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1024 Exam One
Astronomy 1024 Exam One
75
Astronomy
Undergraduate 1
02/10/2010

Additional Astronomy Flashcards

 


 

Cards

Term

 

 

Axis

Definition



imaginary line running through its center between north and south poles

Term

 

 

Celestial Sphere

Definition


Picture of the sky as a huge hollow globe that turns around the earth used to locate stars and galaxies

Term

 

 

Apparent Magnitude

Definition



measure of the observed brightness as seen from Earth

Term

 

 

Who divided the stars into six classes of brightness?

Definition

 

 

Hipparchus

Term

 

 

Photometer

Definition

 

used to measure brightness


magnitudes for the brightest stars are negative

Term

 

 

Celestial Globe

Definition

 

 

helps you locate sky objects

Term

 

 

Terrestrial Globe

Definition



helps you locate places on Earth

Term

 

 

Celestial Equator

Definition

 


is the projection of the Earth's

equator out to the sky

Term

 

 

Declination

Definition
angular distance above or below the celestial equator
Term

 

 

Right Ascension

Definition



distance measured eastward along the celestial equator from the

zero point (Vernal Equinox)

Term

 

 

Epoch

Definition

 

 

point of time selected as a fixed reference

Term

 

 

Zenith

Definition

 


point on the celestial sphere directly over your head

Term

 

 

Celestial Horizon

Definition

 

 

the great circle on the celestial sphere 90 degrees from your zenith

Term

 

 

Celestial Meridian

Definition

 

 

great circle passing through your Zenith and the north and south points on your horizon

Term

 

 

Diurnal Circles

Definition



the daily paths around the celestial poles when you observe them from

the spinning Earth

Term

 

 

North Circumpolar Stars

Definition



stars that are within 40 degrees of the north pole, are always above your horizon, and never set

Term

 

 

South Circumpolar Stars

Definition



stars that never rise and stay within 40 degrees of the south celestial pole 

Term

 

 

Ecliptic

Definition

 

 

the apparent path of the sun against background stars

Term

 

 

Stars

Definition



blazing suns racing though space at different distances from Earth

Term
How do you measure the Terrestrial Sphere?
Definition
by dividing the sphere into 360 sections called degrees
Term
Which three stars mark the points of the Summer triangle?
Definition
Vega, Deneb, Altair
Term
Zodiac
Definition
a band 16 degrees wide around the sky that is centered on the ecliptic
Term
Wave
Definition
a rising and falling disturbance that transports energy from a source to a receiver without the actual transfer of material
Term
Light Wave
Definition
an electromagnetic disturbance consisting of rapidly varying electric and magnetic effects
Term
Wavelength
Definition
the distance from any point on a wave to the next identical point (crest to crest, or trough to trough)
Term
How are waves measured?
Definition
nanometers/angstrom
Term
Visible Spectrum
Definition
the arrangement of colors according to wavelengths
Term
Electromagnetic Spectrum
Definition
whole family of electromagnetic waves, arranged according to wavelength
Term
Speed of Light
Definition
(c) - empty space/3,000,000km/sec (186,000 miles per second)
Term
Light Year
Definition
the distance that light can travel in a year through empty space
Term
Frequency of Wave Motion
Definition
the number of waves that pass by a fixed point in given time (measured in cycles per minute)
Term
Thermal Radiation
Definition
energy due to temperature
Term
Blackbody
Definition
theoretical perfect radiator
Term
Stefan Boltzmann Radiation Law
Definition
total energy is proportional to the fourth power of its absolute temperature
Term
Radiation Spectrum
Definition
shows how much energy a body radiates at different wavelengths, which wavelength radiates most intensely, and the total amount of energy it radiates
Term
Atmospheric Windows
Definition
spectral ranges within which air is largely transparent to radiation
Term
Astronomical Observatory
Definition
a place equipped for the observation of sky objects
Term
Spectropsy
Definition
analysis of spectra or spectrums
Term
Three types of Spectra
Definition
1. Continuous Spectrum- rainbow colors 2. Emission Spectrum- bright colored lines 3. Absorption Spectrum- dark lines
Term
Atom
Definition
smallest particle of a chemical element
Term
Binding Energy
Definition
Energy required to remove an electron from the atom
Term
Energy Levels
Definition
allowed electron orbits
Term
Ion
Definition
a positively charged ion who has lost its electrons
Term
Emission Lines
Definition
produced when electrons jump from higher energy level back down to lower energy levels
Term
Perfect Cosmological Principle
Definition
the universe is the same everywhere on the large scale, at all times
Term
Cosmic Background Radiation
Definition
a vestige of the heat of its Big Bang origin
Term
Copernican System
Definition
heliocentric, sun-centered model that said all planets orbited around the sun
Term
Optical Telescope
Definition
forms images of faint and distant stars, collects more light than the human eye
Term
Light Gathering Power
Definition
ability of a telescope to collect a light
Term
Galileo
Definition
first point a refracting telescope skyward in 1609
Term
Light Gathering Power
Definition
ability of a telescope to collect a light
Term
Galileo
Definition
first to point a refracting telescope skyward in 1609
Term
AU
Definition
earth to sun distance (1.5x10^8)
Term
Speed of Light
Definition
(c) - 3.0 x 10^5 km/s
Term
Light Year
Definition
the distance light can travel in a year
Term
Parsec
Definition
distance at which 1 AU subtends 1/3600 degrees = 3.3LY
Term
Solar System
Definition
11 Light Hours
Term
How fast do planets revolve around the sun?
Definition
10 km/sec
Term
Idealization
Definition
observation, experience, and self evident postulates -> hypothesis (initial explanation) -> systematic and objective testing -> theories
Term
Theories
Definition
the best current explanations, falsifiable, subject to revision (not hypothesis or prediction)
Term
Pseudoscience
Definition
claims to be scientific, but violates at least one scientific practice
Term
Religion
Definition
belief in and reverence for superhuman powers that created and or govern the universe
Term
Astrology
Definition
ancient superstition of celestial influences on man, based on the location of the sun and planets relative to the 12 zodiacal constellations
Term
Altazimuth Coordinates
Definition
specify directions relative to the observer on ground; depend on observers position and the time
Term
Pythagorus
Definition
sphereical earth is the center of the universe, surrounded by 8 celestial spheres and an air sphere
Term
Aristotle
Definition
observes no stellar parallax and concludes that universe in geocentric
Term
Aristarchus
Definition
applies geometry to observations of eclipses and lunar phase to estimate 19x further than moon and 7x bigger than earth = therefore the universe is heliocentric
Term
Ptolemy
Definition
perfects a complex geocentric system of epicycles, deferments, and equations to explain the planets non-uniform and reversing motion
Term
Magellan
Definition
circumnavigates the Earth to discover it must be round
Term
Copernicus
Definition
revives the heliocentric hypotheses
Term
Hubble
Definition
stars of known brightness in spiral nebulae show they are outside of the milky way = discovery of other galaxies
Term
Steady State Hypothesis
Definition
universe does not evolve or change in time
Term
Big Bang Theory
Definition
the universe should still be filled with cosmic background radiation - the primeval fireball would have sent strong shortwave radiation in all directions like exploding gigantic bombs
Term
Galileo Galilee
Definition
Notion of acceleration
Term
Sir Isaac Newton
Definition
Laws of Motion, worked on theoretical physics, law of universal gravitational force, law of conservation of angular momentum
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