Astronomy Test 1 2
Terms
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- What is astronomy?
- The study of the physical universe
- What is a scientific attitude?
- Knowing that science changes based on current information
- AU
-
Astronomical Unit
-distance from earth to sun
-useful for solar system distances - ly
-
Light Year
useful for stellar distances - pc
-
Parsec
3ly
useful for stellar distances - Mpc
-
Mega parsec
3.26million ly
useful for galactic distances - Mercury to Sun distance
- 0.4AU
- Venus to Sun distance
- 0.7AU
- Mars to Sun distance
- 1.5AU
- Jupiter to Sun distance
- 5AU
- Saturn to Sun distance
- 10AU
- Uranus to Sun distance
- 20AU
- Neptune to Sun distance
- 30AU
- Pluto to Sun distance
- 40AU
- Naked Eye Sky
-
6,000 stars
5 Planets
Sun and Moon - How many official constellations are there?
- 88, made with lines of celestial longitude and latitude
- Body Part Angles-fist
- 10 degrees
- Thumb
- 2 degrees
- Pinky
- 1 degree
- 1 degree=
- 60 arc minutes
- Diurnal star motion
-
due to Earth's rotation
east-west - How much earlier do stars rise each night?
- 4 minutes
- Diurnal Sun motion
-
due to earth's rotation
east-west - Sidereal sun motion
-
due to earths revolution
west-east - Ecliptic
- path of sun in celestial field
- Highest Point in ecliptic
- Summer Solstice
- Lowest Point in Ecliptic
- Winter Solstice
- Middle Points
- Vernal/Autumnal Equinox
- Precession
- wobble due to the sun and the moon pulling on the equator
- Noticiable precession changes
- Pole star changes
- Diurnal Motion of the moon
-
due to Earth's rotation
East to West - Moon's sidereal motion
-
due to moons revolution
west to east
takes 27.3 days-13 degrees per day - Moons synodic period
- 29.5 days relative to the sun
- Darkest part of shadow
- Umbra
- Lighter part of shadow
- Penumbra
- Solar Eclipse
-
Moon is in new phase
Moon on the ecliptic - Lunar Eclipse
-
Moon is in full phase
Moon is on ecliptic - Diurnal Motion of the planets
-
Due to earths rotation
East to west - Sidereal motion of planets
-
west to east or
east to west (retrograde) - Inner Planet between the Sun and Earth
- inferior conjunction
- Sun between Earth and inner planet
- superior conjunction
- Maximum angle away from sun in our sky
- Greatest Elongation
- Earth between outer planet and sun
- Opposition
- Aristotle
-
Universe is geocentric
Doesn't explain retrograde - Ptolmey
- Adds epicycles to Aristotle's universe
- Copernicus
-
Heliocentric universe in perfect circles
inner planets faster than outer
retrograde due to inner planets passing outer planets - Brahe
-
measured planets to high accuracy for 20 years
built large instruments - Kepler
- 3 Laws of Planetary Motion
- Law One
- planets orbit in an elipse with the sun at one focus
- Law Two
- a planet-sun line sweeps out equal areas in equal intervals of time
- Law Three
-
P years squared=Semi-major axis AU's cubed
P=time to complete one orbit
A=avg. planet sun distace - Galileo
-
Telescopic observations
Discovered jupiters 4 moons
Phases of venus proved heliocentrism