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92 Cards in this Set
- Front
- Back
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The Seven Conspicuous Motions
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1. Daily rotation at 1,670 km/h at the equator
2. Monthly rotation about E- Moon center of mass 3.Yearly rotation about the Sun at 106,000 km/h 4.Center of MIlky Way at 370,000 km/h 5. Orbital motion within the Sun's local star group at 1,000,000 km/h 6. Motion of Milky Way galaxy relative to remote galaxies at 580,000 km/h 7. MInor motions: Changes in shape and size of Earth's orbit. Changes in tilt of axis |
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Shape and Size of Earth
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oblate spheroid, slightly pear shaped
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Revolution
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Earth's movement around the Sun
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Ecliptic
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apparant path of Sun through the heavens as seen from Earth
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Elliptical orbit, not circulur
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-2.5 million km closer in January
-2.5 million km more distant in July -Earth receives about 6% more solar energy in January |
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Rotation
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Earth's Rotation axis is 23.5 degrees
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Seasons
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Determined by orientation of rotation axis.
- shortest: Winter solstice - longest: Summer solstice - Equal day and night: spring equinox and autumnal |
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Celestial Equator
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Line on celestial sphere above Earth's equator
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Other celestial bodies that are seen rotating?
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Jupiter, Sun
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Foucault Pendulum
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- Pendulum oscillates in fixed direction
- Orientation changes as Earth rotates |
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Coriolis Effect
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Deflection of paths as Earth rotates beneath moving objects
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Precession
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- slow wobble on Earth's rotation axis
- Reaction of Earth to gravitation pull on its equatorial bulge by the Moon and Sun - 26,000 years for one procession |
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Changes Direction of Rotation axis on Celestial Sphere
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- Polaris not always the North Star
- Position of equinoxes in the zodiac changes |
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Position on Earth
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- Intersection of parallels and meridians defined with respect to rotation axis
- Parallels: latitude - Meridians: longitude |
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Earth- Sun motion
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- Viewed from above N. Pole
- Earth revolves counterclockwise (west to east) - On Earth - Sun rises in the E & sets in W |
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Standard Time Zones
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360 degrees of longitude divided into 24 15 degree zones. Time decreases to W and increases in E.
- adjusted for local consistency |
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Daylight savings time
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clocks set ahead in spring and back in fall for one extra hour of sunlight during summer evenings
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International Date Line
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- change of a day. East: lose a day. West: Gain a day
- 180 degree meridian - Designated to correlate days with 24 hour time zones |
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Earth's Interior
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- Early Earth had molten surface from bombarding materials
- Surface cooled and crystallized to igneous rocks - Heat accumulated from radioactive decay lead to a second melting of the interior. This time, melting occured in pockets and not through interior. - Differentiation |
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Earth formed 4.6 million years ago in the solar nebula.
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- Melting and gravitational settling of heavier elements
- Gave Earth its present stratified structure |
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Conditions at Earth's center
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- Pressure= 3.5 million atmospheres
- Temperature= 6,000 C |
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Three Main Zones
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- Crust: outer thin shell
- Mantle: much thicker than crust - Core: central part |
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Theory of Plate Tectonics
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- Individual continents shift positions on Earth's surface
- Patterns between continental shapes can be fit together - All were once part of a single large landmass, "Pangea" - Orginial Concept: "Continental drift" |
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Earth's Magnetic Field
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Igneous rocks record Earth's magnetic filed strength and direction.
- Magnetic poles locked into alignment with Earth's field upon crystallization. - 22 reversals over the past 4.5 million years |
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Basis of Plate Tectonics Theory
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- Lithosphere broken into fairly rigid plates
- Plates move on asthenosphere: upper mantle - Earthquakes, volcanoes, and other rapid changes in Earth's crust occur most often at plate edges |
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Plate Motions
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1. Divergent (apart)
2. Convergent (together) 3. Transform (side to side) |
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Composition of the atmosphere
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Nitrogen (78%) Oxygen (21%) Argon (1%)
- Nitrogen and Oxygen cycle in and out of atmosphere - Argon: inert, or radioactive origins |
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Trace Components
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Water, Carbon Dioxide, Neon, Helium, Xenon, Hydrogen, Methane, Nitrous Oxide
Aerosols: Dust, Smoke, Salt and other tiny solid or liquid particles |
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History of the Moon
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Stage One:
- Formed from material ejected from a collision of a large object with Earth Stage Two: Molten Surface Stage - Molten Surface 100 km deep - 200 m. years after formation - Heating from solar system debris impacts Stage 3: molten interior stage - accumulated heat from radioactive decay - Began 3.8 million years ago; ended about 3.1 million years ago Stage 4: Cold and Quiet Stage - 3.1 million years ago to present - Surface scarred by micometeorites and meteorites |
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Eclipses
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occur when the Moons shadow falls on part of Earth.
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Eclipse
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- Solar Eclipse (New)
- Lunar Eclipse (Full) *Tides * Result from different gravitational pulls on front and back of Earth. |
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Lunar Eclipse
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when Earth is between sun and moon
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Earth, Moon and Sun positions
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Spring tides when aligned; neap tides when Moon and Sun are at 90 degrees.
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Elliptical Orbit of Moon
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- Greatest pull at perigee; less effect at apogee
- 48,000 km difference |
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Size, Shape, and depth of water basin
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Ranges from 1/3 m in Gulf of Mexico to 15 m in Bay of Fundy Planets, moons and other bodies
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Astronomical Unit (AU)
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Average Earth- Sun distance
1.5 X 10^8 km |
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Planet classification
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SIze, Density, and Atmosphere
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Terrestrial Planets
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Mercury, Venus, Earth, and Mars
Mostly rocky materials, metallic nickel and iron |
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Giant Planets
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- Jupiter, Saturn, Uranus, and Neptune
- Mostly hydrogen, helium, and methane |
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Mercury
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- Innermost planet
- Highly elliptical orbit - Average Distance ~ 0.4 AU - Orbital Period ~ 3 months - Rotational Period ~ 59 days - Visible shortly after sunset or before sunrise - Highly cratered; no atmosphere |
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Venus
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- orbital distance ~0.7 AU
- Morning and evening "star" - Exhibits, phases, like the Moon - Rotational motion opposite orbital motion - Venusian "day" longer than Venusian "year" - Visited by numerous probes - Mostly CO2 atmosphere, high temperature and pressure - Surface mostly flat but varied |
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Mars
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- Orbital distance ~1.5 AU
- Geologically active regions *Inactive volcanoes * Canyons * Terraced plateaus near poles * Flat regions pitted with craters -Thin atmosphere, mostly CO2 - Strong evidence for liquid water in past - Numerous space probes |
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Jupiter
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- ~5 AU from Sun
-Most massive planet * 318 times Earth's mass - Mostly H and He with iron- sillicate core - Dynamic atmosphere * H2, He, ammonia, methane, water * Great Red Spot - 63 widely varying satellites |
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Saturn
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-~9.5 AU from Sun
- Rings of particles - Density= 0.7 that of water - Surface similar to Jupiters - 60 satellites * Titan: only moon with substantial atmosphere |
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Uranus (~ 19 AU) Neptune ( ~30 AU)
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- outermost giant planets
- similar internal structures |
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Pluto
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planetoid (minor planet)
- Smaller than the Moon |
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Smaller Bodies
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mass of smaller bodies may be 2/3 of total Solar System mass
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Bombard larger objects
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Comet Shoemaker: Levy 9 fragments (bottom)
- and strikes Jupiter ( July ' 94) |
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Oort Cloud
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- Origin of long period comets (>200 yrs)
- 30 AU to light year away |
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Kuiper Belt
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- Origin of short period comets (<200 yrs)
- Disk shaped region 30- 100 AU from Sun |
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Comet structure
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- Small, solid objects
- "Dirty snowball" objects * frozen water, CO2, ammonia, and methane * Dusty and rocky bits |
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Comet head
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solid nucleus and coma of gas
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Two Types of Tails
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1. Ionized gases
2. Dust ** Tails point away from Sun |
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Asteroids
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- Located in belt between Mars and Jupiter
- Sizes: up to 1000 km - Varied composition - Inner belt: stony - Outer belt: dark with carbon - Others: iron and nickel ** Formed from original solar nebula ** Prevented from clumping by Jupiter nearby |
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Meteorids
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Remnants of comets and asteroids
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Meteor
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- Meteoroid encountering Earth's atmosphere
- Meteor showers: Earth passing through comet's tail |
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Meterorite
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- Meteoroid surviving to strike Earth's surface
- Iron, stony (chondrites and achondrites) on stony- iron |
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Protoplanet nebular model: Stage A
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- Formation of heavy elements in many earlier stars and supernovas
- Concentration in one region of space as dust, gas and chemical compounds |
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Stage B
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- Formation of large, rotating nebula
- Gravitational contraction, spin rate increases - Most mass concentrates in central prostar - Remaining material forms accretion disk - Material in accretion disk begins clumping |
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Stage C
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- Protosun becomes a star
- Solar ignition flare up many have blown away Hydrogen and Helium atmospheres of inner planets - Protoplanets heated, seperating heavy and light minerals - Larger bodies cooled slower, with heavy materials settling over longer times into central cores |
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Stars
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- appear as point sources
- Twinkle from atmospheric turbulence - Distance measured in light years (ly): 9.5 x 10 ^12 km |
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Altitude angle and Azimuth angle
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Determine location on celestial sphere
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Celestial Meridian
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E/ W location of observer
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Outer Appearance of Stars
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- Massive, dense balls of incandescent gas
- Powered by fusion reactions in their core |
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Origin of Stars
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- Gaseous Nebula; Mostly hydrogen
- Shock waves induce gravitational collapse * Gravitational energy released into higher temperatures and pressures |
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Protostar
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Accumulation of gases that will become a star
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Core of Star:
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Very hot, most dense region Nuclear fusion releases gamma and x- ray radiation
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Radiation Zone
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Radiation diffuses outward over millions of years
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Convection Zone
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structured by hot material rising from the interior, cooling, and sinking
- Upper reaches" Visible "surface" of star. - Sun surface temp ~5800 K |
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Lifetime of the Sun
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- Converts about 1.4 x 10^ 17 kg of matter to energy each year
* About 2,700 6000 lb SUV's - Born 5 billion years ago. Enough hydrogen for another 5 billion years - Lifetime depends on stellar mass * Less massive stars have longer lifetimes, more massive stars has shorter lifetimes |
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Stars
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- appear as point sources
- Twinkle from atmospheric turbulence - Distance measured in light years (ly): 9.5 x 10 ^12 km |
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Altitude angle and Azimuth angle
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Determine location on celestial sphere
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Celestial Meridian
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E/ W location of observer
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Outer Appearance of Stars
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- Massive, dense balls of incandescent gas
- Powered by fusion reactions in their core |
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Origin of Stars
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- Gaseous Nebula; Mostly hydrogen
- Shock waves induce gravitational collapse * Gravitational energy released into higher temperatures and pressures |
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Protostar
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Accumulation of gases that will become a star
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Core of Star:
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Very hot, most dense region Nuclear fusion releases gamma and x- ray radiation
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Radiation Zone
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Radiation diffuses outward over millions of years
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Convection Zone
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structured by hot material rising from the interior, cooling, and sinking
- Upper reaches" Visible "surface" of star. - Sun surface temp ~5800 K |
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Lifetime of the Sun
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- Converts about 1.4 x 10^ 17 kg of matter to energy each year
* About 2,700 6000 lb SUV's - Born 5 billion years ago. Enough hydrogen for another 5 billion years - Lifetime depends on stellar mass * Less massive stars have longer lifetimes, more massive stars has shorter lifetimes |
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Differences in Stellar Brightness
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Amount of light produced by star, size of star, distance to star
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Apparent Magnitude
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Scheme to quantify observed brightness.
* First magnitude star 100 times brighter than sixth magnitude star |
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Absolute Magnitude
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Brightness adjusted to a defined, standard disease
* Example: Sun Apparent Magnitude= -26.7 Absolute Magnitude= +4.8 |
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Luminosity Total Energy
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raditated into space per second. Directly related to absolute magnitude.
* Units correlated to Sun: 1 solar luminosity |
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Star Temperature
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Color variations apparant: Red (cooler stars), Blue (hotter stars), Yellow (in between, Sun)
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Hertzsprung- Russell Diagram
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Plot of absolute magnitude versus stellar temperature
- Each dot= star - Characteristic grouping * Main sequence stars, Red Giants, Novas, White Dwarfs, Cepheid Variables |
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Binary Systems: Two gravitational bound stars
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- Most stars are in binary pairs, not ours
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Star Cluster
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- Tens to hundred of thousands or more gravitationally bound stars
- often share a common origin |
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Galaxies
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- basic unit of the Universe
- Billions and Billions of gravitationally bound stars |
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Larger scale still
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- clusters of galaxies
- superclusters of galaxies - Billions and Billions of galaxies |
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The MIlky Way Spiral
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- Visible as a diffuse band on a dark night. Billions of stars, some bound in galactic clusters
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Structure of MIlky Way
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- Galactic nucleus rotating galactic disk
- Diameter: ~ 100,000 ly - Spherical galactic halo; contains ~150 globular clusters |
