The Oort Cloud is a theoretical, massive spherical shell surrounding the Sun and planets. Though invisible due to its vast size and faint particles, astronomers infer its existence as it explains the appearance of long-period comets. In The Conversation, James Wray,  professor in the School of Earth and Atmospheric Sciences, discusses his research on the Oort Cloud, along with two comets—Tsuchinshan-ATLAS (Comet C/2023 A3) and C/2024 S1 (ATLAS)—which are expected to be visible this month.