Not to be confused with Plan Nine. Apparently the guy who killed Pluto thinks he may have found a new planet. I’m thinking his daughter must have made him do it.
13 thoughts on “Planet Nine”
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Not to be confused with Plan Nine. Apparently the guy who killed Pluto thinks he may have found a new planet. I’m thinking his daughter must have made him do it.
Comments are closed.
News link here:
http://www.sciencemag.org/news/2016/01/feature-astronomers-say-neptune-sized-planet-lurks-unseen-solar-system
Interesting story but, as the writer says, the new planet’s not been discovered until it’s been found.
To my layman’s mind, this sounds legit. It’s certainly the best case that’s been made for Planet X to date.
Computer models have shown that the early solar system was a tumultuous billiards table, with dozens or even hundreds of planetary building blocks the size of Earth bouncing around.
I wonder how many of those Earth-sized objects may also have been perturbed into distant orbits?
Given the proposed orbit, I speculate that this planet (if it exists) may be a rogue that was kicked out from another solar system and captured by ours. Here’s a link to an article about rogue planets, including one detected 100 light years from us.
For an explanation, I prefer MOND . . .
“Predicted” would be more accurate than “found.”
Stories like this are always cool because they fire the imagination and remind us of the uncertainty of science. How many times have we been told this is impossible and yet it could be.
I hope they have learned something from the awful name they picked for the gas giant “Uranus.”
I would propose: “Urectum.”
Myanus. We already have a planet named for your anus.
It’s not a planet, it’s a massive ball of carbon contributing to Solar System Warming!
As I’ve said before, I’d like to see a Mars-sized body out there, with an exobase cold enough to retain some helium in its atmosphere. Such a planet might be the easiest place in the solar system to mine 3He, if it’s not too distant.
Wait a minute. The diagram in the Science article shows “Planet X” crossing orbits with Sedna and at least half a dozen other trans-Kuiper objects. Which would seem to indicate that it has not “cleared the neighbourhood around its orbit”, and thus per official IAU definition, cannot be a “planet”.
Now, I’m on record as saying that the IAU definition sucks harder than the vacuum through which not-planet-X orbits, on account of vagueness if nothing else. But Mike Brown is one of the guys who championed the new definition. So apparently, if it means Mike Brown gets to be famous as The Guy Who Killed Pluto, a planet has to clean up its orbit, but if it means Mike Brown gets to be famous as The Guy Who Discovered Planet X, a planet can be as messy as it wants so long as it’s big.
John, did you see Mike Brown’s blog post on this subject? If not, I think you’ll enjoy reading it. Here it is:
http://www.findplanetnine.com/2016/01/is-planet-nine-planet.html
Here is the key excerpt:
But is it a planet? The IAU definition of planet includes the clunky phrase that it has to “clear its orbit.” Really, this phrase is just an attempt to explain the concept that planets are the gravitational dominant things of planetary system and that one of the ways they display their gravitational dominance is by pushing around everything in their path. Overly literal critics of the IAU definition will insist that because Jupiter has asteroids which co-orbit with it (the Jupiter Trojans) that Jupiter is not a plane by this definition, etc. etc., but that is simply a problem with the clunkiness of the statement of the definition, not of the underlying concept.
Is Planet Nine gravitationally dominant? I think it is safe to say that any planet whose existence is inferred by its gravitational effects on a huge area of the solar system is gravitationally dominant.
If that is not good enough for you, though, astronomer Jean-Luc Margot at UCLA has recently written a nice paper finally quantifying what the phrase “clear its orbit” really means.
Click the link above to get the link to Margot’s paper.
“Planet X” produces a barely-detectable perturbation on the orbits of a few bodies, therefore it is “safe to say [that it is] gravitationally dominant”? I don’t buy it. Jupiter exerts a greater gravitational influence on e.g. Sedna than does the proposed “Planet X”. And, clunky as the definition is, the IAU is explicit that a planet has to clear its orbit, not “dominate” it.
The IAU passed over several proposed mathematically rigorous definitions in favor of one that Mike Brown calls “clunky” even though he also called it “he best possible scientific definition we could have had”, The only possible advantage of the clunky definition over the rigorous ones is that it allows people like Brown to say that it’s obviously a planet if they say it is and obviously not a planet if they say it isn’t, whichever gets their name in print this week.