Young, Eliot Department of Space Studies, Southwest Research Institute, Boulder, Colorado.
Beatty, J. Kelly Senior Editor, "Sky and Telescope Magazine," Cambridge, Massachusetts.
Last reviewed:August 2018
Show previous versions
- Origins and taxonomy of the Sun's planets
- Definition of “planet”
- Minor bodies
- Possible unknown planets
- Planetary orbits and motions
- Planetary characteristics
- Planetary interiors
- Composition and phase changes
- Surface geology
- Impact cratering
- Catastrophic disruption and reaccretion
- Magnetic fields
- Characteristics of a dynamo
- Planetary atmospheres
- Links to Primary Literature
- Additional Readings
A relatively large, rounded, celestial body that developed around a star and cannot sustain nuclear fusion reactors in its interior. Although humankind has known about the existence of planets in our solar system for centuries, recent discoveries have challenged a simple, conventional definition of planethood. These discoveries in the last few decades include “failed” stars called brown dwarfs, thousands of “exoplanets” beyond our solar system, including “rogue” exoplanets that do not orbit stars, as well as several new, planet-like bodies in the region beyond Pluto. Based on the richness displayed in our solar system and by exoplanets, planets are extremely diverse as a class of celestial object, existing across a wide range of masses, sizes, and compositions (Fig. 1). See also: Brown dwarf; Exoplanets; Solar system
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