ISP205 Spring 2001 Exam #2 Study Guide:
guide is intended to highlight the important material you should know for the
second exam. It is intended that everything on the exam is covered in this
6 – Solar System
- What are the properties of our solar system?
- Planets lie in the same plane
- Orbits around the Sun are counterclockwise
- Most spins are counterclockwise (Venus is
clockwise, Uranus is sideways)
- Inner planets are more dense, 5 g/cm2
(rock and iron) than the outer planets 1 g/cm2.
- The Sun has only 2% of the angular momentum of
the solar system.
- Be able to recognize orbits of the planets,
comets, etc. (The CAPA problem)
- Know the names and order of the planets.
- The solar system is about 4.5 billion years
- Dating Methods for things in our solar system
- Counting Craters
number of craters per unit area can be used to date a surface.
in the history of the solar system, meteor bombardment was very intese
4 billion years ago the intense bombardment stopped
very heavily cratered surface means it is older than around 4 billion years.
- Radioactive Rocks
is the time for half of the atoms in a sample to decay.
Atom B decays to atom C with a certain half-life. If we start with a ratio of
A:B as 10:1 what is the ratio after 2 half-lives? Answer 40:1 .
ratio of one type of atom to another can be used to date objects.
Comets form without argon. However they do contain potassium-40. Potassium-40
decays to argon with a half-life of 1.3 billion years. How old is the comet is
the ratio of potassium-40 to Argon is 1 to 7 (1:7)? Answer: 3 half-lives or 3.9
7 - Earth
- How do we use seismic studies to learn about the
interior of the Earth?
- What is escape velocity?
- Depends on mass and radius of a planet; more
mass higher EV; larger radius, smaller EV.
- The temperature of a gas is related to the
average kinetic energy of gas molecules. Planets with low temperature
are better able to keep their atmosphere.
- What are tides? How often do they occur? What
causes them? Have they affected the rotation of the Moon?
- Atmosphere of the Earth is mostly nitrogen and
oxygen from the process of life and death.
- Know what the greenhouse effect is. What gasses
cause the greenhouse effect? (CO2 – carbon dioxide, water
- Earth has a modest greenhouse effect that raises
the average temperature by more than 20 centigrade.
- How are the Earth's magnetic fields are
generated. Know what is needed for a dynamo effect (liquid core and rapid
- Know the theories for the formation of the Moon
and the arguments for and against each theory.
- Density = mass/volume (1.0 g/cm3
Water) (3.3 g/cm3 rock) (5.5 g/cm3 rocky planet
with iron core). How do we determine the density of a planet? Orbital
period of a moon gives the mass and diameter gives the volume.
- The Earth has a young surface (200 million years
old) due to plate tectonics and volcanic activity.
8 - Moon and Mercury
- due to tides it always keeps the same face
toward the Earth
- has highlands (older heavily cratered) and
maria (younger, smoother, less heavily cratered)
- water has been found in craters near the poles
- overall density around 3.3 g/cm3
implies it is mostly rock.
- We think the Moon was formed in a giant
collision between the Earth and another Planet early in the history of
the solar system. This is called the giant impact or collision theory.
- surface similar to the highlands on the Moon
- most heavily cratered planet
- wide variation in surface temperature due to
the lack of an atmosphere
- Why are craters circular? Impact causes the
meteor to explode, making a circular impression.
9 – Venus and Mars
- Venus, very hot, volcanic activity, massive
greenhouse effect from a thick carbon dioxide atmosphere, sulfuric acid
clouds; Earth, life, ozone layer, a moderate greenhouse effect
- Mars, ancient volcanoes (volcanic activity
stopped about 3 billion years ago); CO2 atmosphere, very low
pressure; Olympus Mons + Valley of the Mariners; has a polar ice cap;
shows lots of evidence for large amounts of water on its surface at one
time; evidence from meteorites hints at early life on Mars.
- Nature of atmospheres:
- Mercury - low gravity + near the Sun means no
- Venus - no liquid water means high CO2
levels (greenhouse effect)
- Earth - liquid water mean CO2
absorbed; life leads to nitrogen and oxygen; just the right greenhouse
- Mars – major volcanic activity stopped early
due to Mars’s small size; low CO2 means no greenhouse effect
and water remains frozen
10 – Gas Giant Planets
- Know roughly the characteristics of the Jovian
- Jupiter - great red spot (a big hurricane),
mostly hydrogen and helium
- Saturn - density less than water (it would
float if we had a big bathtub, mostly hydrogen and helium, the upper
atmosphere is depleted in helium
- Uranus - tipped on its side (most extreme
- Neptune – had the Great dark spot ( a big storm
like the great red spot on Jupiter)
- Know the structures shown in figure 10.7
- Know what excess energy is and which planets
have it. Where does the excess energy come from? Jupiter – left over,
Saturn – falling helium, Neptune – probably falling heavier gasses
- Know which planets have magnetic fields.
11 – Rings, Moons and Pluto
- Know the features of Jupiter’s Galilean
satellites and the explanation for these features.
- Io – giant spherical pizza
- Europa – ice crust, water ocean underneath,
chance of life
- Ganymede – largest moon (bigger than Mercury
and almost the size of Mars), differentiated
- Callisto – very heavily cratered
- Know about Saturn’s moon Titan – atmosphere 60%
greater than Earth’s, hydrocarbons in atmosphere and on the surface
- Know about Triton, a moon of Neptune – has
- Is like Triton, the frozen moon of Neptune
- It is possible Pluto and Triton were both moons
of Neptune and an interaction through Pluto out and Triton ended up
- Pluto has a moon Charon
- Jupiter - close to the cloud tops, made from
volcanic activity and debris chipped of the inner moons.
- Saturn -many (complicated) rings made up of chunks
of ice, spokes, braided rings
- Uranus - many thin widely spaced rings
- Neptune - material of varying composition. Has
bright sections that look like arcs.
12 – Comets and Asteroids
- Know the parts of a comet
- Know what the Oort and Kuiper comet clouds are.
- Comet details
- Very elliptical orbits
- Appear to come from all directions on the
- Short-period comets (100 years) come from the
Kuiper belt. Halleys (76 year period) comet is an example.
- Long-period comets come from the Oort Cloud
- Asteroids (Minor Planets)
- Characteristics (3 main types, made of carbon, metals, rock)
- Know orbits (most are found in the asteroid
belt and have nearly circular orbits)
- Know where the Trojan asteroids are located.
13 – Meteors and the Origin of the Solar system
- Know some of the
details of the nebular hypothesis for the formation of the solar system
- Large cloud
collapses, angular momentum keeps all the material from falling into the
- Potential energy is
converted to kinetic energy and the inner part of the solar system is
- The Sun has only 2%
of the angular momentum of the solar system. This is a problem for the
- The inner planets
formed in a hotter environment and thus are made of metals. Outer
planets have gas because they were cooler.
- Meteors, meteor shows and meteorites
- What causes a meteor shower?
- Meteor is a comet that enters the Earth’s
atmosphere. Meteorite is the object found on the Earth.
- A meteorite from Mars shows evidence for
- Chpt. 14 – Our Sun
- Know the basics of the structure of our Sun and
what goes on in the various parts (see figure 14.1)
- photosphere - bright visible surface where
absorption lines form; shows granulation
- chromosphere - cooler pinkish region beyond the
photosphere (can be seen during an eclipse)
- corona – hot, thin outermost region of the Sun
- solar wind – stream of fast particles leaving
- know about prominences and flares (flares are
tremendous explosions with the power of a million hydrogen bombs)
- what is the Sun spot cycle in years? 11 years
between maximums, 22 years total
- What causes the Sunspots? Twisting of the Sun's
- Low sunspot activity around 1300 appears
correlated with a mini ice age.
- The Sun appears to be variable in its output.