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How do we know how old the Earth is
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From radioactive dating of rocks and meteorite
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Which is not an essential requirement for life as we know
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The ability to breathe oxygen The ability to make energy from sunlight, or to eat things that
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Which of the following lists the ingredients of the solar nebula from highest to lowest percentage of mass in the nebula?
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light gases (H, He), hydrogen compounds (H2O, CH4, NH3), rocks, metal
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What do meteorites reveal about the solar system?
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They reveal that the age of the solar system is approximately 4.6 billion year
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Why does the plasma (ion) tail of a comet always point away from the Su
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The solar wind electromagnetically "blows" the ions directly away from the Sun
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Which living organisms most resemble the common ancestor of all life according to genetic testing
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Large impacts fractured the Moon's lithosphere, allowing lava to fill the impact basins
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Life on Earth originated from
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We don't know for sure
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Mars has an atmosphere that is almost entirely carbon dioxide.Why isn't there a strong greenhouse effect keeping the planet warm?
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the atmosphere on Mars is too thin to trap a significant amount of hea
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Which of the following is/are NOT caused by orbital resonance
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Breaking of small Jovian moons to form ring materials.
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How do scientists know that the majority of meteorites come from the asteroid be
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The spectra of some meteorites are similar to the spectra of asteroids in the asteroid bel
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The nebular theory of the formation of the solar system successfully predicts all but one of the following. Which one does the theory not predict?
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the equal number of terrestrial and jovian planets
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Which of the following methods has led to the most discoveries of massive planets orbiting near their parent stars?
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detecting the gravitational effect of an orbiting planet by looking for the Doppler shifts in the star's spectrum
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What Mars mission will be landing on May 25, 2008 and will dig a trench into (hopefully) ice-rich soil?
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Phoenix Mars Lande
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How do we think the "hot Jupiters" around other stars were forme
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They formed as gas giants beyond the frost line and then migrated inward
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How do astronomers think Jupiter generates its internal heat
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by contracting, changing gravitational potential energy into thermal energy
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Which property of our solar system does a formation theory NOT need to explain
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he presence of life on Earth
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Most rocks on the Moon's surface are older than those on the Earth's surface. The best evidence for this is:
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Radioactive dating of lunar samples shows that they are olde
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Why doesn't Venus have seasons like Mars and Earth do
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Its rotation axis is nearly perpendicular to the plane of the Solar Syste
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What is true about the rotation of a solid disk?
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The period of rotation is the same on every point on the dis
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Jupiter's orbital distance is roughly 5 AU. How many times brighter would the Sun have to be for Europa to receive the same solar flux that we currently receive on Earth (1380W/m2)?
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25 times brighter
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Which living organisms most resemble the common ancestor of all life according to genetic testing
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organisms living deep in the oceans around seafloor volcanic vents and in hot spring
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The combined mass of all the asteroids in the asteroid belt is
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less than that of any terrestrial planet.
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Europa moon is considered likely to have a
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deep, subsurface ocean of liquid water
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the size of the largest asteroid
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is 1,000 km
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How many more times is the atmospheric pressure in Jupiter's core greater than the atmospheric pressure at the earth's surface?
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100 million
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the Sun generates energy today
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by nuclear fusion
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When do comets generally begin to form a tail?
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inside of Jupiter's orbit
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Why do asteroids and comets differ in composition?
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Asteroids formed inside the frost line, while comets formed outside.
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Falling stars and shooting stars are simply other names for
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meteors.
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the Sun loses 4 million tons of its mass through
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nuclear fusion per second.
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the average temperature of the surface of the Sun is
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6,000 K
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How do astronomers think Jupiter generates its internal heat?
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by contracting, changing gravitational potential energy into thermal energy
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The overall fusion reaction by which the Sun currently produces
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energy is 4 H =1 He + energy
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the most abundant gas in Titan's atmosphereis
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nitrogen
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What is the Great Red Spot?
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The Great Red Spot is a long-lived, high-pressure storm on Jupiter.
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What is the hydrosphere?
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a name for the liquid and frozen water on Earth's surface
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An icy leftover planetesimal orbiting the Sun is
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a comet.
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What process has shaped Earth's surface more than any other?
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plate tectonics
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In order to have a comet named after you, you have to be one of
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the first three discoverers who report it to the International Astronomical Union (IAU).
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Titan moon has
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a thick atmosphere.
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Which is closest to the average distance between asteroids in the asteroid belt
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1 million km
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How much energy does Jupiter emit compared with how much it receives from the Sun?
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It emits twice as much.
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How do the jovian planet interiors differ?
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All have cores of about the same mass, but differ in the amount of surrounding hydrogen and helium.
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The most volcanically active body in our solar system is
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Io
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How thick are Saturn's rings from top to bottom?
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a few tens of meters
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What are coronal holes?
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areas of the corona where magnetic field lines project into space, allowing charged particles to escape the Sun, becoming the solar wind
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What is the most important reason why an icy moon is more likely to be geologically active than a rocky moon of the same size?
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Ice has a lower melting point than rock.
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Most meteorites are
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rocky and primitive
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How does the largest asteroid, Ceres, compare in size to other solar system worlds?
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It is about half the size of Pluto
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What is the Sun made of?
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70 percent hydrogen, 28 percent helium, 2 percent other elements
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) The phase of matter in the Sun is
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plasma.
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Europa thought to have a
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deep, subsurface ocean of liquid water
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Where are the Trojan asteroids located?
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along Jupiter's orbit, 60degree ahead of and behind Jupiter
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When is/was gravitational contraction an important energygeneration mechanism for the Sun?
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when the Sun was being formed from a collapsing cloud of gas
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Overall, Jupiter's composition is most like that of
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the Sun.
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Why do Uranus and Neptune have blue methane clouds but Jupiter and Saturn do not?
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Methane does not condense into ice in the warmer atmospheric temperatures of Jupiter and Saturn.
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Why do sunspots appear dark in pictures of the Sun?
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They actually are fairly bright but appear dark against the even brighter background of the surrounding Sun
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What observations characterize solar maximum?
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We see many sunspots on the surface of the Sun
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What is the solar wind?
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It is the name we give to the gas (or plasma) particles flowing outward from the surface of the Sun into the solar system.
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Pluto was discovered
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about 70 years ago
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Uranus and Neptune have methane clouds but Jupiter and Saturn do not. Which factor explains why?
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Temperatures on Jupiter and Saturn are too high for methane to condense.
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The four Galilean moons around Jupiter are
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a mixture of rock and ice, with the ice fraction increasing with distance from Jupiter.
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How can we best observe the Sun's chromosphere and corona?
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The chromosphere is best observed with ultraviolet telescopes and the corona is best observed with X-ray telescopes.
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What are the spokes in Saturn's rings?
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particles of dust suspended above the rings by magnetic forces
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What is the typical size of comets that enter the inner solar system?
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10 km
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CO2, H2O, are
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greenhouse gases
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the plasma tail of a comet
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points most directly away from the Sun
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What drives the motion of the continental plates on Earth?
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convection cells in the mantle
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Comets are
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balls of ice and dust.
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Ganymede is
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the largest moon in the solar system
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Why does Jupiter have several distinct cloud layers?
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ifferent layers represent clouds made of gases that condense at different temperatures.
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How does the strength of Jupiter's magnetic field compare to that of Earth's magnetic field?
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Jupiter's magnetic field is about 20,000 times as strong as Earth's.
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Which layer of the Sun do we normally see?
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photosphere
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The core of the Sun is
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hotter and denser than the surface.
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Meteorites can come from
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the cores of asteroids. ancient lava flows. the Moon. Mars.
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How is the sunspot cycle directly relevant to us here on Earth?
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Solar flares and other activity associated with the sunspot cycle can disrupt radio communications and knock out sensitive electronic equipment.
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What is a meteorite?
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a fragment of an asteroid from the solar system that has fallen to the earth's surface
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What did Nicholas Copernicus, Tycho Brahe, Johannes Kepler, andGalileo Galilei each contribute to astronomy?
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Copernicus published work describing the Sun-centered solar system model. Brahe made what is generally considered the best set of naked-eye observations ever made that enabled Kepler to discover the laws of planetary motion. Kepler, Brahe's apprentice, discovered the basic laws of planetary motion. Galileo:Amongst his many accomplishments as arguably the greatest scientist of his time, Galileo was the first to use the telescope (he did not invent it) to take observations of the heavens that sealed the case for the Sun-centered solar system (e.g., Venus's phases, Jupiter's moons).
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Why is astrology a pseudoscience and astronomy is not? Explain.
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Pseudoscience means "false science". To be science, a subject must conform to the hallmarks of science listed in the text: (summed up) being able to test ideas of how natural processes work that can, in principle, be disproven. Astrology seeks to explain how the positions of astronomical objects affect our lives, yet such forecasts do not stand up to scrutiny; no causual relationship has ever been established.
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A small comet was discovered with an orbital eccentricity of e=0.6 and a semi-major axis of 46 AU. It passed closest to the Sun in 2010. When (what year) will it make its next close passage?
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Since the object is orbiting the Sun and we want to express the answer in years, we can use the simple form of Kepler's third law: p 2 years = a 3 AU ) pyears = (46 AU)3/2 = 312 years The next passage of the comet will be in 2010 + 312 = 2322 .
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Halley's Comet. Halley's Comet orbits the Sun every 76.0 years and has an orbital eccentricity of 0.97. Find its average distance from the Sun (semimajor axis). Find its perihelion and aphelion distances.
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p 2 years = a 3 AU ) aAU = (76 yrs)2/3 = 17.9 AU Perihelion distance = a(1 − e) = 17.9 AU(1 − 0.97) = 0.5 AU Aphelion distance = a(1 + e) = 17.9 AU(1 + 0.97) = 35.3 AU
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What is the circumference of Nearth?
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On the equinox, the sun is directly overheard in the city of Nyene, located 1000 km due north of Alectown, and on the equinox in Alectown, the altitude of the sun is 80°. Angle from the zenith = 90° - altitude = 90° - 80° = 10° (Angle found above is the latitude difference between Nyene and Alectown) Nearth's circumference = (360° / latitude difference) * distance between citiesCircumference = (360° / 10°) * 1000 km = (36*1000 km) = 36,000 km
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Halley's comet orbits the Sun every 76.0 years and has an orbital eccentricity of 0.97. (a) Find its average distance by using Kepler's Third Law (applies here because Halley's comet orbits the Sun).
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P2 = a3 P = 76.0 years a = P2/3 = (76.0 years)2/3 = 17.94 AU
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Where does Halley's comet spend most of its time?
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Use Kepler's Second Law: As a planet moves around its orbit, it sweeps out equal areas in equal times. So when it is closest to the Sun, the comet will be moving fastest, and conversely when it is furthest from the Sun, the comet will be moving the slowest. Therefore, Halley's comet must spend most of its time at aphelion, when it is furthest from the Sun, because it moves the slowest at that point.
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If Earth were twice as far from the Sun, what would the force of gravity between them be?
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The equation needed here is the universal law of gravitation, discovered by Newton:F = (GM1M2)/d2 (Note: the force depends on the inverse of distance squared.) Current force of gravity on Earth: F1 = (GM1M2)/d2 "New" force of gravity on Earth: F2 = (GM1M2)/(2d)2 F2 = (F1)/4, therefore the answer is (c) one-quarter as strong.
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If the Sun were replaced by a black hole of the same mass, what would happen to Earth's orbit?
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F = (GM1M2)/d2 The law of gravity depends on only the following: 1] the Universal Gravitation constant, G, which will not be affected. 2] the masses of both the Sun/black hole and Earth. 3] the distance between the Sun/black hole and Earth Because the mass of the black hole will be the same as the mass of the Sun, and Earth will not start at a different orbital distance when the change occurs, the correct answer must be (c) Earth's orbit would not change.
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What is the orbital period of the planet?
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For this problem, we must use Newton's form of Kepler's Third Law. P2 = [(4pi2)/G(M1 + M2)]*a3 Mass of star (M1) is 4 times the mass of the Sun. M1 = 4*(1.98892 x 1030 kg) Planet (M2) is same mass as Earth. M2 = 5.9742 x 1024 kg (Mass of planet << Mass of Sun, can be neglected) The planet is orbiting at 1 AU. a = 1 AU = 1.496 x 1011 m The gravitation constant G is 6.67 x 10-11 m3 /kg*s2 P = sqrt([(4pi2)/G(M1)]*a3) P = sqrt([7.44 x 10-20 s2/m3] * [1.496 x 1011 m]3) = 1.58 x 107 s = 182.9 days SIMPLER ANSWER: Think of the mass as 4Msun. Then (4pi2)/G(Msun) = 1 and the new equation is P2 = a3/4 where P is in years and a is in AU. P = sqrt((1 AU)3/4) = sqrt(1/4) = ½ year (note: ½ years = 182.5 days)
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(a) What is the mass of the Earth? Moon's period of orbit is 27.3 days, and semi-major axis is 384,000 km. Can neglect mass of Moon (Mass of Moon << Mass of Earth)
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P2 = [(4pi2)/G(M1 + M2)]*a3 = [(4pi2)/G(M)]*a3 P = 27.3 days = 2.36 x 106 seconds a = 384,000 km = 3.84 x 108 m The gravitation constant G is 6.67 x 10-11 m3 /kg*s2 Solve for M: M = [(4pi2)/(G*P2)]*a3 = [0.106 kg/m3] * (3.84 x 108 m)3 = 6.02 x 1024 kg
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What is the mass of Jupiter? Io orbits Jupiter every 42.5 hours, at an average distance of 422,000 km. Can neglect mass of Io (Mass of Io << Mass of Jupiter)
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P2 = [(4pi2)/G(M1 + M2)]*a3 = [(4pi2)/G(M)]*a3 P = 42.5 hours = 1.53 x 105 seconds a = 422,000 km = 4.22 x 108 m The gravitation constant G is 6.67 x 10-11 m3 /kg*s2 Solve for M: M = [(4pi2)/(G*P2)]*a3 = [25.3 kg/m3] * (4.22 x 108 m)3 = 1.90 x 1027 kg
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What is planet's orbital distance? Mass of star is the same as Sun, orbital period is 63 days.
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Because planet is going around an object that is the same mass as the Sun, the more simple Kepler equation (P2 = a3) can be used. P2 = a3 P = 63 days = 0.172 years a = P2/3 = (0.172 years)2/3 = 0.309 AU
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According to Kepler's third law, (b) Jupiter orbits the Sun more quickly than Saturn.
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Because the semimajor axis is smaller, the orbital period P = a3/2 will be smaller
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. Problem 3‐40 (2 pts). The recently discovered object Sedna orbits our sun beyond Pluto, at an average distance of 509 AU. What is its orbital period?
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a=509 AU, P2 = a3. P = a3/2 = 5093/2 = 11,480 years
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The recently discovered Eris, which is slightly larger than Pluto, orbits the Sun every 560 years. What is its average distance (semimajor axis) from the Sun? How does its average distance compare to that of Pluto?
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a = P2/3 = 5602/3 = 67.9 AU. This is further from the Sun than Pluto, which has a semimajor axis of ~40AU.
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When visiting another planet, (b) your mass would be the same as on Earth, but your weight would be different
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Weight depends on the strength of gravity.
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If Earth were twice as far from the Sun, the force of gravity attracting Earth to the sun would be
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one‐quarter as strong. Gravity follows an inverse square law in proportion to distance.
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If the Moon were closer to the Earth, high tides would be
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higher than they are now. As the Moon gets closer, the gravitational force of attraction increases. The difference in the force of attraction between different parts of Earth and the Moon will also increase.
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Imagine another solar system, with a star of the same mass as the Sun. Suppose there is a planet in that solar system with a mass twice that of Earth orbiting at a distance of 1 AU, what is the orbital period of this planet? Explain
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Making the approximation MPlanet << MStar, Newton's version of Kepler's 3rd Law tells us PPlanet2= aPlanet3 / MStar (solar masses). Since the mass of the star hasn't changed in this problem, M=1 and P = a3/2 = (1 AU) 3/2 = 1 year.
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Suppose a solar system has a star that is four times as massive as our Sun. If that solar system has a planet the same size as Earth orbiting at a distance of 1 AU, what is the orbital period of the planet? Explain.
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Again, Newton's version of Kepler's 3rd Law is PEarth2 = aEarth3 / M(solar masses). Here, M=4. So P2 = a3 / 4 = (1 AU) 3 / 4 = 0.25. P= √0.25 = 0.5 years
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Use the data in Table 4.1 to answer each of the following questions. a) Compare the energy of a 1‐megaton H‐bomb to the energy released by a major earthquake
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The energy released by an earthquake is 2.5*1016 J / 4*1015 J =6.25 times larger
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b) If the United States obtained all its energy from oil, how much oil would be needed each year
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Annual US energy consumption / Energy released by burning 1 liter of oil = 1020 J / 1.2*107 J = 8.3*1012 liters of oil
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c) Compare the Sun's annual energy output to the energy released by a supernova.
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The energy released by a supernova is ~1044 J / 1034 J = 1010 times larger
