Kwok, Sun Faculty of Science, University of Hong Kong, Pokfulam, Hong Kong.
- Discovery and catalogs
- Spectral characteristics
- Observing techniques
- Internal dynamics
- Importance of studying nebulae
- Links to Primary Literature
- Additional Readings
A concentration of interstellar matter that is largely gaseous but can contain almost all states of matter, including solid particles, and that is a constituent of the Milky Way Galaxy or another galaxy. The term “nebula” was originally used to refer to any fixed, extended, and usually fuzzy luminous celestial object. With increased angular resolution of telescopes, astronomers learned that nebulae can be separated into two classes: those that are stellar systems made up of individual stars, and those that are gaseous in nature and diffuse in appearance. Examples of stellar systems include galaxies (which contain billions of stars and are located outside our own Milky Way Galaxy) and star clusters such as open clusters and globular clusters (which contain thousands of stars and are within the Milky Way Galaxy). This article is restricted to the modern definition of nebulae, which are gaseous objects usually located within the Milky Way Galaxy, although with increasingly powerful telescopes gaseous nebulae can now be observed in external galaxies. See also: Galaxy, external; Milky Way Galaxy; Star
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information