chapter 2 Flashcards
describe a galaxy
galaxy; flattened, disk-shaped collection of starts in the form of a barred-spiral, elongated core,
Describe the suns operation, and explain the characteristics of the solar wind and the electromagnetic spectrum of median energy
solar wind; sun emits clouds of electrically charged particles, ionized gases, travelling in all directions from the sun, create auroras, disturbance of radio signals, and possible influences on weather
Illustrate the interception of solar energy and its uneven distribution at the top of the atmosphere
earths curved surface presents a continually varying angle to the incoming parallel rays of isolation, differences in the angle at which solar rays meet the surface at each latitude result in an uneven distribution of insolation and heating
Define solar altitude, solar declination, and day length, and describe the annual variability of each earths seasonality
equator is 12 hours long, year round, 40 degree latitude, 6 hours difference in daylight between winter (9 hours) and summer (15 hours), at 50 degree latitude, 8 hours of annual daylength variation
The nebular hypothesis
our solar system condensed from a large, slowly rotation and collapsing cloud of dust and gas, a nebula
Milky Way Galaxy
include our solar system, as 400 billion stars
Planetesimal hypothesis
process by which early protoplanets formed from the condensing masses of a nebular cloud of dust, gas, and icy comets
A light year
9.5 million km
Perihelion
the point of earths closest approach to the sun in its elliptical orbit, reached on January 3
Aphelion
point of earths greatest distance from the sun in its elliptical orbit, reached on July 4
Fusion
process of forcibly joining positively charged hydrogen and helium nuclei under extreme temperature and pressure; occurs naturally in the thermonuclear reactions within stars, such as our sun
Sunspots
magnetic disturbances on the surface go the sun, related flares, prominences, and outbreaks produce surges in solar wind
Magnetosphere
earths magnetic force field, deflects the solar wind flow toward the upper atmosphere above each pole
Electromagnetic spectrum
the spectrum of all possible wavelengths of electromagnetic energy produced by the sun
Wiens displacement law
all objets radiate energy in wavelength relate to their temperature , hight energy hight temperature, low energy Leo temperature
Thermopause
a zone approximately 480 km in altitude that serves conceptually as the top of the atmosphere; an altitude used for the determination of the solar constant
Insolation
solar radiation that is intercepted by earth
Solar constant
is the average insolation received at the thermopause when earth is at tis average distance form sun
Subsolar point
the only point receiving perpendicular insolation at a given moment
The suns delineation
is the latitude of the subsolar point
The suns altitude
is the angle between the sun and the horizon
Declination
the latitude that receives direct overhead (perpendicular) insolation on a particular day
Analemma
8 snapped path represent daily marking of the sun declination, which is the latitude of the sebsolar point, can locate any date
Daylenght
the duration of exposure to insolation
Revolution
orbit around the sun, 365,24 days at 107 280 km per h
Rotation
24h, apparent deflection of winds and ocean currents, and produces the twice-daily rise and fall of the ocean tides
Circle of illumination
the dividing line between day and night
Axial tilt
23,5degree from a perpendicular to the plane of the ecliptic
Plane of the ecliptic
a flat surface intersecting all the points of earths orbit
Axial parallelism
unchanging axial alignment , with Polaris directly overhead at the north pole throughout the year
Sphericity
oblate spheroidal shape lit by suns parallel rays; the geoid, shape of earth, spherical shape
Tropic of Cancer
he parallel that marks the farthest north the subsolar point migrates during the year; June solstice
Tropic of Capricorn
the parallel that marks the farthest south the subsolar point migrates during the year; December solstice
Arctic circle
southernmost parallel that experiences a 24-hour period of darkness, same for antarctic circle
March equinox
the circle of illumination passes through both pole, so that all locations on earth experience a 12-hour day and a 12-hour night, same for September equinox
Solar cycle
is the periodic variation in the suns activity and appearance over time, 11 years periods of sunspots activities
Solar minimum
a period of years when few sunspots are visible
Solar maximum
a period during which sunspots are numerous
Solar flares
magnetic storms that cause surface explosions
Prominence eruptions
outbursts of gases arcing from the surface of the sun
Net radiation
the balance between incoming shortwave energy from the sun and all outgoing radiation from earth and the atmosphere
seasons varies because of what
with the suns altitude, the suns declination, the daylength, and the earth revolution in orbit around the sun, its daily rotation and its tilted axis, and its sphericity
dawn
the period of diffused light that occur before sunrise,
twilight
the corresponding evening time after sunset
