Mysterious structures found at the edge of the Solar System

Astronomers find evidence that the Solar System may be larger than previously expected.

The Kuiper Belt may hide a mysterious structure beyond what was expected. Credit: NASA
The Kuiper Belt may hide a mysterious structure beyond what was expected. Credit: NASA

Many people may have the idea that the end of the Solar System is where Pluto is located. However, our place in the Universe is much larger than the orbit of the dwarf planet and extends for several light years. One of the most famous structures is the so-called Oort Cloud, which would be a cloud of ice and rocks that would surround the entire Solar System at a distance of 1 light year from the Sun.

Comets and asteroids are believed to originate in the Oort Cloud and the idea is that they are attracted towards the Sun after some external object disturbs the balance of the cloud. It would be located in the most extreme part of the Solar System where other stars and other objects interact with our system. Despite this, it is not the only structure located at the farthest end of the Sun.

Most of the known dwarf planets, including Pluto, would be located in another structure called the Kuiper belt. The belt is composed of smaller objects, most of which are asteroids, similar to the asteroid belt. However, a new study suggests there is more to the Kuiper belt than previously thought, changing our understanding of the Solar System.

Kuiper Belt

Beyond Neptune's orbit lies a region of small rocks and objects like dwarf planets called the Kuiper belt. The dwarf planet Pluto is one of the inhabitants of this region, which extends between 30 and 50 astronomical units from the Sun. Other famous dwarf planets such as Haumea, Makemake, and Eris can also be found in this belt.

Some comets may originate from the Kuiper belt, which has objects made of ice due to its distance from the Sun.

Because it is an object far from the Sun and has little interference from massive objects such as Jupiter and other planets, the Kuiper belt has a more primordial composition. It is expected that the belt still contains traces of the cloud material that formed the Solar System. Because they are beyond the orbit of Neptune, the objects in the belt are called trans-Neptunian objects (TNOs) or Kuiper belt objects (KBOs).

Nebula

Studying the Kuiper belt involves studying the material that gave rise to the Solar System, known as a nebula. The nebula that is called the solar nebula was a cloud of gas and dust that collapsed under its own gravitational field. This cloud was composed mainly of hydrogen and helium, in addition to a few metals that are found even on Earth.

It is not known exactly what started the formation of the Solar System, but some studies suggest that external factors such as a nearby supernova may have started the process. Since the Kuiper belt may still have traces of this primordial cloud, astronomers have focused on missions to understand and analyze this region of the Solar System in search of answers about the formation of the Sun and planets.

New Horizons

One of the missions designed to study the Kuiper Belt was the New Horizons probe, which was launched in 2006. On a trip to the edge of the Solar System, New Horizons was responsible for photographing Pluto in detail. This happened in July 2015 when the probe flew over the dwarf planet and took the most detailed photos of the object. The photos showed ice mountains, geological processes and the thin atmosphere.

Pluto was captured in detail when the New Horizons probe passed close to the dwarf planet. Credit: New Horizons/NASA
Pluto was captured in detail when the New Horizons probe passed close to the dwarf planet. Credit: New Horizons/NASA

After Pluto, New Horizons continued its mission to the object Arrokoth, which became the most distant object ever explored by a probe. The probe has now passed the belt and is located about 60 astronomical units from the Sun. And new data that the probe has found is showing that it is possible that there is a mysterious structure around the Kuiper belt.

Discovery

In a new paper published in The Planetary Science Journal, a group of astronomers report that they have found about 11 objects far beyond the Kuiper belt. These new objects could indicate that the Kuiper belt is not as small as previously thought or that there is a second, Kuiper belt-like structure a little further away. This discovery changes models of how the solar system formed and evolved.

The Kuiper Belt extends about 20 astronomical units just beyond the orbit of Neptune. Credit: NASA
The Kuiper Belt extends about 20 astronomical units just beyond the orbit of Neptune. Credit: NASA

In the region between 55 and 70 astronomical units, nothing was found by New Horizons, confirming the old prediction of the size of the Kuiper belt. The 11 objects found were even further away than expected, indicating that something is different than expected. The team is still waiting for confirmation of the position and size of the planets to know whether we are dealing with a new structure or not.

New model

The confirmation could shed light on the formation process of the Solar System, as the model could be more detailed. Furthermore, the objects could contain primordial material from the Solar System, providing a rich source for understanding the early stages of formation and how this would be related to the existence of life on Earth.

Reference of the news:

Fraser et al. 2024 Candidate Distant Trans-Neptunian Objects Detected by the New Horizons Subaru TNO Survey The Planetary Science Journal.