Life in the Universe (4th Edition)
4th Edition
ISBN: 9780134089089
Author: Jeffrey O. Bennett, Seth Shostak
Publisher: PEARSON
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Question
Chapter 13, Problem 41POS
To determine
Write the opinion for the assumption that neither the planet Earth nor its species are considered to be special.
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Which of the following is least reasonable regarding the difficulty in contacting extraterrestrial life using space flight and radio communication.
Group of answer choices
Space flight to the nearest star would take thousands of years with current technology.
Even if another intelligent civilization is within a few hundred light-years of us, conversations would be very slow with a turnaround time of decades or even centuries.
The spacecraft that NASA sent to Proxima Centauri a few years ago should be approaching its target within a decade or two, depending on solar wind conditions.
Earth has been broadcasting at radio wavelengths since the 1930's, so any civilization within a radius of about 100 light-years or so could have received the broadcast by now.
Without some major breakthrough, interstellar space flight is totally impractical.
200 years has passed and now it is year 2220. The Earth is out of basic resourcesas they have been drastically drained in the past 200 years. The president of theUnited World Council (UWC) has approved you and your crew’s Mission toMars. You will pilot the most advanced spaceship the world has ever known, theExcelsior! It will carry equipment that will help to transform Mars so as toresemble the Earth, especially so that it can support human life.Before the mission can launch a few items need to be figured out. What is thecapacity of the fuel tank? How long should the fuel burn to achieve escapevelocity (otherwise the Excelsior will be stuck in the Earth’s gravitational pull)?How long will it take the Excelsior to arrive at Mars?1. The ground crew is filling the fuel tanks. You know th
Tutorial
A radio broadcast left Earth in 1925. How far in light years has it traveled?
If there is, on average, 1 star system per 400 cubic light years, how many star systems has this broadcast
reached?
Assume that the fraction of these star systems that have planets is 0.30 and that, in a given planetary
system, the average number of planets that have orbited in the habitable zone for 4 billion years is 0.85. How
many possible planets with life could have heard this signal?
Part 1 of 3
To figure out how many light years a signal has traveled we need to know how long since the signal left Earth.
If the signal left in 1925, distance in light years = time since broadcast left Earth.
d = tnow - tbroadcast
d =
light years
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Chapter 13 Solutions
Life in the Universe (4th Edition)
Ch. 13 - Prob. 1RQCh. 13 - How does the speed of light affect the possibility...Ch. 13 - Prob. 3RQCh. 13 - Prob. 4RQCh. 13 - What is the rocket equation used for? Based on the...Ch. 13 - Prob. 6RQCh. 13 - Discuss a few ways of reaching the stars (other...Ch. 13 - How would time dilation affect space travel at...Ch. 13 - Prob. 9RQCh. 13 - What is the Fermi paradox? What two seemingly...
Ch. 13 - Why does it seem that other civilizations, if they...Ch. 13 - What arc Von Neumann machines? How do they affect...Ch. 13 - Describe the coral model of galactic colonization....Ch. 13 - Briefly discuss possible motives for galactic...Ch. 13 - Summarize the three general categories of possible...Ch. 13 - Briefly discuss the profound implications of the...Ch. 13 - What known problems were solved when Einstein...Ch. 13 - Prob. 18RQCh. 13 - Besides the idea that you cannot reach the speed...Ch. 13 - Prob. 20RQCh. 13 - Prob. 21TYUCh. 13 - Prob. 22TYUCh. 13 - Each of the following describes some futuristic...Ch. 13 - Prob. 24TYUCh. 13 - Prob. 25TYUCh. 13 - Prob. 26TYUCh. 13 - Prob. 27TYUCh. 13 - Prob. 28TYUCh. 13 - Prob. 29TYUCh. 13 - Prob. 30TYUCh. 13 - Prob. 31TYUCh. 13 - The amount of energy that would be needed to...Ch. 13 - The rocket engines of our current spacecraft are...Ch. 13 - Suppose that a spaceship was launched in the year...Ch. 13 - Prob. 35TYUCh. 13 - Prob. 36TYUCh. 13 - Which of the following questions best represents...Ch. 13 - Prob. 38TYUCh. 13 - Which of the following is not relative in the...Ch. 13 - Prob. 40TYUCh. 13 - Prob. 41POSCh. 13 - Prob. 42POSCh. 13 - Prob. 44IFCh. 13 - What's Wrong with This Picture? Many science...Ch. 13 - Large Rockets. Suppose we built a rocket that...Ch. 13 - Prob. 47IFCh. 13 - Solution to the Fermi Paradox. Among the various...Ch. 13 - Prob. 50IFCh. 13 - Cruise Ship Energy. Suppose we have a spaceship...Ch. 13 - Prob. 52IFCh. 13 - The Multistage Rocket Equation. The rocket...Ch. 13 - Relativistic Time Dilation. Use the time dilation...Ch. 13 - Testing Relativity. A + meson produced at rest has...Ch. 13 - Prob. 57IFCh. 13 - Prob. 58IFCh. 13 - Prob. 59IFCh. 13 - Prob. 60IFCh. 13 - The Turning Point. Discuss the idea that the...
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- Tutorial A radio broadcast left Earth in 1923. How far in light years has it traveled? If there is, on average, 1 star system per 400 cubic light years, how many star systems has this broadcast reached? Assume that the fraction of these star systems that have planets is 0.50 and that, in a given planetary system, the average number of planets that have orbited in the habitable zone for 4 billion years is 0.40. How many possible planets with life could have heard this signal? Part 1 of 3 To figure out how many light years a signal has traveled we need to know how long since the signal left Earth. If the signal left in 1923, distance in light years = time since broadcast left Earth. d = tnow - broadcast d = 97 97 light years Part 2 of 3 Since the radio signal travels in all directions, it expanded as a sphere with a radius equal to the distance it has traveled so far. To determine the number of star systems this signal has reached, we need to determine the volume of that sphere. V, = Vb…arrow_forwardWhich of the following is not considered a likely solution to the question of why we are not currently aware of an extraterrestrial civilization? Group of answer choices There is no civilization because civilizations are not common. The civilization is probably undetectable to us because it makes use of technologies that do not obey the known laws of physics. There is no galactic civilization because civilizations do not leave their home worlds. There is no civilization because most civilizations destroy themselves before achieving interstellar travel. The civilization is deliberately avoiding contact with us.arrow_forwardA radio broadcast left Earth in 1911. How far in light years has it traveled? If there is, on average, 1 star system per 400 cubic light years, how many star systems has this broadcast reached? Assume that the fraction of these star systems that have planets is 0.50 and that, in a given planetary system, the average number of planets that have orbited in the habitable zone for 4 billion years is 0.20. How many possible planets with life could have heard this signal?arrow_forward
- Suppose astronomers discover a radio message from a civilization whose planet orbits a star 35 lightyears away. Their message encourages us to send a radio answer, which we decide to do. Suppose our governing bodies take 2 years to decide whether and how to answer. When our answer arrives there, their governing bodies also take two of our years to frame an answer to us. How long after we get their first message can we hope to get their reply to ours? (A question for further thinking: Once communication gets going, should we continue to wait for a reply before we send the next message?)arrow_forwardWhy are we limited to finding life on planets orbiting other stars to situations where the biosphere has created planet-scale changes?arrow_forwardWhat is the difference between chemical evolution and biological evolution?arrow_forward
- Most of the stars we can see with the unaided eye in our night sky are hundreds or even thousands of lightyears away from Earth. (The very closest ones are only a few dozen lightyears away, but most are much further.) The vast majority of stars in our galaxy are many tens of thousands of lightyears away. IF intelligent life existed on planets orbiting some of these stars – and that’s a huge IF! – comment on the likelihood and practicality of (a) visiting, (b) communicating with, or (c) verifying the existence of those life forms. Describe how you might go about approaching EACH of these three tasks, or if you think they are even possible. (One or two sentences for each part would be appropriate.)arrow_forwardIn this experiment, as a form of sheltering-at-home fantasy, we adopt a science=fiction scenario. It’s the year 2520 and you are an astronaut working for a private entity simply called The Company. The CEO of The Company is the 8th clone of Elon Musk. Elon 9 has provided you with a small interstellar spacecraft about a million times faster than anything we can conceive of today. It is your job to check out the potential habitability of a few relatively near potentially habitable planets to see if human colonies can be established there to mine materials for the latest version of the Tesla automobile. But there is a problem. Shortly before your launch, a solar-system-wide pandemic ground human economy to a standstill. So Elon 9 had to cut corners. The only device he could afford for you to measure gravity acceleration on the subject planets is a pendulum with a length of 100 cm. After landing, you will determine the gravitational acceleration at the surface of…arrow_forwardFor which of the following reasons (select all that apply), is it useful/important to send rovers to other planetary bodies in our solar system? O a. The engineering innovations developed to produce successful/viable rovers and landers on other planets can help lead to developments in the technology used here on Earth that may have taken far more time to develop without the limitations provided by space travel to foreign worlds. O b. The data collected can help improve our understanding of the evolution/development of our solar system. O. Rovers/landers can be outfitted with various tools and equipment that can be used to inform of us of the geological histories of each of the planets they visit. O d. More direct probes of the planetary surface are possible to detect signs of the building blocks of life. O e. Rock samples can be used to calibrate our estimations of the age of the solar system.arrow_forward
- In a globular cluster, astronomers (someday) discover a star with the same mass as our Sun, but consisting entirely of hydrogen and helium. Is this star a good place to point our SETI antennas and search for radio signals from an advanced civilization? Group of answer choices No, because such a star (and any planets around it) would not have the heavier elements (carbon, nitrogen, oxygen, etc.) that we believe are necessary to start life as we know it. Yes, because globular clusters are among the closest star clusters to us, so that they would be easy to search for radio signals. Yes, because we have already found radio signals from another civilization living near a star in a globular cluster. No, because such a star would most likely not have a stable (main-sequence) stage that is long enough for a technological civilization to develop. Yes, because such a star is probably old and a technological civilization will have had a long time to evolve and develop there.arrow_forwardAfter completing this Lecture Tutorial, students should be able to: distinguish between scientific hypotheses and nonscientific ideas. Part 1: Comprehension of Hypotheses A scientific hypothesis needs to (1) be supported by the majority of current data and (2) be testable. An alien on Earth is wondering why a rubber ball falls back down to the ground after it is thrown into the air. It comes up with several ideas about the ball. a. Gravity is pulling the ball to the ground. b. A mystical force that cannot be measured is pushing the ball down. c. Earth's magnetic field is pulling on the rubber ball. 1. Which statement is NOT a hypothesis because it is not testable? a b c 2. Which statement is NOT a hypothesis because it is not supported by current data? a b c 3. Which statement IS a scientific hypothesis? a b c Part 2: Application to Dinosaur Extinction Below are possible scenarios explaining the extinction of the dinosaurs. a. Dinosaurs were killed off by a virus. b. A large meteorite…arrow_forwardThe principle cause of our intense interest in Mars in the decades before the dawn of the space age was that Answers: A. a few astronomers believed that they saw evidence of an intelligent civilization on Mars. B. Mars has seasons just like the Earth and therefore should be inhabitable by humans. C. Mars has an unusual surface color and global dust storms, creating strange weather patterns. D. Mars has unusual orbital properties making our understanding of its motion around the Sun very difficult.arrow_forward
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