Astronomy
1st Edition
ISBN: 9781938168284
Author: Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher: OpenStax
expand_more
expand_more
format_list_bulleted
Concept explainers
Textbook Question
Chapter 20, Problem 35E
Consider a grain of sand that contains 1 mg of oxygen (a typical amount for a medium-sized sand grain, since sand is mostly SiO2). How many oxygen atoms does the grain contain? What is the radius of the sphere you would have to spread them out over if you wanted them to have the same density as the interstellar medium, about 1 atom per cm3? You can look up the mass of an oxygen atom.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
In the deep space between galaxies, the number density of atoms is as low as 106 atoms/m3, and the temperature is a frigid 2.7 K.
part (a) What is the pressure, in pascals, in the region between galaxies?
part (b) What volume, in cubic meters, is occupied by 3.5 mol of gas? Part (c) If this volume is a cube, what is the length of one of its edges, in kilometers?
A star is formed when the gravitational attraction overcomes the pressure due to the gases inside.Thus we can write(in-picture) .... Assuming the ideal gas equation, we can write P = nkT, where n is the number of atoms/volume. Let M and m denote the total mass and the mass of each gas atom. Using the above equation, show that the condition for star formation is that the mass of the star obeys M > MJ, where : (in-picture)
How do I convert m^3 to Barrels of Oil? I know 1 Barrel of Oil equals 42 US Gallons. How do I convert 1580 m^3 to Barrels of Oil? Thank you!
Chapter 20 Solutions
Astronomy
Ch. 20 - Identify several dark nebulae in photographs in...Ch. 20 - Why do nebulae near hot stars look red? Why do...Ch. 20 - Describe the characteristics of the various kinds...Ch. 20 - Prepare a table listing the different ways in...Ch. 20 - Describe how the 21-cm line of hydrogen is formed....Ch. 20 - Describe the properties of the dust grains found...Ch. 20 - Why is it difficult to determine where cosmic rays...Ch. 20 - What causes reddening of starlight? Explain how...Ch. 20 - Why do molecules, including H2 and more complex...Ch. 20 - Why can’t we use visible light telescopes to study...
Ch. 20 - The mass of the interstellar medium is determined...Ch. 20 - Where does interstellar dust come from? How does...Ch. 20 - Figure 20.2 shows a reddish glow around the star...Ch. 20 - If the red glow around Antares is indeed produced...Ch. 20 - Even though neutral hydrogen is the most abundant...Ch. 20 - The terms H II and H2 are both pronounced “H two.”...Ch. 20 - Suppose someone told you that she had discovered H...Ch. 20 - Describe the spectrum of each of the following: A....Ch. 20 - According to the text, a star must be hotter than...Ch. 20 - From the comments in the text about which kinds of...Ch. 20 - One way to calculate the size and shape of the...Ch. 20 - New stars form in regions where the density of gas...Ch. 20 - Thinking about the topics in this chapter, here is...Ch. 20 - Stars form in the Milky Way at a rate of about 1...Ch. 20 - The 21-cm line can be used not just to find out...Ch. 20 - Astronomers recently detected light emitted by a...Ch. 20 - We can detect 21-cm emission from other galaxies...Ch. 20 - We have said repeatedly that blue light undergoes...Ch. 20 - Suppose that, instead of being inside the Local...Ch. 20 - Suppose that, instead of being inside the Local...Ch. 20 - A molecular cloud is about 1000 times denser than...Ch. 20 - Would you expect to be able to detect an H II...Ch. 20 - Suppose that you gathered a ball of interstellar...Ch. 20 - At the average density of the interstellar medium,...Ch. 20 - Consider a grain of sand that contains 1 mg of...Ch. 20 - H II regions can exist only if there is a nearby...Ch. 20 - In the text, we said that the five-times ionized...Ch. 20 - Dust was originally discovered because the stars...Ch. 20 - How would the density inside a cold cloud (T=10K)...Ch. 20 - The text says that the Local Fluff, which...
Additional Science Textbook Solutions
Find more solutions based on key concepts
What is the role of “loose” electrons in heat conductors?
Conceptual Physics (12th Edition)
3. What is free-fall, and why does it make you weightless? Briefly describe why astronauts are weightless in th...
The Cosmic Perspective (8th Edition)
2. Choose a device that reduces the pressure caused by a force.
a. Scissors
b. Knife
c. Snowshoes
d. Nail
e. Sy...
College Physics
3. What is free-fall, and why does it make you weightless? Briefly describe why astronauts are weightless in th...
The Cosmic Perspective
A. Suppose that glider D is free to move and glider C rebounds. 1. In the spaces provided, draw separate free-b...
Tutorials in Introductory Physics
5. Why don’t equal masses of golf balls and Ping-Pong balls contain the same number of balls?
Conceptual Physical Science (6th Edition)
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
- In the deep space between galaxies, the density of atoms is as low as 106 atoms/m3, and the temperature is a frigid 2.7 K. What is the pressure (in Pa)? What volume (in m3) is occupied by 4 mol of gas? If this volume is a cube, what is the length of its sides in kilometers?arrow_forwardModels of the first star-forming clouds indicate that they had a temperature of roughly 150 K and a particle density of roughly 400,000 particles per cubic centimeter at the time they started trapping their internal thermal energy. ▼ Part A Estimate the mass at which thermal pressure balances gravity for these values of pressure and temperature. Express your answer in kilograms. —| ΑΣΦ Mcloud Submit Part B = Mcloud How does that mass compare with the Sun's mass? Express your answer in solar masses. Submit Request Answer = ΤΙ ΑΣΦ Request Answer ? ? kg MSun Reviewarrow_forward1. A simple model of a star of radius R assumes (not very realistically!) that the density p is constant. We further assume that the star is made up of pure hydrogen, obeying the ideal gas law. (a) We assume that the gas pressure P drops to zero at the star's surface, e.g., we adopt the boundary condition P(R) = 0; for this part, solve the equations of stellar structure to get the pressure profile P = P(r). (Note: in this particular case, it does not matter whether you use the boundary condition P(R) = 0 or dP/dr = 0 at r=0!) (b) Find the temperature profile T = T(r). (c) If the nuclear energy generation rate ɛ scales with temperature as ɛ * T, determine the radius at which ɛ drops to 10% of its central value. (d) Suppose that ɛ ~ T17. immediately above? What would be the corresponding radius, as computed in (c)arrow_forward
- The initial stage of star formation is the collapse of a gravitationally unstable volume of gas within a molecular cloud. a Find the Jeans mass and radius for a molecular cloud at a temperature T = 10 K and number density n = 106 cm-3. Assume the mean particle mass is umH, where u = 2.8. Give your answers in solar masses and au, respectively. b Assuming the molecular gas follows the ideal gas law, calculate |dP/dr| = JAP/Ar| ~ Pe/RJ (units [N m-³]) at the beginning of the collapse, where P. is an approximate value for the central pressure of the cloud. Assume that P molecular cloud, and the mass and radius are the values determined above. 0 at the edge of the c Show that |dP/dr| is significantly smaller than GM,p/r². What can you interpret about the core's dynamics from this result?arrow_forwardThe equation of hydrostatic equilibrium is dP/dr = ( −GMr / r2 ) ρ where Mr is the mass interior to the radius r, and ρ is the density.Consider the atmosphere of a star which is isothermal. You may assume that the mass of theatmosphere does not contribute significantly to the total mass of the star, so that the surfacegravity g = GMr/r2 is constant at all heights in the isothermal atmosphere. Assume an idealgas law P = nkT = (ρ/µmH) kT, where µ is the mean molecular weight and mH is the mass of ahydrogen atom. By solving the equation of hydrostatic equilibrium with these approximations, show that P(r) = P(0) exp ((−gµmH/kT)r) Briefly describe the meaning of the expression kT/gµmH. Some white dwarfs have an atmosphere of mostly hydrogen plasma, whereas others have an atmosphere dominated by helium plasma. For the simple model above, briefly discuss what major difference would be seen between these two cases. You can assume the same temperature and surface gravity for the two cases.arrow_forwardIn the deep space between galaxies, the density of atoms is 1 million atoms per m3 (i.e. there are 1 million atoms in a cubic meter), and the temperature is 3 K. (a) What is the pressure in space? (b) What volume (in cubic meters) is occupied by 100 moles of space gas? (c) If this volume is a cube, what is the length of one its sides in kilometers?arrow_forward
- The initial stage of star formation is the collapse of a gravitationally unstable volume of gas within a molecular cloud. a Find the Jeans mass and radius for a molecular cloud at a temperature T = 10 K and number density n = 106 cm-3. Assume the mean particle mass is umH, where u 2.8. Give your answers in solar masses and au, respectively. b Assuming the molecular gas follows the ideal gas law, calculate |dP/dr| ~ JAP/Ar| Pe/ RJ (units [N m-³]) at the beginning of the collapse, where Pe is an approximate value for the central pressure of the cloud. Assume that P molecular cloud, and the mass and radius are the values determined above. 0 at the edge of the c Show that |dP/dr| is significantly smaller than GM,p/r. What can you interpret about the core's dynamics from this result? d Show that if the excess energy due to the change in gravitational potential energy during the core's collapse is radiated away efficiently, and the collapse is therefore isothermal, the contribution of dP/dr…arrow_forwardDetermine the Miller indices. Don't skip any mathematical solution and solve it step by step. thank youarrow_forwardThe number density of air in a child's balloon is roughly the same as sea level air, 1019 particles/cm3. If the balloon is now 20 cm in diameter, to what diameter (in km) would it need to expand to make the gas inside have the same number density as the ISM, about 1 particle/cm3?arrow_forward
- Our galaxy is approximately 100,000 light years in diameter and 2,000 light years thick through the plane of the galaxy. If we were to compare the ratio of the diameter galaxy and its thickness to the ratio of the diameter of a CD and its thickness (CD has a diameter of 12 cm and thickness of 0.6 mm), what would be the factor differentiating those ratios? Put differently, if the galaxy were scaled down to the diameter of a CD, how many times thicker or thinner would the galaxy be than the CD? (For example if it would be twice as thick, you would answer 2 and if it were twice as thin you would answer 0.5 (aka 1/2))arrow_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_forwardThe relationship between the average luminosity and pulsation period for Cepheid variable stars can be written L = L⊙P3.7, where the period P is measured in days. A cepheid variable is observed in a distant galaxy, and is determined to have a pulsation period of 50 days. The average flux received from this star is measured to be 2.14×10−16Wm−2. Determine the distance to the galaxy and express your answer in units of Mpc.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- AstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStaxStars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
Astronomy
Physics
ISBN:9781938168284
Author:Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher:OpenStax
Stars and Galaxies (MindTap Course List)
Physics
ISBN:9781337399944
Author:Michael A. Seeds
Publisher:Cengage Learning
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
General Relativity: The Curvature of Spacetime; Author: Professor Dave Explains;https://www.youtube.com/watch?v=R7V3koyL7Mc;License: Standard YouTube License, CC-BY