ASTRO Exam One (homework)
The Moon is nearly tidally locked to the Earth, which means the Moon's rotation period is almost the same as its orbital period. If you were camped at the equator of the Moon, you would experience (approximately) -sunshine all the time, except when the Earth blocks the Sun. -(14 × 24) hours of darkness followed by (14 × 24) hours of sunshine. -sunshine (day) all the time. -14 hours of darkness followed by 14 hours of sunshine.
(14 × 24) hours of darkness followed by (14 × 24) hours of sunshine.
As shown in the figure, a solar day requires about an extra 1° of rotation, or a total of about 361° of rotation for Earth. Therefore, a solar day is longer than a sidereal day by about __________. -1 minute -24 hours -1/360 of a minute -1/360 of 24 hours
1/360 of 24 hours
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? -Jupiter's orbital period is 5.203^2 times Earth's orbital period. -11.86^2=5.203^3 -Jupiter's orbital period is 5.203^3 times Earth's orbital period. -5.203^2=11.86^3
11.86^2=5.203^3
Based on observations of the universal expansion, the age of the universe is about ________. -14 billion years -14 million years -14 trillion years -14,000 years
14 billion years
From Kepler's third law, an asteroid with an orbital period of 8 years lies at an average distance from the Sun equal to -4 astronomical units. -8 astronomical units. -2 astronomical units. -16 astronomical units. -It depends on the asteroid's mass.
4 astronomical units.
Sunlight takes 8.4 minutes to get from the Sun to Earth. When NASA's New Horizons Spacecraft passed Pluto in 2016, it was 33 AU from Earth. How long did it take for its transmitted images of Pluto to arrive at Earth? -One Plutonian year -277.3 hours -4.6 hours -They arrived almost instantaneously. The transmitted signals were radio signals and therefore traveled at the speed of light.
4.6 hours
If Earth's rotation slowed down so that it completed exactly one rotation about its axis in 100 hours, what would be the typical time interval between sunrise and sunset? -25 hours -100 hours -50 hours -24 hours
50 hours
Astronomer Alan says the universe is expanding at one rate and Astronomer Wendy says it is expanding at a faster rate. All other things being equal, which astronomer would say that the universe is OLDER? -Wendy -Alan -Neither
Alan
Which of the following statements is true? -Both the Northern and Southern hemispheres receive the same amount of sunlight on the equinoxes. -The Southern Hemisphere receives the most direct sunlight on the June solstice. -The Northern Hemisphere receives the most direct sunlight on the June solstice. -Both the Northern and Southern hemispheres receive the same amount of sunlight on the solstices. -Both A and C are true.
Both A and C are true.
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? -The area swept out in January is larger. -The area swept out in July is larger. -Both areas are the same.
Both areas are the same.
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 misjudged the distances between the planets. -Copernicus used perfect circles for the orbits of the planets. -Copernicus placed the Sun at the center, but did not realize that the Moon orbits the Earth. -Copernicus placed the planets in the wrong order going outward from the Sun.
Copernicus used perfect circles for the orbits of the planets.
The total energy of the universe is now thought to be dominated by -Dark Matter. -Dark Energy. -the gas between the stars. -the stars within galaxy clusters and superclusters.
Dark Energy.
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 first law. -It depends on the eccentricity of the orbit, as described by Kepler's second law. -Each orbit should take about 2 years, because the eccentricity is so large. -Each orbit takes about 1 year, which we know from Kepler's third law.
Each orbit takes about 1 year, which we know from Kepler's third law.
What is really happening in space during the periods when we see Mars going through apparent retrograde motion? -Earth and Mars are moving in opposite directions around the Sun. -Mars and the Sun both appear to be in the same constellation as viewed from Earth. -Earth is passing by Mars in its orbit around the Sun. -Mars is moving along its orbit in the opposite direction from the way it usually moves.
Earth is passing by Mars in its orbit around the Sun.
The Sun rises and sets each day because -it undergoes retrograde motion each day -its position seems to change because of stellar parallax -it orbits Earth once each day -Earth rotates once each day
Earth rotates once each day
What is the basic reason that we have seasons on Earth? -The amount of energy put out by the Sun varies over the course of each year. -Earth's axis is tilted relative to the ecliptic plane. -Earth's distance from the Sun varies over the course of each year. -Earth's orbit is not quite a perfect circle.
Earth's axis is tilted relative to the ecliptic plane.
Where does the Sun remain above the horizon all day (never setting) on the December solstice? -Only at the South Pole. -Everywhere between the Arctic Circle (latitude 66.5°N) and the North Pole -Only at the equator -Everywhere between the Antarctic Circle (latitude 66.5°S) and the South Pole -Only on the Antarctic Circle (latitude 66.5°S) -Only at the North Pole
Everywhere between the Antarctic Circle (latitude 66.5°S) and the South Pole
The observable universe is the same size today as it was a few billion years ago. True False
False
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 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 causes the seasons to be more extreme than they would be if the Earth's distance from the Sun were always the same.
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 does not have seasons. -It uses a 23-hour rather than a 24-hour day. -It has about 11 fewer days. -Its new year always occurs in February instead of on January 1.
It has about 11 fewer days.
Relative to the age of the universe, how old is our solar system? -It is between about 5% and 10% as old as the universe. -It is nearly the same age as the universe. -It is about one-third the age of the universe. -It is about 1% as old as the universe.
It is about one-third the age of the universe.
You are standing on Earth's equator. In which direction is Polaris, the North star? -It is on the northern horizon. -The answer depends on what time of day (or night) it is. -It is directly overhead. -The answer depends on whether it is winter or summer.
It is on the northern horizon.
What happens to Earth's axis as we orbit around the Sun over the course of each year? -It remains pointed in the same direction at all times. -It sweeps out a cone while remaining at a 23½° tilt, so that it sometimes points toward Polaris and sometimes toward other stars. -It wobbles back and forth, so that the tilt varies between 0° and 23½°.
It remains pointed in the same direction at all times.
What is special about the June solstice? -It's the longest day of the year for everyone on Earth. -It's the day when the Sun has the longest and highest path through the Southern Hemisphere sky. -It's the day on which the Northern Hemisphere receives its most direct sunlight. -It's the day when Earth has the greatest axis tilt.
It's the day on which the Northern Hemisphere receives its most direct sunlight.
Because we live in an expanding universe, distant galaxies are farther away from us today than they were when the light we see from them started on its journey to us. So what do we mean when we say that a galaxy is 7 billion light-years away? -It was 7 billion light-years away when its light started its journey to us. -Its distance from us has increased by 7 billion light-years since its light started its journey to us. -Its light has taken 7 billion years to reach us. -It is 7 billion light-years away today.
Its light has taken 7 billion years to reach us.
Which of the following statements about Kepler's laws is false? -Kepler's first law states that planetary orbits are shaped as ellipses. -Kepler's laws provide mathematical descriptions of the motion of the planets. -Kepler's second law implies that when planets are closer to the sun, they move faster. -Kepler's laws explain why planets with larger semi-major axes have much longer orbital periods.
Kepler's laws explain why planets with larger semi-major axes have much longer orbital periods.
Regarding the history of the universe, which of the following is true? -The Earth formed quickly after the Big Bang. -All the current stars in our galaxy formed about the same time billions of years ago. -All the chemical elements were created during the Big Bang, but some have been modified since that time as a result of radioactive decay. -Key elements of which Earth and life are made, including carbon, oxygen, and iron, did not exist when the universe was born and were created later in stars.
Key elements of which Earth and life are made, including carbon, oxygen, and iron, did not exist when the universe was born and were created later in stars.
All of the following statements are true. Which one can be explained by Kepler's second law? -The Sun is not in the precise center of Saturn's orbit. -Earth is slightly closer to the Sun in January than in July. -All the planets orbit the Sun in nearly the same plane. -Venus orbits the Sun at a faster orbital speed than Earth. -Mars moves faster in its orbit when it is closer to the Sun than when it is farther from the Sun.
Mars moves faster in its orbit when it is closer to the Sun than when it is farther from the Sun.
Using the ideas discussed in your textbook, in what sense are we "star stuff"? -Movie stars and other people are all made of the same stuff, so we all have the potential to be famous. -We could not survive without light from our star, the Sun. -Nearly every atom from which we are made was once inside of a star. -The overall chemical composition of our bodies is about the same as that of stars.
Nearly every atom from which we are made was once inside of a star.
Has Polaris always been the "North Star", also known as the "Pole Star"? -Yes, because stars position change little over many centuries. -No, because the Earth's axis slowly changes the direction it points. -No, because the Milky Way blocked our line of site to it for a long time. -No, because it is a young star which formed only a few hundred years ago.
No, because the Earth's axis slowly changes the direction it points.
The Sun-centered system pictured in the lower window of the video offers a simple explanation for observations of apparent retrograde motion. Should these facts alone have been enough to convince the ancient Greeks that Earth really does go around the Sun? -Yes, but the Greeks were unable to detect apparent retrograde motion and therefore didn't know that it ruled out an Earth-centered universe. -No, because apparent retrograde motion still happens in an Earth-centered system as the Sun passes by a planet in its orbit around Earth. -Yes, but the Greeks did not realize it because they never even considered a Sun-centered model. -No, because the Greeks had an Earth-centered model that also accounted for apparent retrograde motion.
No, because the Greeks had an Earth-centered model that also accounted for apparent retrograde motion.
Consider three circles that may be imaginatively "drawn" across the night sky (note that we see only parts of each circle at any time): the Milky Way; the ecliptic; and the celestial equator. Which statement about these circles is true? -The celestial equator is unique, since it traces the path of an object, namely, the Sun. -The ecliptic circle is unique as it traces a broad band of stars. -The Milky Way and the ecliptic are the only two circles that are tilted relative to each other. -Only the ecliptic circle passes through all the zodiacal constellations. -All three circles cross at the same two points: the equinoxes.
Only the ecliptic circle passes through all the zodiacal constellations.
Which of the following changes would cause the solar day to be shorter (rather than longer) than the sidereal day? -Increasing Earth's orbital speed around the Sun -Decreasing Earth's orbital speed around the Sun -Increasing Earth's rotation period -Decreasing Earth's rotation period -Reversing the direction of Earth's rotation
Reversing the direction of Earth's rotation
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. -Scientific explanations should be based solely on natural causes. -Science consists of proven theories that are understood to be true explanations of reality.
Science consists of proven theories that are understood to be true explanations of reality.
Which of the following statements about the celestial sphere is not true? -The "celestial sphere" is another name for our universe. -The Earth is placed at the center of the celestial sphere. -When we look in the sky, the stars all appear to be located on the celestial sphere. -The celestial sphere does not exist physically.
The "celestial sphere" is another name for our universe.
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 shares the same orbit around the Sun as Earth. -The asteroid's average (semimajor axis) distance from the Sun is 1AU. -The asteroid will eventually collide with Earth. -The asteroid has the same perihelion distance as Earth. -The asteroid has a more eccentric orbit than Earth.
The asteroid's average (semimajor axis) distance from the Sun is 1AU.
Which of the following statements about stellar parallax is true? -We observe all stars to exhibit at least a slight amount of parallax. -The amount of parallax we see depends on how fast a star is moving relative to us. -The closer a star is to us, the more parallax it exhibits. -It takes at least 10 years of observation to measure a star's parallax. -Stellar parallax was first observed by ancient Greek astronomers.
The closer a star is to us, the more parallax it exhibits.
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. -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 we observe a galaxy that is 13 billion light-years away. Which of the following can we conclude? -The galaxy formed before the universe was 1 billion years old. -The galaxy is older than the Milky Way. -We see the galaxy as it looked when it was 13 billion years old. -We see the galaxy as it looked when it was 1 billion years old.
The galaxy formed before the universe was 1 billion years old.
What conditions are required for a lunar eclipse? -The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. -The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. -The phase of the Moon must be new, and the Moon's orbital plane must lie in the ecliptic. -The phase of the Moon can be new or full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun.
The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun.
The video states that the planetary orbits are shown to scale. Which statement correctly describes the way the planet sizes are shown compared to their orbits? -The planet sizes are correctly shown on the same scale as the orbits. -Jupiter is shown correctly to scale with its orbit, but all the other planets are too large. -The planets should all be about twice as large as shown. -The planets are all much too large compared to their orbits.
The planets are all much too large compared to their orbits.
Suppose that Earth orbited the Sun 10 times as fast as it actually does but kept the same rotation period it has now. Which of the following would be true? -The solar day would actually be a bit shorter than the sidereal day. -The sidereal day would still be 23 hours, 56 minutes, but the solar day would be a little over 24 1/2 hours. -The solar day would still be 24 hours, but the sidereal day would be a little less than 23 1/2 hours. -The solar day would be 10 times as long, or about 240 hours.
The sidereal day would still be 23 hours, 56 minutes, but the solar day would be a little over 24 1/2 hours.
Falsifiability. Which of the statements can be falsified by scientific experiment? -War is morally justified. -A supernatural being created the world. -Picasso was the best artist of his generation. -The stars at your birth predict your personality and health.
The stars at your birth predict your personality and health.
Why don't star systems, galaxies and galaxy clusters themselves expand as the universe around them expands? -Actually, they do. -Expansion pertains to the space between objects, and not the objects themselves. -Their inter-gravitational attraction is strong enough to keep them bound together against the expansion of space. -They were formed before the period of expansion began and are thus unaffected.
Their inter-gravitational attraction is strong enough to keep them bound together against the expansion of space.
In what sense are telescopes like time machines? -They allow us to see what Earth looked like long ago. -They allow us to see distant objects as they will be in the future. -They allow us to look at a galaxy and see it as it was at many different times in the past. -They allow us to see distant objects as they were long in the past.
They allow us to see distant objects as they were long in the past.
RXJ1800, a galaxy, lies very near in the sky to the bright star Vega. What is the best explanation for them appearing close together? -They coincidentally lie along the same line of sight. -Vega orbits the center of mass of RXJ1800. -Their random motions have caused RXJ1800 and Vega to drift to within a few light-years of each other. -Vega must have recently formed in RXJ1800 and been ejected.
They coincidentally lie along the same line of sight.
The Greeks rejected the notion that the Earth orbits the Sun. Why? -They were not as smart as we are. -They could not measure a change in stars' positions on the sky. -They believed that the Sun is a God. -They could not measure how big the Earth was.
They could not measure a change in stars' positions on the sky.
Why were ancient peoples unable to detect stellar parallax? -They did not observe for long enough periods of time. -They did not look for it. -They did not have the ability to measure very small angles. -They could not see distant stars. -They did detect it, but they rejected the observations.
They did not have the ability to measure very small angles.
Why did the Greeks conclude that the Earth was stationary, and that the Sun and the planets orbited around the Earth? -They did not understand the concept of stellar parallax. -They knew that everything in the heavens had to be a perfect circle. -They did not observe any change in the separation of stars during Earth's orbit. -They felt that the Sun was really the god Apollo.
They did not observe any change in the separation of stars during Earth's orbit.
All of the following statements are true. Which one can be explained by Kepler's third law? -Venus orbits the Sun at a faster orbital speed than Earth. -All the planets orbit the Sun in nearly the same plane. -Earth is slightly closer to the Sun in January than in July. -Mars moves faster in its orbit when it is closer to the Sun than when it is farther from the Sun. -The Sun is not in the precise center of Saturn's orbit.
Venus orbits the Sun at a faster orbital speed than Earth.
Today the Sun is in the middle of the constellation Virgo. Therefore, tomorrow the Sun will be in the constellation -Libra. -Sagittarius. -Virgo. -Leo.
Virgo
What is the evidence for the existence of the mysterious "Dark Matter"? -The outer parts of galaxies rotate about their centers at unexpected velocities. These velocities indicate that there are massive halos around each galaxy made of matter invisible to astronomers. -Anti-matter (expected to be formed in the Big Bang) has never been seen. Hence, it is referred to as the "Dark Matter". -We are unable to see the stars that are located at large distances from us across the Milky Way Galaxy suggesting unknown "Dark Matter" is absorbing their light. -The expansion of the universe is observed to be accelerating, implying a repulsive force due to the unknown presence of "Dark Matter".
We are unable to see the stars that are located at large distances from us across the Milky Way Galaxy suggesting unknown "Dark Matter" is absorbing their light.
Today, the evidence that we live in an expanding universe is extremely strong because astronomers have measured the motions of millions of galaxies. Nevertheless, in science, we must always remain open to the possibility that some future observation could call even our most strongly supported theories into question. Which of the following hypothetical observations would not be consistent with what we expect in an expanding universe? -You discover an extremely distant galaxy that is moving toward us. -You discover a pair of distant galaxies that are colliding with one another. -You discover an extremely distant galaxy that is moving away from us at 90% of the speed of light.
You discover an extremely distant galaxy that is moving toward us.
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 won't see the Moon tonight, because it is up only in the morning. -Your friend will see a first quarter moon. -Your friend will see a gibbous moon. -Your friend will also see a crescent moon.
Your friend will also see a crescent moon.
What is represented by the figure-eight analemma? -an eight-fold intermediate analytical theorem (lemma) pertaining to all astronomical motions -the time-lapse photograph of a planet (e.g., Mars) as it undergoes retrograde motion -a positional map of Earth's wandering north celestial pole projected into the sky over the course of the next 10,000 years -a composite snapshot of the Sun taken from the same location at the same time of day over one year
a composite snapshot of the Sun taken from the same location at the same time of day over one year
You observe a full moon rising at sunset. What will you see 6 hours later? -a first quarter moon -a third quarter moon -a waning gibbous moon -a full moon on or near your meridian
a full moon on or near your meridian
What is meant by a scientific paradigm? -a radical change in scientific thought -a paradox: two theories, each believed to be true, that contradict each other -a historical theory that has been proved inaccurate -a generally well-established scientific theory or set of theories -a model that tells a story in the form of a parable
a generally well-established scientific theory or set of theories
The Moon takes about 1 month to orbit Earth (more precisely, about 27 1/3 days), and it travels in the same direction that Earth orbits the Sun. Therefore, during the time it takes the Moon to complete one orbit around Earth, Earth moves __________ around its orbit of the Sun. -about 12∘ -about 1∘ -about 1/12 of the way -exactly 27.333∘
about 1/12 of the way
According to current scientific estimates, when did the Big Bang occur? -about 20 billion years ago -about 14 billion years ago -about 10 billion years ago -about 4 1/2 billion years ago -about 65 million years ago
about 14 billion years ago
The Andromeda Galaxy is faintly visible to the naked eye. When you look at the Andromeda Galaxy, the retina of your eye is absorbing light that has traveled through space for ______ to reach you. -about 250 years -a few minutes -about 2 ½ million years -about 100,000 years
about 2 ½ million years
The Jewish calendar is kept roughly synchronized with a solar calendar by -having a thirteenth month with 5 days each year. -having the first lunar month begin on the spring equinox. -skipping a month every 7 out of 19 years. -having the first lunar month begin on the June solstice. -adding a thirteenth lunar month to 7 out of every 19 years.
adding a thirteenth lunar month to 7 out of every 19 years.
The universe is defined as -the entire Milky Way Galaxy. -all the stars and galaxies that we can see with telescopes. -all material, space, and energy that exist: everything. -all the objects we can see and the space between them.
all material, space, and energy that exist: everything.
Galileo refuted the idea that -heavenly bodies are perfect. -objects require an external force to keep moving. -the Sun orbits Venus. -all of the above
all of the above
The fact that the expansion of the universe is seen to be accelerating suggests -the Big Bang explosion caused the constant expansion of space. -the universe is destined to contract in the distant future. -an unknown repulsive force, called "Dark Energy", is present in the universe. -the gravity of distant galaxies is pulling the universe apart ever faster. -"Dark Matter" is present between galaxies.
an unknown repulsive force, called "Dark Energy", is present in the universe.
When the Moon's phase is a first quarter moon, it rises -around noon. -just after sunset. -close to sunrise. -just before sunset.
around non
Suppose that someone in the Andromeda galaxy had a super-telescope through which they were looking at Earth right now. They would see Earth ______. -as it is right now -as it was about 100,000 years ago -as it will be about 2 ½ million years from now -as it was about 2 ½ million years ago
as it was about 2 ½ million years ago
When we look toward the constellation Sagittarius, we are looking -toward Polaris, the "Pole Star." -toward the Winter Triangle. -out towards the outer Milky Way. -at the galaxy's central bulge.
at the galaxy's central bulge.
The Muslim fast of Ramadan occurs -during the ninth month of the lunar calendar, between new moons. -on the December solstice, coincident with the Saturnalia. -at the beginning of each Metonic Cycle. -on the 15th day of Nisan, the first month of the lunar calendar.
during the ninth month of the lunar calendar, between new moons.
As seen from Earth, the Sun appears to follow the annual path that we call the __________ around the celestial sphere. -north celestial pole -ecliptic -constellations -south celestial pole -milky way -celestial equator
ecliptic
The Polynesian navigators of the South Pacific found their way primarily by observing the position of Polaris in the night sky. True False
false
During a lunar eclipse the Moon's phase must be -full. -1st quarter. -new. -3rd quarter.
full
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? -crescent on the right side -new -crescent on the left side -gibbous (nearly full)
gibbous (nearly full)
What is the Sun mainly made of? -carbon and nitrogen -hydrogen and oxygen -nearly equal portions of all the elements -oxygen and carbon -hydrogen and helium
hydrogen and helium
If we have a new moon today, when we will have the next full moon? -in about 1 week -in about 1 month -in about 6 months -in about 2 weeks
in about 2 weeks
On the cosmic calendar, which compresses the history of the universe into a single year, about when did Earth form? -very early in January -in mid-February -in June -in early September -in mid-December
in early September
The principle of Occam's Razor states that -only a model that has survived repeated observational tests deserves to be called a scientific theory. -no scientific theory, no matter how well tested, can ever be proved absolutely true. -while personal biases may influence individual scientists, the process of science itself can uncover these biases. -a disciplined approach is required for separating false hypotheses from true hypotheses. -in explaining natural phenomena, the simplest explanation consistent with the observations is to be preferred.
in explaining natural phenomena, the simplest explanation consistent with the observations is to be preferred.
Where was the Hydrogen in the universe formed? -in chemical reactions in interstellar space -in the Big Bang -in the cores of stars -from the dissociation of water (H2O)
in the Big Bang
We never see a crescent Jupiter from Earth because Jupiter __________. -does not go around Earth -is farther than Earth from the Sun -shines with its own light -orbits the Sun in the same direction as Earth
is farther than Earth from the Sun
On the cosmic calendar, which compresses the history of the universe into a single year, about when did early humans first walk on Earth? -in June -in September -in mid-December -on December 30 -just a few hours before midnight on December 31
just a few hours before midnight on December 31
Based on your answer to Part E, the time from one new moon to the next must be _________. -longer than the Moon's actual orbital period by about 1/12 of a year -shorter than the Moon's actual orbital period by about 1/12 of a year -shorter than the Moon's actual orbital period by about 1/12 of the 27-day orbital period -longer than the Moon's actual orbital period by about 1/12 of the 27-day orbital period
longer than the Moon's actual orbital period by about 1/12 of the 27-day orbital period
Eratosthenes measured the circumference of Earth to within 4% of the correct value -sighting the stars from within the deepest well in Egypt on the day of the solstice. -noting how much more of the celestial sphere came into view when walking south. -looking at stick shadows on the solstice. -using the detailed reports of far-sailing mariners.
looking at stick shadows on the solstice.
The reason galaxies that are distant from our galaxy move away from our galaxy more rapidly than those that are near is -more space expands between us and the distant galaxies. -the more distant galaxies are smaller and less massive, so they can move faster. -the nearby galaxies are slowed by our galaxy's gravitational pull. -the more distant galaxies formed first with higher speeds.
more space expands between us and the distant galaxies.
From Kepler's third law, a hypothetical planet that is twice as far from the Sun as Earth should have a period of -1/2 Earth year. -more than 2 Earth years. -2 Earth years. -1 Earth year. -It depends on the planet's mass.
more than 2 Earth years.
In Ptolemy's Earth-centered model, when would Venus appear directly behind the Sun as viewed from Earth? -when it is in closest to Earth -never -when it is in farthest from Earth -when it is in a crescent phase
never
A total solar eclipse can only happen during what lunar phase? -first quarter -waning gibbous -new -full
new
The great contribution of Tycho Brahe was to ________. -offer the first detailed model of a Sun-centered solar system, thereby beginning the process of overturning the Earth-centered model of the Greeks -discover that planets orbit the Sun in elliptical orbits with varying speed -discover four moons orbiting Jupiter, thereby lending strong support to the idea that the Earth is not the center of the universe -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 ________. -inventing the telescope -observing sunspots on the Sun and mountains on the Moon -proving Kepler's laws were correct -showing that heavy objects fall at the same rate as lighter objects
observing sunspots on the Sun and mountains on the Moon
Suppose you live at a mid-latitude in the Southern Hemisphere (such as in Australia, New Zealand, Chile, or South Africa). When will you have 12 hours of daylight and 12 hours of darkness? -on the June solstice only -on the March equinox only -on both the March and September equinoxes -on both the June and December solstices -on the December solstice only
on both the March and September equinoxes
The Moon orbits the Sun -once a year. -once a day. -once a month.
once a year
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
From Kepler's Second Law: Planetary orbits, when drawn with a line connecting the planet to the Sun, show that this line sweeps out equal areas in equal times, no matter where the planet is in its orbit, we may conclude that -planets move faster when they are closer to the Sun. -planets have elliptical orbits. -planets have circular orbits. -planets move slower when they are closer to the Sun.
planets move faster when they are closer to the Sun.
Note that an observer located at the Local Raisin would see Raisins 1, 2, and 3 all move away from her during the video. What would an observer located at Raisin 2 see? -Raisin 1 and Raisin 3 both move away from her. -Raisin 1 moves toward her while Raisin 3 moves away from her. -Raisin 1 and Raisin 3 both move toward her. -Raisin 1 moves away from her while Raisin 3 moves toward her.
raisin 1 and raisin 3 both move away from her
Where is our solar system located within the Milky Way Galaxy? -very near the center of the galaxy -in the halo of the galaxy -roughly halfway between the center and the edge of the visible disk of the galaxy -at the far edge of the galaxy's visible disk
roughly halfway between the center and the edge of the visible disk of the galaxy
The Sun -seems to move around the celestial sphere daily to the East. -circles around the celestial equator once each year. -is a fixed point on the celestial sphere at its distance from Earth. -is the fixed point at the north celestial pole.
seems to move around the celestial sphere daily to the East.
Which is an essential quality of an accepted scientific result? -mathematical elegance -testability -agreement with previous models -support by many scientists
testability
The term observable universe refers to ________. -that portion of the universe that we can see in principle, given the current age of the universe -that portion of the universe that we have so far photographed through telescopes -the portion of the universe that can be seen by the naked eye -the portion of the universe that is not hidden from view by, for example, being below the horizon
that portion of the universe that we can see in principle, given the current age of the universe
Which of the following statements best describes what astronomers mean when they say that the universe is expanding? -All objects in the universe, including Earth and everything on it, are gradually growing in size. -The average distance between galaxies is increasing with time. -The observable universe is growing larger in radius at a rate of one light-year per year. -The universe itself is not growing, but our knowledge of the universe is increasing with time. -The average distance between stars in the Milky Way Galaxy is increasing with time.
the average distance between galaxies is increasing with time
The ecliptic crosses the celestial equator on the celestial sphere at points called -aphelion and perihelion. -the solstices. -the equinoxes. -the nodes.
the equinoxes
What do astronomers mean by the Big Bang? -the event that marked the birth of our solar system -the event that marked the beginning of the expansion of the universe -a gigantic explosion that blew all the galaxies in the universe to smithereens -the explosion of a massive star at the end of its life
the event that marked the beginning of the expansion of the universe
What is the ecliptic? -the path traced by the Moon's shadow on Earth during a solar eclipse -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 the Sun appears to trace around the celestial sphere each year
Consider the hypothetical observation "a planet beyond Saturn rises in west, sets in east." This observation is not consistent with a Sun-centered model, because in this model __________. View Available Hint(s) -all objects in space must orbit the Sun in the same direction -planets beyond Saturn must orbit the Sun more slowly than closer-in planets -the rise and set of all objects depends only on Earth's rotation -there are no planets beyond Saturn
the rise and set of all objects depends only on Earth's rotation
Based on what you've learned from the raisin cake analogy, which two properties of distant galaxies do astronomers have to measure to show that we live in an expanding universe? -their ages and masses -their distances and masses -their ages and distances -their distances and speeds
their distances and speeds
Suppose we look at a photograph of many galaxies. Assuming that all of these galaxies formed at the same time after the Big Bang, which galaxies, as seen in the photo, would appear to be the youngest? -those galaxies that are the furthest away -those galaxies that are closest to us -those galaxies whose actual size is small -those galaxies that appear to be the bluest -All of the galaxies would appear to be at the same age.
those galaxies that are the furthest away
Why did Ptolemy have the planets orbiting Earth on "circles upon circles" in his model of the universe? -to explain why Venus goes through phases as seen from Earth -to explain why the Greeks were unable to detect stellar parallax -to explain the fact that planets sometimes appear to move westward, rather than eastward, relative to the stars in our sky -to explain why more distant planets take longer to make a circuit through the constellations of the zodiac -to properly account for the varying distances of the planets from Earth
to explain the fact that planets sometimes appear to move westward, rather than eastward, relative to the stars in our sky
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 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
to the right of Polaris; that is, 90 degrees counterclockwise from its current position
If you hold your hand out at arm's length, you can block the entire disk of the Sun with your little finger. True False
true
The Metonic cycle is -used to predict the future orientation of the Earth's axis in space. -used to keep lunar calendars approximately synchronized with solar calendars. -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.
The Milky Way shows itself as a blurry circle of light in the sky because -the spinning Earth blurs the stars above its equator onto this faint circle of blurry starlight and dust. -the Sun is at the center of the Milky Way Galaxy. The galaxy is a flat disk of stars appearing as a blurry band or ring of stars and dust in the sky, all seen at great distances. -it is a ring-like structure of stars and dust located hundreds of thousands of light-years from Earth. It is blurry because it is so far away. -we are looking along the plane of our galaxy that is filled with stars. When we look in other directions, we see fewer stars because we are looking through (at a steep angle to) the plane of our galaxy. We actually see only a small fraction of the stars of the Milky Way Galaxy.
we are looking along the plane of our galaxy that is filled with stars. When we look in other directions, we see fewer stars because we are looking through (at a steep angle to) the plane of our galaxy. We actually see only a small fraction of the stars of the Milky Way Galaxy.