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What are the three types of visible spectra?
Continuous- an uninterrupted band of light emitted by an incandescent solid, liquid, or gas under pressure.
Absorption/Dark Line- A continuous spectrum with dark lines superimposed.
Emission/Bright Line Spectrum- The bright lines provided by an incandescent gas under low pressure.
How do astronomers determine the composition of stars and galaxies?
They look at the type of spectrum that the star makes.
What can astronomers determine from looking at the light from stars and galaxies?
They can determine if the star/galaxy is moving away or toward us, how fast the star or galaxy is moving, and what it is made of.
What is the Doppler effect and why does it occur?
It is the apparent change in wavelength of radiation caused by the relative movement of the source and the absorber.
What units are used when measuring distances in space?
The A.U.- about 93,000,000 miles or 150,000,000 kilometers, used for distances inside our solar system.
The Light Year- about 6 trillion miles, used for distances outside our solar system.
From smallest to largest, which is the order of these objects: star, galaxy, nebula, black hole?
Black hole, star, nebula, galaxy.
What are the various forms of radiation?
Radio (lowest energy/frequency, longest wavelength)
Visible (red, orange, yellow, green, blue, violet)
Gamma-Ray (highest energy/frequency, shortest wavelength)
What are the 4 radiation laws?
1. All objects, at whatever temperature, emit radiant energy.
2. Hotter objects radiate more total energy per unit area than colder objects do.
3. The hotter the radiating body, the shorter the wavelength of maximum radiation.
4. Objects that are good absorbers of radiation are also good emitters.
How does the Sun compare with other stars in our galaxy?
It is 109x bigger than Earth; it is an average yellow star.
How does the Sun produce energy?
By nuclear fusion. Nuclear fusion is the process in the Sun's core that combines 4 hydrogen atoms and produces 1 helium atom and energy, which powers the Sun. This energy then moves through the lower envelope through radiation, and the upper envelope through convection.
What will eventually happen to our Sun (stellar evolution)?
It will become a red giant, then an orange giant (at this stage it starts to burn helium) and then a red giant once again. At this point the star will explode and form a planetary nebula, sending off it's outer layers. This then reduces to a white dwarf, which then fades and cools to become a non-luminous black dwarf.
What are some properties and characteristics of stars?
Red Giant- large, cool, high luminosity, occupies upper right portion of HR diagram
Supergiant- large, high luminosity
White Dwarf- very dense, small, slowly cooling
What are Keplar's Three Laws?
1. Law of Ellipses- The path of each planet around the Sun, while almost circular is actually an ellipse, with the Sun at one focus.
2. Law of Equal Area- Each planet revolves so that an imaginary line connecting it to the Sun sweeps over equal areas in equal intervals of time. The Law of Equal Area geometrically expresses the variations in orbital speeds of the planets, such that the planet has a higher velocity when orbiting closer to the Sun than further away from the Sun.
3. Harmonics Law- The orbital periods of the planets and their distances to the Sun are proportional, in simplest form. The orbital period is measured in Earth years, and the planet's distance to the Sun is expressed in terms of Earth's mean distance to the Sun. The planet's orbital period (p) squared is equal to its mean solar distance (a) cubed. Solar distances of planets can be calculated when their periods of revolution are known.
What are the names of the points when Earth is closest to and farthest away from the Sun and when do they occur?
Aphelion- the place in orbit where the planet is farthest from the Sun, occurs in our summer
Perihelion- the point in orbit of a planet where it is closest to the Sun, occurs in our winter
What is the Big Bang Theory?
The theory that proposes that the universe originated as a single mass, which subsequently exploded.
What evidence exists to support the Big Bang Theory?
The red shift (Doppler effect) of galaxies (indicates that the universe is still expanding) and cosmic background radiation, which scientists believe was produced by the Big Bang.
What is the difference between the geocentric model and the heliocentric model of the solar system?
The geocentric model puts Earth at the center of the solar system, while the heliocentric model puts the Sun at the center of the solar system.
What are the three types of eclipses?
Solar Eclipse- an eclipse of the sun when the moon moves between the sun and earth and blocks out the disc of the sun, lasts 4 to 7 minutes, penumbra is the lighter part of the shadow, umbra is the darker part of the shadow.
Lunar Eclipse- most often seen, an eclipse of the moon, when the moon moves into the earth's shadow, when totally eclipsed moon at first disappears then shows up coppery red because the sunlight gets filtered through earth's atmosphere
What are the types of tides?
Tide- periodic change in the elevation of the ocean surface
Spring Tides- highest high tide and the lowest low tide; occurs during the full and new moon
Neap Tides- lowest high tide and the highest low tide; occurs during the 1st and 3rd quarter moon
What are the tidal patterns?
Diurnal Tidal Pattern- exhibits one high tide and one low tide during a tidal day; a daily cycle
Semidiurnal Tidal Pattern- exhibits two high tides and two low tides per tidal day with small inequalities between successive high and successive low; a semi-daily cycle
Mixed Tidal Pattern- exhibits two high tides and two low tides per tidal day with a large inequality in high water heights, low water heights, or both. Coastal locations that experience such a tidal pattern may also show alternating periods of diurnal and semidiurnal tidal patterns; also called mixed semidiurnal
What are the phases of the moon in order?
New, waxing crescent, 1st quarter, waxing gibbous, full, waning gibbous, 3rd quarter, waning crescent.
How do seasons in the northern hemisphere compare to seasons in the southern hemisphere?
They are the opposite.
What are the reasons for seasons?
The earth revolves around the sun, the earth is tilted on its axis, parallelism of its axis. NOT caused by the distance between the earth and the sun.
How long does it take for earth to make one complete rotation in space?
2 hours, 56 minutes, 4 seconds (called sidereal day).
What is a mean solar day?
The time interval from one noon to the next noon where noon is when the sun has reached its zenith (highest possible point) in the sky.
What are the basic ingredients of earth's atmosphere and how are they useful?
Nitrogen and oxygen- need oxygen to breathe
Argon and carbon dioxide- helps keep heat in the earth's atmosphere
What are the layers of the atmosphere?
1. Troposphere (Tropopause)- temperature decreases with altitude
2. Stratosphere (Stratopause)- temperature increases with altitude, contains ozone layer
3. Mesosphere (Mesopause)- temperature decreases with altitude, meteors burn up here
4. Thermosphere (slowly fades into background of space)- temperature increases with altitude, contains satellites
What happens to substances when they are heated?
Their molecules begin to move faster and more freely.
Which heats faster: land or water?
Land heats faster than water, and to a higher temperature. Land also cools faster and to a lower temperature than water.
How does sun angle affect temperature?
The more direct the sun is over a surface, the greater the solar energy and the greater the temperature.
How does latitude affect temperature?
The higher the latitude the less direct the sun is over the surface, creating colder temperatures.
How do cloud cover and albedo affect temperature?
It takes away some of the heat that the sun provides, making the temperature less than it could be.
What is the greenhouse effect?
The transmission of short-wave solar radiation by the atmosphere, coupled with the selective absorption of longer-wavelength terrestrial radiation, especially by water vapor and carbon dioxide (which warm the atmosphere because they absorb heat).
How does the greenhouse effect affect temperature?
It keeps heat in the atmosphere, so it increases temperature.
What are the three heat transfer methods?
Conduction- the transfer of heat through a subject
Convection- the transfer of heat by the rising of the hot substance and the sinking of the cool substance
What is air pressure?
The weight of the atmosphere. Also called barometric pressure, measured with a barometer.
How long does it take the earth to revolve around the sun?
365.242 days- rotates west to east/counterclockwise above North pole, rotates east to west/clockwise above South pole
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