Astronomers Spot Most Distant Object In the Solar System (sciencemag.org)

sciencehabit writes: Astronomers have found the most distant known object in our solar system, three times farther away than Pluto. The dwarf planet, which has been designated v774104, is between 500 and 1000 kilometers across. It will take another year before scientists pin down its orbit, but it could end up joining an emerging class of extreme solar system objects whose strange orbits point to the hypothetical influence of rogue planets or nearby stars. In other planetary science news, UCLA professor Jean-Luc Margot has proposed a new definition of the term "planet" which would allow for the inclusion of exoplanets. His metric is laid out in an academic paper available at the arXiv.

Comments

It's so ridiculously easy

[Rei]

.. to make up a formula to say what you want it to say for data like this.

Here, want an alternative formula to declare the 8 IAU "planets" as planets as well as exoplanets but exclude the IAU "dwarf planets", without using any of the terms he uses, and to be able to classify 100% (rather than the 99%) of exoplanets?

MeanDistanceFromTheSun / DiscoveryYear ^5 > 0.21mm/y^5

It's a functional formula. Does this mean that it's a reasonable formula? Of course not; it has no connection with the reality of what they actually are. But you know what? Neither does his or the IAU's "cleared the neighborhood" concept. There are no credible planetary models that show for example that Mars cleared its own neighborhood. While they differ on the details, they all agree that Jupiter cleared it (and cleared most of the debris from the inner solar system in general, with some help from Saturn). Neptune has (despite its distance from the sun) orders of magnitude more orbit-clearing power than Mars yet nonetheless contains multiple objects a couple percent the size of Mars in its "neighborhood". Is Mars not a "planet"?

I have a giant list of reasons why the IAU decision is poor and unscientific, but no need to post it again.

Re:Does this mean??!

[Rei]

Nope. A tiny fraction of a group who is overwhelmingly not planetary scientists has spoken and made their internally-inconsistent definition. It stands until they revoke or alter it.