Ch. 7 Problems

The path of a star as it moves through its orbit, and from the point of view of an observer at the telescope, determine how the light from the star will be affected by the Doppler shift, and label each point accordingly. You may assume that the center of the star's orbit is not moving with respect to the observer. A. blueshifted B. redshifted C. no Doppler shift

blue shifted > no doppler shift > red shifted

Drag each type of material to the bar indicating where each could be found in the forming Solar System. -Water ice -Highly volatile materials -Refractory materials

-Refractory materials (longest gray line) -Water ice (medium blue line) -Highly volatile materials (short yellow line)

Correctly position these four planets within the accretion disk of our early Solar System based on the materials that were present where they formed. Uranus, Jupiter, Saturn, Earth

(Refractory materials) Earth > (Water ice) Jupiter > (Highly volatile materials) Saturn > (Accretion disk) Uranus

A meteorite has been sliced open to show its interior, use your observations to determine the most likely formation scenario for a planet. Choose one: A. Individual particles in the nebula stick together to form larger pieces which later collide with and stick to other pieces to gradually form larger objects, which eventually grow to the size of a planet. B. All of the gas in the nebula collapses to the center to form the Sun, which then expels a piece of itself in a violent solar flare that is blown outward and becomes a planet. C. A single isolated clump inside the nebula gravitationally collapses into a planet.

A. Individual particles in the nebula stick together to form larger pieces which later collide with and stick to other pieces to gradually form larger objects, which eventually grow to the size of a planet.

What is an accretion disk, and what are its characteristics? Select the true statements regarding accretion disks. Choose one or more: A. An accretion disk forms because there is nothing to stop the collapse of an interstellar cloud toward its axis of rotation. B. An accretion disk's radius is typically hundreds of AU. C. Conservation of angular momentum leads a cloud to form a disk rather than collapse entirely. D. Most of the material in an accretion disk that does not end up in the protostar is available to form its planets. E. The shape and motion of the accretion disk are the reason that the subsequently formed planets all orbit in or near the equatorial plane of the star.

B. An accretion disk's radius is typically hundreds of AU. C. Conservation of angular momentum leads a cloud to form a disk rather than collapse entirely. E. The shape and motion of the accretion disk are the reason that the subsequently formed planets all orbit in or near the equatorial plane of the star.

Based on the figure in the Introduction, and the fact that an object with an increasing moment of inertia will spin more slowly to conserve angular momentum, choose the figure that best depicts how a cloud of gas will collapse to form a star system. A. Form a circle B. Form a disk C. Form an oval

B. Form a disk

Astronomers have determined that the gas giants are made mostly of hydrogen and helium. Given what you have learned about planetesimal formation through accretion, and the types of materials that condensed at certain distances from the Sun, which of the following is the most likely way that the gas giants formed? Choose one: A. Because hydrogen and helium could not condense into a solid at the temperature of the Solar Nebula, the gas giants must have formed elsewhere and been captured by the Sun's gravity. B. Rock, metal, and ices made of materials such as water, ammonia, and methane, condensed into a solid and grew large enough to gravitationally attract hydrogen and helium gas from the Solar Nebula. C. Hydrogen and helium condensed into a solid and accreted to form the gas giants.

B. Rock, metal, and ices made of materials such as water, ammonia, and methane, condensed into a solid and grew large enough to gravitationally attract hydrogen and helium gas from the Solar Nebula.

Imagine that a star-forming cloud collapses but retains all of its mass in a single blob. In order to conserve angular momentum, the cloud must Choose one: A. Come to a complete stop. B. Spin faster. C. Spin slower. D. Spin at the same rate.

B. Spin faster

Based on the law of conservation of angular momentum, what would happen to a collapsing cloud of gas and dust--isolated in space with no external forces--as its size decreases? Choose one: A. The cloud will lose mass. B. The cloud will spin faster. C. The cloud will spin more slowly. D. The cloud will not be able to collapse at all. E. The cloud will gain mass.

B. The cloud will spin faster.

Comparing objects in a related group can reveal patterns among them. These patterns in turn can help us learn more about those objects than we could by studying each individually. Think of the planets in the Solar System and select all of the following choices that describe the patterns. As you do so, think about the implications of how the Solar System may have formed. Choose one or more: A. Planets orbit the Sun in random directions. B. The orbits of the outer planets (those most distant from the Sun) are spaced farther apart from one another than the orbits of the inner planets. C. All planets orbit the Sun in the same direction. D. The closest planets to the Sun are much smaller than the planets that are farther away. E. All planets orbit the Sun in a spherical distribution. F. The size of all planets increases with distance from the Sun. G. The orbits of the planets are evenly distributed in distance from the Sun. H. All planets orbit the Sun in a roughly flat plane.

B. The orbits of the outer planets (those most distant from the Sun) are spaced farther apart from one another than the orbits of the inner planets. C. All planets orbit the Sun in the same direction. D. The closest planets to the Sun are much smaller than the planets that are farther away. H. All planets orbit the Sun in a roughly flat plane.

Angular momentum is only approximately conserved. This is because... Choose one: A. No quantities are ever really conserved. B. There are small external forces acting—friction and air resistance, for example. C. The measurement of angular momentum depends on your reference frame. D. The person on the platform is exerting a force when she pulls her arms in and pushes them out.

B. There are small external forces acting—friction and air resistance, for example

A new star is forming inside this glowing cloud of gas. The dark band in the middle is made of a disk of thick dust, which obscures the light within it and hides the forming star from view. Newly forming stars are surrounded by gas and dust. Based on this observation--and your previous observations about the relative orbits, positions, and sizes of the planets--what is the most likely scenario for the formation of the Solar System? Choose one: A. A cloud of gas and dust collapsed into a spherical shape, within which the Sun and planets formed. B. Two stars collided and broke apart to form the Sun and the planets. C. A cloud of gas and dust collapsed into a flattened disk, within which the Sun and planets formed. D. The Sun formed by itself from a collapsing cloud of gas and dust, then later gravitationally captured the planets as they happened to pass by.

C. A cloud of gas and dust collapsed into a flattened disk, within which the Sun and planets formed.

Study the sizes of the gas giants, (the distance from the Sun increases from left to right), and choose the best explanation that accounts for their differences in size. Choose one: A. Gas giants increase in size with increased distance from the Sun because the Solar Nebula was denser farther out. B. Gas giants decrease in size with increased distance from the Sun because fewer types of materials could condense farther out. C. Gas giants decrease in size with increased distance from the Sun because the Solar Nebula was less dense farther out. D. Gas giants increase in size with increased distance from the Sun because more types of materials could condense farther out.

C. Gas giants decrease in size with increased distance from the Sun because the Solar Nebula was less dense farther out.

What is the name of the brown disk rotating around the protostar in the following image? Choose one: A. planetary disk B. stellar disk C. protoplanetary disk D. protostellar disk

C. protoplanetary disk

The terrestrial planets and the giant planets have different compositions because Choose one: A. the giant planets are much larger. B. the terrestrial planets have few moons. C. the terrestrial planets are closer to the Sun. D. the giant planets are mostly made of solids.

C. the terrestrial planets are closer to the Sun.

The search for extrasolar planets has uncovered a phenomenon astronomers call a "hot Jupiter." If our Solar System had one, where would it orbit, relative to the other planets? Earth Jupiter Mars Mercury Hot Jupiter Venus

Closest to sun... Hot Jupiter Mercury Venus Earth Mars Jupiter Farthest from sun...

The composition of the protoplanetary disk varies with distance from the protostar due to temperature. Starting with those closest to the protostar, place these materials in order based on where they can be found predominantly in their solid states. -Methane, ammonia, CO -Iron, silicates, carbon -Water

Closest... -Iron, silicates, carbon -Water -Methane, ammonia, CO Farthest...

If a quantity is conserved, it means that it Choose one: A. Can be saved for a later time. B. Changes only if an external force acts. C. Changes only if an internal force acts. D. It doesn't change.

D. It doesn't change

Put the following stages of planet formation in order of occurrence. -Larger dust grains grow into clumps -Planets of various sizes form -An interstellar cloud collapses into a disk of gas, dust -Km sized planetesimals attract other objects by gravity -Clumps of dust collide and stick, forming planetesimals -Gas pushes smaller dust grains into larger grains

Earliest stage... -An interstellar cloud collapses into a disk of gas, dust -Gas pushes smaller dust grains into larger grains -Larger dust grains grow into clumps -Clumps of dust collide and stick, forming planetesimals -Km sized planetesimals attract other objects by gravity -Planets of various sizes form Latest stage...

Rank the following events in the order that corresponds to the formation of a planetary system. -Small bodies collide to form larger bodies -A stellar wind turns on and sweeps away gas and dust, removing primary atmospheres from planets -Gravity collapses a cloud of interstellar gas -Secondary atmospheres form -A rotating disk forms and dust grains stick together by static electricity -Primary atmospheres form

Earliest... -Gravity collapses a cloud of interstellar gas -A rotating disk forms and dust grains stick together by static electricity -Small bodies collide to form larger bodies -Primary atmospheres form -A stellar wind turns on and sweeps away gas and dust, removing primary atmospheres from planets -Secondary atmospheres form Latest stage...

Sort the Solar System's eight planets and three large dwarf planets according to their basic composition. Neptune Earth Ceres Saturn Eris Pluto Uranus Mercury Jupiter Venus Mars

Gaseous: Jupiter Saturn Uranus Neptune Rocky: Mercury Venus Earth Mars Ceres Rock/ice mixture: Pluto Eris

Graphs shows multiple transit events recorded while observing a star. The colored arrows indicate transits caused by three different planets. Rank the orbital periods of these planets, from shortest to longest. -purple planet -red planet -blue planet

Shortest period... -red planet -blue planet -purple planet Longest period...

The diagram shown indicates the location of exoplanets orbiting their star. The light green ring represents the habitable zone for that star. Determine whether each of the planets in this system is located in a region that is too hot, too cold, or just right for liquid water to potentially exist on the surface. Planet b (inner) Planet c (inner) Planet d (inner) Planet e (inner) Planet f (outer)

Too hot for liquid water: Planet b Planet c Planet d Planet e Too cold for liquid water: Just right for liquid water: Planet f