New Planet Found Deep in the Solar System

Caltech researchers have discovered an immense planet known as Planet Nine that orbits approximately 20 times further from the Sun than Neptune and 10 times greater in mass than Earth, taking between 10,000-20 years for one orbit around our solar system.

Size

An enormous planet that dwarfs Earth has been discovered slumbering at the edges of our solar system, found within an obscure corner of Kuiper Belt that receives minimal sunlight or energy, 10x further away than Neptune but only 380 times further than Earth itself.

Astronomers published in the Astronomical Journal have released a preprint suggesting that Planet Nine may have left its formation disk 3-10 million years after being formed – an event with profound ramifications for understanding how our solar system formed.

Scientists have proposed several theories as to how Planet Nine might have formed from the outer Solar System. One possibility suggests it formed out of a mass ring of ice or solid material propelled outward from its disk by centrifugation of gas from within it, while another possibility involves its formation accumulating material from planetesimals remaining from initial formation of our Solar System.

This model would significantly alter our understanding of solar system evolution, since it implies that its first eight planets formed out of an expanded disk of matter than previously imagined. Furthermore, this would explain a number of strange features within the Kuiper Belt area located beyond Neptune.

At its heart lies this intriguing theory’s potential to explain the orbits of Sedna and other clustered Kuiper Belt objects like it: mean-motion resonance is responsible for curving their orbits and giving rise to mean-motion resonance patterns that arise when one object interacts with another from faraway.

These interactions have led some scientists to interpret them as signs that the gravity of Planet Nine may have had an impact on some Kuiper Belt objects during early solar system development – something which has revived interest in Planet Nine theory.

Arizona State University researchers are conducting this study by using computer simulations to model Planet Nine’s orbit and its influence on Kuiper Belt in depth. If they locate this planet, it could likely be closer than initially believed.

Orbit

Long has it been speculated that there could be an unseen planet far beyond Pluto and other dwarf planets in our solar system, yet far beyond Pluto itself and some dwarf planets like Ceres and Ceres II. Now Caltech scientists have provided mathematical evidence supporting this idea, suggesting there could be an unseen Neptune-sized world in an extremely long orbit around our Sun that takes it 20 times further out than Neptune to an average distance of 56 billion miles from us.

The notion of a ninth planet provides an explanation for some of the more peculiar orbital behavior observed in the outer solar system, specifically with regard to Kuiper Belt objects (KBOs), small icy bodies that reside beyond Neptune in orbit and appear tilted at an odd angle – perhaps being drawn in by some unseen force that pushes these KBOs in their strange orbits.

These orbits are held together by the gravity of an unknown planet — Planet Nine — believed to be between five and 10 times larger than Earth and 250 times further away from the Sun than Pluto. Most intriguingly, though, Planet Nine may actually be an exotic explanation for those curious orbits: perhaps even acting like a mini black hole!

Astronomers have begun searching the night sky in search of any signs of this elusive object, though their odds of discovery are slim. Next-generation telescopes that can see faint, distant planets such as James Webb Space Telescope or Vera Rubin Observatory offer better chances of discovering any such planets.

Brown and Batygin provided circumstantial evidence for the existence of Planet Nine by noting that KBO orbits are consistent with a planet similar to Neptune in size with an inclination angle of 16 degrees; such orbits could represent what an early solar system gas giant might have looked like.

Mean-motion resonance may explain these orbits; this effect only became noticeable early on in our solar system’s history, possibly as the result of close passes between planets as they formed.

Gravity

Gravity is the force that attracts objects together in space, responsible for sublunar tides on Earth and antipodal tides in space, essential to living organisms’ functioning. Gravity also accounts for weightlessness on the Moon as well as planet orbits within our Solar System.

Astronomers have proposed that an unidentified ninth planet exists beyond Neptune but have not found any direct evidence for its existence. Their belief stems from observations that suggest its gravity had an influence on some small bodies beyond Neptune that appear to have orbital parameters that suggest possible influence by this unknown giant planet.

Researchers reported in 2014 that they had discovered that certain Kuiper Belt objects located beyond Neptune had distinctive clustering patterns. All their orbits appeared tilted by 90 degrees with respect to solar system plane, and these objects showed unusual perihelion and retrograde motions relative to other Kuiper Belt objects.

Renu Malhotra of the University of Arizona used observations from Kepler Space Telescope to analyze orbits of objects near Neptune that appeared to be moving away from it and determine their motions as they moved further from Neptune. They determined that their orbits may have been caused by massive masses 10 times greater than Earth, possibly creating their circularity.

This model suggests that Saturn and Jupiter created an instability which propelled Uranus and Neptune toward the outer regions of our Solar System, prompting their journey as Uranian planets into trans-Neptunian regions. Their interactions may have also created “Planet Nine,” a gas giant whose gravitational pull should have tilted Kuiper Belt objects present therein.

Brown and Batygin conducted computer modeling simulations of Kuiper Belt objects to examine how they might respond to an hypothetical Planet Nine. They discovered that any objects within its orbits must move into positions at right angles to Planet Nine in order to move into perpendicular orbits that remained perpendicular to the sun’s plane – something Brown and Batygin believe fits five known objects perfectly.

Origin

Uranus and Neptune played an instrumental role in this process of formation, but two astronomers now propose another theory as to why these outer planets have extended orbits around our Sun.

Astronomers began proposing the existence of a ninth planet in 2016. Since then, numerous astronomers have searched for it without success.

Scientists speculate that the discovery of a ninth planet could provide new insight into how our solar system evolved during its early days, explaining why Mercury, Venus, Earth and Mars formed in their present forms in the first place.

Researchers suggest that planet formation could have produced an array of small icy objects located beyond Neptune in the Kuiper Belt that share similar orbits as though resulting from one massive object.

They also exhibit anti-aligning orbits, meaning that they never collide with one another – this phenomenon is known as mean-motion resonance.

That explains why six Kuiper Belt objects at great distance orbit around each other with elliptical orbits that loop outward in one quadrant and tilt at roughly the same angle, according to researchers. Such alignment occurs only once every 14,000 cases.

That is why several astronomers, including Caltech’s Mike Brown and Konstantin Batygin, have suggested the possibility of Planet Nine since first suggesting it in January 2016.

Brown and Batygin published several papers in March 2018 which examined all evidence supporting their hypothesis of Planet Nine formation, using it to create models of how it may have formed and its possible orbital effects on Kuiper Belt objects.

The resultant model suggests that Planet Nine orbits much closer to the Sun than previously estimated, making its orbit much smaller and potentially brighter at close approaches to it (known as its perihelion).