Physics 110: Homework Questions

(Handout #6)

Homework #11 Due 22 Apr Deadline 26 Apr

11.1

In what sense is dark mater dark? Briefly explain what we mean by baryonic and nonbaryonic matter. What type are you made of?

11.2

Describe the appearance of the Universe on the largest scales as traced by the distribution of galaxies. Be sure to explain what the Great Wall is.

11.3

How does the age of the Universe depend on the value of the Hubble constant and the mass density of the Universe?

11.4

What evidence has led astronomers to reject the steady-state cosmological theory?

11.5

Compare flat space Universes with positively curved Universes with respect to whether they are finite, whether they are bounded, and whether they have centers.

Homework #12 Due 29 Apr Deadline 3 May

12.1

What do astronomers mean by the decoupling epoch and why is it such a significant milestone in the life of the Universe?

12.2

Why is the present flatness of the Universe a problem for the standard Big Bang model? How has this problem been ``solved''?

12.3

What properties of water are crucial to life on Earth? Discuss the advantages and disadvantages of ammonia and methyl alcohol versus water as liquids on which life might be based.

12.4

How have astronomers detected planetary systems around nearby stars? In what ways do these recently discovered planetary systems support the possible presence of life elsewhere in the Galaxy.

12.5

How do the speeds of current spacecraft compare to the speed of light? How long would it take to travel to the nearest star at the speed of current spacecraft?

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