Exam 2 Review – Earth in Space, Atmosphere-Hydrosphere, Meteorology
Review all questions discussed in class (see lecture pdfs for review)
The Universe:
Electromagnetic spectrum – Radio-Microwave-Infrared-Visible-UV-X-ray-Gamma Ray
Naked eye astronomy – stars vs. planets (planets change positions, stars are fixed)
Telescopes – gather light and magnify, Galileo observes lunar features, moons of Jupiter,
rings of Saturn, confirms heliocentric theory of Copernicus and demonstrates Moon
and planets are other worlds
Charles Messier – charts nebulous objects in sky mistaken for comets
Kepler’s laws of planetary motion – allow relative distances between planets and sun to
be determined (but not absolute / actual distances)
Astronomical Unit – Earth Sun distance
Parallax method for determining distance – how does it work?
Stellar parallax using the AU as a baseline – distance to nearby stars
Definition of a parsec – distance at which a star has a parallax of one arc second
Definition of a standard candle – object of known absolute brightness used to measure
stellar distances by comparing known brightness to observed (apparent) brightness –
inverse square law
Hertsprung Russell Diagram – main sequence stars – relation of color to temperature and
brightness
Standard candles – Cepheid variable stars, supernovae – relation of period to distance in
cepheids discovered by Henrietta Swan Leavitt, used by Edmund Hubble to prove
that the Andromeda nebula was actually another galaxy
Redshift / blueshift – increase / decrease in wavelength of light cause by movement away
from / toward the observer
Hubble’s Law – more distant objects are increasingly redshifted / moving away faster,
evidence that the universe is expanding, evidence for the Big Bang as the origin of the
universe.
Evidence for the Big Bang – Hubble’s Law, CMB (cosmic microwave background),
inhomogeneity of the CMB
CMB – light released when the universe became transparent to photons app. 400,000
years after the BB, redshifted into the microwave range.
Planets and Solar System:
Nebula hypothesis for the formation of the Solar System – initial collapse, formation of a
proto-Sun, planetary accretion (refractory materials from the Sun out to the snowline,
volatile materials beyond the snowline), fusion ignition of the Sun, formation of the
planets.
Evidence for multiple impact events between new planets – formation of the Moon, loss
of Mercury’s mantle, retrograde rotation of Venus, extreme axial tilt of Uranus
Rearrangement of orbits of outer planets, perturbation of the asteroid belt, icy asteroids /
comets as a source of water in the inner Solar System
Sun – source of energy (fusion of hydrogen to helium), evolution from main sequence
yellow dwarf to red giant to white / brown / black dwarf
Formation of elements from carbon to iron in stellar cores, heavier elements formed
during supernova explosions – Solar nebula contained elements from two previous
generations of stars (Sun is 3rd generation star)
8 planets – rocky inner (Mercury, Venus, Earth, Mars), asteroids, gas giants (Jupiter,
Saturn), ice giants (Uranus, Neptune), plutinos
Differences in atmospheres and lithospheres of Venus, Earth, Mars
Relationship of crater density to age of a planetary surface
Kuiper Belt, Oort Cloud
Earth-Sun-Moon:
Earth’s orbit – low eccentricity ellipse, aphelion, perihelion
Earth’s axial tilt – 23.5° - cause of seasons due to shifting location of direct solar heating
throughout the year. Tropic of Cancer, Tropic of Capricorn, Arctic / Antarctic Circle,
Position of the Sun overhead at Equinoxes, Winter Solstace, Summer Solstace, change in
density of solar radiation and daylength
Change in visible stars through the year due to change in position of nightside of the
Earth.
Ecliptic – imaginary circle defined by the Earth’s orbit around the Sun. Zodiacal
constellations defined by path of Sun around the ecliptic.
Inclination of lunar orbit relative to the ecliptic – lunar nodes where orbit crosses the
ecliptic.
Tides – gravitational vs. centrifugal (inertial) forces, spring vs. neap tides, lunar and solar
eclipses
Phases of the Moon – position of the Moon relative to the Earth and Sun during each
phase. Time of rising and setting of different phases.
Gravitational locking of Earth and Moon.
Atmosphere and Hydrosphere:
Water cycle – majority of water is saltwater in oceans. Most freshwater is ice or
groundwater.
Composition of the atmosphere – nitrogen, oxygen, water, greenhouse gases (carbon
dioxide, methane)
Structure of the atmosphere – troposphere, stratosphere, mesosphere, thermosphere
exosphere – temperature trends
Greenhouse effect – how it works (gases trap IR radiation near the surface of the Earth)
Pattern of global circulation in the atmosphere caused by distribution of solar heating,
circulation cells, regions of high vs. low pressure.
Wind patterns generated by vertical circulation combined with the coriolis effect –
doldrums, trade winds, horse latitudes, westerlies, polar easterlies.
Global ocean currents driven by winds, oceanic gyres
Ocean circulation conveyor belt – causes of deep ocean circulation (thermohaline
circulation). Ocean circulation redistributes heat around the globe from the tropics to
the high latitudes. Vertical ocean circulation oxygenates the deep ocean and stores
CO2 in deep, cold water for hundreds of years.
Meteorology:
Humidity – absolute vs. relative humidity, temperature dependence of absolute humidity,
saturation, dew point, condensation
Adiabatic cooling – dry vs. wet adiabatic lapse rate, why humid air can rise farther than
dry air
Clouds – cirrus, alto-, low level, cumulus, nimbus, stratus
High pressure, low pressure, anticyclonic, cyclonic flow
Polar front – mixing of cold and warm air masses along fronts, cold front, warm front,
occluded front, stationary front, precipitation – rain, snow, sleet, freezing rain, fog