Final answer:
Asteroids are the smallest celestial bodies mentioned, with diameters up to about 500 km, with objects in the Kuiper Belt like Pluto being larger, around 2,000 km in diameter. Major planets vary significantly in size, with Jupiter being the largest at 139,820 km in diameter.
Step-by-step explanation:
The cosmos is vast and filled with a myriad of different celestial bodies. When we categorize them by actual size, starting from the smallest we encounter are the asteroids or minor planets, which can be up to about 500 kilometers in diameter. Next, there are objects in the Kuiper Belt, like Pluto, that roughly compare to the size of our own Moon, about 2,000 kilometers in diameter. The major planets in our solar system have sizes that greatly vary. Beginning with the smallest, Mercury, to the largest, Jupiter, with its diameter spanning an impressive 139,820 kilometers. It's important to note that many planets also have moons (satellites) that vary in size, and the four outer planets—Jupiter, Saturn, Uranus, and Neptune—also possess ring systems composed of many smaller particles.
The types of celestial bodies listed here give us a glimpse into the diversity of objects that make up our solar system. Each body, from the small Kuiper Belt objects like Pluto to the gigantic planets like Jupiter, represent the different components that an astronomer would study to learn more about our celestial neighborhood.