Loose Leaf For Explorations: Introduction To Astronomy
9th Edition
ISBN: 9781260432145
Author: Thomas T Arny, Stephen E Schneider Professor
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Concept explainers
Textbook Question
Chapter 18, Problem 2P
The temperature of Universe at recombination was about 3000 K. If the ratio of the temperature of the background
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents 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.
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?
Assume a flat Friedmann-Robertson-Walker universe.Calculate the redshift z at which the temperature of the CMB was T = 10 T0, where T0 is thetemperature of the CMB today. Assuming the universe was matter dominated throughout itsevolution, calculate the time at which T = 10 T0 in Gigayears.
Chapter 18 Solutions
Loose Leaf For Explorations: Introduction To Astronomy
Ch. 18 - Why do astronomers think that the Universe is...Ch. 18 - What is meant by the age of the Universe? How old...Ch. 18 - Prob. 3QFRCh. 18 - What is Olbers paradox?Ch. 18 - Prob. 5QFRCh. 18 - Prob. 6QFRCh. 18 - Prob. 7QFRCh. 18 - Prob. 8QFRCh. 18 - Prob. 9QFRCh. 18 - Prob. 10QFR
Ch. 18 - Prob. 11QFRCh. 18 - Prob. 12QFRCh. 18 - Prob. 13QFRCh. 18 - Prob. 14QFRCh. 18 - Prob. 15QFRCh. 18 - Prob. 16QFRCh. 18 - Prob. 17QFRCh. 18 - Prob. 18QFRCh. 18 - Prob. 19QFRCh. 18 - Prob. 20QFRCh. 18 - Prob. 1TQCh. 18 - Prob. 2TQCh. 18 - Prob. 3TQCh. 18 - Prob. 4TQCh. 18 - Prob. 5TQCh. 18 - Prob. 6TQCh. 18 - Prob. 7TQCh. 18 - Why are there points below the green line (instead...Ch. 18 - Prob. 9TQCh. 18 - Until recently, experimental results for the...Ch. 18 - The temperature of Universe at recombination was...Ch. 18 - Prob. 3PCh. 18 - Prob. 4PCh. 18 - The temperature of the Universe at recombination...Ch. 18 - One second after the Big Bang, the density of the...Ch. 18 - Prob. 7PCh. 18 - Prob. 8PCh. 18 - Prob. 1TYCh. 18 - Prob. 2TYCh. 18 - Prob. 3TYCh. 18 - Which of the following statements about the first...Ch. 18 - Prob. 5TYCh. 18 - Prob. 6TYCh. 18 - Prob. 7TYCh. 18 - Prob. 8TYCh. 18 - Prob. 9TYCh. 18 - Prob. 1EQFRCh. 18 - Prob. 2EQFRCh. 18 - Prob. 3EQFRCh. 18 - Prob. 4EQFRCh. 18 - Prob. 5EQFRCh. 18 - Prob. 6EQFRCh. 18 - Prob. 7EQFRCh. 18 - Prob. 8EQFRCh. 18 - Prob. 9EQFRCh. 18 - What is meant by the Gaia hypothesis?Ch. 18 - Prob. 11EQFRCh. 18 - Prob. 1ETQCh. 18 - Prob. 2ETQCh. 18 - Prob. 3ETQCh. 18 - Prob. 4ETQCh. 18 - Prob. 5ETQCh. 18 - Prob. 6ETQCh. 18 - Prob. 7ETQCh. 18 - Prob. 8ETQCh. 18 - Prob. 1EPCh. 18 - Prob. 2EPCh. 18 - Prob. 3EPCh. 18 - Prob. 4EPCh. 18 - Prob. 5EPCh. 18 - Prob. 6EPCh. 18 - Prob. 1ETYCh. 18 - Prob. 2ETYCh. 18 - Prob. 3ETYCh. 18 - Prob. 4ETYCh. 18 - Prob. 5ETYCh. 18 - Prob. 6ETYCh. 18 - Prob. 7ETY
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
- Would a human have been possible during the first generation of stars that formed right after the Big Bang? Why or why not?arrow_forwardThe background radiation has an average temperature of 2.7 K, using Wien’s Law, the current background radiation in the microwave region, the peak wavelength is 1mm. In the past, when the cosmic background radiation had a peak wavelength of 51.1 µm, calculate the relative size of the universe compared to the current size of the universe, that is, the universe was how much smaller by a factor of what? Round to TWO places past the decimalarrow_forwardIf you observe light emitted from a distance object when the cosmic background temperature was Tz=54K, what is the redshift z of that light? At that redshift, what was the diameter Dz of the universe at that time compared to the diameter of today's universe D0?arrow_forward
- If the universe had a density equal to its estimated critical density of 9= 10-30 g/cm3, and if it were composed entirely of one-solar-mass stars (mass 2.0 x1030 kg) distributed uniformly across the universe, what would be the distance between stars? Compare your result with the density of stars in the neighborhood of the sun and comment on the result.arrow_forwardAssume the observable Universe is charge neutral, and that it contains n nuclei (hydrogen plus helium nuclei, ignoring other elements). Take the helium mass fraction as 1/4. How many electrons are there in the observable Universe? Enter your answer in scientific notation with one decimal place. Values: n = 1*10^80arrow_forwardIf we assume that the universe has been expanding at its current rate for its entire history, how old is the universe?arrow_forward
- The present number density of electrons in the Universe is the same as that of protons, about 0.2 m-3. Consider a time long before the formation of the microwave background, when the scale factor was x times smaller than its present value. What was the number density of electrons then? Value: x = 12×106arrow_forwardAssume a flat FRW universe, dominated by radiation throughout its history. Calculate the physical, cosmological horizon size at t=t_0 The initial conditions for the scale factor are a=a_0 at t=t0(today). Which asnwer is correct; a)R_H=2a_0ct_0 b) R_H = 3a_0ct_0 c)R_H = ct_0 d) R_H=2ct_0arrow_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_forward
- Assume the observable Universe is charge neutral, and that it contains n nuclei (hydrogen plus helium nuclei, ignoring other elements). Take the helium mass fraction as 1/4. How many electrons are there in the observable Universe? Enter your answer in scientific notation with one decimal place. Value: n = 4*1080arrow_forwardWhat is the evidence that the universe was very uniform during its first 400,000 years?arrow_forwardExplain the Higher-Order Systems?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Stars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage LearningFoundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage LearningAstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStax
Stars and Galaxies (MindTap Course List)
Physics
ISBN:9781337399944
Author:Michael A. Seeds
Publisher:Cengage Learning
Foundations of Astronomy (MindTap Course List)
Physics
ISBN:9781337399920
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
Astronomy
Physics
ISBN:9781938168284
Author:Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher:OpenStax
General Relativity: The Curvature of Spacetime; Author: Professor Dave Explains;https://www.youtube.com/watch?v=R7V3koyL7Mc;License: Standard YouTube License, CC-BY