The Newest Member of the Solar System: A Mysterious Dwarf World Beyond Neptune

Introduction

Our Solar System, once thought to contain only nine planets, has undergone dramatic changes in recent decades. With Pluto’s reclassification as a “dwarf planet” in 2006 and the subsequent discovery of new celestial bodies, the definition of what constitutes a planet has continued to evolve. Among the latest additions is a distant, icy world that scientists have tentatively named "Farout" and its even more mysterious companion "Farfarout"—both located in the outer reaches of the Solar System. These newly discovered objects have redefined the limits of our planetary neighborhood and sparked excitement about what else may lie beyond.

A Changing Solar System

Traditionally, our Solar System included the Sun, eight planets, their moons, and a collection of asteroids and comets. However, advances in telescopic technology and the increased interest in deep space exploration have led to the discovery of several Trans-Neptunian Objects (TNOs). These objects orbit the Sun at incredible distances, far beyond Neptune—the eighth and farthest recognized planet.

The recognition of dwarf planets like Eris, Haumea, and Makemake was just the beginning. In 2018 and 2019, astronomers announced the discoveries of "Farout" and "Farfarout," the most distant known objects orbiting our Sun, with Farfarout being the farthest.

Meet Farfarout: The Current Farthest Object in the Solar System

Discovered in 2018 by astronomers using the Subaru Telescope in Hawaii, Farfarout (official designation: 2018 AG37) is a celestial body located at an astonishing average distance of 132 astronomical units (AU) from the Sun. For comparison, Pluto orbits at about 39 AU.

Farfarout's distance is so extreme that sunlight takes over 13 hours to reach it. It is estimated to be around 400 kilometers (248 miles) in diameter, which puts it near the boundary of being considered a dwarf planet.

Because of its elongated and eccentric orbit, Farfarout travels in and out of the Solar System over a period of about 1,000 years. This highly stretched path may have been shaped by gravitational interactions with Neptune—or possibly even Planet Nine, a hypothetical massive planet theorized to exist beyond Neptune.

Discovery and Observation

Farfarout was first spotted in January 2018 but took years of follow-up observation to confirm its orbit. Astronomers Scott Sheppard, David Tholen, and Chad Trujillo are credited with its discovery. The team was specifically hunting for new planetary objects that might support the existence of Planet Nine.

Farfarout’s detection wasn’t easy. Because it's so distant and dim, it appeared as a tiny dot in the telescope’s camera. Confirming its orbit required tracking its slow movement over several years. Only with repeated observations were scientists able to calculate its elliptical trajectory and classify it officially as part of the Solar System.

Why Farfarout Matters

While Farfarout itself is relatively small, its discovery has enormous implications for astronomy. Here’s why:

1. Clues About the Solar System’s Formation

Studying distant objects like Farfarout helps scientists understand the early evolution of our Solar System. These bodies are believed to be primordial remnants, frozen in time since the Solar System’s birth over 4.6 billion years ago. Their composition, orbit, and interactions may reveal secrets about how planets formed and migrated over time.

2. Evidence for Planet Nine

Farfarout’s orbit, like those of several other distant TNOs, is highly elliptical and oddly aligned. Some astronomers believe that this unusual pattern could be the result of a large, unseen planet—Planet Nine—exerting gravitational influence. While Planet Nine has not yet been directly observed, the discovery of Farfarout and similar objects adds weight to the theory.

3. Redefining Planetary Boundaries

Farfarout pushes the limits of how we define a Solar System object. If such small, distant bodies are still gravitationally bound to the Sun, should we reconsider what constitutes a "planet"? The ongoing debate about classification challenges our current understanding and may lead to updated definitions in the future.

What Lies Beyond?

If Farfarout exists, could there be more? The answer is almost certainly yes. Astronomers believe there may be hundreds or even thousands of similarly distant bodies in the outer Solar System, collectively forming a region known as the Inner Oort Cloud. This zone is beyond the Kuiper Belt and thought to be the source of long-period comets.

With better telescopes and more powerful detection algorithms, astronomers hope to identify even more of these distant worlds in the coming years.

Is Farfarout a Planet?

Technically, Farfarout is not considered a planet. Its small size and lack of gravitational dominance in its orbit disqualify it under current definitions. However, it is a candidate for dwarf planet status, much like Pluto, Eris, and others.

Still, its nickname and its status as the farthest known Solar System object have earned it considerable attention. In the realm of cosmic discoveries, even small bodies can have big significance.

Upcoming Missions and Tools

Discoveries like Farfarout inspire further investment in deep-space observation. Upcoming telescopes like the Vera C. Rubin Observatory in Chile (expected to begin operations soon) are expected to revolutionize our view of the outer Solar System.

These telescopes will scan the night sky with unprecedented detail and may discover many more distant Solar System members—perhaps even the elusive Planet Nine.

Conclusion

The discovery of Farfarout, the newest confirmed member of the Solar System, highlights just how little we truly know about the distant reaches of our own cosmic neighborhood. At over 132 AU from the Sun, this icy body challenges our definitions, inspires fresh theories, and fuels a renewed sense of wonder about what else might be out there.

As technology improves and new observatories come online, we are poised to learn even more about the frontier of the Solar System. Farfarout is not just a distant rock in space; it’s a symbol of how exploration is still very much alive, even within our own backyard.

The Solar System may be far larger—and far stranger—than we ever imagined.