Universe: Stars And Galaxies
6th Edition
ISBN: 9781319115098
Author: Roger Freedman, Robert Geller, William J. Kaufmann
Publisher: W. H. Freeman
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 27, Problem 25Q
To determine
(a)
The frequency of this
To determine
(b)
The merits of this suggestion.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
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.)
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.
Suppose we find an Earth-like planet around one of our nearest stellar neighbors, Alpha Centauri (located only 4.4 light-years away). If we launched a "generation ship" at a constant speed of 1500.00 km/s from Earth with a group of people whose descendants will explore and colonize this planet, how many years before the generation ship reached Alpha Centauri? (Note there are 9.46 ××1012 km in a light-year and 31.6 million seconds in a year.
Chapter 27 Solutions
Universe: Stars And Galaxies
Ch. 27 - Prob. 1QCh. 27 - Prob. 2QCh. 27 - Prob. 3QCh. 27 - Prob. 4QCh. 27 - Prob. 5QCh. 27 - Prob. 6QCh. 27 - Prob. 7QCh. 27 - Prob. 8QCh. 27 - Prob. 9QCh. 27 - Prob. 10Q
Ch. 27 - Prob. 11QCh. 27 - Prob. 12QCh. 27 - Prob. 13QCh. 27 - Prob. 14QCh. 27 - Prob. 15QCh. 27 - Prob. 16QCh. 27 - Prob. 17QCh. 27 - Prob. 18QCh. 27 - Prob. 19QCh. 27 - Prob. 20QCh. 27 - Prob. 21QCh. 27 - Prob. 22QCh. 27 - Prob. 23QCh. 27 - Prob. 24QCh. 27 - Prob. 25QCh. 27 - Prob. 26QCh. 27 - Prob. 27QCh. 27 - Prob. 28QCh. 27 - Prob. 29QCh. 27 - Prob. 30QCh. 27 - Prob. 31QCh. 27 - Prob. 32QCh. 27 - Prob. 33Q
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
- Suppose that stars were born at random times over the last 1010 years. The rate of star formation is simply the number of stars divided by 1010 years. The fraction of stars with detected extrasolar planets is at least 10 %. The rate of star formation can be multiplied by this fraction to find the rate planet formation. How often (in years) does a planetary system form in our galaxy? Assume the Milky Way contains 9 × 1011 stars.arrow_forwardWhat are some answers to the Fermi paradox? Can you think of some that are not discussed in this chapter?arrow_forwardSuppose 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_forward
- Suppose a spaceship has the mass of a typical ocean cruise ship, then it can be assumed that it has a mass of 2.1 × 108 kg. Consider the kinetic energy required at 13 % of the speed of light. If energy to get a spaceship to cruising speed is generated using matter-antimatter annihilation, what mass of antimatter in kg is required? Hint: Matter-antimatter annihilation converts an entire mass of matter and antimatter into pure energy with no loss.arrow_forwardI don’t understand how that it was estimated as length of a mouse is 4 to 15 cm in length. Is that a guess and the answer just varies?also where did 10^-1 come fromarrow_forwardthis question just got rejected due to complexity, and it already has answer on chegg. I guess I won't be staying here for long..arrow_forward
- In 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_forwardSuppose that stars were born at random times over the last 10e10 years. The rate ofstar formation is simply the number of stars divided by 10e10 years. The fraction ofstars with detected extrasolar planets is at least 9 %. The rate of star formation can bemultiplied by this fraction to find the rate planet formation. How often (in years) doesa planetary system form in our galaxy? Assume the Milky Way contains 7 × 10e11 stars. I've done this problem 3 different times from scratch and looked at similar problems here. Each time my answer is 1.587 (1.59 rounded to 2 significant figures), but when I submit, it says the answer is wrong. What do you think?arrow_forwardThe speed of light is the same for all observors. True Falsearrow_forward
- Suppose there are 9000.0 civilizations broadcasting radio signals in the Milky Way Galaxy at the moment. On average, how many stars would have to be searched before a signal is heard? Assume that there are 8 × 1011 stars in the Galaxy and one civilization per star.arrow_forwardAnother commonly calculated velocity in galactic dynamics is the escape velocity vesc, that is the minimum velocity a star must have in order to escape the gravitational field of the galaxy. (a) Starting from the work required to move a body over a distance dr against f show that the escape velocity from a point mass galaxy is vsc = 2GM/r where r is your initial distance. (b) Since we know galaxies aren't actually point-masses, also show that vesc from r for a galaxy with a p(r) xr¯² density profile is vese that R is a cutoff radius at which the mass density is zero. = 2v(1+ ln(R/r)). Here you must assume (c) The largest velocity measured for any star in the solar neighbourhood, at r=8 kpc, is 440 km/s. Assuming that this star is still bound to the galaxy, find the lower limit (in kiloparsecs), to the cutoff radius R and a lower limit (in solar units) to the mass of the galaxy. Note the solar rotation velocity is 220 km/s.arrow_forwardThink of our Milky Way Galaxy as a flat circular disk of diameter 100,000 light-years. Suppose we are one of 1000 civilizations, randomly distributed through the disk, interested in communicating via radio waves. How far away in light years would the nearest such civilization be from us on average? Show your working. (Hint: Begin by calculating the area of the disk. Find the area of one of a 1,000 squares. Consider the separation of the centres of two adjacent squares.)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 LearningStars 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
General Relativity: The Curvature of Spacetime; Author: Professor Dave Explains;https://www.youtube.com/watch?v=R7V3koyL7Mc;License: Standard YouTube License, CC-BY