ASTR MIDTERM 1

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  • Created by: Angel9119
  • Created on: 03-03-19 21:16
How do the Earth's rotation and revolution around the Sun affect what we see in the night sky?
Where you stand and what season it is affects what we see. Only one half of the celestial sphere (imaginary globe with the positions of celestial objects) is available to us at one time.
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What is the zenith and meridian?
The zenith is the point of the celestial spehere directly above your head, the meridian is the imaginary line that runs from the south, through the zenith to the north.
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What is a sidereal and solar day?
A sidereal day is the time Earth takes to rotate on its axis (23 hours 56 mins). The solar day is the time between successive crossings of the same celestial meridian by the sun. (24 hours)
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Describe the sky during the seasons:
In summer the Sun is higher on the sky, the summer solstice is the day with the most hours of sunlight. The Winter solstice is the day with the least hours. The autumn and spring equinoxes have an equal amount of daylight and darkness.
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Why do the seasons work this way?
In Summer the Earth's axis (on its elliptical orbit) is tilted toward the Sun and in Winter the Earth is tilted away from the Sun. Earth's tilt explains the changing length of days.
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Describe the yearly motions of the stars (constellations):
The view of the celestial sphere determines which stars are visible, as the Earth moves throughout the year the portion of the sky we see changes.
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What are the monthly phases of the moon?
A new moon = moon is closest to the Sun and all in shadow. Waxing crescent phase = Eastward moon occuring during the 1st quarter moon. 1st Quarter moon = moon highest at sunset. Waxing gibbous phase = full moon. Full moon = highest at midnight.
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Continue the second half of the monthly phases of the moon, after the completion by the full moon:
Waning gibbous phase = 3rd quarter moon. 3rd quarter moon. Waning crescent.
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Why do the moon's phases occur?
This is a direct result of the moon's position between the Sun and biewers on Earth, the moon only shines due to sunlight. We only see the illuminated sections of the moon.
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What is a total lunar eclipse?
When the Moon passes through the centre of Earth's shadow, sun, Moon and Earth align. Can only happen during a full moon
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What is a partial lunar eclipse?
When the moon partially passes through the penumbra or umbra.
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What is a solar eclipse?
The Moon blocks all or some of the Sun, only happens during a New Moon.
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Describe Kepler's Laws:
1. All planets move around the Sun is elliptical orbits. 2. Planetary motion, planets speed up as they near the point closest to the Sun and slow down as they near the point farthest from the Sun. 3. A planet's period squared equals its average cubed
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Describe Newton's Laws:
1. The internal law. 2.The force law. 3. The reaction law. (and gravity duh)
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What were the 6 contributions Galileo had to astronomy?
1.Mountains on the Moon. 2. Phases of Venus. 3.Moons of Jupiter. 4.Sunspots. 5.The milky way. 6.New Physics
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What are the basic properties of light?
Wavelength, frequency, amplitude and speed. Light from the Sun is white light due to composition of electromagnetic waves. Refraction.
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What is the electromagnetic spectrum? (largest to smallest)
Radio waves, microwaves, infrared waves, ultraviolet light, X-Rays, gamma rays
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What are the types of atomic spectra and how are they produced?
1. Continuous spectrum, from an opaque body 2.Emission lines, from hotter rarefied gas. 3. Continous spectrum with dark lines (ABSORPTION LINES) from colder rarefied gas.
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What is blackbody radiation (Kirchoff's Law)/Wien's Law?
Kirchoff's law on continous spectra stated that matter can produce a continous spectrum, link between heat and light leading to blackbody radiation. Wien's Law states that stars are blackbodies.
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What determines an object's luminosity? What determines an object's brightness?
(Standard candle, astronomical light source). Brightness determines distance and luminosity is the light energy from a star.
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What are Doppler shifts?
The change in frequency and wavelength of waves brought about by an object's motion.
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What kind of objects are found in our solar system?
Terrestrial planets, gas giants, ice giants, dwarf planets, aestroids (debris rock and metal, belt), comets (debris from formation of our solar system), meteoroids (smallest class of debris, become meteors when captured by Earth's gravity)
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What is required for an object to be considered a planet?
Independently orbits the Sun. It must have enough mass that its own gravity pulls it into a roughly spheroidal shape. It must be large enough to dominate its orbit.
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What is the condensation theory?
Condensation theory states that a solar system forms from a spinning, collapsing interstellar cloud of gas and dust.
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What is core accretion?
The core accretion model isa model of giant gas planet formation in which an icy terrestrial planet grows by accretion up to a critical point and then rapidly pulls gas in from the surrounding disk.
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What is the hydrodynamic instability model?
A model of giant gas planet formation in which small regions collapse to form planets within a gravitationally unstable disk.
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What is the radial velocity method and transit method? (finding exoplanets)
The radial velocity method is where astronomers watch the star move back and forth for a full orbit, by measuring the shift you get the mass of the planet. The transit method is where they look for a small decrease in starlight as the planet passes.
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What are Hot jupiters?
A hot jupiter is a plenty size of jupiter that orbits very close to its star.
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What is the habitable zone? (super-earths)
The region around a star where liquid water can exist on the surface of a planet
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What are the major processes that occur on the terrestrial planets?
1. differentiation, 2. cooling, 3. cratering, 4. magma flooding, 5. weathering.
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What are primary atmospheres and secondary atmospheres? Why did terrestrial planets lose their primary atmospheres?
A primary atmosphere forms by accretion of gaseous matter from the sun. A secondary atmosphere forms from volcanic activity, or by accumulation of material from comet impacts. The terrestrial planets lost their primaries due to low gravity
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Describe the greenhouse effect on terrestrial planets:
Greenhouse effects are where much of the Sun's solar energy makes it to the surfact, greenhouse gases trap heat and warm the atmosphere, causing climate change. A planet is a blackbody absorbing and re radiating energy from the Sun.
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Describe tides, craters and the formation of the Moon:
Moon causes two tidal bulges on earth, Earth's gravity has tidally locked the Moon, aestroids and meteoroids have impacted the Moon creating craters. There are 3 theories on the creation of the Moon (Capture, Fission and Impact)
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What are the properties of giant planets?
Large, Sun does not provide energy, cold, lack surfaces, beyond the snow line, gaseous make up, fast rotation, deep atmospheres, ring systems maintained and supplied by their moons.
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What things affect the location of the habitable zone?
Liquid water, atmosphere, luminosity of a star, stars magnetic field,
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What is the Drake equation?
Probabilities that estimate the number of intelligent civilizations in our galaxy. POSS 1, only life on Earth. 2, hundreds to thousands. 3, many thousands.
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What is the fermi paradox?
If there are extraterrestrial civilizations capable of interstellar travel, why aren't they already here.
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Other cards in this set

Card 2

Front

What is the zenith and meridian?

Back

The zenith is the point of the celestial spehere directly above your head, the meridian is the imaginary line that runs from the south, through the zenith to the north.

Card 3

Front

What is a sidereal and solar day?

Back

Preview of the front of card 3

Card 4

Front

Describe the sky during the seasons:

Back

Preview of the front of card 4

Card 5

Front

Why do the seasons work this way?

Back

Preview of the front of card 5
View more cards

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