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Midterm

Astronomy 1021 Midterm: Mid Term Exam #2 Prep


Department
Astronomy
Course Code
ASTR 1021
Professor
Robert Cockcroft
Study Guide
Midterm

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Tuesday, January 24, 2017
Mid Term Exam #2 Prep
Astronomy
-CHAPTER 6
-Solar System and Telescopes
All three techniques used in study of Solar System:
-Imaging
-Spectroscopy
-Timing
Major focus in last year or so:
-Asteroids, Comets, Kuiper Belt objects, Moon, Mars
-Measuring Distances
Kepler gave us relative (proportion to something else) distances
Transit of Venus gave us absolute distances
-Measuring size:
Telescopes can measure the angular diameter of the planets
With distance and angular size we can know the actual size of planet
-Measuring masses:
Observe moons going around planets
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Tuesday, January 24, 2017
Measure angular distances, orbits and periods
With the mass and radius we can calculate average density
-Telescopes vs Spacecraft
Telescopes:
-Hampered by location (Earth or Earth orbit)
-Cheaper, can be used long-term and upgraded.
-Lots of new objects still to find
-Can study many objects
Spacecraft
-Can get closer to solar system objects
-Bring back samples
-Takes a long time to build, launch, travel
-Expensive
-Orbiter: A spacecraft that goes into orbit around worlds. More time to gather data but
cannot obtain detailed info about the worlds surface.
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Tuesday, January 24, 2017
-Sample Return Mission: Not only land on the surface of another world, but bring back
samples.
Moon (automated and human missions - Apollo 11)
-Combination Spacecraft: Includes more than one of the previous (orbiter and lander
for example)
-Solar System: Consists of the Sun, and tiny bit of other stuff
8 planets
170+ known moons
5+ dwarf planets
Billions of smaller objects including asteroids, comets, Kuiper Belt objects
-1-to-10^10 Scale:
Sun is the size of a large grapefruit (14 cm)
Earth is the size of a ball point, 15 meters away
Almost entirely made of nearly empty space
-Four Features of the Solar System:
1. Patterns of motion:
All planetary orbits are nearly circular and lie nearly in the same plane
Nearly everything moves counterclockwise as viewed from our north pole
2. Two major types of planets: terrestrial and Jovian
SUN:
-Mostly hydrogen and helium
-Contains over 99% of solar systems mass
-5800 K at photosphere (surface)
-Increase depth and increase pressure and temperature
-Converts 4 millions tons of mass into energy per second
MERCURY:
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