Another one bites the cosmic dust

We've had "hidden" planets multiple times actually. In one case, we discovered Neptune by observing that Uranus' orbit was wonky, and this really Bolstered peoples' trust of Newton's gravitational theory.

The existence of another planet even closer to the sun than Mercury, Vulcan, was also hypothesized by the same astronomer who predicted Neptune's existence. This was due to Mercury also having a wonky orbit. After Einstein's general relativity came about though, it was found that no new planet was necessary to explain Mercury's orbit.

I think this new planet is the one predicted by Cal Tech "Planet Nine", is supposedly 10 Earths in size, orbits on average 20 times further out than Neptune, and has a very oblong orbit out in deep space.

As another 'fun' tangent, there is some debate every now and again that dark matter may demonstrate that Einstein's Theory of Relativity is also flawed and that we're in need of a new theory. Currently, though, there has not been a sufficient new theory to take its place, so the existence of 'unseen' matter still is the strongest explanation we have. I put 'fun' in quotes because it seems like this debate is starting to affect astronomers and physicists the same way that 'The Orangutan" affects Edgar Allen Poe experts. Video related

I thought we figured out why the calculations were off and it wasn't actually because of an unknown body out yonder? Is there new evidence or am i just misremembering stuff?

The proposed 9th planet is beyond Sedna and is hypothesized because Kuiper belt objects are orbiting strangely to they figure a gravitational influence from further out is causing it. Uranus was seen doing the same thing and that's how Neptune was confirmed found.

between Jupiter and Saturn* that we’ve simply been unable to physical observe.

*I don’t remember the actual placement

If it were as close as Saturn, we'd be able to easily see it. If additional planets exist, they would be beyond Neptune, and likely quite far beyond it.

Do you have a link for that? Pluto is tiny and much farther away and we can easily see it. There's no reason I can think of why we couldn't see a planet in that orbit, even a small one.

We definitely have the telescopes to find it now if it exists, so I'd say it doesn't exist. What if it's a tiny black hole? Maybe it's a wormhole to Alpha Centauri!

Wait a minute, how did this happen? we're smarter than this!

My Lord, is that legal?

I'll make it legal

My powers have doubled since the last time we met

You are god-damn right they are