<< Chapter < Page Chapter >> Page >

Local fluff.

Diagram of the Local Fluff. In this plot the vertical axis is labeled “Distance (light years)”, and runs from -20 to 20 in increments of 10. The horizontal axis is labeled “Distance (light years)”, and also runs from -20 to 20 in increments of 10. The Sun is plotted in the center of the plot (0, 0) as a yellow circle. A grey arrow is drawn from the Sun pointing toward the upper right and is labeled “Direction of sun’s motion”. Two stars are plotted; “Alpha centauri” as a yellow dot at about (4, -4), and “Sirius” as a blue dot near (-8, -8). Along the bottom a blue arrow points to the right and is labeled “Galactic Center”. Some cloud names are given; the “Local Cloud” near the Sun, “Blue” near bottom center, and the “G cloud” to the right of the Sun. Five unlabeled arrows are drawn above the Sun pointing to the upper left indicating motions of the local cloud. A further unlabeled arrow is drawn starting near (-2, -2) pointing up. An arrow is drawn starting near (1, 20) pointing left and labeled “Mic”. An arrow is drawn starting near (-10, 10) pointing upward and labeled “Hyades”. An arrow is drawn starting near (-12, 4) pointing left and labeled “Aur”. Finally, an arrow is drawn starting near (-11, -3) pointing left and labeled “Gem”. To the right and slightly above the Sun are the constellations “Aql”, “Eri” and “Oph”.
The Sun and planets are currently moving through the Local Interstellar Cloud, which is also called the Local Fluff. Fluff is an appropriate description because the density of this cloud is only about 0.3 atom per cm 3 . In comparison, Earth’s atmosphere at the edge of space has around 1.2 × 10 13 molecules per cm 3 . This image shows the patches of interstellar matter (mostly hydrogen gas) within about 20 light-years of the Sun. The temperature of the Local Interstellar Cloud is about 7000 K. The arrows point toward the directions that different parts of the cloud are moving. The names associated with each arrow indicate the constellations located on the sky toward which the parts of the cloud are headed. The solar system is thought to have entered the Local Interstellar Cloud, which is a small cloud located within a much larger superbubble that is expanding outward from the Scorpius-Centaurus region of the sky, at some point between 44,000 and 150,000 years ago and is expected to remain within it for another 10,000 to 20,000 years. (credit: modification of work by NASA/Goddard/Adler/University Chicago/Wesleyan)

Key concepts and summary

The Sun is located at the edge of a low-density cloud called the Local Fluff. The Sun and this cloud are located within the Local Bubble, a region extending to at least 300 light-years from the Sun, within which the density of interstellar material is extremely low. Astronomers think this bubble was blown by some nearby stars that experienced a strong wind and some supernova explosions.

For further exploration

Articles

Goodman, A. “Recycling the Universe.” Sky&Telescope November (2000): 44. Review of how stellar evolution, the interstellar medium, and supernovae all work together to recycle cosmic material.

Greenberg, J. “The Secrets of Stardust.” Scientific American December (2000): 70. The makeup and evolutionary role of solid particles between the stars.

Knapp, G. “The Stuff between the Stars.” Sky&Telescope May (1995): 20. An introduction to the interstellar medium.

Nadis, S. “Searching for the Molecules of Life in Space.” Sky&Telescope January (2002): 32. Recent observations of water in the interstellar medium by satellite telescopes.

Olinto, A. “Solving the Mystery of Cosmic Rays.” Astronomy April (2014): 30. What accelerates them to such high energies.

Reynolds, R. “The Gas between the Stars.” Scientific American January (2002): 34. On the interstellar medium.

Websites and apps

Barnard, E. E., Biographical Memoir: http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/barnard-edward.pdf.

Cosmicopia: http://helios.gsfc.nasa.gov/cosmic.html. NASA’s learning site explains about the history and modern understanding of cosmic rays.

DECO: https://wipac.wisc.edu/deco. A smart-phone app for turning your phone into a cosmic-ray detector.

Hubble Space Telescope Images of Nebulae: http://hubblesite.org/gallery/album/nebula/. Click on any of the beautiful images in this collection, and you are taken to a page with more information; while looking at these images, you may also want to browse through the slide sequence on the meaning of colors in the Hubble pictures (http://hubblesite.org/gallery/behind_the_pictures/meaning_of_color/).

Questions & Answers

What is inflation
Bright Reply
a general and ongoing rise in the level of prices in an economy
AI-Robot
What are the factors that affect demand for a commodity
Florence Reply
price
Kenu
differentiate between demand and supply giving examples
Lambiv Reply
differentiated between demand and supply using examples
Lambiv
what is labour ?
Lambiv
how will I do?
Venny Reply
how is the graph works?I don't fully understand
Rezat Reply
information
Eliyee
devaluation
Eliyee
t
WARKISA
hi guys good evening to all
Lambiv
multiple choice question
Aster Reply
appreciation
Eliyee
explain perfect market
Lindiwe Reply
In economics, a perfect market refers to a theoretical construct where all participants have perfect information, goods are homogenous, there are no barriers to entry or exit, and prices are determined solely by supply and demand. It's an idealized model used for analysis,
Ezea
What is ceteris paribus?
Shukri Reply
other things being equal
AI-Robot
When MP₁ becomes negative, TP start to decline. Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 • Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of lab
Kelo
Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 • Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of labour (APL) and marginal product of labour (MPL)
Kelo
yes,thank you
Shukri
Can I ask you other question?
Shukri
what is monopoly mean?
Habtamu Reply
What is different between quantity demand and demand?
Shukri Reply
Quantity demanded refers to the specific amount of a good or service that consumers are willing and able to purchase at a give price and within a specific time period. Demand, on the other hand, is a broader concept that encompasses the entire relationship between price and quantity demanded
Ezea
ok
Shukri
how do you save a country economic situation when it's falling apart
Lilia Reply
what is the difference between economic growth and development
Fiker Reply
Economic growth as an increase in the production and consumption of goods and services within an economy.but Economic development as a broader concept that encompasses not only economic growth but also social & human well being.
Shukri
production function means
Jabir
What do you think is more important to focus on when considering inequality ?
Abdisa Reply
any question about economics?
Awais Reply
sir...I just want to ask one question... Define the term contract curve? if you are free please help me to find this answer 🙏
Asui
it is a curve that we get after connecting the pareto optimal combinations of two consumers after their mutually beneficial trade offs
Awais
thank you so much 👍 sir
Asui
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities, where neither p
Cornelius
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities,
Cornelius
Suppose a consumer consuming two commodities X and Y has The following utility function u=X0.4 Y0.6. If the price of the X and Y are 2 and 3 respectively and income Constraint is birr 50. A,Calculate quantities of x and y which maximize utility. B,Calculate value of Lagrange multiplier. C,Calculate quantities of X and Y consumed with a given price. D,alculate optimum level of output .
Feyisa Reply
Answer
Feyisa
c
Jabir
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Astronomy. OpenStax CNX. Apr 12, 2017 Download for free at http://cnx.org/content/col11992/1.13
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Astronomy' conversation and receive update notifications?

Ask