A black hole is no more massive than the star from which it collapsed. Why, then, is gravitation so intense near a black hole?

With respect to stellar evolution, what is meant by the statement The bigger they are, the harder they fall?

Elements heavier than iron are created in stars. Are they formed in the same way as elements lighter than iron? Explain.

Why will the Sun not be able to fuse carbon nuclei in its core?

Why are supermassive stars relatively rare?

Why are massive stars generally shorter lived than low-mass stars?

Why do nuclear fusion reactions not occur on the outer layers of stars?

What keeps a main-sequence star from collapsing?

Why is there a lower limit on the mass of a star? (What cant happen in a low-mass accumulation of hydrogen atoms and other interstellar material?)

Some stars contain fewer heavy elements than our Sun contains. What does this indicate about the age of such stars relative to the age of our Sun?

What evidence suggests that our Sun is a relatively young star in the universe?

Would you expect metals to be more abundant in old stars or in new stars? Defend your answer.

How is the gold in your mothers ring evidence of ancient stars that ran through their life cycles long before the solar system came into being?

In what sense are we all made of star dust?

When can a burnt-out collapsing star rekindle itself?

What is expected to happen to the Sun in its old age?

What event marks the birth of a star? When does a star die?

What do the outward and inward forces acting on a star have to do with its size?

What is the relationship between a planetary nebula and a white dwarf?

If an entire solar mass were to fall into the Sun, what would happen to its color?

How is the H-R diagram like the periodic table?

In terms of the life cycle of the Sun, explain why life on Earth cannot last forever.

Does a yellow star contain blue light?

Does a blue star contain yellow light?

Why dont we see the ultraviolet color of stars?

Which has the highest surface temperature: a red star, a white star, or a blue star?

What type(s) of motion do we see with the Sun? Daily? Yearly? Intrinsic?

Why does the Big Dipper change its position in the night sky over the course of the evening, whereas Polaris, the North Star, remains relatively fixed in its position?

The Big Dipper is sometimes right side up (could hold water) and at other times upside down (could not hold water). What length of time is required for the Dipper to change from one position to the...

Which moves faster from horizon to horizon: the Sun or the Moon? Explain.

Distinguish between the daily motion and the intrinsic motion of celestial objects.

We see the constellations as distinct groups of stars. Discuss why they would look entirely different if viewed from some other location in the universe, far distant from Earth.

Which figure in this chapter best shows that a constellation seen in the background of a solar eclipse is one that will be seen 6 months later in the night sky?

On the Moon, stars other than the Sun can be seen during the daytime. Why?

Is there any star bright enough for us to see it on a sunny day?

The 19th-century author and social commentator Thomas Carlyle wrote, Why did not somebody teach me the constellations and make me at home in the starry heavens, which are always overhead and which I...

Rank in order of increasing size: (a) Solar system, (b) Local Group, (c) Galaxy.

Rank the following features of a black hole in order of increasing radius: (a) Photon sphere, (b) Singularity, (c) Event horizon.

Rank the nuclear fuels in order of being consumed, from first to last: (a) Carbon, (b) Helium, (c) Hydrogen

Rank these stages of stellar development from earliest to latest: (a) White dwarf, (b) Nova, (c) Red giant

Rank the following stars in order of increasing radius: Star A Star B 6,000 4,000 Star C 30,000 Surface temperature (K): Luminosity (solar units): 100 0.01

Rank the objects in order of increasing intrinsic motion as viewed from Earth: (a) The Moon, (b) Venus, (c) The North Star.

Rank the appearance of the North Star in order of increasing height from the horizon as seen from (a) Alaska, (b) Florida, (c) Vermont

From your answer to the preceding problem, would it be possible for two galaxies with stars evenly distributed to pass right through each other?

Use the information in the preceding problem to figure out the average amount of space around a single star in units of AU (1 light-year = 63,000 AU.)

Assume the Milky Way contains 100 billion stars evenly distributed with none concentrated toward the center. What would be the surface area density of stars? Use the equation surface area density =...

If you were to travel straight up from the core of our galaxy and then look back, you would have a grand view of the Milky Ways spiral shape. If the distance from the core to the outer edges was...

To observe the revolutionary motion of Earth around the Sun, go star watching and make note of the stars directly above you. Sketch their pattern on a piece of paper and write down the date and time...

To observe the daily motion of the stars, go star watching tonight. Pick a star or constellation that lines up with a stationary landmark such as a tree or house. Then come back in an hour or so and...

Name three galactic clusters found in our Local Supercluster

Is the Local Group a relatively small or large cluster of galaxies?

How many spiral galaxies are in the Local Group?

What is a starburst galaxy?

What are the consequences of galaxies colliding?

What type of galaxy is the Milky Way?

Is a black holes event horizon a physical or mathematical boundary?

If black holes are invisible, what is the evidence for their existence?

How does the mass of a star before its collapse compare with the mass of the black hole that it becomes?

Why dont we think the Sun will eventually become a black hole?

What is the relationship between a supergiant star and a black hole?

What is the relationship between a neutron star and a pulsar?

What is the relationship between a supernova and a neutron star?

What is the relationship between the heavy elements that we find on Earth today and supernovae?

Is the lifetime of a high-mass star longer or shorter than that of a low-mass star?

When will our Sun reach the red-giant stage?

What are the inward forces that act on a star?

What are the outward forces that act on a star?

What process changes a protostar into a full-fledged star?

Among stars originating from the main sequence, which are larger: red stars or yellow stars?

Where does our Sun reside on an HR diagram?

Where are the great majority of stars plotted on an HR diagram?

What is an HR diagram?

What is the difference between apparent brightness and luminosity?

Which is hotter: a red star or a blue star?

Is the light-year a measurement of time or distance?

Why do the stars appear to turn on an imaginary north south axis once every 24 hours?

Why does an observer at a given location see one set of constellations in the winter and a different set of constellations in the summer?

What are constellations?

Un-manned space probes are a very cost-effective and safe way to explore our solar system and beyond. Why should we bother to send humans to another planet, such as Mars?

How does the brightness of a quasar compare with that of a large galaxy?

Where do most of the worlds earthquakes occur? Discuss features of various earthquakes in terms of: geologytype of plate boundary, fault, and rock type; and geographyeconomic development,...

As global temperatures increase, the polar ice caps melt. What influence will this have on the isostatic balance of the lithosphere?

The FYI about the 2010 Chilean earthquake suggests that the quake caused a shift in Earths distribution of mass, which changed Earths rate of rotation and resulted in a change in the day length. If...

What clues can we use to recognize the boundaries between ancient plates no longer in existence?

What geologic features are explained by plate tectonics?

How do P-waves travel through Earths interior? How do S-waves travel through Earths interior?

Name the two types of surface waves and describe the motion of each.

What was the major contribution of Andrija Mohorovii to Earth science?

How did seismic waves contribute to the discovery of Earths core?

What is the evidence that Earths inner core is solid?

What is the evidence that Earths outer core is liquid?

In what ways are the asthenosphere and the lithosphere different from each other?

How does continental crust differ from oceanic crust?

Why does continental crust stand higher on the mantle than oceanic crust?

What key evidence did Alfred Wegener use to support his hypothesis of continental drift?

Wegener proposed that the worlds continents had at one time all been joined together into one supercontinent. What name is given to this supercontinent?

What role did paleomagnetism play in supporting the theory of continental drift?

Where are the deepest parts of the ocean?

What was the major discovery of Harry Hess?

How is the ocean floor similar to a gigantic, slow-moving tape recorder?