astronomy 2 notes Essay

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Astronomy exam 2 notes

1) Mirror: incoming parallel rays reflect from mirror and come to a focus at the focal point.
a.i) What would happen if the mirror had a smaller radius of curvature
(a.i.1) It would bring it closer to the mirror
b) Lenses
b.i) Real images are on the opposite side of the lens from the object
(b.i.1) Always up side down
b.ii) Virtual images are on the same side of the lens as the object
(b.ii.1) Always right side up
b.iii) For mirrors it is the opposite
c) Newtonian telescopes
c.i) Easy to make
d) Cassegrain telescope
d.i) Mirror in middle, not on side
e) Properties
(e.i.1) Light gathering power
(e.i.1.a) How big of a light bucket do you have?
(e.i.1.b) Goes as area of collector
(e.i.2) How does the LGP of the blue mountain 16’’ telescope compare to the LGP of 8’’
(e.i.2.a) 4 times more*
e.ii) How does the LGP of the blue mountain 16’’ telescope compare to the LGP of a normal dark adapted eye (7mm=.28 inch)?
(e.ii.1) About 3000 times more*
e.iii) Magnification
e.iv) Size of image/size of object = F objective/F eyepiece
2) Next day in note book
3) Oct 23
a) The acceleration due to gravity on the surface of a planet can be determined if you know
a.i) A planet’s mass and diameter
b) Easier to build mountain on low surface gravity then high surface gravity
c) Height of mountains depends on
c.i) Strength of materials (forces holding rocks together)
c.ii) Strength of gravity (force pulling rocks down)
4) Escape velocity: Vescape = sq root of (2GM/radius)
5) Orbital velocity: easy way v = d/t = 2pi Rorbit/P
6) Axial Tilt
a) Determine by observing rotation of planetary features ( visually or from spectrum)
7) Eccentricity of orbit
a) Can observe how earth-planet distance changes during orbit of the planet
8) Rotation rate
a) Planets with slower rotation have less weather, less erosion, and a weak magnetic field
b) Faster rotation have more weather, more erosion, and a stronger magnetic field
9) For these questions, assume that the planets described
a) Orbit about a sun like star
10) Which of these planets are likely to have a substantial atmosphere?
a) Only wash
11) Which of these planets probably have a heavily cratered surface?
a) Only wash
12) Which planets are most likely to have had relatively recent volcanism and or tectonic activity
a) Zoe, inara, and bok
13) Which planets are likely to experience pronounced seasonal differences
a) Axial tilt and orbital eccentricity wash zoe inara and bok
14) Which planets may show evidence of a large impact early in their history
a) Axial tilt large, inara bok and jayne

1. Heavy bombardment
a. Leftover planetesimals bombarded other objects in the late stages of solar system formation
2. Differentiation
a. As gravitational encounters and impacts build the inner planets, the temp of the planets increases
a.i. Moons formed by collision
a.i.1. Mars size body collides with the earth
a.i.2. Vaporizes the impactor and part of the already differentiated earth
a.i.3. Volatile components are lost
a.i.4. Tilts the earths rotation axis
a.i.5. Forms a ring system around the earth
a.i.6. Refractory elements from earth’s crust and mantle accrete to form the moon
b. Captured moons
b.i. Unusual moons of some planets may be captured planetesimals
3. Odd rotation
a. Giant impacts might also explain the range in axial tilts
4. Origin of earth’s water
a. Much of earth’s water was outgassed from its interior
b. Water may also have been imported via icy planetesimals
5. Kuiper belt objects
a. Beyond the orbit of Neptune, out to about 50 AU
a.i. Tens of thousands of these
a.ii. Probably formed closer to sun
a.iii. Pushed out by the outward migration of Neptune
b. Oort cloud
b.i. 3-50-100000 AU
6. Planetary Migration
a. Jupiter was probably the first gas giant to form
b. Saturn formed next
c. Uranus and Neptune last
d. Uranus and Neptune must have formed