Essential Cosmic Perspective
9th Edition
ISBN: 9780135795033
Author: Bennett
Publisher: PEARSON
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Chapter 1, Problem 50EAP
Age of the Universe. Suppose we did not yet know the expansion rate of the universe, and two astronomers came up with two dif-ferent measurements: Wendy measured an expansion rate for the universe that was 50% faster than the expansion rate Allan measured. Was the age of the universe that Allan inferred older or younger than the age that Wendy inferred? By how much? Explain. (Hint: Read the discussion of the raisin cake analogy carefully, and the answer should become clear.)
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Students have asked these similar questions
Consider three periods in the history of the Universe: one million years after the Big Bang (age = 1 million years), about five billion
years ago (age = 9 billion years), and today. What is the ranking in the expansion rate of the Universe in these three period, from
fastest to slowest expansion:
O 1 million years, today, 9 billion years.
today, 1 million years, 9 billion years.
today, 9 billion years, 1 million years.
O 1 million years, 9 billion years, today.
Stuck on homework, especially the significant part.
If the value of the Hubble constant is 70 kilometers per second per Mpc, then what is the Hubble time – that is, the amount of time the universe has been expanding since the Big Bang? Give your answer first in units of seconds, and then in units of billions of years. Your answer is significant to two digits.
Your 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?
Chapter 1 Solutions
Essential Cosmic Perspective
Ch. 1 - Prob. 1VSCCh. 1 - Prob. 2VSCCh. 1 - About how far away from Earth would the Sun be...Ch. 1 - Prob. 4VSCCh. 1 - Prob. 1EAPCh. 1 - Define astronomical unit and light-year.Ch. 1 - Explain the statement The farther away we look in...Ch. 1 - Prob. 4EAPCh. 1 - Prob. 5EAPCh. 1 - What do we mean when we say that the universe is...
Ch. 1 - In what sense are we “star stuff”?Ch. 1 - Use the cosmic calendar to describe how the human...Ch. 1 - Briefly explain Earth’s daily rotation and annual...Ch. 1 - Prob. 10EAPCh. 1 - Prob. 11EAPCh. 1 - Prob. 12EAPCh. 1 - Prob. 13EAPCh. 1 - Prob. 14EAPCh. 1 - Decide whether the statement makes sense (or is...Ch. 1 - Prob. 16EAPCh. 1 - Prob. 17EAPCh. 1 - Prob. 18EAPCh. 1 - Decide whether the statement makes sense (or is...Ch. 1 - Prob. 20EAPCh. 1 - Decide whether the statement makes sense (or is...Ch. 1 - Prob. 22EAPCh. 1 - Prob. 23EAPCh. 1 - An astronomical unit is (a) any planet’s average...Ch. 1 - The star Betelgeuse s about 600 light-years away....Ch. 1 - Prob. 26EAPCh. 1 - Prob. 27EAPCh. 1 - Prob. 28EAPCh. 1 - Prob. 29EAPCh. 1 - Prob. 30EAPCh. 1 - Prob. 31EAPCh. 1 - Prob. 32EAPCh. 1 - Prob. 34EAPCh. 1 - Thinking About Scale. One key to success m science...Ch. 1 - Prob. 36EAPCh. 1 - A Human Adventure. Astronomical discoveries...Ch. 1 - Prob. 38EAPCh. 1 - Group Activity: Counting the Milky Way’s Stars....Ch. 1 - Prob. 40EAPCh. 1 - Prob. 41EAPCh. 1 - Prob. 42EAPCh. 1 - Prob. 43EAPCh. 1 - Prob. 44EAPCh. 1 - Moonlight and Sunlight. How long does it take...Ch. 1 - Prob. 46EAPCh. 1 - Driving Trips. Imagine that you could drive your...Ch. 1 - Prob. 48EAPCh. 1 - Prob. 49EAPCh. 1 - Age of the Universe. Suppose we did not yet know...
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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 a hypothetical universe is expanding (at some moment in time) at a rate of H. What would the density of this universe need to be (at this same moment in time) in order for it to be spatially flat? Value: H = 80 km s-1 Mpc-1 Give your answer in units of (kg m-3), in scientific notation with one decimal place (two sig figs). Please show work because I have trouble following alongarrow_forwardRank these models based on the present age of the universe that they predict (from youngest to oldest)(SEE DIAGRAM BELOW).A) criticalB) acceleratingC) coastingD) recollapsingarrow_forwardFor the graph shown above, a) what quantity would you label the y-axis with if the distance is between galaxies and the Earth? Explain your answer. Think through what we know is happening, motion-wise, out there in the galaxy. b) Also explain why you think there are dots and a solid line, on the graph.arrow_forward
- Studying for test: A new astronomical measurement suggests that the Hubble constant is 1112 kilometers per second per Megaparsec. If this measurement is correct, what would the Hubble time be in units of years? Is this a plausible value based on other astronomical evidence? Why or why not?arrow_forwardStars form in the Milky Way at a rate of about 1 solar mass per year. At this rate, how long would it take for all the interstellar gas in the Milky Way to be turned into stars if there were no fresh gas coming in from outside? How does this compare to the estimated age of the universe, 14 billion years? What do you conclude from this?arrow_forwardWhat does it mean to say that the universe is expanding? What is expanding? For example, is your astronomy classroom expanding? Is the solar system? Why or why not?arrow_forward
- Think of our Milky Way Galaxy as a flat 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 would the nearest such civilization be from us (on average)?arrow_forwardWould a human have been possible during the first generation of stars that formed right after the Big Bang? Why or why not?arrow_forwardIn which type of model universe is space-time infinite in extent and positively curved? List all possibilities.arrow_forward
- What evidence shows that the Universe is expanding? What evidence shows that the Universe began with a Big Bang?arrow_forwardUsing our example from the previous unit, let's try to determine the Hubble time for this example universe. You were given that a good representative galaxy receded at a speed of 4000 km/s and was found to be 20 Mpc away. With that in mind, what would the age of that universe be in years (aka what is that universe's Hubble time)? Go ahead and take the number of kilometers per Mpc to be approximately 3.1*10^19 km/Mpc. While this problem may look scary at first, this is really just bringing you full circle to one of the unit conversion problems you encountered at the beginning of this course.arrow_forwardState three pieces of evidence that support the idea that the Universe began in a hot Big Bang, and explain how each piece of evidence supports the hot Big Bang model. Describe the ob- servational evidence that supports the idea that the Universe is pervaded by Dark Energy, and explain why each piece of evidence you cite supports the Dark Energy model.arrow_forward
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