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The Riddle of Time | |
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The Riddle of Time | |
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The Nature of Time | |
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What Is Time? | |
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Date, Time Interval, and Synchronization | |
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Ancient Clock Watchers | |
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Clocks in Nature | |
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Keeping Track of the Sun and Moon | |
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Thinking Big and Thinking Small--An Aside on Numbers | |
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Everything Swings | |
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Getting Time from Frequency | |
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What Is a Clock? | |
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The Earth-Sun Clock | |
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Meter Sticks to Measure Time | |
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What Is a Standard? | |
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How Time Tells Us Where in the World We Are | |
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Building a Clock that Wouldn't Get Seasick | |
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Hand-Built Clocks and Watches | |
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Early Clocks | |
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Sand and Water Clocks | |
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Mechanical Clocks | |
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The Pendulum Clock | |
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The Balance-Wheel Clock | |
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Further Refinements | |
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The Search for Even Better Clocks | |
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"Q" Is for Quality | |
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The Resonance Curve | |
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Energy Build-up and the Resonance Curve--An Aside on Q | |
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The Resonance Curve and the Decay Time | |
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Accuracy, Stability, and Q | |
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High Q and Accuracy | |
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High Q and Stability | |
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Waiting to Find the Time | |
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Pushing Q to the Limit | |
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Building Even Better Clocks | |
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The Quartz Clock | |
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Atomic Clocks | |
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The Ammonia Resonator | |
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The Cesium Resonator | |
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One Second in 10 000 000 Years | |
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Atomic Definition of the Second | |
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The Rubidium Resonator | |
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The Hydrogen Maser | |
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Can We Always Build a Better Clock? | |
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A Short History of the Atom | |
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Thermodynamics and the Industrial Revolution | |
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Count Rumford's Cannon | |
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Saturn's Rings and the Atom | |
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Bringing Atoms to a Halt | |
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Atoms Collide | |
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Cooling the Atom | |
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Pure Light | |
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Shooting at Atoms | |
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Optical Molasses | |
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Trapping Atoms | |
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Penning Traps | |
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Paul Traps | |
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Real Cool Clocks | |
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Capturing Neutral Atoms | |
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Atomic Fountains | |
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Quantum Mechanics and the Single Atom | |
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The Time for Everybody | |
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The First Watches | |
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Modern Mechanical Watches | |
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Electric and Electronic Watches | |
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The Quartz-Crystal Watch | |
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How Much Does "The Time" Cost? | |
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Finding and Keeping the Time | |
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Time Scales | |
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The Calendar | |
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The Solar Day | |
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The Stellar or Sidereal Day | |
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Earth Rotation | |
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The Continuing Search for More Uniform Time: Ephemeris Time | |
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How Long Is a Second? | |
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"Rubber" Seconds | |
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The New UTC System and the Leap Second | |
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The Length of the Year | |
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The Keepers of Time | |
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World Time Scales | |
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Bureau International de Poids et Mesures | |
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The Clock behind the Clock | |
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Flying Clocks | |
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Time on a Radio Beam | |
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Time in the Sky | |
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Accuracy | |
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Coverage | |
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Reliability | |
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Other Considerations | |
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Other Radio Schemes | |
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The Time Signal on Its Way | |
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Choosing a Frequency | |
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Very Low Frequencies | |
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Low Frequencies | |
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Medium Frequencies | |
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High Frequencies | |
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Very High Frequencies | |
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Frequencies above 300 megahertz | |
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Noise--Additive and Multiplicative | |
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Three Kinds of Time Signals | |
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The Uses of Time | |
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Standard Time | |
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Standard Time Zones and Daylight-Saving Time | |
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Time as a Standard | |
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Is a Second Really a Second? | |
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Who Cares about the Time? | |
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Time, The Great Organizer | |
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Electric Power | |
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Transportation | |
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Navigation by Radio Beacons | |
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Navigation by Satellite | |
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The Global Positioning System | |
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Some Common and Some Far-out Uses of Time and Frequency Technology | |
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Ticks and Bits | |
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Divide and Conquer | |
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Sending Messages the Old Fashioned Way, One Bit at a Time | |
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Automated Telegraphy | |
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Frequency Division Multiplexing | |
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Simultaneous Time and Frequency Multiplexing | |
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Don't Put All Your Messages in one Basket | |
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Keeping the Clocks in Step | |
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Time, Science, and Technology | |
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Time and Mathematics | |
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A New Direction | |
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Taking Apart and Putting Together | |
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Slicing up the Past and the Future--Calculus | |
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Conditions and Rules | |
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Getting at the Truth with Differential Calculus | |
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Newton's Law of Gravitation | |
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What's Inside the Differentiating Machine?--An Aside | |
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Time and Physics | |
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Time Is Relative | |
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Time Has Direction | |
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Time Measurement Is Limited | |
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Atomic and Gravitational Clocks | |
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The Struggle to Preserve Symmetry | |
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The Direction of Time and Time Symmetries--An Aside | |
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Time and Astronomy | |
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Measuring the Age of the Universe | |
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The Expanding Universe--Time Equals Distance | |
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Big Bang or Steady State? | |
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Stellar Clocks | |
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White Dwarfs | |
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Neutron Stars | |
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Black Holes--Time Comes to a Stop | |
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Time, Distance, and Radio Stars | |
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Until the End of Time | |
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Paradoxes | |
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Time Is Not Absolute | |
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General Theory of Relativity | |
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A Bang or a Whimper? | |
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Time's Direction, Free Will, and All That | |
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Time's Direction and Information | |
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Disorganization and Information | |
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Phase Space for the Universe | |
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Black Holes and Entropy | |
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The Problem of Free Will | |
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Cleopatra's Nose | |
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Computing the Future | |
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The Brain Problem | |
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Clockwork and Feedback | |
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Open-Loop Systems | |
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Closed-Loop Systems | |
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The Response Time | |
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System Magnification or Gain | |
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Recognizing the Signal | |
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Fourier's "Tinker Toys" | |
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Finding the Signal | |
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Choosing a Control System | |
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Time as Information | |
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Three Kinds of Time Information Revisited | |
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Time Information--Short and Long | |
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Geological Time | |
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Interchanging Time and Location Information | |
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Time as Stored Information | |
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The Quality of Frequency and Time Information | |
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How Many Seconds in a Meter? | |
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Measurements and Units | |
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Relativity and Turning Time into Space | |
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Nature's Constants and the Number of Base Units | |
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Length Standards | |
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Measuring Volts with Frequency | |
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Student Redux | |
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The Future of Time | |
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Using Time to Increase Space | |
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Time and Frequency Information--Wholesale and Retail | |
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Time Dissemination | |
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Clocks in the Future | |
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The Atom's Inner Metronome | |
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Particles Faster than Light--An Aside | |
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Time Scales of the Future | |
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The Question of Labeling--A Second is a Second is a Second | |
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Time through the Ages | |
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What Is Time--Really? | |