Scientists Find Evidence for Unknown Objects in Distant Solar System

The Kuiper Belt is a vast ring with thousands of large, unknown, icy objects and small planets that orbit our solar system.

In a recent study, which hasn’t been published yet but is getting attention from the scientific community, experts discovered signs of about twelve large objects beyond the farthest edge of the belt. This discovery shows that the Kuiper Belt may be much bigger than originally believed.

Size of the Kuiper Belt

Scientists currently believe the Kuiper Belt stretches out to about fifty astronomical units (AU) from the center of our solar system. An astronomical unit is the distance between the Earth and Sun.

However, although it is cautioned that findings may not be conclusive, researchers in this study suggest there might be certain strange objects tucked away in even more distant areas, possibly more than 60 AU from the center. This is a difference of at least ten AU, which is quite expansive and roughly the same as that between the Sun and Saturn.

Another possibility to consider is that there might be a “second” belt of objects out there, positioned beyond the Kuiper Belt, a less-explored part of our distant solar system.

Discovery of the Kuiper Belt

The discovery was made thanks to the sensors on NASA’s New Horizons spacecraft. Launched in 2006, this probe was the first to get a close look at Pluto, which is part of the Kuiper Belt. It acts as the eyes of astronomers right on the edge of our solar system.

Even though New Horizons is now quite far from the Sun, about fifty-seven astronomical units away, it is supposed to have left the Kuiper Belt behind. However, its sensors are still picking up traces of dust, which is a sign objects nearby are colliding.

Alan Stern, the main scientist in charge of the New Horizons mission and a planetary scientist at the Southwest Research Institute, said, “The number of impacts is not declining.” He added that “the simplest explanation for that is…there is more stuff out there that we haven’t detected.”

Lookout for hidden objects

The discovery caught the attention of astronomers. They used New Horizons’ path to figure out where to look for hidden objects in the Kuiper Belt. They searched through hundreds of pictures of the night sky taken by Japan’s Subaru Telescope and detected twelve objects that seemed to fit the bill.

However, the findings are still not definite. Other telescopes that have looked at different parts of the outer solar system haven’t found much evidence beyond the Kuiper Belt’s boundaries.

Interesting fact: There are an estimated trillion or more comets within the Kuiper Belt… hundreds of thousands of which are larger than 100 km (62 miles) in diameter.

It is not clear if worlds in this distant, cold region are capable of supporting life as we know it. pic.twitter.com/4FUzPDiAQV

— World and Science (@WorldAndScience) October 4, 2023

Pedro Bernardinelli, an astronomer from the University of Washington who wasn’t part of this research, raised a question: “Why are we not seeing these things? Did everyone get unlucky? It’s possible, but it’s hard.”

Hilke Schlichting, an astrophysicist at the University of California, Los Angeles, pointed out that the Hubble Space Telescope spotted the faint glimmering of stars that might have been caused by unknown objects from the Kuiper Belt passing by them.

Schlichting wondered if “there [is] a larger population beyond 60 AU” and added that “maybe that’s what we’re seeing.” However, he did admit he was uncertain.