Astronomers may have detected signs of an ancient, untouched cluster of icy objects far beyond Neptune, offering new clues about how the early solar system formed, according to a report by NDTV citing Daily Galaxy.
Scientists believe the grouping—located inside the Kuiper Belt, the solar system's distant "third region"—could be a "primordial cluster" that has remained stable for billions of years. The Kuiper Belt stretches from roughly 30 to 50 astronomical units (AU) from the Sun and contains millions of icy remnants from the earliest stages of planet formation, including bodies more than 100 kilometers wide.
While the region is often compared to the asteroid belt, researchers say it is far thicker and shaped heavily by the gravitational pull of giant planets, especially Neptune. This influence has changed the distribution of objects over time, making the belt more complex than once thought.
A Princeton University team led by astrophysicist Aamir Siraj has now identified a new structure about 43 AU from the Sun. The group's extremely calm and stable orbits suggest it has remained largely undisturbed since the solar system's formation. Siraj told New Scientist that this stability could help scientists better understand how the early solar system evolved.
Researchers say the finding may also shed light on how giant planets gradually shifted to their current orbits and what interstellar conditions the solar system faced during its birth.
The discovery builds on a 2011 finding of a "kernel"—a region in the Kuiper Belt with long-term stable, low-eccentricity orbits. The newly observed grouping sits just inside that kernel and appears even more stable, raising the possibility of an "inner kernel."
Princeton researchers now suggest the classical Kuiper Belt includes three major components: a wide-ranging "hot" population and two colder, more stable regions known as the core and the kernel. The potential new inner kernel at 43 AU could represent an even older, less disturbed structure from the solar system's earliest days.