DISCLAIMER: This article is being kept online for historical purposes. Though accurate at last review, it is no longer being updated. The page may contain broken links or outdated information.
Galaxy evolution in the early universe
Shapiro, Kristen L. Department of Astronomy, University of California, Berkeley, California.
- Looking backward through the universe
- The nature of galaxies in the early universe
- Drivers of galaxy evolution
- Linking galaxies across cosmic time
- Related Primary Literature
- Additional Reading
Galaxies are the fundamental building blocks of the universe. There are several hundred billion galaxies in the universe, each containing tens to hundreds of billions of stars. In the local universe, three general classes of galaxies are observed: spiral, irregular, and elliptical. Spiral galaxies, such as the Milky Way, are stellar systems characterized by a thin, rotating disk surrounding a central spherical bulge (Fig. 1). A small fraction of the matter in these galaxies (roughly 5%) is gas, located primarily in the thin disk and continuously forming new stars. Irregular galaxies are the less massive cousins of spiral galaxies; these systems have slightly larger gas fractions, little or no coherent spiral structure in their disks, and no central bulge. At the other extreme, elliptical galaxies are gas-poor, roughly spherical systems that resemble scaled-up bulges.
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 10,000 highly qualified scientists and 45 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