Exam 1 Flashcards
Which is the correct sequence of planets, based on increasing average radius of their orbits?
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto
The inner planets ______________________.
Have the same composition as the outer planets
Same size as the outer planets
Have an orbiting system of rings
Have several moons
Which statement is true for the outer planets of our solar system?
They are largely made of hydrogen and helium.
Water ice is __________________________.
most abundant on the moons
What sets the composition of the moons of the outer planets apart from the inner planets?
The moons of the outer planets generally have lower densities.
Which objects have orbits that take them the farthest from the Sun in our solar system?
Comets
Some comets have orbital periods of hundreds of thousands of years. The group of comets that occupies the outermost limits of the solar system is called the Oort cloud.
Which of the following objects is most like Earth in size and composition?
A. Mercury
B. Ida
C. Mars
D. Venus
Venus
What is a major difference between planets and stars?
A. Planets are much smaller in diameter than the stars around which they revolve.
B. Planets do not generate energy through nuclear fusion.
Planets have rings and systems of orbiting moons and some planets (the outer planets) lack solid surfaces.
What are the major differences between a moon and a planet?
A.Planets revolve around the Sun.
B. Moons revolve around a Sun-orbiting planet.
A few moons are actually bigger than Pluto and Mercury. By definition, moons (natural satellites) don’t orbit the Sun but instead revolve around another planetary body. Some asteroids even have moons.
Which of the following are the characteristics of the asteroid belt?
B. The asteroids mark the transition from the rocky terrestrial planets to the outer planets.
C. Some asteroids appear to be rocky; some seem covered with lava; others seem to be metallic; and yet others may have water ice.
D. Many meteorites that fall on Earth come from the asteroid belt.
According to our best modern day evidence, how long ago was the Big Bang?
About 14 billion years ago.
the most basic subatomic particles include which of the following? (Select all that apply.)
A. Protons B. Neutrons C. Isotopes D. Ions E. Electrons
A, B & E
How are elements heavier than iron produced?
During a supernova explosion
What is the principal method of light element (up to iron, atomic number 26) production?
nuclear fusion
The T-Tauri phase of a star’s history ______________________.
s typified by extreme fluctuations in energy and a strong magnetic field
Many supernovas are the result of _____________________.
collapse of a star with multiple burning shells
How will the Sun’s life probably end?
With the formation of a planetary nebula.
Which of the following are correct about red giant stars? (Select all that apply.)
A. Krypton, home to Superman, was a red giant.
B. They form as a star expands and the surface cools.
C. They are among the stars with the hottest surfaces.
D. They evolve from medium-sized stars.
They evolve from large stars.
Heavy elements like uranium and thorium form in their interiors.
B&D
Put the following stages in the evolution of a medium-sized star in the correct time order, placing the first stage on the top and the last stage on the bottom. Don’t use those that don’t apply to a medium-sized star.
Gas and Dust, Protostar, Main sequence star, red giant, planetary nebula
Which kind of stars have the longest lifetimes (~10 billion years)?
Medium-sized stars like our Sun.
A giant molecular cloud is best described by which statement?
It is a cool mass of gas and dust that can be light years across.
Which of the following is correct about the nebulas we see in the sky today? (Select all that apply.)
A. They formed during the “Big Bang.”
B. They are concentrations of interstellar gas and dust.
C. Many are the birth grounds of stars.
D. Some form when stars explode.
B, C, & D
A “star” that shines, but not as a result of nuclear reactions, is called a __________.
protostar
Condensation in the solar nebula and accretion of planets is thought to have occurred about how many years ago?
Ages from meteorites suggest condensation occurred 4.5 billion years ago.
Most of the mass of the solar nebula resided in materials which
did not condense to form solids.
What were the most common solids that condensed from the solar nebular gases?
They were water ice.
Examples of highly refractory materials are ____________________________.
. tungsten (W), osmium (Os), and zirconium (Zr)
Refractory elements are those that condense at high temperatures. Volatile elements condense at low temperatures.
Which list is made of very volatile materials?
helium (He), argon (Ar), ammonia (NH3), and methane (CH4)
Helium, argon, methane, and ammonia are very volatile elements and only condense at extremely cold temperatures.
Why are the inner planets depleted (poor) in volatile elements?
Their constituents condensed at high temperatures.
Which of the following is involved in collisional accretion?
The aggregation of planetesimals when they impact one another.
Which of the following are true about planetary accretion? (Select all that apply.)
A. As these particles accreted, the planets became hot as kinetic energy was converted to thermal energy.
B. The planets grew larger and larger via repeated impact.
C. The planets became internally differentiated to different degrees.
D. The particles that accreted to form the planets were in orbit around the Sun.
A, B, C & D
When did the planets form?
the planets formed about the same time as the Sun in a relatively short period of time only a few million years long.
Which of these is evidence for planetary accretion?
A. The heavily cratered surfaces of the Moon and other planetary bodies.
B. The absence of atmospheres on the Moon and Mercury
C. The rings of Saturn.
D. The abundance of water on Earth.
A. The heavily cratered surfaces of the Moon and other planetary bodies.
How did the giant outer planets obtain their thick atmospheres?
By collapse of nebular gas onto a protoplanet’s icy core
Large planetary bodies failed to accrete in some parts of the solar system and did not sweep their neighborhoods clear of debris. Select the two most prominent zones of this “debris.”
A. between Venus and Earth
B. between Mars and Jupiter
C. between Uranus and Neptune
D. beyond Neptune
B & D
Which of the following are characteristics of the orbits of the objects that accrete to make planets? (Select all that apply.)
A. Their orbits form a flattened disk shape.
B. Their orbits form a spherical zone centered on the star.
C. Their orbits define an elliptical zone tilted about 90° to the elliptic.
D. They orbit in the equatorial plane (ecliptic) of the star.
A & D
The spin axes of some planets are tilted relative to the plane in which most orbit. What could have caused this?
The impact of a large object late in the history of accretion changed the spin.
Think about the process of planetary accretion. Which statement best describes our current ideas about the rate of impact cratering in the inner solar system?
Initially, the rate declined smoothly, but there was a later episode of heavy bombardment followed by resumption of the decline.
Which of the following best describes the orbital evolution of the planets in our solar system according to the Nice Model?
A. The orbits of the planets have been more or less the way they are today for over 4.5 billion years.
B. The orbits of the inner planets were once much closer to the Sun than they are now and they have slowly moved outward by centripetal forces.
C. Earth, Mars, and Venus formed in the outer solar system, but they have slowly spiraled inward to their present orbits near the Sun.
D. The orbits of the outer planets changed significantly about 3.9 billion years ago as Uranus and Neptune moved outward from the Sun.
D
Which is true about our current understanding of extrasolar planets (exoplanets)?
Exoplanets are common and found around many different types of stars.
In general , large planets cool _____________________.
more slowly than small planets of similar compositions
Important sources of planetary heat include all of the following except _______________.
A. accretion B. core formation C. tidal heating D. decay of radioactive elements E. the Big Bang
E
Which of the following is not a mechanism of heat transport.
magnetism
What is the weak layer within a terrestrial planet that behaves like a viscous (flowing) fluid?
the asthenosphere
Consider two planets that are the same age. Which one will have the thicker lithosphere?
a small rocky planet
Why are the rocks found at the surface of a planet, say Mercury, so different in elemental composition from the meteoritic material from which it formed?
The planet differentiated after accretion.
Initially all the planets were homogeneous and accreted from materials of the same composition as meteorites. However, density differences of the various elements allowed segregation. Layers of varying composition formed, with each layer being a different composition than its average composition.
LABEL THE AVERAGE TEMP OVER AGE SPIKE DIAGRAM
Large planets will have the highest initial internal temperature and will cool more slowly. So the larger the planet the higher the internal temperature at any given time.
Consider the interior structure of a planet. How is a lithosphere different from a crust?
A lithosphere is a mechanical subdivision, and crust is a compositional term.
Where did the water in Earth’s hydrosphere come from?
From the volatiles released by volcanoes.
What properties of the atmophile elements (hydrogen, helium, carbon, nitrogen, oxygen) allow them to generate atmospheres?
They are volatile elements.
They form molecules with low densities
Which of the following is not a way that a planet’s atmosphere can lose gas?
A. escape to space
B. formation of limestone or carbonate materials
C. formation of polar ices
D. the process of outgassing
D
Outgassing is the processes of moving volatiles from the interior to above the surface. This process introduces gas into the atmosphere, it does not take away gas.
Why do the inner planets lack thick atmospheres of hydrogen and helium?
Because they are too small to have retained such gases.
How did Earth’s atmosphere form?
By gaseous exhalations from rocks deep inside
Why do the planets have different densities?
The planets have different mixtures of ice, silicates, iron, and gas
What is the age of most meteorites that fall to Earth?
almost all have ages of about 4.6 billion years.
Why are chondritic meteorites so important?
They are undifferentiated, and preserve evidence about the age and nature of condensation in the ancient solar nebula.
Most meteorites that fall to Earth are of which type?
stony meteorites
Which is true about iron meteorites?
Iron meteorites formed during the internal differentiation of small asteroids.
The best way to get high concentration of iron is differentiation of planetary bodies. So these meteorites must have settled to the core of asteroids that were then broken up by a large impact.
Some stony-iron meteorites appear to have ______________________.
been formed at the core-mantle boundary of an asteroid
What is one evidence suggesting that SNC meteorites came from Mars?
their young ages
What is the size range of asteroids?
0 to 1000 km across
Most asteroids are probably in which size range?
0 to 10 km across
What geologic process is most common on asteroids?
Impact cratering
Which of the following is most accurate about volcanic activity on the asteroids?
A. Volcanism never occurred because they are so small.
B. On a few asteroids, it is still going on today.
C. Volcanism occurred anciently on at least some asteroids.
D. Explosive volcanic eruptions propelled fragments to Earth, which we call meteorites.
Volcanism occurred anciently on at least some asteroids.
Why is there a density difference between Vesta and Ceres? (Select all that apply.)
A. Because Vesta is rich in silicates and metals.
B. Because Ceres has an outer shell of water ice.
C. Because Ceres is rich in silicates and metals
D. Because Vesta has an outer shell of water ice.
E. Because Vesta is more strongly fragmented by impact than Ceres is.
A & B
What is the most likely cause of the linear ridges and grooves (see Review PP) near equator of Vesta
Near disruption by a large impact
Why are asteroids closer to Jupiter so much darker than those near Mars?
Dark carbonaceous materials are common on the asteroids near Jupiter.
What is the best explanation for this dome shaped mound on Ceres?
Cryovolcanism (ice volcano).
The surface of the Moon can be divided into two general terrains. What are they?
the maria and the terrae
The lunar highlands, or terrae, are typified by ___________.
closely spaced impact craters
The most important mineral in the upper mantle of the Moon is _______.
olivine
Which of the following statements about the Moon’s core are correct? (Select all that apply.)
A. The Moon’s core is much larger than expected for a planet of its size.
B. The Moon’s core is probably made of iron.
C. The Moon’s core was once molten and convected to make a magnetic field.
D. As far as we can tell, the Moon is not differentiated, and has no core.
B & C
The energy of crater formation is expended in all of the following ways except:
A. slumping to create terraces B. heat C. seismic (earthquake) waves D. sound E. fracturing of the bedrock
D
Which of the following types of energy is mostly responsible for crater generation?
A. potential energy
B. thermal energy
C. kinetic energy
D. radiogenic energy
C
Which of the following is not a feature formed by impact on the Moon?
A. overturned flap on the crater rim
B. radiating arms of ejecta around the crater
C. terraces on the side of the crater
D. sinuous rilles
D
Which of the following is least important for the appearance of an impact crater developed on the surface of a planet?
A. the size of the planet B. the size of the impacting body C. the nature of the surface material (target) D. the presence of a magnetic field E. the presence of an atmosphere
D
Craters with central peaks generally ______________.
have terraced walls
PHOTO - Arrange these impact craters from smallest to larges.
With increasing size a craters morphology changes from bowl shaped, to terraced, to a central peak, to a peak ring/s.
sort the lunar time periods chronologically by placing the youngest period on top and the oldest on bottom.
Imbrian
Eratosthenian
Nectarian
Copernican
Copernican (youngest)
Eratosthenian
Imbrian
Nectarian (oldest)
Why do impact craters make good geologic time indicators? (Select all that apply.)
A. They are laterally extensive (they cover large areas).
B. They are produced instantaneously.
C. Their features change with time as a result of degradation.
A, B & C
Do the principles of superposition and cross cutting relations tell us how old a particular crater or surface is in number of years (the absolute age)?
No
What is the basis for our understanding of the absolute time scale of the Moon?
Rock samples brought back from the Moon have been dated using radiometric techniques to give their absolute ages.
What do the absolute ages of lunar rocks tell us about changes in the rate of impact cratering during the Moon’s history?
The rate of impact on the Moon has declined dramatically with time so that modern impact rates are much lower than they once were.
How old are the oldest rocks found so far on the Moon?
. The oldest rocks found on the Moon so far are about 4.5 billion years old.
Landforms produced by lunar volcanism include which of the following? (Select all that apply.)
A. lava flows B. low shield volcanoes C. stratovolcanoes D. ash flow calderas E. lava channels
A, B & E
What process formed these sinuous valleys?
The eruption of lava flows.
Mare basalts are characteristically _________________________.
very fluid
Which is true about the most common volcanic rocks found on the Moon?
Lunar volcanic rocks are similar to the most common volcanic rocks on asteroids and other terrestrial planets.
About how old are the lunar maria?
They range in age from about 4.0 billion years old to at least 2.5 billion years old.
What was the orientation of the stress that created the wirnkle ridges in this image (North is upward)?
Compression from W-E
Which is the oldest tectonic feature
The Linear rille
The presently favored theory for the origin of the Moon calls for
the impact of a large body into the Earth.
What is the major difference between the composition of the Moon and Earth?
The Moon is poorer in water than Earth.
The Moon’s highland crust consists largely of plagioclase feldspar. Since no magma has that composition, how was plagioclase concentrated in the crust?
By flotation of plagioclase feldspar in a magma ocean.
At one time the Moon may have _______________.
been volcanically active
On the Moon the highlands appear to be older than the low lands because
the highlands have abundant impact craters.
Which describes the Moon’s history better?
The Moon first expanded slightly because of heating and has since been contracting.
why is the present day Moon less dynamic than the planet Earth? (Select all that apply.)
A. Its lithosphere is thin, preventing new landforms.
B. Its lithosphere is thick.
C. It cooled quickly because of its small size.
D. It has no liquids flowing across its surface.
B, C & D
