Answers (2)
Astronomers suggest that these objects grew from an early cloud of dust particles and condensing ice, which stuck together to form larger objects. However, these objects were too thinly spread out to continue to grow into large planets.
Researchers now know that comets have a solid nucleus, generally between 1 and 12 miles [1 and 20 kilometers] across. The nucleus can best be described as a dark, dirty iceberg made up mostly of water ice mixed with dust. Close-up images of Halley’s Comet taken by the Giotto spacecraft in 1986 show jets of gas and dust emanating from the comet. These emissions make up the bright comet head and tail seen from the earth.
When a comet approaches the sun, its icy nucleus gradually disintegrates, releasing a trail of rock grains, or meteoroids. These grains are not as light as the dust in a comet tail and are thus not blown out into space by the solar wind. Instead, they form a swath of debris that orbits the sun along the parent comet’s path.
The new discoveries and understanding of distant objects orbiting the sun add force to the Bible passage recorded at Isaiah 40:26: “Raise your eyes high up and see. Who has created these things? It is the One who is bringing forth the army of them even by number, all of whom he calls even by name.”
Who knows what may yet be found in our solar system?
More information on this an other related subject can be explored on jw.org
There is no defined difference between bodies in space. That is to say there is no way to say you are looking at a comet, asteroid, meteoroid, moonlet, or planet. A meteoroid is defined to be a rock in space, but when it enters the Earth's atmosphere then it is a meteor, and when it strikes the ground it is a meteorite. Other than that the names are assigned arbitrarily.