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Definition
| Systems Composed Of Hundreds Of Billions Of Stars |
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Definition
| Several billion galaxies in the universe, each containing an average of 200 billion stars |
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Definition
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Definition
| contain more than 1000 galaxies, are mostly elliptical, and are crowded at the center (Virgo cluster contains 2500 galaxies) |
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Definition
| contain less than 100 galaxies, are irregularly shaped, and less concentrated in the center |
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| Clusters, in turn, group into |
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| are bound together into even larger structures shaped like filaments and pancakes |
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| our place in the universe |
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Definition
| The Virgo Supercluster is but one of many Superclusters |
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Definition
| M13, Andromeda, Milkyway, small magellanic cloud, large magellnic cloud, NGC 6822 (cluster of over 30 galaxies) |
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Definition
| The Milky Way is one of several galaxies in the Local Group of galaxies |
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| describe The Milky Way Galaxy |
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Definition
A typical spiral galaxy
–Contains 100 x 109 stars
–Is 100,000 light years across
–Is 1,000 light years thick
–Takes 225 x 106 years to revolve once |
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| Where are we located in the milkyway? |
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Definition
| bottom part close to the inner center |
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Definition
–Occurs near the third arm of the Milky Way spiral galaxy
– Consists of the Sun, 8 planets (Pluto recently demoted), over 100 moons and a multitude of asteroids, comets and meteoroids
–The orbits of the planets are elliptical around the sun |
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Term
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Definition
The planets generally revolve in the same direction (counterclockwise) around the sun and within the plane of the ecliptic
Most of the moons revolve around the planets in the same direction as the planets revolve around the sun.
Meteoroids, asteroids and comets also follow orbits around the sun. |
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| Newton’s first law of motion |
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Definition
| –Objects in motion remain in motion and objects at rest remain at rest, unless they are acted upon by an outside force |
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| Gravity And The Solar System |
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Definition
Because planets change both speed and direction, there had to be a force which Newton called gravity
Gravitation force is balanced by the centrifugal force |
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Term
| formula for force of gravity (longhand) |
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Definition
| force of gravity = gravitational constant x (mass 1 x mass 2/distance^2) |
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| formula for force of gravity (shorthand) |
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Definition
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| What involves gravity on the planet: |
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Definition
| velocity, centrifugal force, gravity |
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| Centrifugal force of orbiting planet tends to |
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Definition
| pull planet away from the Sun |
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Definition
| forces causes planet to orbit around Sun |
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Term
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Definition
| The Sun, planets, and other objects in our solar system formed from a giant cloud of gases and dust called the solar nebula beginning ~5 billion years ago |
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| Solar Nebula 5 Billion Years Ago |
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Definition
A. Gases and dust in the rotating nebula start to gravitationally collapse
B. Nebula contracts into a rotating disk, heated by conversion of gravitational to thermal energy. Most material migrates to center to form proto-sun
B1: Most of the mass migrates towards center. surrounding disk begins to condense solid particles
C. Nebula cloud cools, causing condensation of tiny rocky and metallic particles. Sun undergoes gravitational contraction, eventually igniting fusion reactions in core
D. Repeated collisions among particles orbiting sun cause them to coalesce into asteroid-sized bodies (planetismals)
E. Bodies accreted into planets within a few million years |
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| Planetesimals Aggregated into |
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Definition
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Definition
| Protoplanets that then became Planets |
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Term
Formation of Planets
Accretion of inner planets was fast: |
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Definition
– Heat was enormous (over 2000 oC)
–Softening and melting of early planets caused differentiation (separation and migration) of heavy and light elements based on densities |
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Term
| Further out, gaseous planets formed around rocky cores: |
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Definition
| When these planets reached 10-15 times the mass of the earth, their strong gravity drew in all the gases around them |
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| ....drives motion within their interiors |
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Definition
| Heat of condensation of all the planets |
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| Heating of the Early Planets |
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Definition
a) collision of planetesimals with primitive earth
b) compression of planet under its own growing weight
c) disintegration of radioactive elements |
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Term
| Hot, softened Earth separated into layers based on densities of different materials: |
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Definition
Heavy metals (mostly iron) sank to the center
–Lighter, molten material migrated towards the surface to produce a primitive crust
–Gases escaping from Earth’s interior (outgassing) formed the primitive atmosphere
–This chemical separation established the basic divisions of Earth’s interior and surface |
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Term
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Definition
Large Mars-sized
Body 4.5 B.Y. Ago |
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Term
Earth Was Hit With Large Mars-sized
Body 4.5 B.Y. Ago |
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Definition
Material thrown off
earth aggregated in
orbit to form early
moon |
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Term
Early Lunar Magma
Ocean Eventually
Cooled And
Crystallized Minerals |
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Definition
| result of hot accretion of light minerals floated, dense minerals sank, whole mantle/partial mantle convection |
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Definition
Meteorite bombardment following
accretion |
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Definition
| mantle, mare material, crust, moonquake zone, probable metallic core |
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Definition
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Definition
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| Earth’s Magma Ocean Eventually |
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Definition
Cooled
And Solidified Into The Earliest Crust |
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Definition
~4.45
b.y. ago formed early
atmosphere and oceans |
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Definition
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Term
| The Terrestrial (Rocky) Planets |
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Definition
Closest to the Sun and consist of Mercury,
Venus, Earth and Mars
Generally small, rocky bodies with
densities greater than 3gm/cm3
Composed mainly of silicates, Fe and Ni
Volcanism mostly basaltic |
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Term
Terrestrial Planets and Size
Earth and Venus: |
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Definition
– Larger than Mercury and Mars
– Geologically active (volcanic activity and
earthquakes)
– Well-developed atmospheres |
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Term
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Definition
– Smaller planets
– Geologically dead (although Mars was
volcanically active in the past)
– Atmosphere thin to absent |
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Term
How does size determine whether or not a
planet has an atmosphere? |
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Definition
| The value of gravity and hotness of the planet decide the existance of the atmosphere. |
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Definition
| only Earth developed photosynthesis |
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Definition
– Mercury and Mars: none and little
– Earth (1atm, O2, N2) vs Venus (90 atm, CO2) |
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Definition
– Mercury is hot while Mars is cold
– Venus: very hot
– Earth: cozy |
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Definition
– Mercury and Mars: early but now tectonically
dead
– Venus and Earth: currently geologically active |
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Definition
| size and distance from sun |
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Term
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Definition
•Thick
atmosphere
masks surface
•Radar
penetrates
atmosphere and
reflects off
surface
• Data sent back
to Earth for
analysis |
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Term
| Computer Image of Venus Based on Radar |
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Definition
A planet with:
•Volcanoes
•Vast volcanic plains
•Basaltic lava flows
•Mountain ranges
•Deep rift valleys |
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Definition
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| Huge shield volcanoes like Olympus Mons suggest extensive volcanism in the past |
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Definition
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| Are the Canyons on Mars Relicts of Ancient Waterways? |
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Definition
| Martian surface exhibits system of ancient canyons and branching valleys similar to those cut by desert streams on Earth |
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| Did Life Once Exist on Mars? |
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Definition
SNC meteorites collected in Antarctica are considered martian in origin
One SNC meteorite contains microscopic features that look like fossil bacteria |
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| meteor had bacteria on it |
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Definition
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Definition
| sedimentary and volcanic rocks much like those found on Earth |
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| Car-sized robotic rover includes |
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Definition
High resolution cameras
–Laser to irradiate surface
–Spectrometers to determine composition of rocks and soil
–Robotic arm
–Environmental monitoring station for measuring atmospheric humidity, temperature, pressure, wind speed, and uv radiation |
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| Extensive Belt of Asteroids Between |
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Definition
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Term
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Definition
Possibly fragments of broken planets
Can reach 1,000 km in diameter
Most asteroids are only ~1 km or less in diameter
Some have collided with Earth in the past |
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| There are ~200 known asteroids whose paths take them near the Earth (within several hundreds of thousands to millions of kilometers): |
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Definition
–Most are a few kilometers or less in diameter, but some are much larger
–Many are rocky, a few are metallic
–Some are rich in organic matter
About 20% of them will eventually hit Earth |
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Term
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Definition
• Approximately 180 km in diameter
• Impact may have caused extinction of dinosaurs and other life forms
• Shown are impact breccia & gravity anomaly map |
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| Meteor Crater, Arizona, formed |
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Definition
| 25,000 – 50,000 years ago |
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Term
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Definition
Consist of Jupiter, Saturn, Uranus, and Neptune
Large with strong gravitational pull
Low densities 0.71 to 1.70gm/cm3
Each has a rocky core surrounded by layers of hydrogen, helium and other compounds
We only see the outer layer of visible clouds
Orbited by numerous and compositionally variable moons of probable different origins |
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Definition
| (Three Earth’s Would Fit Inside) |
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Definition
Jupiter has over 60 known moons
Europa, Ganymede and Callisto may have small metallic cores surrounded by thick mantles of ice and silicate minerals |
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| Some of Jupiter’s better known moons: |
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Definition
Io (sulfur rich, volcanically active)
–Europa
–Ganymede
–Callisto |
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Term
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Definition
Volcanically active moon with basaltic lava flows, molten sulfur and sulfurous gases
Heat energy caused by tidal stresses exerted by Jupiter’s gravitational pull |
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Definition
| Icy surface crisscrossed with fractures due to tidal stresses from Jupiter |
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Definition
| Icy surface pitted with craters |
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Term
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Definition
Second largest planet in the solar system
Chemical composition similar to Jupiter
Fifty three named moons |
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Term
| Immense rings tens of thousands of km wide but averaging a little over 100m thick: |
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Definition
Each ring composed of dust- to boulder-sized particles of mostly ice, some stained with iron oxide
–Variable colors indicate slight compositional differences among the rings |
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Term
| Where does it rain methane? |
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Definition
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Term
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Definition
| extends beyond Neptune to ~55 AU and consists of small bodies, including Pluto, composed largely of frozen methane, ammonia and water |
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Term
| Largest known kuiper belt objects |
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Definition
Xena (has a moonish thing)
Pluto (also has a moonish thing)
2005 FY9
2003 EL61 (has 2 moon things)
Quaoar |
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Definition
| too small to be visible to the unaided eye |
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Definition
| originate in the Oort Cloud beyond the Kuiper Belt in the outer regions of the solar system |
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Definition
Dirty snowballs of frozen gases in addition to rocky and metallic minerals
Some may contain organic material
Millions may orbit the Sun beyond Pluto |
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| Thought to be relicts of the early Solar Nebula: |
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Definition
| Swept to the far reaches of the solar system by the solar wind after formation of the sun and planets |
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| Comets Develop a Tail of Dust and Ionized Gasses When |
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Definition
| Approaching Sun Due to Solar Wind |
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| The balance between ______ and _______ forces keeps a planet in orbit around the Sun? |
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Definition
| Gravitational and centrifugal |
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Term
| Thermonuclear reactions within the Sun's core include each of the following except.. |
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Definition
| Conversion of electrons to protons |
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Term
| The following are steps in the formation of our solar system from an initial gas cloud called the solar nebula: (a) Smaller planetesimals accrete into larger bodies; (b) Nebular dust and gases undergo gravitational collapse; (c) Formation of the proto-sun; (d) Larger bodies accrete into protoplanets; (e) Earth's interior differentiates to form a core, mantle, and crust. Which of the following is the correct order of events from earliest to latest? |
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| Collision of the Earth with a Mars-sized object 4.5 billion years ago, followed by ejection of Earth material into space, is thought to have been responsible for formation of the _________ |
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Definition
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Term
| Outside of Earth, what two solar system bodies have recently been found by spacecraft to contain water? |
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Definition
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Term
| The largest volcanoes discovered in our solar system to date are found on __________ |
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Definition
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| Which of the following statements does NOT apply to the Kuiper Belt? |
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Definition
| Also known as the Asteroid Belt |
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Term
| Dark lines within the Sun's spectrum, known as Fraunhofer lines, are thought to |
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Definition
| represent wavelengths within the Sun's spectrum that are absorbed by elements like hydrogen on the Sun |
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| The intensity of the solar wind reaching Earth is thought to increase during times of decreased sunspot activity. |
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Definition
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Term
| Which of the following statements regarding solar radiation is TRUE? |
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Definition
| Radiation emitted by Earth is of longer wavelength than radiation received from the Sun |
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Term
| For the following figure, note that the white dots on top of the various images of Earth represent the North Pole. Which image of Earth, relative to the Sun, corresponds to Spring (Vernal) Equinox? |
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Definition
| Earth position directly above the Sun |
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| Which of the following statements regarding the figure below is TRUE? |
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Definition
| The greatest intensity of solar radiation occurs within the visible portion of the electomagnetic spectrum |
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