What does the word comet come from?

The word comet comes from the Greek ??????? (kometes), which means "long-haired." Indeed, it is the appearance of the bright coma that is the standard observational test for whether a newly discovered object is a comet or an asteroid.

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What is planet Killer?

The "planet killer" was an informal name given by Spock in 2267, based on a description given by Commodore Matt Decker, to an automated, self-propelled doomsday machine capable of destroying entire planets. This robot was encountered by two Federation starships: the USS Constellation and the USS Enterprise. Keeping this in consideration, is didymos a threat? DART will reach the asteroid Didymos and its smaller moonlet Dimorphos when they are around 6.8 million miles away from Earth, slamming into the smaller body. It presents no impact threat to Earth. The fact that the asteroid system occasionally passes close to Earth was the reason they were chosen as a target for DART.

How big is a comet?

Comets are very small in size relative to planets. Their average diameters usually range from 750 meters (2,460 feet) or less to about 20 kilometers (12 miles). How long do comets stay in the sky? Comets are primitive bodies that formed at the same time as the Sun and planets about 4.6 billion years ago. But once they come close enough to be seen, comets begin to fall apart and they must eventually vanish from sight, often in less than a million years after first sighting.

Where do most comets arrive from?

Where Do Comets Come From? It is thought that most comets originate in a vast cloud of ice and dust that surrounds the solar system. The Oort Cloud, as it is called, extends several thousand times farther from the Sun than Pluto, the outermost planet.