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Pathways to Astronomy

Stephen E. Schneider

Chapter 84

The Search for Life Elsewhere - all with Video Answers

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Chapter Questions

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Problem 1

How long would it take to get to the nearest star at the Space Shuttle's speed of 30,000 kph?

James Kiss
James Kiss
Numerade Educator
01:49

Problem 2

Use a method similar to the Drake equation to estimate the number of people getting a haircut at some given moment. That is, identify the different factors involved in deciding to get a haircut, estimate the probabilities of each, then multiply the probabilities times the number of people in, for example, the United States (approximately 260 million).

Gregory Higby
Gregory Higby
Numerade Educator
01:51

Problem 3

The U.S. Department of Labor estimates that there were 651,000 barbers, hairdressers, and cosmetologists in the United States in $2002 .$ Does this workforce level appear to be consistent with your result from problem $2 ?$

Lucas Finney
Lucas Finney
Numerade Educator
01:57

Problem 4

Make your own estimate of the number of habitable planets within the Milky Way. What is the average distance between them?

Alex Garger
Alex Garger
Numerade Educator
01:25

Problem 5

After 20 years, the two Voyager spacecraft have reached about twice Pluto's distance from the Sun. How long will it take them to travel 4.2 ly-the distance to the nearest star?

Supratim Pal
Supratim Pal
Numerade Educator
00:45

Problem 6

Suppose that we are the only civilization in the Galaxy, and all the other civilizations have died out. For a possible 10,000 civilizations calculated by the Drake equation and a Galaxy with an age of 10 billion years, what is the typical life span of a civilization? How old is our civilization?

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:18

Problem 7

One solution suggested for our growing population in the far future is to construct a sphere surrounding the Sun with a radius of $1 \mathrm{AU}$ (Earth's orbital distance). The amount of light received per square meter on the inside of this sphere would be similar to what we receive on Earth now. What is the surface area of such a sphere compared to the surface of the Earth?

Khushbu Rani
Khushbu Rani
Numerade Educator