Astronomy Chapter 14: Concept Questions

Which of the following statements about degeneracy pressure is not true?

The more massive a white dwarf, the _________.

Which of the following best describes why a white dwarf cannot have a mass greater than the 1.4-solar-mass limit?

The white dwarf that remains when our Sun dies will be mostly made of ______.

Which statement about accretion disks is not true?

According to present understanding, a nova is caused by _________.

Which of the following is not true about differences between novae and supernovae?

Will our Sun ever undergo a white dwarf supernova explosion? Why or why not?

Which of the following best describes what would happen if a 1.5-solar-mass neutron star, with a diameter of a few kilometers, were suddenly (for unexplained reasons) to appear in your home town?

Each Voyager spacecraft carries a "postcard" designed to be understandable to any aliens that might someday encounter it. On the "postcard," scientists pinpointed the location of Earth by triangulating it between pulsars. Why did the scientists choose pulsars rather than some other type of star?

Which statement about pulsars is not thought to be true?

How does an accretion disk around a neutron star differ from an accretion disk around a white dwarf?

Which statement concerning black hole masses and Schwarzschild radii is not true?

Suppose you drop a clock toward a black hole. As you look at the clock from a high orbit, what will you notice?

Which of statement below about black holes is not true?

When we see X rays from an accretion disk in a binary system, we can't immediately tell whether the accretion disk surrounds a neutron star or a black hole. Suppose we then observe each of the following phenomena in this system. Which one would rule out the possibility of a black hole?

Which of the following observatories is most likely to discover a black hole in a binary system?

Which of the following statements about gamma ray bursts is not true?

Imagine an advanced civilization living on a planet orbiting at a distance of 10 AU (1.5 billion kilometers) from a close binary star system that consists of a 15 MSun red giant star and a 10 MSun black hole. The black hole is surrounded by an accretion disk. Sometime within the next million years or so, the civilization's planet is likely to be doomed because ________.

Consider again the civilization described in the previous question. (They live on a planet orbiting 10 AU from a close binary star system that consists of a 15 MSun red giant star and a 10 MSun black hole surrounded by an accretion disk.) One foolhardy day, a daring individual in their space force (let's call him Major Tom) decides to become the first of his species to cross the event horizon of the black hole. To add to the drama, he decides to go in wearing only a thin space suit, which offers no shielding against radiation, no cushioning against any forces, and so on. Which of the following is most likely to kill him first (or at least to start the process of killing him first)?

Consider again the civilization described in the previous question. (They live on a planet orbiting 10 AU from a close binary star system that consists of a 15 MSun red giant star and a 10 MSun black hole surrounded by an accretion disk.) Through a bizarre (and scientifically unexplainable) fluctuation in the space-time continuum, a copy of a book from that civilization arrives on your desk; it is entitled Iguoonos: How We Evolved. In the first chapter, you learn that these beings evolved from organisms that lived 5 billion years ago. Which of the following statements should you expect to find as you continue to read this book?