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Midterm 1 topic guide

A list of key topics in the class. This is not guaranteed to be comprehensive, and I may add to it as I remember things I forgot. The lectures associated with each section are in parentheses (week.lecture), and all the lectures have been posted.

 

Size and shape of the Earth, how it orbits the sun, and how that affects our observations of the sun, stars, and seasons. (1.1-2.1)

    • Eratosthenes
    • Solar and stellar days (sidereal), how they appear to move on the sky
    • Solar & stellar elevation (latitude & seasons)
    • Sundials & analemmas 
    • Leap years
    • Local time & transit telescopes

Finding where you are, latitude & longitude (2.1)

    • Ancient way finding (stellar elevation, sun stones, compass)
    • The problem of longitude
    • Simultaneous observations (eclipses, Jupiter's moons)
    • Harrison and the development of the marine chronometer
    • Process of finding latitude & longitude with a chronometer (astronomer, transit telescope, time ball, ...)
    • History of time zones

Waves (2.2)

    • Features of a wave (amplitude, wavelength, speed, restoring force, wave speed, motion of wave vs. medium)
    • Types of waves (transverse, compression)
    • Kinds of common waves
    • How waves add
    • Diffraction
    • Interference

Moving like a wave and hitting like a particle (3.2)

    • Double slit experiment
    • Big interferometer (including blocking of arms)
    • Effects of color (stripe spacing, how hard photons/particles hit)
    • Single photon limit (pointillism paintings, blocking of paths, stripe spacing, strength of photon hits, interpretation of a single particle's path)
    • "Moves like a wave and hits like a particle"
    • Electrons, neutrons, molecules (how they behave in a double slit or interferometer)

Electromagnetic spectrum (3.2)

    • The 'colors' of light (radio, microwave, IR, visible, UV, X-ray, gamma-ray)
    • Artificial light sources (radio, light sources)
    • Natural light sources & temperature
    • Examples of natural sources & the telescopes used to see them

Speed of light & special relativity (4.1)

    • Galilean moons, Michelson & Morley
    • Speed of light is constant for all observers (time is not)
    • Light clocks and perception of time
    • Time dilation (e.g. muons)
    • Lack of simultaneity 
    • Doppler shift of light
    • Looking back in time 

Surveying (4.1)

    • Ancient surveying (Egyptian, roman)
    • Renaissance & Victorian surveying (triangulation, reference baselines, key historical surveys)
    • Measuring distance with light, geodimeter & LiDAR, and how they work

Particle melting pot (4.2)

    • Mixing of particles
    • Mixing waves of different color (tuning forks, beats, how beats vary with wavelength difference)
    • Mixing particles of different color
    • Optical comb in depth (how it works, steady and pulsed light, colors, single photon regime)
    • Astrocomb

History of clocks & timekeeping (4.2)

    • Mechanical clocks (tower clocks, pendulum, marine chronometers, watches, etc.)
    • Quarts & atomic clocks, and the importance of faster oscillation
    • TAI, UT1, UTC (history, what they are measuring, why the differ)
    • How an optical clock works

GPS (5.1)

    • How does it work? (physics required, including clocks & relativity)
    • The work needed to really make it work (clock correction, orbit correction, etc.)
    • Applications (location finding, accurate remote clocks, surveying, geology)