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Scientist Claims There's Even More Evidence of Planet Nine's Existence (theverge.com)
An anonymous reader cites an article on The Verge: More evidence is pointing toward a mysterious Neptune-sized planet lurking at the outer edges of our Solar System. One of the scientists who claimed in January to have found strong evidence for a ninth planet -- temporarily named 'Planet Nine' -- now says there are even more clues that support the world's existence. Mike Brown, a planetary astronomer at Caltech University, originally concluded that Planet Nine most likely exists after studying the behaviors of six objects in the Kuiper Belt -- the large cloud of icy bodies that orbit the Sun beyond Neptune. Now Brown is claiming that another Kuiper Belt object supports his theory. The object shares some of the same behavior as the other six Kuiper Belt bodies, suggesting it has also been pushed by a large planet that is between 200 and 1,200 times the distance from the Sun to Earth.
There will always be nine planets. If you get rid of one of the planets, it is inevitable another will come along to fill the void.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
No matter how many more such bodies are found, the story won't be complete until and unless Planet Nine is actually observed and its orbital parameters calculated (I assume that precovery images will be located after the first observations).
. . . . it's Planet Ten, and the Red Lectroids that worry me. . . And no sign of Buckaroo Banzai OR the Hong Kong Cavaliers. . . .
Or Planet XI, if they hadn't demoted Ceres in 1860.
I vote for Planety McPlanet.
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
Lord John Whorfin: Where are we going?
The Red Lectroids: Planet Ten!
Lord John Whorfin: When?
The Red Lectroids: Real soon!
A far out planet could be useful for gravitational assists to the outer solar system.
Pedantically speaking... An actual gravity assist from the planet itself would be worth little - certainly not enough to justify the 1,000+ year diversion (not exaggerating) required to actually take advantage of it.
Getting a gravity assist is analogous to bouncing off of the assisting body. If the body is moving quickly and in an appropriate direction, the spacecraft can pick up a lot of speed (relative to the rest of the solar system) in the process. These conditions would certainly not apply to the hypothetical planet discussed above though:
1) A planet orbiting at that altitude would have an orbital velocity no more than ~7% that of Earth - maybe much less. A gravity assist cannot boost the velocity of the spacecraft by more than the velocity of the assisting body.
2) Achieving a worthwhile gravity assist requires waiting for the orbital phase of the assisting planet and the actual destination to line up right. This could be a loooonnnnggggg wait given that the planet in question would have an orbital period between about 3,000 and 40,000 years...
Having said that, if the planet just so happened to be in roughly the right place already, it might still be worth swinging by it for two reasons:
A) If it had a large moon in a relatively low orbit that was roughly aligned with the plane of the ecliptic, that moon might provide the gravity assist which the planet itself could not.
B) The point of closest approach to the planet may be a good place for an engine burn, to take advantage of the Oberth Effect (which is distinct from a true gravity assist).
Of course - all this "orbital ballet" gravity assist stuff is only necessary because our current propulsion technology is inadequate; any realistic plan for humans to explore the outer solar system would require an upgrade.
Thou shalt not make a machine in the likeness of a human mind.
> So.. the orbits of several comets were disturbed by something large moving through our solar system at some point in the past.
Actually, by repeatedly disturbing the orbits of these Scattered Disk objects, so their orbital parameters are opposite the proposed planet. In that location, the planet doesn't disturb them any more, so they stay put. A single pass of a rogue planet would not change the orbits of *anything* that much, and once that one pass was done with, the Scattered Disk Objects would drift away from their anti-alignment.
We see other examples of this "gravity shepherding". For example, Pluto and the Plutinos stay in a 3:2 resonance orbit with Neptune, because Neptune's gravity keeps them there.
in order to "get" a planet for political reasons!
Out of curiosity - what were these "political reasons"? Was Pluto threatening to run as a third party candidate or something?