Astronomy final notes
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- What is planetary elongation?
- to view a planet, it must be above the horizon while the sun is below the horizon
- what is elongation?
- angle subtended b/w sun & planet as seen from Earth. 0 degrees has planet in same direction and 180 degress is opposite in sky
- what happens if the elongation angle is small?
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-there is a small amount of time to observe a planet (after sunset, before sunrise)
-when viewed near horizon, it suffers a lot of atmosphere distortion - what happens if the elongation angle is large?
- there is a longer viewing time and is seen higher in the sky b/c of less atmospher distortion
- what are superior planets?
- Mars through pluto
- What are inferior planets?
- Mercury and Venus
- what is the opposition of superior planets?
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has elongation angle of 180 degrees
has longest viewing time-all night
this is cloest position to earth and is largest and brightest - what is the conjunction of superior planet?
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has elongation angle of 0 degrees
furthest position from Earth
planet is behind sun and you cannot see it - What angles are possible for superior planets?
- all elongation angles are possible
- what is the conjunction of inferior planets?
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when elongation is 0 degress
is closest to Earth
looking directly into the sun
and view the night side of the planet - what is the viewing time of Mercury & venus?
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always have a small elongation angle
there is a short viewing time - what is the effect of a long rotation period on Mercury?
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day is a day for a very long time - very hot (700)
night is night for a long time - very cold (-300) - What is the consequence of Mercury with no atmosphere?
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no protection from UV & X rays from sun
No greenhouse effect
no burnup of meters that will hit Mercury - What is the suface analysis of Mercury?
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NO VOLCANOES
lots of craters areas- old surface
inter crater plains -young surface and repaving process - What is the repaving process on Mercury?
- impacts crack surface and lave oozed through cracks and repave the surface
- What is Caloris Basin?
- huge asteroid impact that is 1300 KM in size
- What is unique about Venus?
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rotates backwards
1 day is 243 earth days
no moons
day temp=night temp - what is unique about the atmosphere of Venus?
- completely covered in thick clouds of CO2, very thick atmosphere 90x earth
- what is the consequence of a thick atmosphere?
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greenhouse effect that enables the night temp and day temp to be equal at about 900 degrees
very few craters that are burned up - Does Venus have volcanoes?
- lots of dormant volcanoes that have repaved the surface volcanoes also increase the greenhouse effect
- What planet experiences seasons?
- Mars
- What is the temp of Mars?
- day usually below 32 degress and night is nearly -200 degress
- What is the consequence of Mars' thin atmosphere?
- lots of craters - old surface
- What is the evidence of past h2o on Mars?
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dry river beds
dry tributaries
tear drop islands
rounded boulders & pebbles from errosion - what does the evidence of h2o on mars prove?
- the planet must have been warmer in the past and had a much thicker atmosphere
- What are the common themes for terrestrial planets?
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rockey surface/interior
dense composition
very little atmosphere
-atm. represents a tiny amount of total planet's mass - what are the common themes for jovian planets?
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very large rock ice core
develop huge atmospheres of gas
atm. is huge amount of planet's total mass - What are the atm. features of Jupiter?
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zones- latitudes which are bright where warm gas rises
belts- darker latitudes where cool gas falls - convection - What is differential rotation on Jupiter?
- each latitude has winds moving at diff. speeds/directions
- What is the Great Red Spot on jupiter?
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huge hurricane
lasted for centuries
3 earth diameters - What are the atm. features of Saturn?
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very windy
has zones/belts too
very hot south pole -mystery? - What are the atm. features of Uranus?
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featureless
tipped on its side - collision?
blue color - methane gas - What are the atm. features of Neptune?
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blue color - methane gas
fast wind speeds
has methane ice cirrus clouds
great dark spot - tornado that is 1 earth diameter - What are the Galilean moons of Jupiter?
- Io, Europa, Ganymede, Callisto
- Give some facts about Io?
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size of earth moon
most volcanic moon- lead to new surface and few craters
heating from jupiter causes hot interior on Io - Give some facts about Europa?
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size of earth moon
very reflective moon b/c it is icy
heavily cracked with few craters - What is so unique about Europa?
- liquid h20 may flow through cracks, freeze and repave
- What may the tidal heating cause on Europa?
- Warm interior with liquid oceans of water which may indicate life
- Give some facts about Ganymede?
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largest moon in SS
bigger than mercury
very old surface with many craters - Give some facts about Callisto?
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3rd largest moon in SS
most cratered object in SS - Name 6 Saturn Moons of interest?
- Mimas, Phoebe, Hyperion, Iapetus, Enceladus, Titan
- Give some facts about mimas?
- has huge impact crater
- Give some facts about Phoebe?
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heavily cratered
comet like
captured object from SS - Give some facts about Hyperion?
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irregular shape & small
fragment of larger moon
sponge-like crater appearance
cavernous interior-low density moon - Give some facts about Iapetus?
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2 toned moon
1 hempisphere bright and other is dark - Give some facts about Enceladus?
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extremely bright and reflective
old surfaces and new
has huge faults - tiger stripes - Give some facts about Titan?
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2 nd largest moon
larger than mercury
thick atmosphere - What does studies of Titan resemble?
- may be similar to atm. of earth before life
- What are the rings of Saturn?
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Very reflective - icy composition
made of small particles of rock and ice
thousands of rings
very few large gaps b/w rings - What about the rings of Jupiter?
- there are very thin rings
- What about the rings of Uranus/Neptune?
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very large gaps
rings are very thin
much darker and less reflective
very few rings made up of larger ice particles - What is unique about Pluto?
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spins backwards
tilt at 120 degrees
spins slowly
highly inclined orbit to ecliptic plane
very eccentric orbit - Where is PLuto at its perihelion?
- b/c of such an eccentric orbit, pluto becomes 8th planet and passes neptune for 20 year period
- What are the arguments for pluto being a planet?
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it has history for being a planet?
it is spherical (asteriod ceres is also spherical)
has 3 moons - what are the arguments against pluto being a planet?
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its uniqueness from other planets
it de-emphasizes the meaning of a planet
at least 3 other pluo sized objects were found in Kuiper Belt - discuss triton moon of neptune
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coldest moon recorded
active geysers and volcanoes of ice - discuss phobos of Mars
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7 mile crater caused by great shockwave
humans may be able to go to phobos to study mars - discuss the earth moon
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oldest rocks found 4.5 billion ys.
moon may have derived from hitting earth & formed moon
may have previously been filled with hot volcanic surface