Life in the Universe (4th Edition)
4th Edition
ISBN: 9780134089089
Author: Jeffrey O. Bennett, Seth Shostak
Publisher: PEARSON
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Chapter 3, Problem 63IF
To determine
Evaluate the number of Earth-like planets in the Milky Way Galaxy and observable universe.
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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 11 %. 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 3 × 1011 stars.
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.)
Why 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!
Chapter 3 Solutions
Life in the Universe (4th Edition)
Ch. 3 - List three major ideas of astronomy that help...Ch. 3 - Briefly define and describe each of the various...Ch. 3 - Describe the solar system as it looks on the...Ch. 3 - Prob. 4RQCh. 3 - Prob. 5RQCh. 3 - Prob. 6RQCh. 3 - Prob. 7RQCh. 3 - What do we mean when we say that Earth and life...Ch. 3 - Imagine describing the cosmic calendar to a...Ch. 3 - Prob. 10RQ
Ch. 3 - Prob. 11RQCh. 3 - Prob. 12RQCh. 3 - What is the difference between matter in the...Ch. 3 - Define and give examples of kinetic energy,...Ch. 3 - Prob. 15RQCh. 3 - Prob. 16RQCh. 3 - Briefly describe the four major features of our...Ch. 3 - Briefly describe the nebular theory and how it...Ch. 3 - What was the close encounter hypothesis for our...Ch. 3 - How have recent discoveries led scientists to...Ch. 3 - Prob. 21TYUCh. 3 - At a middle school talent show, 14-year-old Sam...Ch. 3 - SETI researchers announced today that if they...Ch. 3 - A noted physicist today announced that he has...Ch. 3 - Prob. 25TYUCh. 3 - Astronomers have discovered a galaxy in the far...Ch. 3 - Inventor John Johnson has patented a device that...Ch. 3 - Prob. 28TYUCh. 3 - Prob. 29TYUCh. 3 - Using new, powerful telescopes, biologists today...Ch. 3 - Prob. 31TYUCh. 3 - Prob. 32TYUCh. 3 - A television advertisement claiming that a product...Ch. 3 - When we say the universe is expanding, we mean...Ch. 3 - Prob. 35TYUCh. 3 - The age of our solar system is about (a) one-third...Ch. 3 - Prob. 37TYUCh. 3 - How many of the planets orbit the Sun in the same...Ch. 3 - Prob. 39TYUCh. 3 - Prob. 40TYUCh. 3 - Explaining the Past. Is it really possible for...Ch. 3 - A Strange Star System. Suppose that we discovered...Ch. 3 - Prob. 44IFCh. 3 - Alien Technology. Some people believe that Earth...Ch. 3 - Atomic Terminology Practice. a. The most common...Ch. 3 - Prob. 49IFCh. 3 - Prob. 50IFCh. 3 - Patterns of Motion. In one or two paragraphs,...Ch. 3 - Two Kinds of Planets. The jovian planets differ...Ch. 3 - Pluto and Eris. How does the nebular theory...Ch. 3 - Rocks from Other Solar Systems. Many leftovers...Ch. 3 - Prob. 55IFCh. 3 - Prob. 56IFCh. 3 - Scale of the Solar System. The real diameters of...Ch. 3 - Prob. 58IFCh. 3 - Prob. 59IFCh. 3 - Prob. 60IFCh. 3 - Prob. 61IFCh. 3 - Prob. 62IFCh. 3 - Prob. 63IFCh. 3 - Prob. 67WPCh. 3 - Tour of the Solar System. Visit one of the many...
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- Suppose 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_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_forwardWhich of the following statements best describes our galaxy, the Milky Way? O A bulge dominated system, with little or no disk, approximately 27,000 light years across. A disk 100,000 lightyears across filled with gas and stars, with a bulge of older stars in the galaxy centre. A disk 27,000 light years across with a bulge of gas and newly formed stars in the galaxy centre. O A spherical (elliptical) galaxy, 100,000 lightyears across, with no gas and no new stars.arrow_forward
- 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_forward18 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_forwardThe Tully-Fischer method relies on being able to relate the mass of a galaxy to its rotation velocity. Stars in the outer-most regions of the Milky Way galaxy, located at a distance of 50 kpc from the galactic centre, are observed to orbit at a speed vrot determine the mass in the Milky Way that lies interior to 50 kpc. Express your answer in units of the Solar mass. 250 km s-1. Using Kepler's 3rd Law,arrow_forward
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