dwarf planet, a nonluminous body of rock or gas that orbits the sun and has a rounded shape due to its gravity. Unlike a planet, a dwarf planet is not capable of clearing its orbit of smaller objects by collision, capture, or other means. The recognized dwarf planets in the solar system are Ceres, Pluto, Haumea, Makemake, and Eris. All of these are significantly smaller in size and mass than Mercury. Eris, which is slightly larger than Pluto, is the largest known dwarf planet. Except for Ceres, all of the dwarf planets follow orbits that lie or take them beyond Neptune into the outer reaches of the solar system.
Ceres and Pluto have been considered planets at time in the past. The discovery of other bodies in the asteroid belt led to the reclassification of Ceres in the mid-19th cent. as an asteroid. The discovery of other bodies beyond the orbit of Neptune that were similar in size to Pluto led to the declassification of Pluto as a planet in 2006, when the International Astronomical Union adopted the classification of dwarf planet.
"dwarf planet." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (August 19, 2019). https://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/dwarf-planet
"dwarf planet." The Columbia Encyclopedia, 6th ed.. . Retrieved August 19, 2019 from Encyclopedia.com: https://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/dwarf-planet
Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).
Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.
Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:
Modern Language Association
The Chicago Manual of Style
American Psychological Association
- Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
- In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.