Long-period comets originate from which region?

• A. Kuiper Belt
• B. Oort Cloud
• C. Asteroid Belt
• D. Interstellar space

Answer: (B)

Long-period comets come from a distant, roughly spherical reservoir called the Oort Cloud. This vast shell of icy bodies surrounds the solar system far beyond the outer planets, and gravitational nudges from passing stars or the Milky Way can send some of these bodies into highly elongated orbits that bring them into the inner solar system. Their orbits take thousands to millions of years to complete, which is why they’re classified as long-period comets and can appear from any direction.

In contrast, the Kuiper Belt sits in a disk beyond Neptune and mainly supplies short-period comets with much shorter orbital cycles, because these objects are much closer to the Sun and more strongly perturbed by Neptune. The Asteroid Belt between Mars and Jupiter is rocky and not the source of icy comets. Interstellar space is outside the Sun’s gravitational domain, so it isn’t a typical birthplace for these bodies.