As I have already written in another comment, only if we would see changes in the orbits of the known bodies, then that would be evidence for a currently existing outer planet.
The parent article contains several sentences like "The six most distant known objects in the solar system with orbits exclusively beyond Neptune (magenta) all mysteriously line up in a single direction."
All those sentences do not support the existence of an outer planet now, they only demonstrate that at some moment in the past there was a big body in that direction.
The papers that I have linked report the results for the simulation of the close passage of a star in the past, which match pretty well what we see now in the outer Solar System.
Such close encounters between stars are known to happen from time to time, because superposed on the general rotation around the galaxy center all stars have random own motions, so the distances between them are changing all the time and even collisions are possible.
We detect planets elsewhere by either them passing in front of the star or star wobbling IIRC. How come we can't detect this hypothetical big outer body by Sun wobbling a bit? We are pretty close to see minute changes. If its there it must have some effect, no?
There are other ways besides seeing changes in orbits to confirm the existence of a body. Venus, Mars, Jupiter, and Saturn are easily seen with the eye, for instance.
Planet 9 might be confirmed with infrared surveys as a post from last week discussed or some other method.
adrian_b|10 months ago
The parent article contains several sentences like "The six most distant known objects in the solar system with orbits exclusively beyond Neptune (magenta) all mysteriously line up in a single direction."
All those sentences do not support the existence of an outer planet now, they only demonstrate that at some moment in the past there was a big body in that direction.
The papers that I have linked report the results for the simulation of the close passage of a star in the past, which match pretty well what we see now in the outer Solar System.
Such close encounters between stars are known to happen from time to time, because superposed on the general rotation around the galaxy center all stars have random own motions, so the distances between them are changing all the time and even collisions are possible.
jajko|10 months ago
bagels|10 months ago
Planet 9 might be confirmed with infrared surveys as a post from last week discussed or some other method.