Final answer:
Comets are mostly ice and have lengthy orbital periods ranging from a few years to tens of thousands of years; an example calculation of an orbital period is about 350 years for an object, indicating a position beyond the orbit of Pluto.
Step-by-step explanation:
Objects with a composition that is mostly ice and having orbital periods ranging from 3.3 to 70,000 years are typically comets. Comets are celestial bodies composed mainly of ice and dust that, when near the sun, display a visible atmosphere and sometimes a tail. These objects follow highly elliptical orbits that take them to the outer reaches of the solar system and back. The orbital period of a hypothetical object can be calculated assuming a semi-major axis. For instance, if the square root of 125,000 is taken, the resulting figure is approximately 353.6 years, thus the orbital period of this object would be about 350 years. This long orbital period suggests that such an object would reside well beyond the orbit of Pluto. Comets are part of the dynamic and ever-changing solar system, influenced by the gravitational forces of the sun and planets as well as the structure and evolution of their own orbits.