This hypothesized ninth planet (not you, sorry Pluto) might explain the unusual commonalities of extreme trans-Neptunian objects (ETNOs) 100s of AU from the sun. These ETNOs (such as dwarf planets and sednoids) have remarkably aligned orbits, suggest the existence of an undiscovered celestial body, dubbed Planet Nine, influencing them gravitationally.
Potentially stupid question: Granted that we have such good vision for planets an incomprehensible distance away from us, why wouldn’t we be able to detect, with certainty, if this planet is actually present in our system? I’m guessing it would take longer to orbit around the sun, than Pluto’s 247 years, but it’d still be detectable because of the distance away from us
The problem is the potential planet is so far that it would barely reflect any light. We have inferred from computer models that for known planet and object orbits in our neck of the woods, there needs to be a planet there to create those orbits.
We just can’t see it because it’s so far out there, it’s really really dark, and it doesn’t pass in front of a star to see the dimming effect that would let us know it’s there. If we knew where to exactly point telescopes, it’s possible with enough study we could say it’s really there.
That makes sense. Thanks for the answer!
Not a stupid question.
Beyond the too far to reflect light aspect, the evidence we do have is gravitational effects to other bodies we can see and track. So there is evidence that something is out there. It’s just a matter of what and exactly where.