UNIVERSE (LOOSELEAF):STARS+GALAXIES
UNIVERSE (LOOSELEAF):STARS+GALAXIES
6th Edition
ISBN: 9781319115043
Author: Freedman
Publisher: MAC HIGHER
bartleby

Concept explainers

Question
Book Icon
Chapter 26, Problem 1Q
To determine

The definition of horizon and flatness problem and the steps adopted to resolve them by the idea of inflation.

Expert Solution & Answer
Check Mark

Explanation of Solution

Introduction:

Horizon problem originates due to the observation of constant temperature of (CMBR) cosmic microwave background radiation. During the observation, it is found that the cosmic microwave radiation has nearly the same temperature in each direction, which is not possible.

Flatness problem is the cosmological problem, which describes that the density of the universe is close to the critical value of density, which is impossible and leads to the flatness problem.

Horizon problem originates due to the observation of the nearly constant temperature of the cosmic microwave background radiation. After the big bang, the radiation emitted is continuously traveling in the observable universe. Two points in the universe which are at very distant locations to each other, that is nearly a million light-years, cannot have the temperature of cosmic microwave background radiation similar to each other. This is because the radiation from the big bang cannot reach such a distant point in the space, so it leads to the horizon problem.

On the other hand, flatness problem arises due to the observation of density of the universe to be nearly equal to the critical density, which is considered impossible. After the billion light-years from the big bang, still the geometry of the universe resembles that of flat surface which is considered a problem in cosmology.

The solution to the horizon and the flatness problem is cosmic inflation which states that the universe is expanding after the big bang at an exponential rate in the initial inflationary period resulting in the isotropic nature of the universe observed today. This theory also states the fact that during the inflationary period the energy and mass were equally distributed resulting in constant temperature observed in the universe.

Conclusion:

Therefore, the cosmic inflation theory gives the solution to Horizon and Flatness problems.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Astronomers now think that there is a black hole with more than 4 milliion times the mass of our Sun at the center of our galaxy? Roughly how large would the event horizon of such a supermassive black hole be? a. the size of our moon b. about 4 light years across c. about 17 times the size of our sun d. about the size of an atom (so much mass really compresses the event horizon) e. this question can't be answered without knowing what kind of stars were swallowed by the black hole
The mass density of our universe is measured to be about 10-29 kg/m3. If an arbitrary point is chosen as the center, how large is the radius of a spherical surface centered at the point so that the mass enclosed in the surface will become a blackhole observed by someone outside the surface? A. 4.2 trillion light years B. 420 billion light years C. 42 billion light years D. 4.2 billion light years   Is the answer D? Thanks!
Based on what you have learned about galaxy formation from a protogalactic cloud (and similarly star formation from a protostellar cloud), the fact that dark matter in a galaxy is distributed over a much larger volume than luminous matter can be explained by I. Dark matter does not emit EM radiations. II. The pressure of an ideal gas decreases when temperature drops. III. The temperature of an ideal gas decreases when its thermal energy decreases. A. I only B. I and III only C. II and III only D. I, II and III   Is the answer C? Thank you!
Knowledge Booster
Background pattern image
Physics
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
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Horizons: Exploring the Universe (MindTap Course ...
Physics
ISBN:9781305960961
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
Text book image
Astronomy
Physics
ISBN:9781938168284
Author:Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher:OpenStax