Two Planets Found Sharing One Orbit 175
dweezil-n0xad writes "Buried in the flood of data from the Kepler telescope is a planetary system unlike any seen before. Two of its apparent planets share the same orbit around their star. If the discovery is confirmed, it would bolster a theory that Earth once shared its orbit with a Mars-sized body that later crashed into it, resulting in the moon's formation."
Re:Time for another IAU meeting (Score:5, Interesting)
Possibly. As neither has "cleared its neighbourhood" [wikipedia.org] of other masses in their neighborhood, they might be back to being called planetoids like Pluto. Both are to be considered "dwarf planets" until they collide and one becomes obviously dominant. There's already bits that cover things like this, but people are already arguing about the exampled in our own solar system. I be something like this would cause even more hub bub and another conference to further define the meaning of planet yet again.
Re:Time for another IAU meeting (Score:3, Interesting)
That's not what "clearing the neighborhood" is defined as. "Clearing the neighborhood" contains an exemption for other objects under the first object's gravitational influence.
If there are two objects in one orbit *and* the objects stay that way because of some complicated gravitational interaction, they are exempt from "clearing the neighborhood" and can still count as planets. In order to not count as planets you'd have to have two objects in the same orbit that just stay there because they happen to be in the same orbit, without any gravitational forces keeping it that way.
It's highly likely that these two objects are staying in that orbit because of gravitational interactions, and therefore they are probably planets.
Or they would be, except that the definition of "planet" used to disqualify Pluto specifically says it only applies to our own solar system. It couldn't be applied to other systems anyway, since we can't see enough smaller objects in other solar systems to know whether the neighborhood has been cleared or not. Currently, the definition used outside the solar system has problems at its lower size limits.
Re:Time for another IAU meeting (Score:5, Interesting)
Is an estimated minimum of 2 million more years not stable enough for you? With the two planets orbiting their star about every 10 earth days, that's over 70 million orbits, at minimum. What makes this an interesting find it that it IS unlikely, and it does NOT require external forces. Hence there's an article about it. :)
As referenced by TFA: http://en.wikipedia.org/wiki/Lagrange_point [wikipedia.org]
Unless you're claiming that nothing is stable because y'know, entropy, man!
It's not a real planet . . . . until . . . (Score:3, Interesting)
Captain Kirk beams down there, takes his shirt off, and gets the chick. Wait, two planets? Wait a second, we'll have to fly in a second, evil, Captain Kirk from a parallel universe. And how about a Spock with a beard? Does Ryanair fly there? Can we get a discount rate for two? Well, knowing them, they'll charge an extra exorbitant fee for Spock's beard. And the plane won't even land in the parallel universe, but in another universe, "Really close by!"