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Is Pluto a Binary Planet?
astroengine writes "If the Pluto-Charon system were viewed in a similar way to binary stars and binary asteroids, Pluto would become a Pluto-Charon binary planet. After all, Charon is 12% the mass of Pluto, causing the duo to orbit a barycenter that is located above Pluto's surface. Sadly, in the IAU's haste to define what a planet is in 2006, they missed a golden opportunity to define the planetary binary. Interestingly, if Pluto was a binary planet, last week's discovery of a fifth Plutonian moon would have in fact been the binary's fourth moon to be discovered by Hubble — under the binary definition, Charon wouldn't be classified as a moon at all."
The issue with using the barycentre, is by moving two objects further apart without changing the mass, eventually the barycentre will be above their surfaces. The Jupiter-Sun barycentre is above the surface of the sun, but wouldn't be if Jupiter were closer. The Earth-Moon barycentre is about 75% of the radius of the Earth, but if the distance between them increased by about 25%, then the Earth-Moon barycentre would be above Earth's surface. So it is quite possible to have two bodies that are very influential on each other, but with the barycentre below the surface due to being too close. And the status could change simply by having one body move further away, like Earth's moon is currently doing.
If the mass part counts at all (Charon being 12% of Pluto's mass), Jupiter is a far smaller fraction of the Sun's mass (something like 0.1% if I did the math right).
William of Ockham had no beard. The most likely explanation is that it was chewed off by squirrels every morning.
"Is it something more personal between individuals in astronomy?"
This, actually. Long story short, there are two camps of astronomers. One of them characterizes bodies based on where they're orbiting, the other characterizes bodies based off what they're made of.
The former pushed this through as an act of political dickmanship on the last day of a conference (after most participants had gone home), in a only tangentially related addition to a talk scheduled for a different topic, breaking IAU rules to do so. It's not a 'scientific' decision, it's a purely political one.
And any definition that has a category 'dwarf planet' that isn't a subset of 'planet' is about as stupid as redefining 'car' so that 'electric cars' are no longer a subset of 'cars'.
The first death star was 160 KM in diameter, so a radius of 80 KM. If you assume the same mass density as, say, an aircraft carrier or other military vessel (about 0.15 kg/m^3), you end up with a Death Star that masses about 3e14 KG. That's absurdly heavy to realistically have engines zipping it about, but it's not going to result in major and instantaneous disruptions of orbits. Even Mars' tiny moon Phobos has 100 times the mass. Although the Death Star II from RotJ was supposed to be 900KM across, so that would put it about even with the mass of Phobos. Put another way, the Earth masses 10,000,000,000 times as much (or only 100,000,000 for the Death Star II), so I don't see how the Death Star is going to be winning that gravitational tug-of-war. If you want to argue "Well maybe they have super cool tractor beams so they can amplify their gravitational pull and their massive engines can keep them stationary while they're doing it!" the obvious counter is "They don't, that's why they went with the laser, since they thought about it. Also big laser is more menacing in a platform which has the primary purpose of intimidation. Additionally the big laser doubles as a way to destroy enemy capital ships from well outside their own engagement radius".
ASCII stupid question, get a stupid ANSI
Wow. Pretty much all completely false. Nearly all of the 9000+ members of the IAU are working astronomers actually using the scientific method. The whole process of deciding on the definition of "planet" was a peer driven. The objections were from a minority who were outvoted. The guy who discovered Eris, and had his own discovery demoted into non-planet status by the decision, admits it was the right decision to make. ("It was hard not to mourn the loss of my now ex-planet, except for the fact that I had to admit that kicking it out was the most scientifically sensible thing to happen to planetary classification since asteroids were also kicked out almost 200 years ago.") Far from arbitrary, it follows the very same rationale that was used to demote Ceres two hundred years ago, keeping the definition of planet as what we decided back then rather than expanding it in ways that would be incompatible with that. Alas, being consistent meant we need to correct the mistake we made with Pluto to begin with. In any case, it wasn't a proclamation by poseurs, it was the consensus of the working astronomers who actually do the work. The ones you want to load into your cannon include the very scientists making lasting contributions to the field. I think discovering Eris was contributing to the field, not sure why you insist people doing stuff like this should be shot into a passing asteroid. I understand you're emotionally upset about Pluto, but making up a largely false story about what actually happened here is silly...
"Convictions are more dangerous enemies of truth than lies."