Ricochet is the best place on the internet to discuss the issues of the day, either through commenting on posts or writing your own for our active and dynamic community in a fully moderated environment. In addition, the Ricochet Audio Network offers over 50 original podcasts with new episodes released every day.
Has Caltech Found a Plausible Giant Outer Planet?
I’ve gotten texted twice today about the story that Caltech astronomers have found more evidence there could be a massive planet in the outer solar system, perhaps ten times the mass of Earth. My initial reaction was to dismiss it as a crackpot theory, because there have been a couple of poorly-supported claims about this kind of thing in the past five-odd years. But this one seems better.
For one thing, the astronomers are well known and have reputations for reliable work and solid accomplishments. Mike Brown and Chad Trujillo have found other ice planets in the outer solar system, at least through direct observation. And whereas the earlier claims were based on pretty thin evidence, this one has stood up to a direct challenge from Brown already.
What’s happening is that the most distant ice planets in our solar system, like Sedna, turn out to have elongated orbits — ellipses — with the Sun near one end. Ordinarily, you’d expect that the point of closest approach, the perihelion, would be randomly distributed for each of these. Some would swing by on one side of the Sun, others on another side. But Trujillo found that they’re mostly oriented to swing past just one side of the Sun.
One possibility is that a massive planet is out there, regularly running through their orbits in such a way that it scattered them away, making them cluster together on the far side.
Mike Brown initially dismissed this idea, saying (pretty much correctly) that planetary astronomers like to invoke Planet X whenever they see something strange in a planet’s orbit. Go read anonymous’s review of The Hunt for Vulcan for a classic example. But as he tried to debunk the idea, he wound up convincing himself it was the best explanation.
The discussion I’m seeing among professional astronomers is a mix of the eager and skeptical, with the skeptics pointing out that there have been some infrared searches of the whole sky that were able to rule out any more undiscovered massive planets … but only for certain limits in mass and distance. There is debate about how brightly such a planet would glow in the infrared, and whether the existing searches should have ruled it out or not.
On a final note, I’ll say that Mike Brown’s scientific work is good enough for me to overlook for the moment his obnoxious behavior regarding Pluto. He was probably the big mover behind the International Astronomical Union’s move to unilaterally redefine the meaning of the word “planet” in every language on Earth just to keep Pluto out of the definition. I’ll write some other time about the dirty tricks that were used to pull that vote off, but I don’t want to go too far out on a tangent now.
Anyway, I’ve had the impression for years that he’s got a big ego, and he has some kind of weird personal grudge against the planet that goes beyond rational explanation. I don’t mean this as a flippant joke. His Twitter handle is @plutokiller. And with that in mind, I am not going to call this thing “Planet Nine.” That’s just feeding his ego about trying to erase Pluto from the books, and it’s really blatant. Notice in the chart above, which comes from Brown’s press release, they show the orbit of Neptune, but not the larger and more relevant orbit of Pluto, which is generally used for these kinds of comparisons. This is just to stroke Mike Brown’s ego and pretend that he has somehow made Pluto physically disappear.
But he does solid work, and while I hold out the possibility that he’s wrong, I’m not dismissing this as a crackpot idea. The next step is to look for the thing, and I read that a couple of observatories are already looking along the proposed orbit for to see if anything’s there. It’s an exciting possibility, and I’m hoping they find it.
For those interested in the details, here’s the paper.
Published in General, Science & Technology
I came across the LA Times article earlier. Super interesting! Thanks for the back story about Brown and Pluto. I did think the name of the new planet was a little odd or off somehow.
Interesting material this as well as thought provoking. According to some minds we will have to migrate to a new planet in the not so near future. Might this be the new front for humankinds survival effort ?
Might require additional sweaters or parkas though, now there is a turn.
Pardon my dalliance and have no disrespect for real science, Yet ? One’s humor aside – Planet 9 or Plan 9 from Outer Space.
Well, if you don’t like “Planet Nine,” you can always call it Nibiru. I’m sure that all the usual suspects will.
I rather prefer Planet X.
As long as it isn’t Bronson Alpha, I’m good.
Why keep referring to it as massive? Jupiter is massive. Ten times Earth’s mass isn’t.
It’s Yuuuge, Randy. It’s so big, they’re going to name it Trump. It will make Jupiter look small, because it will glow so much brighter.
Randy Webster—
Yeah, 10 Earth masses is only borderline “massive” in one sense, but I had in mind a contrast with the typical masses of known ice planets. Pluto is 0.2% the mass of Earth, for example, and the common thinking is that there’s not much total mass available out there in the Kuiper Belt—maybe 4-10% the mass of Earth. So 10 Earth masses is huge for the location, anyway.
I enjoyed Why I Killed Pluto (And Why It Had It Coming), but was simultaneously annoyed at how much biography Brown brought into it. It’d totally appropriate and reasonable for Brown to do that, but it just didn’t fit the book’s purported purpose. Your marriage sounds nice, Mike: now shut-up and talk about Pluto.
I’m not sure about that. Unless I’m very wrong, the chart is also not showing any trans-Neptunian objects, including Orcus, which Brown co-discovered with Trujillo. And wouldn’t it be likely that such objects would be (largely) unperturbed by an undiscovered outer planet, at least as compared to Kuiper Belt objects like Sedna?
I think I worded my critique here wrong. To go a little longer on this point, when the IAU pushed this redefinition of “planet,” there were lots of public assurances that it was just a matter of semantics, and that nothing really had changed, and of course, good ol’ Pluto was just the same as it always had been. In fact, Pluto was even more special, being the prototype of an entire class of dwarf planet, the “Plutinos” (a term that hasn’t gotten picked up that much). But what has happened in practice is an erasing of Pluto from many textbooks and popular writings. (continued…)
[Cont’d]
In the introductory astronomy textbook I use, Astronomy Today, the 6th edition had the chapter, “Uranus, Neptune, and Pluto: The Outer Worlds of the Solar System.” The 7th edition reworked this as, “Uranus and Neptune: The Outer Worlds of the Solar System,” and it moved Pluto to an untitled discussion in the chapter, “Solar System Debris.”
The planetarium I run at the college actually removed Pluto and its orbit from the solar system data. It was erased and unable to be displayed any more.
Since Pluto had been the outermost-known planet since the 1930s (and therefore with the widest planetary orbit), a comparison of scales in our solar system with scales in other solar systems or with distant comets would generally use Pluto’s orbit as a standard of comparison. Now I’m seeing a pattern in which science articles are using Neptune for comparison, despite the fact that it’s closer in, and Pluto’s orbit is still there and familiar to the public.
So what I really should say about this graphic and Brown’s preferred name of “Planet Nine” is that it’s an attempt on his part to reinforce the idea that Pluto isn’t a major planet, and there are only eight discovered planets in the solar system—not directly because of a discovery he’s made, but because he takes perverse pride in pushing Pluto out. That’s where I think the ego comes in.
Back in my homeschooling days, I came across instructions for doing a “solar system walk.” It was designed to show the scale of the planets in terms of their sizes, and also their distances from the sun and each other. That sounded really interesting, so I located a suitable spot, gathered the necessary supplies, and got a bunch of kids together to do it. It was absolutely fascinating! The solar system is far larger than we can easily imagine. Relative to the solar system, the planets are tiny. Any models you see in books or museums are WAY off in terms of scale. I was amazed at how far away the planets are from each other. And it turned out that the location I picked to do the walk was too small for us to walk to Pluto.
I recommend this activity for anybody interested in astronomy. Since it accurately shows the scales, it is not simply a children’s activity. I located some instructions that look like the ones I used back then:
http://www.noao.edu/education/peppercorn/pcmain.html
All this to say that yea, I think I get it as to why Pluto’s orbit is relevant.
So in this, the year 2016, scientists can’t definitively say how many planets are in the solar system.
But climate change is a fact.
Got it.
You might enjoy this:
I wasn’t about to do oops again. Tom beat me to posting the video.
Pluto is a planet and Han shot first
A couple of months ago I was at a talk by Dr. Alan Stern, principle investigator for the New Horizons mission. He asked the audience, “Do you think Pluto is a planet? Before you answer, have a look at this:” And he put up one of the slides of Pluto from New Horizons. Then he said, “If you showed that picture to anyone on Earth who isn’t in the IAU, they’d say that’s a planet.”
And he’s right – Pluto should have remained designated a planet. But I do get the other point of view. As we discover more objects like Pluto and Sedna and the rest, it’s hard to distinguish Pluto from them. And if Pluto’s a planet, why not Ceres? The idea that a planet can’t be a planet unless it clears its own orbit seems like an artificial distinction put in place specifically so that Ceres could be excluded.
As we are finding out from exoplanet discoveries, there’s a huge variation in what planets might look like. Our definition may be too narrow, if anything.
Fascinating about a large planet possibly existing in the Kuiper belt. Any way of guessing whether it would be a gas giant or a large ice ball or rocky ‘Super Earth’ type planet? I imagine the current theories of planet formation would suggest that it’s a gas giant, but if it was a planet flung out of the solar system by Jupiter, perhaps not?
Yeah. I think it’d have been better to use “planet” as a blanket category and then do “major” and “minor” planets as subcategories.
And come on IAU… Charon and Pluto are a binary system. Get with the program.
That was super interesting! The sun and planets are larger, so the distances are greater than what I did. But yea that was very cool.
I once had a crazy idea to setup a solar system walk at Burning Man. There’s nothing like actually walking it. Video just can’t induce the sheer awe one will feel.
Wow, lots of good stuff there. Thanks!
Here’s a page that shows the speeds of the planets relative to each other. It is setup like a music box–as planets pass by the “string,” they “strike” it and it makes a tone. The tones are unique for each planet. You can speed it up or slow it down.
http://www.whitevinyldesign.com/solarbeat/
Alan Stern has made an argument that the understanding of a “planet” should not rest merely on dynamical arguments—the shape of its orbit and whether there are other bodies crossing that orbit—but on intrinsic properties like its geology. The fact that, as we know from his work on New Horizons, Pluto has an active geology, a surprisingly active geology, should count towards its planetary status. I’ve generally followed Stern’s take on this.
The IAU definition would exclude Earth itself, if we were, for whatever reason, in a Pluto-like or asteroid-like orbit, because there would be too many other bodies crossing it.
I think that the big mistake, though, is that the IAU’s nomenclature is operating in what I’ll loosely call a Napoleonic code mentality, where everything needs to be strictly defined from the top down. I dislike this and think it’s inappropriate for science. Instead, our nomenclature should operate more like Common Law, where terms evolve from the bottom up, through common practice.
I work with galaxies. We have, for example, dwarf galaxies, which are small galaxies. Like planets, there’s a wide range of sizes for galaxies, but we manage to operate just fine without a ruling from on high telling us where the dividing mark is between them.
Another note, following up on my idea of Napoleonic Code vs. Common Law approaches to categories:
Too many people (I’m afraid that includes several astronomers) have treated the IAU definition as the definition of a planet. As if this is what the word means, now. Officially. By law.
But that’s not the case. The IAU is simply an association of astronomers, and one among many. As they have admitted,
That is, nobody has to use this definition. (I’ll debate “rational and effective” in this case, but that’s a separate issue.) It’s not as if it were some law, or that the English language has been changed by an official body. Unlike many languages, English has no official governing body. We’re free to use the IAU concept of a planet if we wish, but we’re free not to use it, as well.
The trouble is that, despite the IAU’s admission here, the public has acted as if this were the one and official word on the subject, and they’ve started taking Pluto out of the textbooks, planetariums, and so on, as I mentioned earlier.
That’s really neat. I ran it through long enough to “hear” Pluto pluck the string once.
and Jar Jar Binks is really the galaxy’s Sith lord puppetmaster.
It started as soon as the news broke.
Color me surprised. Or not.
You were at Burning Man? Oh, dear…
Since we seem to have a richness of astronomers on R>, maybe we can get an explanation/exploration from our resident experts regarding the newly discovered super-super-supernova. An anomaly outside conventional understanding or just a freak of nature?
http://www.scientificamerican.com/article/found-the-most-powerful-supernova-ever-seen/
No, I was never at Burning Man. I just wondered if it would be a good place to do something like that.