IS THERE A HIDDEN WORLD IN OUR SOLAR SYSTEM?
Ever since 1846, when the planet Neptune was discovered, astronomers and physicists have entertained the theory that there was another planet in the solar system that was influencing the orbits of Uranus and Neptune.
When Pluto was discovered in 1930 by Clyde Tombaugh, making it the first known object in the Kuiper Belt – a large ring of icy bodies beyond Neptune’s orbit – and hailed as the ninth planet, many believed this was the celestial body responsible for disturbances observed with the orbits of the other two planets.
Ever since 1846, when the planet Neptune was discovered, astronomers and physicists have entertained the theory that there was another planet in the solar system that was influencing the orbits of Uranus and Neptune.
When Pluto was discovered in 1930 by Clyde Tombaugh, making it the first known object in the Kuiper Belt – a large ring of icy bodies beyond Neptune’s orbit – and hailed as the ninth planet, many believed this was the celestial body responsible for disturbances observed with the orbits of the other two planets.
 Image Source: www.animalia-live.club |  Image source: www./pinterest.com |
Additional research made it evident that Pluto’s gravitational influence was too weak to account for the anomalies observed and then, in 2006, Pluto was reclassified as a dwarf planet by the International Astronomical Union “because other objects might cross its orbit” (i.e. It does not clear its orbit of other objects as planets do). That leaves the solar system with only eight “real” planets accounted for and a mystery regarding the existence or non-existence of a ninth planet in the solar system. https://science.nasa.gov/dwarf-planets/pluto/facts/
Because the orbits of the planets within our solar system have been stable for billions of years, the cause of the identified anomalies would support the theory of a planet that was knocked off course long ago and now has an incredibly long orbit around the sun.
Articles published on worldatlas.com website states, “According to theories regarding the effects on the orbits of Neptune and Uranus, experts believe that Planet X could be up to ten times larger than Earth and would take approximately 10,000 to 20,000 years to complete one full orbit around the Sun. Even at its closest approach, Planet X would be seven times farther from the Sun than Neptune is.”
Because the orbits of the planets within our solar system have been stable for billions of years, the cause of the identified anomalies would support the theory of a planet that was knocked off course long ago and now has an incredibly long orbit around the sun.
Articles published on worldatlas.com website states, “According to theories regarding the effects on the orbits of Neptune and Uranus, experts believe that Planet X could be up to ten times larger than Earth and would take approximately 10,000 to 20,000 years to complete one full orbit around the Sun. Even at its closest approach, Planet X would be seven times farther from the Sun than Neptune is.”
Older depiction of Solar System leaving out other dwarf planets
Image Source: www.ar.inspiredartists.com
Image Source: www.ar.inspiredartists.com
THE MYSTERIAL ORBIT ANOMALIES
Decades of observation and research have produced data regarding certain anomalies in the orbits of distant dwarf planets and icy objects in the Kuiper Belt, leading scientists to believe that our understanding of the solar system is still incomplete.
These orbital oddities have caused many astronomers to consider whether a hypothetical celestial body – a real “ninth planet” – remains invisible to astronomers, but the existence of which can be inferred from its influence on other objects. But how could such a thing have eluded the experts all these years?
SEARCH FOR A MISSING PLANET
In the wake of Pluto’s reclassification, finding an explanation for the anomalies in the Keiper Belt has sparked renewed interest. There are numerous efforts underway.
▼Pluto as seen by NASA's New Horizons spacecraft (2015)
Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Image Source: www.cnn.com/planet-y-solar-system-study
Decades of observation and research have produced data regarding certain anomalies in the orbits of distant dwarf planets and icy objects in the Kuiper Belt, leading scientists to believe that our understanding of the solar system is still incomplete.
These orbital oddities have caused many astronomers to consider whether a hypothetical celestial body – a real “ninth planet” – remains invisible to astronomers, but the existence of which can be inferred from its influence on other objects. But how could such a thing have eluded the experts all these years?
SEARCH FOR A MISSING PLANET
In the wake of Pluto’s reclassification, finding an explanation for the anomalies in the Keiper Belt has sparked renewed interest. There are numerous efforts underway.
▼Pluto as seen by NASA's New Horizons spacecraft (2015)
Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Image Source: www.cnn.com/planet-y-solar-system-study
CALTECH
In 2016, Caltech astronomers Konstantin Batygin and Mike Brown proposed that an unknown Planet Nine might still exist in an orbit much further beyond Pluto in the solar system’s outermost region.
“Their idea was that a hidden planet roughly the size of Neptune, and between 5 and 10 times the mass of Earth, might be orbiting the Sun on a highly elongated path that could be 30 times more distant than Neptune, meaning it would take up to 20,000 years to complete just one orbit. While the idea remains possible based on extreme gravitational anomalies observed in trans-Neptunian objects (ETNOs), the question of Planet Nine’s existence remains theoretical.” thedebrief.org/the-hunt-for-planet-x
NATIONAL TSING HUA UNIVERSITY
However, in a recent study conducted at Taiwan’s National Tsing Hua University, Terry Phan and his colleagues studied archival data from decommissioned infrared satellites in search of slow-moving distant objects that might be candidates for the mysterious, hypothetical ninth planet. After filtering out known celestial bodies, Phan and his colleagues identified one good possibility: a faint dot that appeared consistently across both of their datasets and displayed promising characteristics, including moving in a way suggestive of an extremely distant planetary orbit. Their findings have been accepted for publication in Publications of the Astronomical Society of Australia.
While many are skeptical about Phan’s findings, the discrepancies found by dissenting scientists “…don’t necessarily rule out the possibility that the newly discovered candidate might actually be an undiscovered planet. However, if this were the case, its peculiarities seem to suggest that it is not the mystery ‘Planet Nine,’ but instead an entirely separate and unexpected celestial body that, if anything, might disprove original ideas about orbital instabilities in the outer solar system.” Micah Hanks, May, 2025 writing for thedebrief.org/the-hunt-for-planet-x
VERA C. RUBIN OBSERVATORY
In Hawaii, scientists at the Keck and Subaru Telescopes continue the search, but the best hope for success is the Vera C. Rubin Observatory.
In 2016, Caltech astronomers Konstantin Batygin and Mike Brown proposed that an unknown Planet Nine might still exist in an orbit much further beyond Pluto in the solar system’s outermost region.
“Their idea was that a hidden planet roughly the size of Neptune, and between 5 and 10 times the mass of Earth, might be orbiting the Sun on a highly elongated path that could be 30 times more distant than Neptune, meaning it would take up to 20,000 years to complete just one orbit. While the idea remains possible based on extreme gravitational anomalies observed in trans-Neptunian objects (ETNOs), the question of Planet Nine’s existence remains theoretical.” thedebrief.org/the-hunt-for-planet-x
NATIONAL TSING HUA UNIVERSITY
However, in a recent study conducted at Taiwan’s National Tsing Hua University, Terry Phan and his colleagues studied archival data from decommissioned infrared satellites in search of slow-moving distant objects that might be candidates for the mysterious, hypothetical ninth planet. After filtering out known celestial bodies, Phan and his colleagues identified one good possibility: a faint dot that appeared consistently across both of their datasets and displayed promising characteristics, including moving in a way suggestive of an extremely distant planetary orbit. Their findings have been accepted for publication in Publications of the Astronomical Society of Australia.
While many are skeptical about Phan’s findings, the discrepancies found by dissenting scientists “…don’t necessarily rule out the possibility that the newly discovered candidate might actually be an undiscovered planet. However, if this were the case, its peculiarities seem to suggest that it is not the mystery ‘Planet Nine,’ but instead an entirely separate and unexpected celestial body that, if anything, might disprove original ideas about orbital instabilities in the outer solar system.” Micah Hanks, May, 2025 writing for thedebrief.org/the-hunt-for-planet-x
VERA C. RUBIN OBSERVATORY
In Hawaii, scientists at the Keck and Subaru Telescopes continue the search, but the best hope for success is the Vera C. Rubin Observatory.
They began initial on-sky operations on a decade-long survey of the Southern Hemisphere in late 2024. Equipped with the world’s largest digital camera, the observatory could identify many more Kuiper Belt objects with suspiciously aligned orbits, if they exist.Scientists expect great things to come of this project.
CARNEGIE INSTITUTION FOR SCIENCE
A team of scientists at the Carnegie Institution for Science, Washington D.C., believe that in the formation of the solar system there was an additional planet located between Saturn and Uranus which was “flung out” of the solar system while still in its infancy.
“The theory goes that the Sun was once surrounded by a disk of gas and dust. Through countless collisions, planets started to form, orbiting our star at a relatively short distance.
According to Victor Tangermann, in a 2020 article in futurism.com, “The theory goes that the Sun was once surrounded by a disk of gas and dust. Through countless collisions, planets started to form, orbiting our star at a relatively short distance. The more massive planets then kicked off a series of gravitational interactions, causing the planets to reshuffle into their current arrangement.”
The lead author of a paper published in the Icarus Journal, Carnegie postdoctoral fellow Matt Clement, by running 6,000 computer simulations, they found the final arrangement of Neptune and Uranus, was determined “…by both the mass of the Kuiper belt, a region of dwarf planets and planetoids in the far reaches of the solar system, and an “ejected ice giant” that was kicked out when the planetary system was still young.” futurism.com/evidence-another-planet
PRINCETON UNIVERSITY
A recent study suggests a potential new candidate, which the paper’s authors have dubbed Planet Y, although it has not been detected but merely inferred by the tilted orbits of some distant objects in the Kuiper Belt.
The lead author Amir Siraj, an astrophysicist and a doctoral candidate of astrophysical sciences at Princeton University, said, “One explanation is the presence of an unseen planet, probably smaller than the Earth and probably bigger than Mercury, orbiting in the deep outer solar system. This paper is not a discovery of a planet, but it’s certainly the discovery of a puzzle for which a planet is a likely solution.”
TAKE AWAY
These studies add weight to the hypothesis that there is currently an undiscovered planet lurking in the far outer solar system. The studies demonstrate the need to conduct surveys of trans-Neptunian objects, particularly in the distant Kuiper Belt, as they hold the key to a deeper understanding of how our entire solar system formed billions of years ago.
It also points out that knowledge is a work in progress.
JUST SAYIN’
Sources:
https://science.nasa.gov/dwarf-planets/pluto/facts/
https://www.worldatlas.com/space/the-stray-planet-that-escaped-our-solar-system-v2.html
https://thedebrief.org/the-hunt-for-planet-x-is-a-secret-super-earth-lurking-in-our-solar-system/
https://futurism.com/evidence-another-planet-solar-system-escaped
https://www.cnn.com/2025/10/03/science/planet-y-solar-system-study
https://arxiv.org/html/2504.17288v1
https://science.nasa.gov/solar-system/planet-x/
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CARNEGIE INSTITUTION FOR SCIENCE
A team of scientists at the Carnegie Institution for Science, Washington D.C., believe that in the formation of the solar system there was an additional planet located between Saturn and Uranus which was “flung out” of the solar system while still in its infancy.
“The theory goes that the Sun was once surrounded by a disk of gas and dust. Through countless collisions, planets started to form, orbiting our star at a relatively short distance.
According to Victor Tangermann, in a 2020 article in futurism.com, “The theory goes that the Sun was once surrounded by a disk of gas and dust. Through countless collisions, planets started to form, orbiting our star at a relatively short distance. The more massive planets then kicked off a series of gravitational interactions, causing the planets to reshuffle into their current arrangement.”
The lead author of a paper published in the Icarus Journal, Carnegie postdoctoral fellow Matt Clement, by running 6,000 computer simulations, they found the final arrangement of Neptune and Uranus, was determined “…by both the mass of the Kuiper belt, a region of dwarf planets and planetoids in the far reaches of the solar system, and an “ejected ice giant” that was kicked out when the planetary system was still young.” futurism.com/evidence-another-planet
PRINCETON UNIVERSITY
A recent study suggests a potential new candidate, which the paper’s authors have dubbed Planet Y, although it has not been detected but merely inferred by the tilted orbits of some distant objects in the Kuiper Belt.
The lead author Amir Siraj, an astrophysicist and a doctoral candidate of astrophysical sciences at Princeton University, said, “One explanation is the presence of an unseen planet, probably smaller than the Earth and probably bigger than Mercury, orbiting in the deep outer solar system. This paper is not a discovery of a planet, but it’s certainly the discovery of a puzzle for which a planet is a likely solution.”
TAKE AWAY
These studies add weight to the hypothesis that there is currently an undiscovered planet lurking in the far outer solar system. The studies demonstrate the need to conduct surveys of trans-Neptunian objects, particularly in the distant Kuiper Belt, as they hold the key to a deeper understanding of how our entire solar system formed billions of years ago.
It also points out that knowledge is a work in progress.
JUST SAYIN’
Sources:
https://science.nasa.gov/dwarf-planets/pluto/facts/
https://www.worldatlas.com/space/the-stray-planet-that-escaped-our-solar-system-v2.html
https://thedebrief.org/the-hunt-for-planet-x-is-a-secret-super-earth-lurking-in-our-solar-system/
https://futurism.com/evidence-another-planet-solar-system-escaped
https://www.cnn.com/2025/10/03/science/planet-y-solar-system-study
https://arxiv.org/html/2504.17288v1
https://science.nasa.gov/solar-system/planet-x/
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