TNOs orbit the Sun beyond Neptune’s 30 astronomical units (AU), within the Kuiper Belt and farther out. The Kuiper Belt is a region rich with comets, icy bodies, and rocky debris, containing up to 100,000 objects. Scientists are especially interested in extreme TNOs (eTNOs) because of their unusual orbits, which may hint at the presence of a massive, hidden Planet Nine.

The DES team, led by Gary Bernstein and Pedro Bernardinelli from the University of Pennsylvania, adapted data from a camera designed to observe dark energy for TNO detection. By developing unique algorithms, the researchers identified moving objects across multiple images, revealing the 139 minor planets. Seven of these are eTNOs, which could contribute to the search for Planet Nine.

Planet Nine is theorized to be five to 15 times Earth’s mass and to orbit the Sun at around 400 AU. Its gravitational influence might explain why some eTNOs have clustered orbits. While the new study’s eTNOs do not yet confirm the clustering pattern, the team believes further discoveries could bring clarity.

The DES only analyzed a small fraction of its data for TNOs, but researchers predict up to 500 additional TNOs could emerge. Future projects like the Vera C. Rubin Observatory promise even greater sensitivity, potentially revealing thousands more distant objects.

The evidence for Planet Nine remains inconclusive. While some astronomers support the theory, others propose alternative explanations, such as collective gravitational effects among TNOs. Regardless of Planet Nine’s existence, these discoveries provide crucial insights into the early history of the solar system and the dynamics of its outer regions.

“TNOs are like frozen time capsules,” Bernstein explains. They hold clues about the solar system’s evolution and the forces that shaped it. As researchers continue to explore the farthest reaches of the Sun’s domain, each discovery brings us closer to understanding the mysteries lurking in our cosmic backyard.