Black Holes (1)

Sources: A Brief History of Time

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A. From: A Brief History of Time

1. Click on the turtle on Hawking’s desk.

a. What is scientific theory?

2. What examples of scientific theory are presented?

2. Double click on ENTER to the Hawking Craft.

Click on the uppermost blue button at the bottom and then click on
Ballroom Dancing.

What analogy does John Wheeler make?

2. Double click on: Why Call Them Black Holes?

What was Wheeler’s original expression for “black hole”? (Fill in the blanks.)

a gravitationally ____________ ___________________ object

3. Double click on: A Brief Introduction

What definition is given for a black hole? (Complete the definition.)

A black hole is ____________________________________________________.

4. What is the “event horizon”?

B. Click on the third button at the bottom: Genesis of Idea

1. Who first put forth the idea of a black hole? When?

2. What is the “escape velocity”?

3. What is the escape velocity for the earth?

 

4. Under what conditions would the escape velocity of a star be greater than the
   velocity of light?

5. Why can’t we see stars that have an escape velocity greater than the
   speed of light?

 

 

6. If we can’t see a star whose the escape velocity is greater than the speed of
   light, how could we know that it exists?

7. What keeps our sun from contracting?

B. From: Grolier Multimedia Encyclopedia

1. What is a black hole?

2.a. The idea of a black hole is traced to whom?

2. What name was used for his phenomenon?

3. In what way is a black hole like a “one-way membrane”?

4.What is the Schwarzschild radius?

5. How can black holes been identified?

a.

b.

6. What do physicists think about the permanence of black holes?

7. Why are black holes NOT “cosmic vacuum cleaner”?