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78 Cards in this Set
- Front
- Back
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How is geographic longitude measured |
Measured from the international zero circle of longitude in Greenwich England Brandon= 100°w |
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How is geographic latitude measured |
Measured frin the earth's equator, that I'd defined with a latitude of 0° Brandon= +50° |
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Where is the north star |
Polaris -the eartys rotational axis is always looking north -eartys acid I'd pointing to the bright naked eye star (noth star) |
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What are equatorial coordinates |
Break up the sky into a coordinate system -backgroud stars r fixed to coordinate system -sun, moon and planets move through it |
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What is the right ascension |
24 hour coordinate created by astronomers co-creator because the sky appears to revolve around the earth in 24 hours |
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What is declination |
Coordinate that runs from +90 (towards the north star) to -90 (the extension of the earth's south pole into the sky) |
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How to stars have addresses |
From the right ascension and declination Ex. Deneb (RA= 20h42m) (D= +45°18`) |
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What is the ecliptic |
Imaginary line the plants stay on -defines where the plane of the solar system is |
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What is the earthen degrees of tilt |
23.5 degrees always from the ecliptic |
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Why do we have season |
Because of the earth tilt upwards -causes season of winter in the north hemisphere and summer in the south |
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What is the winter solstice |
December 21 -tilter 23.5 untoward so the north hemisphere sees the sun very low in the sky mid-winter in the north and summer in the south |
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What is the summer solstice |
June 21 -equatir is titled 23.5 downward so the north sees the sun high in their sky for a longer amount of time -summer in north and winter in south |
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What causes the ground to get hot |
Spring to fall equinox (sunlight hits ground directly and more concentrated to an area heating up the ground) Fall to spring equinox (sunlight hits the ground more obliquely and across a bigger area making the ground not as hot) |
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What are equinoxes |
Where the sun crosses the equator -sun raised directly in the west and sets directly in the east Sept 21 March 21 (Only day the sun is located on the equator) |
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Sun's position during the solstice |
Winter (sun appears at its lowest point) Summer( sun appears at its highest point) |
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What is the sidereal period |
Moon returns to the same spot in the sky with respect to the background stars -moon orbits earth every 27.3 days |
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What is synodic period |
Moon takes 29.5 days to return to where the sun appears in our sky |
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What is the moons elliptical |
0.0554 |
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Why do we always see the same side of the moon |
Moons mass is distributed uneven on side bulges and is heavier (this side is locked towards the earth |
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What is spin orbit coupling |
The moons orbital period and rotation period are the same |
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How much is the moons orbit tilted and what does it cause |
5° -onky 1 chance personal month for solar eclipse -full moon is the one chance person Monty for lunar eclipse |
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What causes a solar eclipse |
1) the ecliptic and moons orbit cross (these points are called nodes) 2) the moon is the same apparent size in the sky as the sun (Can only happen when the moon is new) |
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What causes a lunar eclipse |
The ecliptic and the moons orbits cross |
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Why are total solar eclipse becoming extinct |
Because the moon is slowly escaping the earth's gravity and moving farther away making it look smaller than the sun (Moon is 400 times smaller than sun but sun is 400times further away) |
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How is time keeping done |
Done by stars (fixed background) -using right ascension to mark time at some fixed reference frame in the sky - |
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What is this reference called |
Meridian -and imaginary line drawn from directly north to directly south (Bisects the sky into east and west hemispheres) |
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What is sidereal time |
The number of hours since right ascension= 0 has crossed the meridian |
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How far does the sun drift in 24 hours |
1 degree |
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What is universal time coordinated |
The average of 400 atomic clocks in 50 different locations on-time where longitude is 0 degrees |
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Time zones |
15 zone across earth -every 15° of longitude to the west is -1 hour -every 15° east is +1 hour - time switches from PM to am at the international date line |
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What is universal time coordinate also known as |
Greenwich mean time |
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Order of planets |
Only rocket plants r near the sun (Eris) Gas planets are more distant Planets, moons and comets make up less than .2% of solar system mass |
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What is the sun made of |
75% H 25% HE |
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What are the types of planets |
Small and rocket (terrestrial) Large and gaseous (gas giants) |
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Why is Pluto a dwarf planet |
It crosses Neptune's orbit and has a satellite nearly as massive as itself |
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What us the planets order |
Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune (Pluto) |
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What is solar nebula theory |
Suggest that the sun and planet were both born at the same time after condensing out of a primeval cloud the solar nebula |
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The cloud solar nebular would have been made out of what |
Dust and gas (all interstellar clouds are made of ) |
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What started the solar nebula theory |
Kant and laplace -propesed that it formed from a rotating spherical cloud of interstellar gas that collapsed and flattened to form a disk with the sun at the centre |
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What are the 4 steps of Cosmogony |
1) solar nebula contracts 2) as nebula shrinks its motion causes it to flatten 3) nebula is a disk of matter with a concentration near the center 4) formation of the protosun (solid particles condense as the nebula cool,creating planetesimals the building blocks of planets) |
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What is ALMA |
actacma large millimetre array -used to image solor system formation like HL Tau (star 450 light years away in Taurus) |
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What is the SNT |
Is the evidence that stars themselves are born in clouds of gas and dust in much the same way |
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What is the process of star formation |
Part if the recycling chain -lighter elemest are manufactured in stars, released into the interstellar medium as the star dies and are then part of the cloudd that collapse into new starts |
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How is the disk shape formed |
-cloud starts with having a net spin -cloud would collapse under its self gravity -because of centrifugal forces the cloud cant collapse as far along 1 direction (centrifugal forces opposed gravity along this direction) |
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What is net spin |
A preferential direction that the majority of gas atoms were moving |
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What causes disk heating |
-gravitational energy if infalling particles turns into heat energy with the collision with larger particles -large particles grow by collision and own self gravity |
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How are planets formed |
-disk collapsed causing intercloud collisions (like a pool table balls eventually come to rest) -Planetesimals would cool and condense out if rings of material orbiting the center |
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How star is formed |
Dinner is hotter Outer is cooler -inner contuiniee to heat and excrete matter growing hot enough to start nuclear fusion and form a star |
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What is our sun |
-has a disk span of .5° -made if hydrogen, helium and metals -surphace is photosphere (sphere of light) - not solid -darker on the edge or limb |
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What are the 3 layers of the sub |
1) photoshere (densest and coolest layer; 300-400km thick) 6000° 2) chromosphere (hotter but less dense; 2 thousand km above) 20,000° 3) Corona (very thin, sphere of colour, very hot) |
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Photosphere |
Layer with the most visible light -granulated appearance (individual convection cells, steam bubbles)
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What caused the darkening of the limb or edge |
1) we can only see a certain depth into the photosphere 2) the upper layers of the photoshere are cooler than the lower |
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Chromosphere |
Red/pink colour comes from the hydrogen alpha, light -we see spectral lines from elements like hydrogen -best viewed in Ha light -rough and made of spicules giving it its grassy field |
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What are spicules |
Brushlije sharp jets of cool gas that rise up into warmer regions of the sun's outer atmosphere -hight of 7000km wise - 700km wise -rise at 20km/s -rise at 20km/s |
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What are prominences |
Giant eruptions of gas climbing well above the suns surface and raining back down |
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Corona (crown) |
2 million Kelvin -total heat energy is low -to fajnt to be seen except during solar eclipses -emite x Ray's -shiws streamers that trace the magnetic field lines of the sun |
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What are CME |
Coronal mass ejections -giabt blobs of very hot gas that are expelled from the sun at high speeds into interplanetary space -happen once per day -cause stress to eartys magnetic field |
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What are sunspots |
Visible features on the sun's surface that radiate less light than their surroundings -keep cool gas from falling and hot gas from rising |
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Sunspot cycle |
-Galileo (25 days) Appear with 11 year cycle -at start sunspots appear at high latitudes -further in sunspots appear more near the equator |
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Suns rotation |
Rotated once every 36 days at the poles Rotates 11days fast at equator (Winds itself up) |
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How far is the sum |
150,000,000 km from earth (1.5km) 1,392,000 km in diameter |
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How sun creates energy |
Only hot by the core so it creates evergy through convection and radiation -creates energy buy smashing 4 hydrogen atoms to make helium |
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How is the pp chain happen from the process of hydrogen to helium |
1) 2 hydrogen nuclei are squeezed close together, making heavy hydrogen atom called deuterium to form 2) then fused together with another to create light helium nucleus 3) 2 He nuclei fuse together to make neutral helium and 2 unisdd hydrogen are returned to gas |
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What are the 3 kinds of neutrino |
Electron Muon Tauon neutrino |
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What are the 4 ways that planetary body's surface |
Impacts Volcanism Erosion Plate tectonics |
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Impacts |
Material falling from space leave craters -all terrestrial planets have an impact era -# if crates indicates age the-most cratering happens in first billion years of solor system |
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Tectonism and erosion |
Tent to erase craters |
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What are central peaks |
Mountains of material that sprang straight up rapidly and settles after the compression if the initial strike (In creaters) |
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Volcanism |
Movement of tectonic plates generates a lot of thermal energy friction |
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What are the 4 theories that describe where thr moon came from |
Capture Fission Co creation Giant impact or collisional ejection |
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Capture |
Moon was formed far from earth and later captured by earth's gravity |
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Fission |
Moon was separated from material that the early earth was forming from |
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Co creation |
Formed near and simultaneously to earth from material with similar abundances of elements |
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Giant impact |
Mars sized plant hiting earth at a glance and ejecting matter that would form into moon |
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What is mercury spin to orbit relation |
3:2 -every 2 revolutions around the sun(88days) goes through 3 full rotations (Caused by dtond gravitational tides from sun |
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What is the sidereal rational period of mercury |
59days |
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What us mercury's surface density |
5.5 grams per cubic centimeter |
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What is the terminator |
The day to night deviding line |
