days. c. The nodes of the moon's orbit precess with an 18-year period. d. The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane.
d.
An angle of 1 arcsecond is __________. a. slightly more than the width of a basketball held at arm's length b. about the width of your fist held at arm's length c. about the width of a finger held at arm's length d. less than the thickness of a human hair held at arm's length
d.
How does Earth's varying distance from the Sun affect our seasons? a. It is responsible for the fact that the seasons are opposite in the Northern and Southern hemispheres. b. It causes the seasons to be more extreme than they would be if the Earth's distance from the Sun were always the same. c. It makes summer warmer in the Northern Hemisphere than in the Southern Hemisphere. d. It doesn't --- Earth's orbital distance plays no significant role in the seasons.
d.
Suppose it is full moon. What phase of Earth would someone on the Moon see at this time? a. full Earth b. first quarter Earth c. Earth does not go through phases as seen from the Moon. d. new Earth
d.
Suppose you are facing north and you see the Big Dipper close to your northern horizon, with Polaris (and the Little Dipper) above it. Where will you see the Big Dipper in six hours? a. Still in the same place, below Polaris b. Directly above Polaris c. To the left of Polaris; that is, 90 degrees clockwise from its current position d. To the right of Polaris; that is, 90 degrees counterclockwise from its current position
d.
Suppose you use the Southern Cross to determine that the south celestial pole appears 40 degrees above your horizon. Then you must be located at _________. a. latitude 50 degrees south b. latitude 40 degrees north c. longitude 40 degrees d. latitude 40 degrees south
d.
Which of the following statements about the celestial sphere is NOT true? a. The celestial sphere does not exist physically. b. When we look in the sky, the stars all appear to be located on the celestial sphere. c. The Earth is placed at the center of the celestial sphere. d. The "celestial sphere" is another name for our universe.
d.
A star's path through your sky depends on your latitude and the star's:
declination
A star that is located 30 degrees north of the celestial equator has:
declination = 30 degrees
According to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them _________.
decreases by a factor of 9. Gravity follows an inverse square law, so the force goes down with the square of the distance; in this case, increasing the distance by a factor of 3 causes the force to decrease by a factor of 32 = 9.
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
The allowed shapes for the orbits of objects responding only to the force of gravity are ______
ellipses, parabolas, and hyperbolas. Ellipses are bound orbits, and parabolas and hyperbolas are both unbound.
Radiative energy is _________.
energy carried by light. Remember that radiation is often used as a synonym for light, so radiative energy is energy carried by light.
Lunar eclipses can occur only during a _________. full moon new moon third-quarter moon first-quarter moon
full moon
When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting _________. dimmer brighter lower in the sky higher in the sky
higher in the sky
When a spinning ice skater pulls in his arms, he spins faster because _________.
his angular momentum must be conserved, so reducing his radius must increase his speed of rotation. Remember that angular momentum is related to an objects mass times velocity time radius. The skater's mass stays the same but pulling in his arms reduces his "radius," so his velocity or rotation must increase to keep his angular momentum constant.
When we say that a planet has a highly eccentric orbit, we mean that:
in some parts of its orbit it is much closer to the Sun than in other parts.
If the Sun rises precisely due east,
it must be the day of either the spring or fall equinox
The energy attributed to an object by virtue of its motion is known as _________.
kinetic energy. Kinetic energy is energy of motion.
We describe a location on Earth's surface by stating its _________. altitude and direction (or azimuth) latitude and longitude latitude and direction meridian and longitude
latitude and longitude
An angle of 1 arcsecond is _________. slightly more than the width of a basketball held at arm's length about the width of a finger held at arm's length about the width of your fist held at arm's length less than the thickness of a human hair held at arm's length
less than the thickness of a human hair held at arm's length
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
Galileo's contribution to astronomy included:
making observations and conducting experiments that dispelled scientific objections to the Sun-centered model.
Newton's Second Law of Motion tells us that the net force applied to an object equals its _________.
mass multiplied by acceleration. We often write this fact simply as F = ma.
Momentum is defined as _________.
mass multiplied by velocity. Notice that because velocity includes direction, momentum also includes direction.
A net force acting on an object will always cause a change in the object's _________.
momentum Force is actually defined as the rate of change in momentum.
Newton showed that Kepler's laws are _________.
natural consequences of the law of universal gravitation Kepler discovered his laws by looking for a mathematical way to explain Tycho's observations of the planets. His laws successfully predicted planetary positions, but he did not know why they were true. Newton showed that they are true as a result of the universal law of gravitation.
Suppose it is full Moon. What phase of Earth would someone on the Moon see at this time? full Earth Earth does not go through phases as seen from the Moon. new Earth first-quarter Earth
new Earth
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
In any particular place on Earth, certain constellations are visible in the evening only at certain times of the year because _________. during some times of year, some constellations drop below the southern horizon some constellations are circumpolar our evening view of space depends on where Earth is located in its orbit around the Sun on any particular night, we can only see stars that are directly opposite (180 degrees away from) the Sun in the sky
our evening view of space depends on where Earth is located in its orbit around the Sun
Suppose you see a photo showing Jupiter half in sunlight and half in shadow (that is, a first-quarter Jupiter). This photo might have been taken by _________. the Hubble Space Telescope (which orbits Earth) the Keck telescope on Mauna Kea, Hawaii the Galileo spacecraft that orbited Jupiter in the 1990s the Arecibo radio telescope in Puerto Rico
the Galileo spacecraft that orbited Jupiter in the 1990s
The Sun's path, as viewed from the equator, is highest in the sky on _________. the day when Earth is closest to the Sun the December solstice the March and September equinoxes the June solstice
the March and September equinoxes
The Moon always shows nearly the same face to Earth because ________. sunlight always hits the same face of the Moon the Moon does not rotate the Moon rotates once in the same amount of time that it takes Earth to orbit the Sun once the Moon rotates once in the same amount of time that it takes the Moon to orbit Earth once
the Moon rotates once in the same amount of time that it takes the Moon to orbit Earth once
If there is going to be a total lunar eclipse tonight, then you know that:
the Moon's phase is full
If our year were twice as long (that is, if Earth took twice as many days to complete each orbit around the Sun), but Earth's rotation period and axis tilt were unchanged, then _________. the Earth would not have seasons stars would take twice as long to rise and set the four seasons would each be twice as long as they are now the cycle of precession would take 13,000 years instead of 26,000 years
the four seasons would each be twice as long as they are now
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 point directly over your head is called _________. the north celestial pole the meridian the North Star the zenith
the zenith
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
A week after full moon, the Moon's phase is:
third quarter
It's 6 a.m. and the Moon is at its highest point in your sky (crossing the meridian). What is the Moon's phase? first quarter third quarter new full
third quarter
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.
