|
|
Article: Dark Matter
- Article from:
- The Gale Encyclopedia of Science
CopyrightCOPYRIGHT 2008 The Gale Group, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
|
Dark Matter
Resources
Dark matter is the term astronomers use to describe material in the universe that is non-luminous
—
that is, material that does not emit or reflect light and that is therefore invisible. Everything seen when looking through a telescope is visible because it is either emitting or reflecting light; stars, nebulae, and galaxies are examples of luminous objects. However, luminous matter appears to make up only a small fraction of all the matter in the universe, perhaps only a small percent. The rest of the matter is cold, dark, and hidden from direct view.
Because dark matter is invisible, it can only be detected through indirect means, primarily by analyzing its ...