Download Cosmology:

KEY
Earth & Environmental Systems Science
Unit II: The Exosphere – Study Guide for Test 1
TEST ON Monday 10/7/2013
Cosmology:
1. What is cosmology?
the study of how our universe formed, how big it is, the shape, how it has changed over time, and its
future.
2. What are theories and how are they different than laws?
Theories describe a complex set of events and are true and revisable as technology develops.
Laws explain simple universal happenings like gravity.
3. True or False: The best way to describe the universe or unknown is to observe what happens on
Earth and apply that knowledge elsewhere.
4. The Universe formed from the Big Bang, and occurred 13.7 years ago in an explosion.
5. True or False: The Big Bang is a series of events that led to the direct formation of our solar
system.
6. What is the name given to the left-over energy from the Big Bang?
Cosmic Background Radiation (form of long microwaves)
7. True or False: Proof that the Universe is constantly expanding can be observed by galaxies moving
further apart.
8. Name the theory that describes the formation of our solar system.
Nebular Theory
9. What force of attraction draws the matter in an interstellar cloud (nebula) together to form a star?
Gravity
10. What were the first two elements in our universe? Think simple.
Hydrogen (H) and Helium (He)
11. How did we get an element rich universe?
Over 9 billion years, many generations of stars lived and died. During their death, there is enough
heat and pressure to form elements heavier than Iron.
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KEY
Earth & Environmental Systems Science
Unit II: The Exosphere – Study Guide for Test 1
TEST ON Monday 10/7/2013
12. After the Big Bang, describe what occurred to create our Solar System?
Over 9 billion years, many generations of stars lived and died. During their death, there is enough
heat and pressure to form elements heavier than Iron.
The element rich area in our galaxy created an environment ready to support a solar system.
Matter rotated and collected at center due to gravity.
Most matter formed the sun and fusion started while other matter collected into orbits.
Orbiting matter collected to form 20 Planetesimals. Planetesimals collected to form Planets.
a. How long after the big bang was it?
9 Billion Years
b. How old is the solar system?
4.5-4.7 Billion Years
c. What are planetismals?
Baby planets that collided and collected to form the larger 8 planets.
13. How does the sun produce energy?
Nuclear Fusion
H + H  He + Energy
14. Name two differences between the terrestrial and gaseous planets?
Terrestrial are made of dense rock materials while gaseous planets a made of gas and are not very
dense. Terrestrial planets are closer to the sun.
15. Where is the asteroid belt located?
Between Mars and Jupiter or splits the gaseous from the terrestrial.
16. What was the iron catastrophe?
Early Earth was made of liquid before it cooled, and liquids easily separated by density to create the
layers of the Earth. The most dense matter is located towards the center of the Earth.
17. What are the four layers of Earth and how are they sorted?
Crust(Lithosphere) – solid Least Dense
Mantle (Asthenosphere)- liquid
Outer Core – liquid
Inner Core – solid Most Dense
18. During the solar stew lab you compared the densities of items to the density of the planets, how
does this apply to our solar system?
The nebula was much like a stew in that the matter was not yet sorted and a mixture. Gravity sorted
this mixture by density. The closest matter is the most dense due to the greater gravitational
attraction.
19. Describe baby Earth. How did we develop oceans? The atmosphere?
Baby Earth was liquid and cooled to form a crust looking like it was covered in volcanoes.
Oceans – water vapor condensed from volcanic gases and brought by ice comets.
Atmosphere – Very poisonous gasses were released by volcanoes. These gases were changed into
oxygen by stromatolites.
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KEY
Earth & Environmental Systems Science
Unit II: The Exosphere – Study Guide for Test 1
TEST ON Monday 10/7/2013
20. What are stromatilites and what role did they play in the development of modern Earth?
Ancient photosynthetic bacteria that turned poisonous gasses into oxygen using photosynthesis.
Orbital Motion:
1. Compare the Geocentric Model to the Heliocentric System. What evidence was used to prove one
of them wrong?
Geocentric – Earth centered
Heliocentric – Sun centered
Geocentric was based on apparent motion. Moons of Jupiter were viewed through a telescope and
proved not everything revolved around Earth.
2. What force attracts all objects to each other?
Gravity
3. Day and night is cause by the Earth’s rotation.
- How long does this take?
23 hours and 56 minutes.
4. What is an orbit?
The path a planet follows around the sun due to gravity (mass and distance) and inertia.
- One complete orbit around the Sun is a planet’s revolution.
- How long does Earth take?
365 days or 1 year
5. To prove that the seasons are not caused by Earth’s elliptical orbit explain what time of year the
Earth is at its closest distance to the sun and what term we use to describe that point in its orbit.
Earth is closest to the sun (perihelion) in January/Winter
6. True or False: the sun produces less energy in the winter and more energy in the summer.
7. What causes the seasons?
Major Axis
The tilt of the Earth Axis – more
to come later.
8. Use the diagram to the right to
label the different parts of an
ellipse:
Perihelion
Aphelion
Focus
Orbit
9. Is Earth’s orbit severely elliptical, elliptical, slightly elliptical, or circular?
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KEY
Earth & Environmental Systems Science
Unit II: The Exosphere – Study Guide for Test 1
TEST ON Monday 10/7/2013
10. How is an ellipse different than a circle?
An ellipse has 2 foci; a circle has 1 focus.
An ellipse has an eccentricity greater than 0 but less than 1; a circle has an eccentricity of 0.
11. Describe Kepler’s 3 Laws of Orbital Motion?
-1st Law – A Planets travel in elliptical (oval) orbits around the sun.
- 2nd Law – Planets sweep out equal areas in equal time as they orbit the sun by changing their
velocity due to a change in the distance from the sun (gravitational attraction).
- 3rd Law – The further a planet is from the sun, the longer the period of revolution (lap time)
12. True or False: A planet moves slowest in an orbit when it is closest to the sun.
13. Using the equation stated in Kepler’s third law of orbital motion, T2=R3 , calculate the orbital
period of the planet Neptune in Earth years given that it has an mean distance (R) from the Sun of
30.06 AUs.
T2=(30.06)3
T2=27162.32
SquareRoot(T2) =SquareRoot(27162.32)
T=164.8 Earth Years
Some Possible Essays to Think About:
1. On WMAP, explain how warmer and cooler areas of the Big Bang’s energy can be used to explain the current
structure of the matter (galaxies and empty space) in the Universe.
2. What is the theory scientists use to explain the formation of our solar system?
3. From the Solar Stew lab, how do the densities of the inner planets compare to the densities of the outer
planets?
4. In Kepler’s 2nd Law, it states within an orbit, a planet will sweep out equal areas in equal time. If the areas are
labeled Area X and Area Y, give 2 similarities and 2 differences for the orbit at these locations.
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