Which statement best describes the location of the Oort cloud?

• A. A disk of debris between Mars and Jupiter
• B. A spherical cloud surrounding the solar system far from the Sun
• C. A belt of asteroids beyond Neptune
• D. A ring of comets near Saturn

Answer: (B)

The idea being tested is that the Oort cloud is a distant, roughly spherical shell that surrounds the Sun and the solar system, far from the Sun itself. This three-dimensional distribution fits what we infer from long-period comets, which arrive from many different directions, suggesting comets are stored in a vast, isotropic halo rather than in a flat ring. The Oort cloud is thought to extend far beyond the outer planets, well past Neptune, making it the outermost reservoir of icy bodies in the solar system. In contrast, the asteroid belt between Mars and Jupiter is a flattened disk of rocky debris, and the Kuiper belt beyond Neptune is also a disk-like region of icy bodies. A ring of comets near Saturn isn’t a recognized, persistent structure like the Oort cloud.