>>20321941
how many coincidences before mathematically impossible?
rather than an undiscovered planet, it is rather more likely to be a brown dwarf companion star to the sun
most stars are binaries, or ternaries
isolated stars are the anomaly, rare actually
the axis of earth's rotation precesses (wobbles) with a period of ~ 25,000 yrs
until recently, that wobble could only be measured against the distant fixed stars
recently, the technology needed to compare the earth's wobble to other bodies in our solar system became available
it was discovered that the entire disk of the solar system is precessing in unison
to cause that would require a truly MASSIVE perturbation
massive like a brown dwarf companion star with an orbital period of ~ 25,000 yrs in a highly eliptical orbit
perihelion could be as close as the inner planets, while aphelion would be in the Oort cloud
every 25,000 years, during it's closest approach, it would drag with it a slew of gravitationally entrained comets
producing a greatly increased risk of comet impacts on the planets
the absence of a cyclic mass extinction events in the fossil record to coincide with this astronomical cycle
suggests impacts are still rare or too small to produce mass extinctions
but a comet impact could cause local devastation, such as an airburst fireball, cratar, or a tsunami
there would also be a risk of damage to the power grid, which wouldn't directly harm animals, but could devastate human populations