comet
/ˈkɒmɪt
/noun
A celestial object consisting of a nucleus of ice and dust and, when near the sun, a ‘tail’ of gas and dust particles pointing away from the sun.Some explanations for extinctions and evolution include strikes by asteroids or comets....
- We have just discussed some of the positive benefits of planetary impact by comets and asteroids.
- There are vast numbers of comets in the solar system, more than there are asteroids, but most lie out of sight beyond Pluto.
Originating in the remotest regions of the solar system, most comets follow regular eccentric orbits and appear in the inner solar system as periodic comets, some of which break up and can be the origin of annual meteor showers. They were formerly considered to be supernatural omens.
Derivatives
cometary
/ adjective ...- Ease of accessibility is itself a natural resource and opens up the economic possibility of efficient exportation of asteroidal or cometary natural resources to Earth and other exploration targets.
- The Hubble Space Telescope captured a picture of starlit asteroidal and cometary debris encircling the yellow dwarf star HD 107146.
- At a distance of one light-week, our solar system is lost in the Sun's glare; even farther out is a collection of cometary objects called the Oort Cloud, depicted as a sphere one light year across.
Origin
Late Old English, from Latin cometa, from Greek komētēs 'long-haired (star)', from komē 'hair'; reinforced by Old French comete.
We get the word comet from Greek komētēs ‘long-haired’. The ancient Greeks gazed into the night sky and observed a comet's long tail. To their eyes it resembled streaming hair, hence their name for what they called ‘the long-haired star’.