Inquiry into Physics
8th Edition
ISBN: 9781337515863
Author: Ostdiek
Publisher: Cengage
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Chapter 12, Problem 43Q
To determine
To Describe:The role of inflation in cosmology.The way it helps to explain that the geometry of the universe is flat.
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Choose the correct statements from the following list. (Give ALL correct answers, i.e., B, AC, BCD...)
A) The inflationary model of the universe solves both the flatness and the horizon problems.
B) The critical density is the density needed to cause the Big Bang.
C) The horizon problem in cosmology is that regions of the universe that should not have ever had thermal contact with one another have the same temperature.
D) A major difference between dark matter and dark energy is that one causes the univserse's expansion to slow down, the other to make it expand faster.
E) Observations show us that the geometry of our universe must be very close to flat.
F) Assuming no dark energy, if the matter density of the universe is less than critical, the universe is closed.
G) Assuming no dark energy, if the matter density of the universe is greater than critical, the universe is will expand forever.
With the aid of a diagram, explain the physical origin of cosmological redshift in an expanding universe, and how this differs from the Doppler shift due to relative motion. Observations of distantgalaxies indicate that their recession velocities, v, and their distances, d, follow a Hubble Law:v = H0d, where H0 is a constant. Using the analogy of an expanding grid or ruler, demonstratethat Hubble’s Law indicates that the Universe is undergoing uniform expansion.
Briefly explain what is meant by “particle horizon” and “event horizon” in cosmology.
Calculate the physical particle horizon, RH(t), at time t. Assume a flat FRW universe whichis dominated by a fluid that gives rise to scale factor evolution
where n is a constant with 0 < n < 1, and a(t0) = a0.
Chapter 12 Solutions
Inquiry into Physics
Ch. 12 - Prob. 1AACh. 12 - Prob. 2AACh. 12 - Prob. 1PIPCh. 12 - Prob. 1MIOCh. 12 - Prob. 2MIOCh. 12 - Prob. 1QCh. 12 - Prob. 2QCh. 12 - Prob. 3QCh. 12 - Prob. 4QCh. 12 - Prob. 5Q
Ch. 12 - Prob. 6QCh. 12 - Prob. 7QCh. 12 - Prob. 8QCh. 12 - Prob. 9QCh. 12 - (Indicates a review question, which means it...Ch. 12 - Prob. 11QCh. 12 - Prob. 12QCh. 12 - (Indicates a review question, which means it...Ch. 12 - Prob. 14QCh. 12 - Prob. 15QCh. 12 - Prob. 16QCh. 12 - Prob. 17QCh. 12 - Prob. 18QCh. 12 - Prob. 19QCh. 12 - Prob. 20QCh. 12 - Prob. 21QCh. 12 - Prob. 22QCh. 12 - Prob. 23QCh. 12 - Prob. 24QCh. 12 - Prob. 25QCh. 12 - Prob. 26QCh. 12 - Prob. 27QCh. 12 - Prob. 28QCh. 12 - Prob. 29QCh. 12 - Prob. 30QCh. 12 - Prob. 31QCh. 12 - Prob. 32QCh. 12 - Prob. 33QCh. 12 - Prob. 34QCh. 12 - Prob. 35QCh. 12 - Prob. 36QCh. 12 - Prob. 37QCh. 12 - Prob. 38QCh. 12 - Prob. 39QCh. 12 - Prob. 40QCh. 12 - Prob. 41QCh. 12 - Prob. 42QCh. 12 - Prob. 43QCh. 12 - Prob. 44QCh. 12 - Prob. 1PCh. 12 - How fast would a muon have to be traveling...Ch. 12 - The lifetime of a free neutron is 886 s. If a...Ch. 12 - Prob. 4PCh. 12 - The formula for length contraction gives the...Ch. 12 - Prob. 6PCh. 12 - Prob. 7PCh. 12 - Prob. 8PCh. 12 - Prob. 9PCh. 12 - . In a particular beam of protons, each particle...Ch. 12 - . A particle of rest energy 140 MeV moves at a...Ch. 12 - . If the relativistic kinetic energy of a particle...Ch. 12 - Prob. 13PCh. 12 - Prob. 14PCh. 12 - Prob. 15PCh. 12 - . How many years would you have to wait to observe...Ch. 12 - Prob. 17PCh. 12 - Prob. 18PCh. 12 - . A compact neutron star has a mass of kg (about...Ch. 12 - Prob. 20PCh. 12 - Prob. 21PCh. 12 - Prob. 22PCh. 12 - Prob. 23PCh. 12 - Prob. 24PCh. 12 - Prob. 25PCh. 12 - Prob. 26PCh. 12 - Prob. 27PCh. 12 - Prob. 28PCh. 12 - Prob. 29PCh. 12 - Prob. 30PCh. 12 - Prob. 31PCh. 12 - . If the average lifetime of a proton was 1033...Ch. 12 - Prob. 1CCh. 12 - Prob. 2CCh. 12 - Prob. 3CCh. 12 - Prob. 4CCh. 12 - Prob. 5CCh. 12 - Prob. 6CCh. 12 - Prob. 7CCh. 12 - Prob. 8CCh. 12 - Prob. 9CCh. 12 - Prob. 10C
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- What does the term Hubble time mean in cosmology, and what is the current best calculation for the Hubble time?arrow_forwardThe matter density in the Universe today is Pm = -27 kg m-3. What would 2.7 x 10 be the value of the density parameter, 2o, if the Hubble constant had the value Ho = 38 km/s/Mpc? Assume the Universe does not contain dark energy and choose the option below that best matches your answer. Select one: O a. 0.1 O b. 2. О с. 1. O d. 0.7 О е. 0.5arrow_forward1. The current (critical) density of our universe is pe = 10-26kg/m³. Assume the universe is filled with cubes with equal size that each contain one person of m = 100kg. What would the length of the side of such a cube have to be in order to give the correct critical density? How many hydrogen atoms would you need in a box of 1 m³ to reach the critical density? The matter we know, which consists mostly of hydrogen, constitutes only 4.8% of the current critical energy density of our universe. So how many hydrogen atoms are actually in a box of 1 m3 in our universe? Deep space is very empty and a much better vacuum than we can obtain on earth in a laboratory.arrow_forward
- What are the possible fates for the universe? What do they depend on? What appears to be the actual fate of the universe, according to current cosmology? Needs Complete solution with 100 % accuracy plz.arrow_forwardQuestion A7 Consider the following line element, ds² = - dt² + a² (t) (da² + dy²) + b² (t) dz², where a(t) and b(t) are distinct functions. State whether or not this line element obeys the Cosmological Principle, if applied to describe the universe on large scales. Justify your answer.arrow_forwardExplain what is meant by the term cosmological redshift, and contrast it with the Doppler shift that is observed when a luminous object recedes from an observer. From the defi- nition of redshift in terms of the observed and emitted wavelengths of photons, obtain an expression that relates redshift to the expansion factor of the Universe. Hence calculate the expansion factor of the Universe while a photon travels from a galaxy with redshift z = 1.arrow_forward
- Hubble'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_forwardI asked the following question and was given the attached solution: Suppose that the universe were full of spherical objects, each of mass m and radius r . If the objects were distributed uniformly throughout the universe, what number density (#/m3) of spherical objects would be required to make the density equal to the critical density of our Universe? Values: m = 4 kg r = 0.0407 m Answer must be in scientific notation and include zero decimal places (1 sig fig --- e.g., 1234 should be written as 1*10^3) I don't follow the work and I got the wrong answer, so please help and show your work as I do not follow along easily thanksarrow_forwardWhich of the following is least reasonable regarding cosmic background radiation (CBR)? Group of answer choices CBR correponds to a solar temperature of about 6,000 degrees and implies that the Universe was about 3K right after the Big Bang. The original CBR corresponded to a much higher temperature, but the expansion of the Universe has caused to be strongly Doppler-shifted toward longer wavelengths. Satellite-based telescopes were crucial to the discovery of CBR because much of the CBR spectrum cannot be detected through our atmosphere. The motion of the Earth produces a Doppler shift, which causes CBR to appear a little hotter in front of us and a little colder behind us. Data for CBR is collected by pointing telescopes to regions that do not appear to have any bright objects.arrow_forward
- Problem 3. Consider a flat, single component universe. 1. For a light source at redshift z that is observed at time to, show that z changes at a rate dz dto = = Ho(1 + 2) — Ho(1+2)³(¹+w)/2 (2.1) 2. For what values of w does the observed redshift increase with time? 3. Assuming the single component is matter and Ho = 68 km/s/Mpc, you observe a galaxy at z = 1. Using Equation 2.1, determine how long you will have to keep observing the galaxy in order to see its redshift change by 1 part in 106.arrow_forwardWhy does primordial nuclesythesis end about 3 minutes after the Big Bang ? select one : a. The number densities of photons is too large at this time and the photons induce fission , stopping nuclei formation b. The universe is tooo hot at t=3 minutes c. The number densities of neutrons and protons and other nuclei are too small at this time and fusion fades out . d. Deuterium has a lifetime of 3 minutes , so after this time no more deuterium survives as it decays away ?arrow_forwardOnset of Cosmic Reionization: Evidence of an Ionized Bubble Merely 680 Myr a er the Big Bang.V. Tilvi et al 2020 ApJL 891 L10. Link: https://iopscience.iop.org/article/10.3847/2041-8213/ab75ecAnswer the following questions related to this article:(a) What is the so called cosmic reionization process?(b) What are Lyα lines and why did the researches want to observe them?(c) What do the authors intend to point out with Figure 1 (see article)?(d) How is confirmed that the peaks seen in Figure 3 are actually from Lyα emissions?(e) How are the bubble sizes of the galaxies estimated?(f) What is special about the findings in the article and what are the scientific implications?arrow_forward
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