The Cosmic Perspective (9th Edition)
9th Edition
ISBN: 9780134874364
Author: Jeffrey O. Bennett, Megan O. Donahue, Nicholas Schneider, Mark Voit
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 19, Problem 42EAP
To determine
To Discuss:The entire galaxy was involved in bringing forth life on Earth
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
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…
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.
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
Submit
Skip (you cannot come back)
Chapter 19 Solutions
The Cosmic Perspective (9th Edition)
Ch. 19 - Prob. 1VSCCh. 19 - Prob. 2VSCCh. 19 - Prob. 3VSCCh. 19 - Prob. 4VSCCh. 19 - Prob. 5VSCCh. 19 - Prob. 6VSCCh. 19 - Prob. 1EAPCh. 19 - Prob. 2EAPCh. 19 - Prob. 3EAPCh. 19 - Prob. 4EAP
Ch. 19 - Prob. 5EAPCh. 19 - Prob. 6EAPCh. 19 - Prob. 7EAPCh. 19 - Prob. 8EAPCh. 19 - Prob. 9EAPCh. 19 - Prob. 10EAPCh. 19 - Prob. 11EAPCh. 19 - Prob. 12EAPCh. 19 - Prob. 13EAPCh. 19 - Prob. 14EAPCh. 19 - Prob. 15EAPCh. 19 - Prob. 16EAPCh. 19 - Prob. 17EAPCh. 19 - Does It Make Sense? Decitie whether the statement...Ch. 19 - Prob. 19EAPCh. 19 - Prob. 20EAPCh. 19 - Prob. 21EAPCh. 19 - Prob. 22EAPCh. 19 - Prob. 23EAPCh. 19 - Prob. 24EAPCh. 19 - Prob. 25EAPCh. 19 - Prob. 26EAPCh. 19 - Prob. 27EAPCh. 19 - Prob. 28EAPCh. 19 - Prob. 29EAPCh. 19 - Prob. 30EAPCh. 19 - Choose the best answer to each of the following....Ch. 19 - Prob. 32EAPCh. 19 - Prob. 33EAPCh. 19 - Prob. 34EAPCh. 19 - Prob. 35EAPCh. 19 - Prob. 36EAPCh. 19 - Prob. 37EAPCh. 19 - Prob. 39EAPCh. 19 - Prob. 40EAPCh. 19 - Prob. 41EAPCh. 19 - Prob. 42EAPCh. 19 - Prob. 44EAPCh. 19 - Prob. 45EAPCh. 19 - Prob. 46EAPCh. 19 - Prob. 47EAPCh. 19 - Prob. 48EAPCh. 19 - Prob. 49EAPCh. 19 - Prob. 50EAPCh. 19 - Prob. 52EAPCh. 19 - Mass of the Central Black Hole. Suppose you...Ch. 19 - Prob. 54EAPCh. 19 - Prob. 55EAPCh. 19 - Prob. 56EAPCh. 19 - Prob. 57EAPCh. 19 - Prob. 58EAPCh. 19 - The Speed of Supernova Debris. The kinetic energy...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- Try Now ... .... Listed below are some distances from Earth to other objects in the Milky Way galaxy. Convert each distance to light-years. (Each of these distances is less than one light-year. For an added challenge, convert each distance to light minutes or light seconds.) 1. The distance from Earth to the Moon is about 384,400 km. How many light-years is this? 2. The distance from Earth to Mars is about 784,000,000 km. How many light-years is this? 3. The distance from Earth to Pluto is about 5,750,000,000 km. How many light-years is this?arrow_forwardWhat is cosmic infalation ? Explain it.arrow_forwardIf you could search for life in the galaxy shown in this image, would you look among stars in the disk, in the central bulge, in the halo, or in all of those places? Discuss the factors that influence your decision.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_forwardBased upon the evolution of stars, place the following elements in order of least to most common in the Galaxy: gold, carbon, neon. What aspects of stellar evolution formed the basis for how you ordered the elements?arrow_forwardWhy are we unlikely to find Earth-like planets around halo stars in the Galaxy? A. Halo stars formed in a different way from disk stars. B. Planets around stars are known to be extremely rare. C. Halo stars formed in an environment where there were few heavy elements to create rocky planets. D. Halo stars do not have enough mass to hold onto planets. Is the answer C? Since halo stars are formed early when the galaxy consisted of mainly hydrogen and helium, there are no heavier elements available to create Earth-like planets so just halo stars are formed? Thanks!arrow_forward
- What is a Worm Hole? How can we travel into the Worm Hole?arrow_forwardHubble's First Attempt. Edwin Hubble's first attempt to measure the universe's expansion rate was flawed because the standard candles he was using were not properly calibrated. Look at (Figure 1) a.Estimate the value of Ho corresponding to the solid line in the figure. Express your answer kilometers per second per million light-years to two significant figures. b.What is the approximate age of the universe indicated by that erroneous value of Ho? Express your answer in years to one significant figure.arrow_forwardThe international space station (ISS) orbits 400 km above Earth's surface at 7.66 km/s (17,100 mph). Suppose the ISS is moved to 400 km above Mars. 1. To maintain its orbit above Mars, will the ISS have to move faster or slower that its orbital speed around Earth? Justify your answer. 2. Will astronauts on the ISS feel lighter, heavier, or no change at all while in orbit around Mars. Explain your answer.arrow_forward
- 18 If we develop spacecraft that can take humans to nearby solar systems at a few percent of the speed of light, how long would it be before we could conceivably populate all habitable planets in the entire Milky Way? A B D E A few hundred thousand years A few hundreds of millions of years We could never colonize the galaxy unless we had ships that could travel very close to the speed of light. A few million years A few billion yearsarrow_forwardYour friends are talking about Olber's Paradox: Friend 1: When the universe was quite young, it was also quite small, and therefore light was trapped inside the universe. This is why we don't see light from the edge of the universe in every direction. Friend 2: No, Olber's Paradox describes only light from stars, not from galaxies, and why you can't use light from distant stars to see at night. Friend 3: You're both right and you're both wrong. The paradox concerns itself with the expansion of the universe, and explains why light from the early universe was able to be released. Are any of them right, in part or in whole?arrow_forwardSuppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2. In this case, A. Galaxy 1 must be twice as big as Galaxy 2. B. we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy 2. C. we are seeing Galaxy 1 as it looked at a later time in the history of the universe than Galaxy 2. D. Galaxy 2 must be twice as old as Galaxy 1.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- AstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStaxFoundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
- Stars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage Learning
Astronomy
Physics
ISBN:9781938168284
Author:Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher:OpenStax
Foundations of Astronomy (MindTap Course List)
Physics
ISBN:9781337399920
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
Stars and Galaxies (MindTap Course List)
Physics
ISBN:9781337399944
Author:Michael A. Seeds
Publisher:Cengage Learning