planetoid
/'plænitɔid/
Definition
- Noun:
- A small celestial body that orbits the sun: A "planetoid" is any of the many small, often irregularly shaped, objects that revolve around the sun, primarily found in the region between Mars and Jupiter (the asteroid belt).
Usage
- The term "planetoid" is used in astronomy to describe small solar system bodies that are larger than meteoroids but smaller than planets. It is often used synonymously with "asteroid," particularly for the larger bodies in the asteroid belt.
- Example:
Examples
- Noun:
- Astronomers have cataloged thousands of planetoids in our solar system.
- The spacecraft was sent to study a large planetoid between the orbits of Mars and Jupiter.
Advanced Usage
- Historical Usage: The term was historically used to describe bodies now classified as "dwarf planets," such as Pluto, before the formal definition of that category.
- Pluto was once considered a planetoid before being reclassified as a dwarf planet.
Variants and Related Words
- Asteroid (n): A more common synonym for a small rocky body orbiting the sun, especially in the asteroid belt.
- The terms "asteroid" and "planetoid" are often used interchangeably.
- Minor Planet (n): Another formal term used in astronomy for a small celestial body in direct orbit around the Sun that is not a planet or a comet.
- The International Astronomical Union maintains a list of numbered minor planets, which include planetoids.
Synonyms
- Asteroid: A small rocky body orbiting the sun.
- Minor Planet: A small celestial body orbiting the sun that is not a planet or a comet.
Related Phrases
- Planetoid Belt: A region of space containing many planetoids, analogous to the asteroid belt.
- Scientists hypothesize that other star systems might have their own planetoid belts.
Noun
-
any of numerous small celestial bodies that move around the sun
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