Puts new meaning in "missed what was right in front of me!"

"2015 RR245 may be one of the last large worlds beyond Neptune to be found until larger telescopes, such as LSST, come online in the mid 2020s."

Despite all the singing and dancing, and there has been plenty, Pluto is still the largest known object in the solar system past Neptune. This is NOT what Mike Brown and members of the IAU predicted so confidently when the rules were rewritten to demote Pluto to dwarf planet status.

"It's a power law with index -4, and it suggests that a few Pluto-sized objects exist, perhaps 5 or 10, of which we know just one." http://science.na...13sep_1/

Mike Brown's "Planet 9" prediction is also in serious question. The jury is still out, but so far he's got nothing and the clock is ticking.

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"Pluto belongs to the class of TNOs, full stop."

So does "Planet 9" then, assuming it even exists. On the other hand, planetary scientists characterize planets by their planetary processes like volcanos, mountain building, etc., not by their location. By that measure, Pluto is a planet and a rock is a rock. The arbitrary "dwarf planet" definition has no basis in science, only the desire to exclude based on erroneous predictions.

"I met Clyde Tombaugh once and he even said that. 'We know that we found Pluto due to a diligent search, but I wonder if it might not be just one of a whole new class of objects'."

In case you are wondering, nobody is buying this.

Despite all the singing and dancing, and there has been plenty, Pluto is still the largest known object in the solar system past Neptune. This is NOT what Mike Brown and members of the IAU predicted so confidently when the rules were rewritten to demote Pluto to dwarf planet status.

You must be talking about radius, of course. Pluto's radius is 1187 +/- 4 km, Eris just a bit smaller (1163 +/- 6 km).

When it comes to mass, Eris is bigger: 1,66 +/- 0.02 x10^22 kg vs. 1,303 +/- 0,003 x10^22 kg of Pluto.

"You must be talking about radius,"

Sure, although volume is probably best, mean radius works pretty well since Pluto and Eris are both gravitationally rounded and in hydrostatic equilibrium. As your numbers show, Pluto is larger and Eris is more massive. At some point in the future it wouldn't surprise me to learn they are both considered planets.

IMHO, the IAU jumped the gun in 2006 based on erroneous projections, so the best thing might be to wait until we actually know what the deal is. Note that while Pluto and Eris are probably the largest and most massive objects in the Kuiper Belt and Scattered Disk, we are still only guessing what is in the Oort Cloud. I expect the Oort Cloud is going to be far more worked over than astronomers have generally predicted because of all the close passes by other stars over the eons.