Koofers

ASTR 1001- Midterm - Flashcards

Flashcard Deck Information

Class:ASTR 1001 - Laboratory
Subject:Astronomy
University:George Washington University
Term:Spring 2013
- of -
INCORRECT CORRECT
- INCORRECT     - CORRECT     - SKIPPED
Shuffle Remaining Cards Show Definitions First Take Quiz (NEW)
Hide Keyboard shortcuts
Next card
Previous card
Mark correct
Mark incorrect
Flip card
Start Over
Shuffle
      Mode:   CARDS LIST       ? pages   PRINT EXIT
Which of the following has your "cosmic address" in the correct order? You, Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe
Using the ideas discussed in your textbook, in what sense are we "star stuff"? Nearly every atom from which we are made was once inside of a star.
How are galaxies important to our existence? Galaxies recycle material from one generation of stars to the next, and without this recycling we could not exist.
When we look at an object that is 1,000 light-years away we see it _________. as it was 1,000 years ago
Generated by Koofers.com
Suppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2. In that case _________. we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy 2
Suppose we make a scale model of our solar system, with the Sun the size of a grapefruit. Which of the following best describes what the planets would look like? The planets are all much smaller than the Sun. Four planets are within about 20 meters of the Sun, while the rest planets are spread much farther apart.
If you could count stars at a rate of about one per second, how long would it take to count all the stars in the Milky Way Galaxy? Several thousand years
The total number of stars in the observable universe is about _________. the same as the number of grains of sand on all the beaches on Earth
Generated by Koofers.com
Where is our solar system located within the Milky Way Galaxy? Roughly halfway between the center and the edge of the visible disk of the galaxy
If we imagine the history of the universe compressed into one year, dinosaurs became extinct _________. yesterday morning
Relative to the age of the universe, how old is our solar system? It is about one-third the age of the universe.
How do the speeds at which we are moving with Earth's rotation and orbit compare to the speeds of more familiar objects? Earth's rotation carries most people around the axis faster than a commercial jet travels, and Earth's orbit carries us around the Sun faster than the Space Shuttle orbits Earth.
Generated by Koofers.com
Why do the patterns of the stars in our sky look the same from year to year? Because the stars in the constellations are so far away.
Astronomers infer that the universe is expanding because distant galaxies all appear to _________. be moving away from us, with more distant ones moving faster
Which statement about motion in the universe is not true? The mysterious dark matter is the fastest-moving material in the universe.
When did humans learn that the Earth is not the center of the universe? Within the past 500 years
Generated by Koofers.com
Which of the following statements about the celestial sphere is NOT true? The "celestial sphere" is another name for our universe.
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? We could not see it at all.
An angle of 1 arcsecond is _________. less than the thickness of a human hair held at arm's length
When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting _________. higher in the sky
Generated by Koofers.com
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
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
In any particular place on Earth, certain constellations are visible in the evening only at certain times of the year because _________. our evening view of space depends on where Earth is located in its orbit around the Sun
The Sun's path, as viewed from the equator, is highest in the sky on _________. the spring and fall equinoxes
Generated by Koofers.com
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 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.
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 four seasons would each be twice as long as they are now
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.
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 also see a crescent moon.
Generated by Koofers.com
Suppose it is full Moon. What phase of Earth would someone on the Moon see at this time? new Earth
It's 6 am and the Moon is at its highest point in your sky (crossing the meridian). What is the Moon's phase? third quarter
You observe a full Moon rising at sunset. What will you see at midnight? A full moon high in the sky
All the following statements are true. Which one explains the reason that there is not a solar eclipse at every new moon? The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane.
Generated by Koofers.com
For most of history, the lack of observable stellar parallax was interpreted to mean that _________. Earth is stationary at the center of the universe
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.
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 Galileo spacecraft that orbited Jupiter in the 1990s
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? A week would have eight days instead of seven.
Generated by Koofers.com
How does a 12-month lunar calendar differ from our 12-month solar calendar? It has about 11 fewer days.
Which of the following best describes a set of conditions under which archaeoastronomers would conclude that an ancient structure was used for astronomical purposes? 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.
How did the Ptolemaic model explain the apparent retrograde motion of the planets? The planets moved along small circles that moved on larger circles around the Earth.
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 used perfect circles for the orbits of the planets.
Generated by Koofers.com
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? Winter
According to Kepler's third law (p2 = a3), how does a planet's mass affect its orbit around the Sun? A planet's mass has no effect on its orbit around the Sun.
All the following statements are true. Which one follows directly from Kepler's third law (p2 = a3)? Venus orbits the Sun at a slower average speed than Mercury.
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? 1 year, which we know from Kepler's third law.
Generated by Koofers.com
Galileo challenged the idea that objects in the heavens were perfect by _________. observing sunspots on the Sun and mountains on the Moon
Galileo observed all of the following. Which observation offered direct proof of a planet orbiting the Sun? Phases of Venus
Which of the following is not consistent with the major hallmarks of science? Science consists of proven theories that are understood to be true explanations of reality.
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.
Generated by Koofers.com
Only one of the statements below uses the term theory in its correct, scientific sense. Which one? Einstein's theory of relativity has been tested and verified thousands of times.
The astrology practiced by those who cast predictive horoscopes can be tested by __________ comparing how often the predictions come true to what would be expected by pure chance.
Imagine for a moment that despite all the evidence, Earth actually is not rotating and orbiting the Sun. Which of these hypothetical observations (none of them are real) would be inconsistent with our Sun-centered view of the solar system? We discover a small planet beyond Saturn that rises in the west and sets in the east each day.
Which of the following represents a case in which you are not accelerating? Driving in a straight line at 60 miles per hour
Generated by Koofers.com
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.
Why are astronauts weightless in the Space Station? Because the Space Station is constantly in free-fall around the Earth
A net force acting on an object will always cause a change in the object's _________. momentum
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.
Generated by Koofers.com
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
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.
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.
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.
Generated by Koofers.com
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.
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.
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.
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.
Generated by Koofers.com
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.
Newton showed that Kepler's laws are _________. natural consequences of the law of universal gravitation
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 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.
Generated by Koofers.com
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.
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.
At which lunar phase(s) are tides most pronounced (for example, the highest high tides)? Both new and full moons
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.
Generated by Koofers.com
Suppose the Moon's orbit were unchanged, but it rotated faster (meaning it did not have synchronous rotation). Which of the following would be true? We would no longer always see nearly the same face of the Moon.
Suppose you have a 100-watt light bulb that you leave turned on for one minute. How much energy does it use? 6,000 joules
Which of the following statements is true of green grass? It absorbs red light and reflects green light.
Suppose you are listening to a radio station that broadcasts at a frequency of 97 Mhz (megahertz). Which of the following statements is true? The radio waves from the radio station are causing electrons in your radio's antenna to move up and down 97 million times each second.
Generated by Koofers.com
Gamma rays have a very small ______. wavelength
Suppose a photon has a frequency of 300 million hertz (300 megahertz). What is its wavelength? 1 meter
Which of the following best describes why we say that light is an electromagnetic wave? The passage of a light wave can cause electrically charged particles to move up and down.
Which of the following statements about X rays and radio waves is not true? X rays travel through space faster than radio waves.
Generated by Koofers.com
Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms different isotopes of the same element? Atom 1: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons; Atom 2: nucleus with 7 protons and 7 neutrons, surrounded by 7 electrons
Suppose you had molecular oxygen (O2) chilled enough so that it was in liquid form. Which of the following best describes the phase changes that would occur as you heated the liquid oxygen to high temperature? It would evaporate into a gas, then the molecules would dissociate into individual oxygen atoms, then the atoms would become increasingly ionized as you continued to raise the temperature.
Which of the following statements about electrons is not true?

Electrons orbit the nucleus rather like planets orbiting the Sun.

Which of the following conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space? The cloud is cool and lies between you and a hot star.
Generated by Koofers.com
No object produces a perfect thermal radiation spectrum, but many objects produce close approximations. Which of the following would not produce a close approximation to a thermal radiation spectrum? a hot, thin (low-density, nearly transparent) gas
Which of the following statements about thermal radiation is always true? A hot object emits more radiation per unit surface area than a cool object.
Betelgeuse is the bright red star representing the left shoulder of the constellation Orion. All the following statements about Betelgeuse are true. Which one can you infer from its red color? Its surface is cooler than the surface of the Sun.
The planet Neptune is blue in color. How would you expect the spectrum of visible light from Neptune to be different from the visible-light spectrum of the Sun? The two spectra would have similar shapes, except Neptune's spectrum would be missing a big chunk of the red light that is present in the Sun's spectrum.
Generated by Koofers.com
All of the following statements about the Sun's corona are true. Which one explains why it is a source of X rays? The temperature of the corona's gas is some 1 to 2 million Kelvin.
Laboratory measurements show hydrogen produces a spectral line at a wavelength of 486.1 nanometers (nm). A particular star's spectrum shows the same hydrogen line at a wavelength of 486.0 nm. What can we conclude? The star is moving toward us.
Suppose that Star X and Star Y both have redshifts, but Star X has a larger redshift than Star Y. What can you conclude? Star X is moving away from us faster than Star Y.
If we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet? The planet is rotating.
Generated by Koofers.com
Studying a spectrum from a star can tell us a lot. All of the following statements are true except one. Which statement is not true? The total amount of light in the spectrum tells us the star's radius.
Suppose that two stars are identical in every way - for example, same distance, same mass, same temperature, same chemical composition, and same speed relative to Earth - except that one star rotates faster than the other. Spectroscopically, how could you tell the stars apart? The faster rotating star has wider spectral lines than the slower rotating star.
Suppose you have two small photographs of the Moon. Although both look the same at small size, when you blow them up to poster size one of them still looks sharp while the other one becomes fuzzy (grainy) looking. Which of the following statements is true? The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy.
The angular separation of two stars is 0.1 arcseconds and you photograph them with a telescope that has an angular resolution of 1 arcsecond. What will you see? The photo will seem to show only one star rather than two.
Generated by Koofers.com
Suppose you point your telescope at a distant object. Which of the following is not an advantage of taking a photograph of the object through the telescope as compared to just looking at the object through the telescope? The photograph will have far better angular resolution than you can see with your eye.
Which of the following best describes the principle advantage of CCDs over photographic film? CCDs capture a much higher percentage of the incoming photons than film.
How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope? The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope.
Which of the following best describes the development of astronomical telescopes over the past 65 years? The world's most powerful telescope remained the same for most of this period, but in the past 20 years many new and more powerful telescopes have been built.
Generated by Koofers.com
Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light? Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light.
Which of the following studies is best suited to astronomical observations that fall into the category called timing? Studying how a star's brightness varies over a period of 3 years.
Which of the following is not a reason why telescopes tend to be built on mountaintops that are relatively far from cities and are in regions with dry climates? The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.
The stars in our sky twinkle in brightness and color because of ______. turbulence in the Earth's atmosphere
Generated by Koofers.com
Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes? It is closer to the stars.
The Chandra X-ray Observatory must operate in space because: X rays do not penetrate Earth's atmosphere.
Which of the following telescopes would benefit most from adaptive optics? The Keck I telescope on Mauna Kea.
Consider two future observatories in space. Observatory X consists of a single 50-meter telescope. Observatory Y is an interferometer consisting of five 10-meter telescopes, spread out over a region 100 meters across. Which observatory can detect dimmer stars, and which one can see more detail in its images? (Assume all else is equal, such as quality of optics, types of instruments, and so on.) Observatory X can detect dimmer stars and Observatory Y reveals more detail in images.
Generated by Koofers.com
Which of the following is not a major reason why astronomers would like an observatory on the far side of the Moon? Telescopes on the Moon could see objects in all parts of the sky equally well, whereas telescopes on Earth can see only portions of the sky that depend on their latitude.
In the late 1800s, Kelvin and Helmholtz suggested that the Sun stayed hot due to gravitational contraction. What was the major drawback to this idea? It predicted that the Sun could shine for about 25 million years, but geologists had already found that Earth is much older than this.  
When is/was gravitational contraction an important energy generation mechanism for the Sun? It was important when the Sun was forming from a shrinking interstellar cloud of gas.
What do we mean when we say that the Sun is in gravitational equilibrium? There is a balance within the Sun between the outward push of pressure and the inward pull of gravity.
Generated by Koofers.com
Which of the following is the best answer to the question, "Why does the Sun shine?" As the Sun was forming, gravitational contraction increased the Sun's temperature until the core become hot enough for nuclear fusion, which ever since has generated the heat that makes the Sun shine.
How does the Sun's mass compare to Earth's mass? The Sun's mass is about 300,000 times the mass of the Earth.
Which of the following best describes why the Sun emits most of its energy in the form of visible light? Like all objects, the Sun emits thermal radiation with a spectrum that depends on its temperature, and the Sun's surface temperature is just right for emitting mostly visible light.
The Sun's surface seethes and churns with a bubbling pattern. Why? We are seeing hot gas rising and cool gas falling due to the convection that occurs beneath the surface.
Generated by Koofers.com
Which of the following correctly compares the Sun's energy generation process to the energy generation process in human-built nuclear power plants? The Sun generates energy by fusing small nuclei into larger ones, while our power plants generate energy by the fission (splitting) of large nuclei.
Every second, the Sun converts about 600 million tons of hydrogen into 596 million tons of helium. The remaining 4 million tons of mass is _________. converted to an amount of energy equal to 4 million tons times the speed of light squared
Which of the following best explains why nuclear fusion requires bringing nuclei extremely close together? Nuclei normally repel because they are all positively charged and can be made to stick only when brought close enough for the strong force to take hold.
If the Sun's core suddenly shrank a little bit, what would happen in the Sun? The core would heat up, fusion rates would increase, the core would re-expand.
Generated by Koofers.com
Why does the Sun emit neutrinos? Fusion in the Sun's core creates neutrinos.
If the Sun suddenly stopped emitting neutrinos, what might we infer (after checking that our neutrino detectors were still operational)? Fusion reactions in the Sun have ceased.
Which of the following best explains why the Sun's luminosity gradually rises over billions of years? Fusion gradually decreases the number of independent particles in the core, allowing gravity to compress and heat the core, which in turn increases the fusion rate and the Sun's luminosity.
Why do sunspots appear dark in pictures of the Sun? They actually are fairly bright, but appear dark against the even brighter background of the surrounding photosphere.
Generated by Koofers.com
Which of the following best describes the current status of our understanding of the solar neutrino problem? Experimental evidence indicates that the problem is solved and the expected number of solar neutrinos are indeed being produced by the Sun.
How can we best observe the Sun's chromosphere and corona? The chromosphere is best observed with ultraviolet telescopes and the corona is best observed with X-ray telescopes.
The intricate patterns visible in an X-ray image of the Sun generally show _________. extremely hot plasma flowing along magnetic field lines
How can we measure the strength of magnetic fields on the Sun? By looking for the splitting of spectral lines in the Sun's spectrum.
Generated by Koofers.com
Satellites in low-Earth orbits are more likely to crash to Earth when the sunspot cycle is near solar maximum because _________. Earth's upper atmosphere tends to expand during solar maximum, exerting drag on satellites in low orbits
Which of the following choices is not a way by which we can study the inside of the Sun? We can send a space probe into the Sun's photosphere.
A computer accessory salesman attempts to convince you to purchase a "solar neutrino" shield for your new computer. (It's even "on sale" !) Why do you turn down this excellent offer? Neutrinos rarely, if ever, interact with your computer.
Generated by Koofers.com

List View: Terms & Definitions

  Hide All 131 Print
 
Front
Back
 Which of the following has your "cosmic address" in the correct order?You, Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe
 Using the ideas discussed in your textbook, in what sense are we "star stuff"?Nearly every atom from which we are made was once inside of a star.
 How are galaxies important to our existence?Galaxies recycle material from one generation of stars to the next, and without this recycling we could not exist.
 When we look at an object that is 1,000 light-years away we see it _________.as it was 1,000 years ago
 Suppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2. In that case _________.we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy 2
 Suppose we make a scale model of our solar system, with the Sun the size of a grapefruit. Which of the following best describes what the planets would look like?The planets are all much smaller than the Sun. Four planets are within about 20 meters of the Sun, while the rest planets are spread much farther apart.
 If you could count stars at a rate of about one per second, how long would it take to count all the stars in the Milky Way Galaxy?Several thousand years
 The total number of stars in the observable universe is about _________.the same as the number of grains of sand on all the beaches on Earth
 Where is our solar system located within the Milky Way Galaxy?Roughly halfway between the center and the edge of the visible disk of the galaxy
 If we imagine the history of the universe compressed into one year, dinosaurs became extinct _________.yesterday morning
 Relative to the age of the universe, how old is our solar system?It is about one-third the age of the universe.
 How do the speeds at which we are moving with Earth's rotation and orbit compare to the speeds of more familiar objects?Earth's rotation carries most people around the axis faster than a commercial jet travels, and Earth's orbit carries us around the Sun faster than the Space Shuttle orbits Earth.
 Why do the patterns of the stars in our sky look the same from year to year?Because the stars in the constellations are so far away.
 Astronomers infer that the universe is expanding because distant galaxies all appear to _________.be moving away from us, with more distant ones moving faster
 Which statement about motion in the universe is not true?The mysterious dark matter is the fastest-moving material in the universe.
 When did humans learn that the Earth is not the center of the universe?Within the past 500 years
 Which of the following statements about the celestial sphere is NOT true?The "celestial sphere" is another name for our universe.
 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?We could not see it at all.
 An angle of 1 arcsecond is _________.less than the thickness of a human hair held at arm's length
 When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting _________.higher in the sky
 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
 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
 In any particular place on Earth, certain constellations are visible in the evening only at certain times of the year because _________.our evening view of space depends on where Earth is located in its orbit around the Sun
 The Sun's path, as viewed from the equator, is highest in the sky on _________.the spring and fall equinoxes
 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 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.
 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 four seasons would each be twice as long as they are now
 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.
 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 also see a crescent moon.
 Suppose it is full Moon. What phase of Earth would someone on the Moon see at this time?new Earth
 It's 6 am and the Moon is at its highest point in your sky (crossing the meridian). What is the Moon's phase?third quarter
 You observe a full Moon rising at sunset. What will you see at midnight?A full moon high in the sky
 All the following statements are true. Which one explains the reason that there is not a solar eclipse at every new moon?The orbital plane of the Moon is tilted slightly (by about 5 degrees) to the ecliptic plane.
 For most of history, the lack of observable stellar parallax was interpreted to mean that _________.Earth is stationary at the center of the universe
 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.
 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 Galileo spacecraft that orbited Jupiter in the 1990s
 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?A week would have eight days instead of seven.
 How does a 12-month lunar calendar differ from our 12-month solar calendar?It has about 11 fewer days.
 Which of the following best describes a set of conditions under which archaeoastronomers would conclude that an ancient structure was used for astronomical purposes?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.
 How did the Ptolemaic model explain the apparent retrograde motion of the planets?The planets moved along small circles that moved on larger circles around the Earth.
 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 used perfect circles for the orbits of the planets.
 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?Winter
 According to Kepler's third law (p2 = a3), how does a planet's mass affect its orbit around the Sun?A planet's mass has no effect on its orbit around the Sun.
 All the following statements are true. Which one follows directly from Kepler's third law (p2 = a3)?Venus orbits the Sun at a slower average speed than Mercury.
 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?1 year, which we know from Kepler's third law.
 Galileo challenged the idea that objects in the heavens were perfect by _________.observing sunspots on the Sun and mountains on the Moon
 Galileo observed all of the following. Which observation offered direct proof of a planet orbiting the Sun?Phases of Venus
 Which of the following is not consistent with the major hallmarks of science?Science consists of proven theories that are understood to be true explanations of reality.
 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.
 Only one of the statements below uses the term theory in its correct, scientific sense. Which one?Einstein's theory of relativity has been tested and verified thousands of times.
 The astrology practiced by those who cast predictive horoscopes can be tested by __________comparing how often the predictions come true to what would be expected by pure chance.
 Imagine for a moment that despite all the evidence, Earth actually is not rotating and orbiting the Sun. Which of these hypothetical observations (none of them are real) would be inconsistent with our Sun-centered view of the solar system?We discover a small planet beyond Saturn that rises in the west and sets in the east each day.
 Which of the following represents a case in which you are not accelerating?Driving in a straight line at 60 miles per hour
 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.
 Why are astronauts weightless in the Space Station?Because the Space Station is constantly in free-fall around the Earth
 A net force acting on an object will always cause a change in the object's _________.momentum
 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.
 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
 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.
 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.
 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.
 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.
 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.
 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.
 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.
 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.
 Newton showed that Kepler's laws are _________.natural consequences of the law of universal gravitation
 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 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.
 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.
 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.
 At which lunar phase(s) are tides most pronounced (for example, the highest high tides)?Both new and full moons
 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.
 Suppose the Moon's orbit were unchanged, but it rotated faster (meaning it did not have synchronous rotation). Which of the following would be true?We would no longer always see nearly the same face of the Moon.
 Suppose you have a 100-watt light bulb that you leave turned on for one minute. How much energy does it use?6,000 joules
 Which of the following statements is true of green grass?It absorbs red light and reflects green light.
 Suppose you are listening to a radio station that broadcasts at a frequency of 97 Mhz (megahertz). Which of the following statements is true?The radio waves from the radio station are causing electrons in your radio's antenna to move up and down 97 million times each second.
 Gamma rays have a very small ______.wavelength
 Suppose a photon has a frequency of 300 million hertz (300 megahertz). What is its wavelength?1 meter
 Which of the following best describes why we say that light is an electromagnetic wave?The passage of a light wave can cause electrically charged particles to move up and down.
 Which of the following statements about X rays and radio waves is not true?X rays travel through space faster than radio waves.
 Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms different isotopes of the same element?Atom 1: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons; Atom 2: nucleus with 7 protons and 7 neutrons, surrounded by 7 electrons
 Suppose you had molecular oxygen (O2) chilled enough so that it was in liquid form. Which of the following best describes the phase changes that would occur as you heated the liquid oxygen to high temperature?It would evaporate into a gas, then the molecules would dissociate into individual oxygen atoms, then the atoms would become increasingly ionized as you continued to raise the temperature.
 Which of the following statements about electrons is not true?

Electrons orbit the nucleus rather like planets orbiting the Sun.

 Which of the following conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space?The cloud is cool and lies between you and a hot star.
 No object produces a perfect thermal radiation spectrum, but many objects produce close approximations. Which of the following would not produce a close approximation to a thermal radiation spectrum?a hot, thin (low-density, nearly transparent) gas
 Which of the following statements about thermal radiation is always true?A hot object emits more radiation per unit surface area than a cool object.
 Betelgeuse is the bright red star representing the left shoulder of the constellation Orion. All the following statements about Betelgeuse are true. Which one can you infer from its red color?Its surface is cooler than the surface of the Sun.
 The planet Neptune is blue in color. How would you expect the spectrum of visible light from Neptune to be different from the visible-light spectrum of the Sun?The two spectra would have similar shapes, except Neptune's spectrum would be missing a big chunk of the red light that is present in the Sun's spectrum.
 All of the following statements about the Sun's corona are true. Which one explains why it is a source of X rays?The temperature of the corona's gas is some 1 to 2 million Kelvin.
 Laboratory measurements show hydrogen produces a spectral line at a wavelength of 486.1 nanometers (nm). A particular star's spectrum shows the same hydrogen line at a wavelength of 486.0 nm. What can we conclude?The star is moving toward us.
 Suppose that Star X and Star Y both have redshifts, but Star X has a larger redshift than Star Y. What can you conclude?Star X is moving away from us faster than Star Y.
 If we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet?The planet is rotating.
 Studying a spectrum from a star can tell us a lot. All of the following statements are true except one. Which statement is not true?The total amount of light in the spectrum tells us the star's radius.
 Suppose that two stars are identical in every way - for example, same distance, same mass, same temperature, same chemical composition, and same speed relative to Earth - except that one star rotates faster than the other. Spectroscopically, how could you tell the stars apart?The faster rotating star has wider spectral lines than the slower rotating star.
 Suppose you have two small photographs of the Moon. Although both look the same at small size, when you blow them up to poster size one of them still looks sharp while the other one becomes fuzzy (grainy) looking. Which of the following statements is true?The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy.
 The angular separation of two stars is 0.1 arcseconds and you photograph them with a telescope that has an angular resolution of 1 arcsecond. What will you see?The photo will seem to show only one star rather than two.
 Suppose you point your telescope at a distant object. Which of the following is not an advantage of taking a photograph of the object through the telescope as compared to just looking at the object through the telescope?The photograph will have far better angular resolution than you can see with your eye.
 Which of the following best describes the principle advantage of CCDs over photographic film?CCDs capture a much higher percentage of the incoming photons than film.
 How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope?The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope.
 Which of the following best describes the development of astronomical telescopes over the past 65 years?The world's most powerful telescope remained the same for most of this period, but in the past 20 years many new and more powerful telescopes have been built.
 Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light?Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light.
 Which of the following studies is best suited to astronomical observations that fall into the category called timing?Studying how a star's brightness varies over a period of 3 years.
 Which of the following is not a reason why telescopes tend to be built on mountaintops that are relatively far from cities and are in regions with dry climates?The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.
 The stars in our sky twinkle in brightness and color because of ______.turbulence in the Earth's atmosphere
 Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes?It is closer to the stars.
 The Chandra X-ray Observatory must operate in space because:X rays do not penetrate Earth's atmosphere.
 Which of the following telescopes would benefit most from adaptive optics?The Keck I telescope on Mauna Kea.
 Consider two future observatories in space. Observatory X consists of a single 50-meter telescope. Observatory Y is an interferometer consisting of five 10-meter telescopes, spread out over a region 100 meters across. Which observatory can detect dimmer stars, and which one can see more detail in its images? (Assume all else is equal, such as quality of optics, types of instruments, and so on.)Observatory X can detect dimmer stars and Observatory Y reveals more detail in images.
 Which of the following is not a major reason why astronomers would like an observatory on the far side of the Moon?Telescopes on the Moon could see objects in all parts of the sky equally well, whereas telescopes on Earth can see only portions of the sky that depend on their latitude.
 In the late 1800s, Kelvin and Helmholtz suggested that the Sun stayed hot due to gravitational contraction. What was the major drawback to this idea?It predicted that the Sun could shine for about 25 million years, but geologists had already found that Earth is much older than this.  
 When is/was gravitational contraction an important energy generation mechanism for the Sun?It was important when the Sun was forming from a shrinking interstellar cloud of gas.
 What do we mean when we say that the Sun is in gravitational equilibrium?There is a balance within the Sun between the outward push of pressure and the inward pull of gravity.
 Which of the following is the best answer to the question, "Why does the Sun shine?"As the Sun was forming, gravitational contraction increased the Sun's temperature until the core become hot enough for nuclear fusion, which ever since has generated the heat that makes the Sun shine.
 How does the Sun's mass compare to Earth's mass?The Sun's mass is about 300,000 times the mass of the Earth.
 Which of the following best describes why the Sun emits most of its energy in the form of visible light?Like all objects, the Sun emits thermal radiation with a spectrum that depends on its temperature, and the Sun's surface temperature is just right for emitting mostly visible light.
 The Sun's surface seethes and churns with a bubbling pattern. Why?We are seeing hot gas rising and cool gas falling due to the convection that occurs beneath the surface.
 Which of the following correctly compares the Sun's energy generation process to the energy generation process in human-built nuclear power plants?The Sun generates energy by fusing small nuclei into larger ones, while our power plants generate energy by the fission (splitting) of large nuclei.
 Every second, the Sun converts about 600 million tons of hydrogen into 596 million tons of helium. The remaining 4 million tons of mass is _________.converted to an amount of energy equal to 4 million tons times the speed of light squared
 Which of the following best explains why nuclear fusion requires bringing nuclei extremely close together?Nuclei normally repel because they are all positively charged and can be made to stick only when brought close enough for the strong force to take hold.
 If the Sun's core suddenly shrank a little bit, what would happen in the Sun?The core would heat up, fusion rates would increase, the core would re-expand.
 Why does the Sun emit neutrinos?Fusion in the Sun's core creates neutrinos.
 If the Sun suddenly stopped emitting neutrinos, what might we infer (after checking that our neutrino detectors were still operational)?Fusion reactions in the Sun have ceased.
 Which of the following best explains why the Sun's luminosity gradually rises over billions of years?Fusion gradually decreases the number of independent particles in the core, allowing gravity to compress and heat the core, which in turn increases the fusion rate and the Sun's luminosity.
 Why do sunspots appear dark in pictures of the Sun?They actually are fairly bright, but appear dark against the even brighter background of the surrounding photosphere.
 Which of the following best describes the current status of our understanding of the solar neutrino problem?Experimental evidence indicates that the problem is solved and the expected number of solar neutrinos are indeed being produced by the Sun.
 How can we best observe the Sun's chromosphere and corona?The chromosphere is best observed with ultraviolet telescopes and the corona is best observed with X-ray telescopes.
 The intricate patterns visible in an X-ray image of the Sun generally show _________.extremely hot plasma flowing along magnetic field lines
 How can we measure the strength of magnetic fields on the Sun?By looking for the splitting of spectral lines in the Sun's spectrum.
 Satellites in low-Earth orbits are more likely to crash to Earth when the sunspot cycle is near solar maximum because _________.Earth's upper atmosphere tends to expand during solar maximum, exerting drag on satellites in low orbits
 Which of the following choices is not a way by which we can study the inside of the Sun?We can send a space probe into the Sun's photosphere.
 A computer accessory salesman attempts to convince you to purchase a "solar neutrino" shield for your new computer. (It's even "on sale" !) Why do you turn down this excellent offer?Neutrinos rarely, if ever, interact with your computer.
36, "/var/app/current/tmp/"