The Evidence for Planet Nine has been Strengthened by a New, More Detailed Simulation

A new, more expansive model of the solar system has yielded further evidence of the existence of the elusive Planet Nine, with the new, more detailed simulation strengthening the case for the presence of a large celestial body lurking the depths of space past the orbit of Neptune.

In 2016, Caltech astronomers Konstantin Batygin and Michael Brown found that the orbits of a number of trans-Neptunian objects (TNOs) on the outer fringe of the solar system were in extremely unusual orbits, orbits that were best explained by the presence of a large planet five to ten times the mass of the Earth in a orbit 13 to 26 times further out from the Sun than Neptune. Their 2016 proposal was accompanied by computer models that backed their hypothesis, and since then more evidence has also been found that may support the existence of an object like Planet Nine, such as the slight tilt in the orbits of the Solar System’s other planets, and anomalies in the Cassini space probe’s orbit.

This new model assembled by Batygin and Brown’s team is far more expansive than their previous simulations: the new model tracks objects with extremely long, comet-like orbits that cross Neptune’s orbit, mapping the effect of Neptune’s gravitational pull on them as they traverse the boundary from the outer reaches of the solar system into the realm of the main planets. The model also incorporates a phenomenon known as galactic tide, the cumulative gravitational pull of the objects that make up the Milky Way outside the heliopause, the boundary marking the edge of the solar system, where the solar wind meets the interstellar medium.

Batygin and Brown’s previous modeling only focused on the unusual scattering of the orbits of trans-Neptunian objects (TNO), minor planets that lie in the depths of space beyond the orbit of Neptune; while these simulations provided Planet Nine-like effects, it was discovered that the model’s outcomes could be explained by other forces. However, in their new model the team found that without the inclusion of a gravitational body with the mass of a large planet, the TNOs failed to fall into the orbits as we see them today, strengthening the case for Planet Nine’s existence.

Unfortunately, Batygin and Brown’s new model wasn’t designed to predict the present location of Planet Nine; between its assumed location in the dark depths of the solar system—and the long orbital period that goes hand-in-hand with such far-flung orbits—the enigmatic planet has managed to elude detection since the search for it began eight years ago.

However, that search is expected to be aided by Chile’s Vera Rubin Observatory when the facility goes online next year. With its broad-angle telescope capable of surveying the entire sky within a handful of nights, Vera Rubin will be capable of producing 3.2 gigapixel images that cover the electromagnetic spectrum from the near infrared through the ultraviolet, including the visible spectrum in between.