LD

Exam 1 Review

Chapter 1

Hypothesis vs Theory

Occam’s Razor

  • simplest and most elegant hypothesis is most likely the correct one

Cosmological Principle

  • our view from Earth is not unique

  • What does this mean?

  • Foundations: universality, homogeneity, isotropy

Known Universe

  • 13.8 billion light years cuz of light being able to travel that distance

    • only see where light has had time to travel

Chapter 2

Celestial Sphere

  • global system based on star’s location

  • declination (latitude)

  • ride ascension (longitude)

  • NCP, SCP, equator, ecliptic (path of the sun)

Horizon System

  • based on your location

  • Zenith, Nadia, Meridian

Star Motion

  • circumpolar

    • rise and set

Circumpolar Stars

  • declination > 90 - latitude

Seasons

  • we have seasons cuz of the concentration of light on the Earth

Phases of the moon

  • don’t see new moon

  • crescents and gibbous

  • waxing - bigger

  • waning - smaller

Eclipses

  • Umbra

  • penumbra

Chapter 3

Models of the Universe

  • geocentric

  • Ptolemy

    • epicycles

  • Brahe

    • geoheliocentric

  • Copernicus

    • heliocentric (circles)

  • Kepler

    • heliocentric (ellipses)

Superior Planets

  • sidereal period

  • synodic period (always be shorter than sidereal period)

  • 1/P=1/E - 1/S

Inferior Planets

  • sidereal period

  • synodic period (always be longer than sidereal period)

  • 1/P=1/E + 1/S

Kepler’s Laws

  1. Law of Ellipses

    1. in ellipses not circles

  2. Law of Equal Areas

    1. quicker near the sun, slower away from the sun

  3. Law of Harmonies

    1. (Pyears)² = (Aau)³

    2. P=Au^ 3/2

Netwon’s Laws

  1. Law of Inertia

    1. a moving object

  2. h

Chapter 4

Newton’s Law of Gravitation

  • Fgrav

Newton’s Version of Kepler’s Third Law

  • P² = 4pi²/GM A³

Gravity and Orbits

  • Newton’s thought experiment

Orbits

  • circular velocity

  • escape velocity

Tidal Forces

  • tidal forces

  • tidal bulges

  • Moon is tidally locked

    • same face is always facing us

  • Earth’s rotation

  • Moons’ acceleration

  • Earth’s internal heat

  • Spring and neap tides

Chapter 5

Light is both a wave and a particle

  • c = lambdaf

  • photons high energy = high frequency, short wavelengths (gamma)

  • photons low energy = low frequency, long wavelengths (radio)

  • E = hf

Electron Energy States

  • certain energy levels

    • unique fingerprint

Emission Spectrum

Absorption Spectrum

  • continuous spectrum inside star

  • do not recieve lines anymore because atoms are absorbing

Spectra

Doppler Effect

  • motion of a light source toward or away from us changes our perception of the wavelength of the waves reaching us

    • towards- smaller wavelength, higher pitch, blue shifted lines

    • away- longer wavelength, lower pitch, red shifted lines

  • V/c = observed - rest / rest

Luminosity

  • how we measure bright

  • constant of sigma is given

Flux

  • how might light grows half a minute

Blackbody Radiation

  • intensity of light as a function of wavelength

    • hotter - blue end

  • T(K) = 0.0029m K/ lambda max

Units

  • know micron or micrometter, millmieters, nanomaeters