Classify the following celestial objects based on their formation and characteristics: a rocky planet, a gas giant, a comet, and an asteroid. Which category best describes each object?

Rocky planets form from solid material that has accumulated in the inner part of the protoplanetary disk, giving them high density and a rocky surface; Earth is a prime example. Gas giants form farther out where the disk is cold enough for hydrogen and helium to be captured, resulting in low-density, massive gaseous envelopes; Jupiter illustrates this. Comets are icy bodies that formed in the far outer solar system and develop glowing comas and tails when they approach the Sun, as seen with Halley’s comet. Asteroids are leftover rocky fragments that never coalesced into a planet, usually found in the asteroid belt between Mars and Jupiter. Thus, each object is best described by its formation zone and material composition.