"Although we were initially quite skeptical that this planet could exist, as we continued to investigate its orbit and what it would mean for the outer solar system, we become increasingly convinced that it is out there." -Konstantin Batygin
Last year, scientists Konstantin Batygin and Mike Brown made a huge splash when they announced that the Solar System likely contained a super-Earth-sized object beyond the orbit of Neptune. They dubbed the world ‘Planet Nine,’ and claimed that it was responsible for the orbits of the longest-period Trans-Neptunian Objects ever discovered. The fact that the orbits were clustered in both ecliptic latitude and longitude cried out for an explanation, and Planet Nine fit.
But an additional world isn’t the only plausible cause of the clustering of these distant objects; another possibility is that the hitherto discovered objects were biased in some way. If you’re only searching for objects in the locations that would show you these correlations, then you’re going to find the correlations. The solution? To do a survey capable of distinguishing between whether the effect is solely due to bias, or the existence of Planet Nine.
The first comprehensive, four-year results from OSSOS are now in, and with eight candidate TNOs with the right properties, they don’t see any signature for Planet Nine. Looks like the evidence has gone up in smoke!