Flashcards
astronomy
Cards in this deck (62)
- 1Surface of celestial sphereconstellations
- 2how many constellations88
- 3celestial sphere appears to revolve around earth for how longonce in each day-night cylcle
- 4how are poles and equator determined?extending the axis of rotation and equatorial plane of earth onto celestial sphere
- 5Earths axis of rotation is titled at ___ degrees23.5
- 6What does the tilt do?causes seasons
- 7How are equinoxes and solstices determined?by the relationship between the sun's path on the celestial sphere and celestial equator
- 8precessionearth's axis of rotation slowly changes direction relative to the stars over thousands of years
- 9what causes precessionsthe gravitational pull of the sun and the moon on earth
- 10length of dayearth's rotation rate + the avg motion of earth around the sun
- 11Equinoxsun directly over equator - 12 hours day and 12 hours of night
- 12vernal equinoxmarch 20
- 13autumnal equinoxsept 22
- 14solsticelocation of the sun relative to the earth - longest/shortest day light
- 15Winter solsticedec 22 - farthest south
- 16summer solsticejun 21 - rises farthest north
- 17what causes the phases of the moonthe relative positions of earth, sun, moon
- 18synodic monthone cycle - 29.5 days
- 19sidereal monthone orbit of moon around earth - 27.3 days
- 20Phases of Moonnew, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, waning cresent
- 21umbradirect light completely blocked
- 22penumbralight source only partially obscured
- 23lunar eclipsemoon moves directly behind earth into its umbra
sun-earth-moon - 24solar eclipsea strip of earth passes through the moon's umbra
sun-moon-earth
(moon covers sun) - 251 AUdistance from sun to earth
93 mill miles - 26scientific notationconvenient shorthand for writing very large or small numbers
- 27scientific methodprocedure for formulation theories that correctly predict how the universe behaves
- 28What makes it scientific?must be testable
- 29Kepler modified Copernicus' heliocentric theory by......showing that orbits are elliptical
- 30Sidereal orbital perioda period of a plant is measured with respect to the stars and determines the length of a planets year
- 31synodic periodmeasured with respect to the sun as seen from the earth
- 32What did Galileo discover that supported the heliocentric viewphases of venus and moons of juptier - by using a telescope
- 33Newtons Laws of motionused to deduce kepler's laws and to describe most planetary motions with extreme accuracy
- 34Newtons First Lawan object either remains at rest or continues to move at a constant velocity, unless acted upon by a net force.
- 35Newtons Second Lawthe sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma
- 36Newtons Third LawWhen one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
- 37Mass of an Objecta measure of the amount of matter in it
- 38Weight of an objectmeasure of the force with which the gravity of a world pulls on an object mass when the 2 objects are at rest with respect to each other
- 39Ellipsethe path of an astronomical object around another
- 40parabola/hyperbolaobjects with these orbits fly away never to return
- 41photonspackets of vibrating electric and magnetic fields - carry energy through space at same speed - speed of light
- 42speed of light300,000 km/s
- 43Longest to shortest wavelengthradio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, x-rays, gamma rays
- 44wavelength of visible light photon is associated with its _____color
range = 400 nm (violet) - 700 nm (red) - 45telescopes most important functiongather as much light as possible
(also resolves and magnifies) - 46Reflecting telescopesproduce images by reflecting light rays from concave mirrors to a focal point
- 47Refracting telescopeproduce images by bending light rays as they pass through a glass lens
- 48problems with refracting telescopesglass impurity, opacity to a certain wavelength, and structural difficulties - cant build very large
- 49Radio telescopes have ______ that are used to focus radio waveslarge, reflecting antennas
- 50interferometrymult telescopes connected to make one large telescope
very sharp radio images are produced this way - 51Earth's atmosphere and photonsfairly transparent to most visible light and radio waves, along with some infrared and ultraviolet arriving from space. absorbs much of the electromagnetic radiation at other wavelengths
- 52Charge-Coupled Devices (CCDs)record images on many telescopes used between infrared and xray wavelengths
- 53by studying the wavelength of electromagnetic radiation emitted and absorbed by an astronomical object, astronomers can learn about the object's...temperature, chemical composition, rotation rate, companion objects, movement through space
- 54blackbodyhypothetical object that completely absorbs all the electromagnetic radiation that strikes it. the relative intensities of radiation at diff wavelengths that is then emits depend only on its temperature
- 55Wien's Lawthe peak wavelength of radiation emitted by a blackbody is inversely proportional to its temp
the higher the temp, the shorter the peak wavelength - 56Stefan - Boltzmann Lawa hotter blackbody emits more radiation at every wavelength than does a cooler blackbody
- 57spectroscopythe study of electromagnetic spectra
provides important info about the chem comp of remote astronomical objects - 58Kirchhoff's 3 Laws of spectral analysisdescribe the conditions under which absorption lines, emission lines, and a continuous spectrum can be observed
- 59Spectral lines serve as...distinctive "fingerprints" that identify the chemical elements and compounds comprising a light source
- 60Atomsmall, dense nucleus (=protons + neutrons) surrounded by orbiting electrons
different elements have diff # of protons
different isotopes have diff #of neutrons - 61the nuclei of some atoms are stable, while others...(radioactive ones) spontaneously split into pieces
- 62—
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- Flashcards on astronomy, created by laura russo on 04/10/2016.
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