Astronomy 101

• -Facts/ Observations
• -Organize ideas/ theory
• -Predictions & testing

• 10^3 = 1000
• 10^2 = 100
• 10^1 = 10
• 10^0 = 1
• 10^-1= .1
• 10^-2=.01
• 10^-3=.001

• Imaginary sphere surrounding earth, which all objects in sky were considered attached to.
• Apparent path of sun, relative to stars on celestial sphere,over course of yr.
• Angle is 23.5 degrees.
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• change in avg temp & length of day due to tilt of earth's axis respect to plane of its orbit.
• 1)Pt on ecliptic where sun is at northermost pt above celestial equator(near June21)
• 2)Pt on ecliptic where sun is at sourthermost pt below celestial eq. (near Dec 21)
• 1) Date when sun crosses celestial eq. moving northward (near march 21)
• 2) Date when sun crosses celestial eq. moving southward (near sept 22)
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• Slow change in the direction of the rotation axis of a spinning object cause by external gravitational influence.
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• Appearance of sunlit face of moon at different pts along orbit(seen fr. earth).
• Phase, none of lunar disk is visible.
• Phase,moon appears half disk.
• Phase,appears complete circular disk in sky.
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• Event during which one body passes in front of another, so light blocked.
• Celestial event which moon passes through shadow of earth(temporary darken surface)Celestial event only part of covered body is blocked from view.
• Celestial event which one body is completely blocked from view by another.
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• One distance measurement method.
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• apparent motion of relatively close object w/ respect to a more distance background as the location of the obserber changes.(shift of object from different line of site)
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• Backward, westward loop traced out by a planet w/ respect to fixed stars.
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• Geocentric: model of solar system that holds earth is at enter of universe & all bodies orbit around it.(Aristotle)
• Heliocentric:model of solar system that is centered on Sun, while earth in motion about sun.(Copernicus)
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• The orbital paths of planets are elliptical with sun at one focus.
• Distance from focus to ellipse to other focus stay same.
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• Imaginary line connecting the Sun to any planet sweeps out equal areas of ellipse in equal intervals of time.
• Swing out equal areas in equal time when close/far to sun.
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• The square of a planet's orbital period is proportional to the cube of its semi major axis.
• P2(yr)= a3(AU)/ M(M0)

Average distance btw earth and sun.

• 1)An object at rest remain at rest, moving object continues straight line at constant speed, unless external force changes their state of motion. ( See Pic)
• 2) The Acceleration(change of speed) of object is directly proportional to the net applied force and inversely proportional to the objects mass.
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• To every action(force) there is an equal and opposite reaction.
• Force= GM1*M2/r2 (product masses/ distance)
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• Light described as wave.
• Number of meters needed for wave to repeat itself at given moment in time.
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Union of electricity and magnetism, which don't exist as independent qualities but in reality are two aspects of single physical phenomenon.

• Radio(AM FM) Inferred (far near) Visible(micron oms) Ultraviolet (near far) x-ray (soft hard)
• Number of crest going by in hertz
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Wavelength(max) = 0.29 cm/ T (temp)

F= o T^4

• spectra in which radiation is distributed over all freqs (EX: blackbody radiation emitted by hot, dense body)
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• bright line in specific location of spectrum of radiating material, corresponding to emission o flight at certain freq. (EX: heated gas in glass container)
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• Dark line in an otherwise continuous bright spectrum, where light within one narrow freq range has been removed. (missing lines is emission lines)
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• -Compostion ( what is there)
• -Abundances ( how much is there)
• -temp ( wiens law, black body,/other)
• -pressure ( Broadens lines)
• - Rotation ( doppler effect)
• -magnetic field( zeeman effect)
• -electric field( stark effect)

• (motion towards/ away from obserber)(pitch high toward, low going away)
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• Visible light telescope, curved mirror to gather& focus light from distance object.
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• Telescope that uses a lens to gather 7 focus light from distance object.( small ie binoculars) ( no modern research use this )
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• side eye view mirror
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• see through lens
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• solid glass w. chemical reaction on surface to make permanent record of observation.
• improved by using larger telescopes and shorter wavelengths.
• smeared out image of a star in long duration exposure
• lights at different telescopes and slight different times

• sensitive to longer wavelength radiation, absorbed by atmosphere, not reflect on mirror, SEE THROUGH DUST.
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• High energy telescope b/c reflected easily by any kind of surface.
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