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astronomy midterm 1

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.
f 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 is not a general difference between a planet and a star? All planets are made of rock and all stars are made of gas.
Our solar system consists of _________. the Sun and all the objects that orbit it
A typical galaxy is a _________. collection of a few hundred million to a trillion or more stars, bound together by gravity
Which of the following best describes what we mean by the universe? The sum total of all matter and energy.
What do astronomers mean by the Big Bang? The event that marked the beginning of the expansion of the universe
What do we mean when we say that the universe is expanding? Average distances between galaxies are increasing with time.
Based on observations of the universal expansion, the age of the universe is about _________. 14 billion years
A television advertisement claiming that a product is light-years ahead of its time does not make sense because _________. it uses "light-years" to talk about time, but a light-year is a unit of distance
The term observable universe refers to _________. that portion of the universe that we can see in principle, given the current age of the universe
On a scale in which the distance from Earth to the Sun is about 15 meters, the distance from Earth to the Moon is _________. small enough to fit within your hand
On a scale where the Sun is about the size of a grapefruit and the Earth is about 15 meters away, how far away are the nearest stars besides the Sun? About the distance across the United States.
The number of stars in the Milky Way Galaxy is approximately _________. a few hundred billion
An astronomical unit (AU) is _________. the average distance between Earth and the Sun
What is the ecliptic plane? The plane of Earth's orbit around the Sun.
How long does it take the Earth to complete one orbit around the Sun? One year.
About how many stars are visible to the naked eye on a clear, dark night away from city lights? A couple thousand.
What do astronomers mean by a constellation? A constellation is a region in the sky as seen from Earth.
What is the ecliptic? The path the Sun appears to trace around the celestial sphere each year.
What is the celestial sphere? The celestial sphere is a representation of how the entire sky looks as seen from Earth.
What do we mean when we talk about the Milky Way in our sky? The patchy band of light that outlines the plane of the Milky Way Galaxy as seen from Earth.
Which of the following statements does not use the term angular size or angular distance correctly? The angular distance between those two bright stars in the sky is about 2 meters.
Which of the following correctly describes the meridian in your local sky? A half-circle extending from your horizon due north, through your zenith, to your horizon due south.
The point directly over your head is called _________. the zenith
Stars that are visible in the local sky on any clear night of the year, at any time of the night, are called _________. circumpolar
We describe a location on Earth's surface by stating its _________. latitude and longitude
If you are located in the Northern Hemisphere, which of the following correctly describes a relationship between the sky and your location? The altitude of the north celestial pole equals your latitude.
Which of the following best describes why we have seasons on Earth? The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year.
Each choice below describes how a few astronomical phenomena are related to time periods. Which list is entirely correct? (Careful: some lists are partially correct.) The cycle of the Moon's phases takes about a month. Earth's orbit defines a year. Earth's cycle of axis precession takes 26,000 years. Earth's rotation defines a day.
If we have a new moon today, when we will have the next full moon? In about 2 weeks.
We cannot see a new moon in our sky because _________. a new moon is quite near the Sun in the sky
The Moon always shows nearly the same face to Earth because ________. the Moon rotates once in the same amount of time that it takes the Moon to orbit Earth once
Lunar eclipses can occur only during a _________. full moon
What is the saros cycle? The roughly 18-year cycle over which the pattern of eclipses repeats
During the time that a planet is in its period of apparent retrograde motion: _________ Over many days or weeks, the planet moves westward relative to the stars, rather than the usual eastward relative to the stars
What is stellar parallax? It is the slight back-and-forth shifting of star positions that occurs as we view the stars from different positions in Earth's orbit of the Sun.
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 . 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
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 How would it appear to the eye in that case? We could not see it at all.
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. Correct
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 400F 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.
The difference between speed and velocity is that _________. velocity also includes a direction
The acceleration of gravity on Earth is approximately 10 m/s2 (more precisely, 9.8 m/s2). If you drop a rock from a tall building, about how fast will it be falling after 3 seconds? 30 m/s.
Momentum is defined as _________. mass times velocity
Suppose you lived on the Moon. Which of the following would be true? Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth.
In which of the following cases would you feel weightless? While falling from a roof.
Which of the following statements is not one of Newton's Laws of Motion? What goes up must come down
Newton's Second Law of Motion tells us that the net force applied to an object equals its _________. mass times acceleration
Suppose that two objects collide. Which of the following things is not the same both before and after the collision? The total temperature of the objects
When a spinning ice skater pulls in his arms, he spins faster because _________. his angular momentum must be conserved, so reducing his radius must increase his speed of rotation
The energy attributed to an object by virtue of its motion is known as _________. kinetic energy
Radiative energy is _________. energy carried by light
Absolute zero is _________. 0 Kelvin
What does temperature measure? The average kinetic energy of particles in a substance
In the formula E=mc2, what does E represent? The mass-energy, or potential energy stored in an object's mass
According to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them _________. decreases by a factor of 9
What is the difference between a bound orbit and an unbound orbit around the Sun? An object on a bound orbit follows the same path around the Sun over and over, while an object on an unbound orbit approaches the Sun just once and then never returns
The allowed shapes for the orbits of objects responding only to the force of gravity are ______. ellipses, parabolas, and hyperbolas
Why is Newton's version of Kepler's third law so useful to astronomers? It can be used to determine the masses of many distant objects.
What do we mean by the orbital energy of an orbiting object (such as a planet, moon, or satellite)? Orbital energy is the sum of the object's kinetic energy and its gravitational potential energy as it moves through its orbit.
Which statement must be true in order for a rocket to travel from Earth to another planet? It must attain escape velocity from Earth.
Approximately where is it currently high tide on Earth? On the portion of Earth facing directly toward the Moon and on the portion of Earth facing directly away from the Moon
What is the difference between energy and power? Power is the rate at which energy is used, so its units are a unit of energy divided by a unit of time.
Visible light from a distant star can be spread into a spectrum by using a glass prism or ______. a diffraction grating
Suppose you watch a leaf bobbing up and down as ripples pass it by in a pond. You notice that it does two full up and down bobs each second. Which statement is true of the ripples on the pond? They have a frequency of 2 hertz
Suppose you know the frequency of a photon and the speed of light. What else can you determine about the photon? its wavelength and energy
When considering light as made up of individual "pieces," each characterized by a particular amount of energy, the pieces are called _________. photons
From shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation? gamma rays, X rays, ultraviolet, visible light, infrared, radio
Which forms of light are lower in energy and frequency than the light that our eyes can see? infrared and radio
If we say that a material is opaque to ultraviolet light, we mean that it _________. absorbs ultraviolet light
Suppose you built a scale-model atom in which the nucleus is the size of a tennis ball. About how far would the cloud of electrons extend? Several kilometers
Which of the following best describes the fundamental difference between two different chemical elements (such as oxygen and carbon)? They have different numbers of protons in their nucleus
Consider an atom of carbon in which the nucleus contains 6 protons and 7 neutrons. What is its atomic number and atomic mass number? atomic number = 6; atomic mass number = 13
An atom which has 4 protons and 6 neutrons will be electrically neutral if it contains ______. 4 electrons
Sublimation is the process in which ___________. molecules go directly from the solid phase to the gas phase
Which of the following transitions within an atom is not possible? An electron begins in an excited state and then gains enough energy to jump to the ground state
An atom that has fewer electrons than protons is called a/an _________. ion
Suppose you look at a spectrum of visible light by looking through a prism or diffraction grating. How can you decide whether it is an emission line spectrum or an absorption line spectrum? An emission line spectrum consists of bright lines on a dark background, while an absorption line spectrum consists of dark lines on a rainbow background.
Thermal radiation is defined as _________. radiation with a spectrum whose shape depends only on the temperature of the emitting object
According to the laws of thermal radiation, hotter objects emit photons with _________. a shorter average wavelength
Suppose you want to know the chemical composition of a distant star. Which piece of information is most useful to you? the wavelengths of spectral lines in the star's spectrum
The spectra of most galaxies show redshifts. This means that their spectral lines _________. have wavelengths that are longer than normal
You observe a distant galaxy. You find that a spectral line of hydrogen that is shifted from its normal location in the visible part of the spectrum into the infrared part of the spectrum. What can you conclude? The galaxy is moving away from you
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
Consider an atom of oxygen in which the nucleus contains 8 protons and 8 neutrons. If it is doubly ionized, what is the charge of the oxygen ion and how many electrons remain in the ion? Charge = +2; number of remaining electrons = 6.
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, 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 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 60 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.
Which observatory can detect dimmer stars which one can see more detail in its images? 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
What is the ecliptic? The path the Sun appears to trace around the celestial sphere each year.
What do we mean when we talk about the Milky Way in our sky? The patchy band of light that outlines the plane of the Milky Way Galaxy as seen from Earth.
Which of the following best explains why a solar day is longer than a sidereal day? Because Earth orbits the Sun at the same time it rotates, Earth must make slightly more than one full rotation between noon one day and noon the next.
When should we next expect to observe a transit of the Sun by Mars? Never
A friend says she saw a planet shining on her meridian at midnight. Which planet can you be sure that she did not see? Venus
Suppose you have a time-keeping device that always reads precisely 12:00 when the Sun crosses your meridian. What kind of time is this clock keeping? apparent solar time
All the following statements are true. Which one explains why mean solar time differs from apparent solar time? The length of a solar day is not always exactly 24 hours.
As viewed from any place within the continental United States, noon on apparent solar time is defined as the moment when the Sun is ______. directly south
All the following statements are true. Which one explains why our calendar has leap years? A tropical year is slightly more than 365 days.
Which of these stars lies closest to the north celestial pole on the celestial sphere? Deneb
Suppose you live at latitude 30S. Which star is circumpolar in your sky? Alpha Centauri
Suppose that you are looking at the sky at about midnight on the winter solstice. Which star will be nearest to your meridian? Sirius
Which of the following statements is not true about the sky at Earth's equator? The Sun will pass directly overhead around noon each day.
Suppose Earth's axis had a greater tilt (more than 23.5 degrees). Which of the following statements would not be true? The celestial sphere would be covered by a different set of constellations than it is with the current axis tilt
Which of the following explains why navigators prior to a few hundred years ago found it much more difficult to determine longitude than latitude? Determining longitude requires an accurate clock, but latitude does not.
It's the summer solstice, the Sun is at your zenith, and you have a UT clock that tells you it is midnight in Greenwich, England. Where are you? On the Tropic of Cancer near the International Date Line.
The north celestial pole appears 30 above your horizon. The star Vega is on your meridian. By studying your star charts and your clocks, you determine that Vega crossed the meridian in Greenwich (England) 3 hours ago. Where are you? latitude 30N, longitude 45 west
Which of the following is not a major pattern of motion in the solar system? Nearly all comets orbit the Sun in same direction and roughly the same plane.
Which of the following is not a major difference between the terrestrial and jovian planets in our solar system? Terrestrial planets contain large quantities of ice and jovian planets do not.
Consider the following statement: "Rocky asteroids are found primarily in the asteroid belt and Kuiper belt while icy comets are found primarily in the Oort cloud." What's wrong with this statement? The Kuiper belt contains icy comets, not rocky asteroids.
Which of the following is not a real difference between asteroids and comets? Asteroids orbit the Sun while comets just float randomly around in the Oort cloud.
The following statements are all true. Which one counts as an "exception to the rule" in being unusual for our solar system? The diameter of Earth's Moon is about 1/4 that of Earth.
Compared to the distance between Earth and Mars, the distance between Jupiter and Saturn is ______. much larger
Einstein's famous equation, E=mc 2, explains the fact that __________. the Sun generates energy to shine by losing some 4 million tons of mass each second
Venus has a higher average surface temperature than Mercury. Why? Because its surface is heated by an extreme greenhouse effect.
In what way is Venus most similar to Earth? Both planets are nearly the same size.
Which of the following statements about the recently-discovered object Eris is not true? It is thought to be the first example of a new class of object
Mars has two moons that are most similar in character to: small asteroids
Imagine that an alien spaceship crashed onto Earth. Which statement would most likely be true? It would crash in the ocean.
Which planet listed below has the most extreme seasons? Uranus
n what way is Pluto more like a comet than a planet? It is made mostly of rock and ice.
Why was it advantageous for the Voyager mission to consist of flybys rather than orbiters? Each individual spacecraft was able to visit more than one planet.
Why has NASA sent recent orbiters to Mars (such as Mars Reconnaissance Orbiter) on trajectories that required them to skim through Mars's atmosphere before settling into their final orbits? It saves money because the spacecraft uses atmospheric drag to slow down rather than needing to carry enough fuel to slow by firing rocket engines.
What is nuclear fusion? the process of combining lightweight nuclei to make heavier nuclei
Why do we see essentially the same face of the Moon at all times? because the Moon's rotational and orbital periods are equal
Why do we have seasons on Earth? As Earth goes around the Sun and Earth's axis remains pointed toward Polaris, the Northern and Southern hemispheres alternately receive more and less direct sunlight.
Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere? The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight.
He discovered that the orbits of planets are ellipses. Kepler
He discovered that Jupiter has moons. Galileo
Which of the following statements correctly describes the law of conservation of energy? The total quantity of energy in the universe never changes.
According to the universal law of gravitation, the force due to gravity is inversely proportional to the square of the distance between objects
What quantities does angular momentum depend upon? mass, velocity, and radius
Newton's second law of motion tells us that the net force applied to an object equals its mass times acceleration.
You are standing on a scale in an elevator. Suddenly you notice your weight decreases. What do you conclude? The elevator is accelerating downwards.
When an atom absorbs a photon containing energy, any of the following can happen except which? An electron moves from an upper energy level to a lower one.
The frequency of a wave is? all of the above
If a material is transparent, then it transmits light well.
Telescopes operating at this wavelength must be cooled to observe faint astronomical objects. extreme infrared
What causes stars to twinkle? bending of light rays by turbulent layers in the atmosphere
What is the purpose of adaptive optics? to eliminate the distorting effects of atmospheric turbulence for telescopes on the ground
Currently, the largest optical telescope mirrors have a diameter of 10 m
What do astronomers mean by light pollution? Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations.
How does the Sun's mass compare with that of the planets? It is a thousand times more massive than all the planets combined.
Which of the following statements is not an observed pattern of motion in our solar system? Most planets orbit at the same speed.
Which planet has the highest average surface temperature, and why? Venus, because of its dense carbon dioxide atmosphere
Which planet, other than Earth, has visible water ice on it? Mars
Which planet has a ring system? all of the above
What are the main constituents of the jovian planets? hydrogen and helium
The most metal-rich terrestrial planet is Mercury.
Aristotle Physics and Elements (water, earth, air, fire)
Eratosthenes Measured the circumference of the earth using the zenith of the sun at noon during the solstice in Syene and again in Alexandria.
Claudius Ptolemy star chart, motion and models of planets moon and sun,
Claudius Ptolemy's geocentric model the planets and sun orbit around the earth in small circles (epicycles) within large circles.
Copernicus Heliocentric model earth and inferior planets orbit the sun, retrograde motion is when we "lap" the other planets.
Tycho Brahe accurately charted position of planets, witnessed a Nova in 1572
Keplers 1st Law Each planets orbit around the sun is an ellipse, with the sun at one focus.
Keplers 2nd Law A planets moves along its orbit with a speed that changes it in such a way that a line from the planet to the sun sweeps out equal areas in equal intervals of time.
Keplers 3rd Law the ratio of the cube of a planets average distance from the sun to the square of its orbital period is the same for each planet. ( a^3=p^2)
Created by: dreamwalker