Back in August, we published our detailed analysis which gave predictions of where we should expect to find Planet Nine and how big and bright it might be when we do find it. One of the very interesting parts of the analysis was the result that Planet Nine should be on the closer and brighter end of our initial range of expectations. Planet Nine might be close enough and bright enough, that it…
Five and a half years after our proposal of the existence of Planet Nine, we have finally accomplished what is perhaps the most important task in aiding the search: we now know where to look. We've had a pretty good general idea for years now, but we couldn't really give a full assessment of the range of uncertainties for where in the sky Planet Nine might be, how massive it might be, and how…
The census of Kuiper belt objects spanning the distant solar system has sure come a long way. Even if we strictly limit our object sample to those with semi-major axes above 250 AU, or equivalently, an orbital period greater than about 4,000 years, the number of TNOs clocks in at nineteen — a staggering improvement from the six we had back in 2016. Some of these TNOs cluster together, while others…
Konstantin and I have a recurring conversation. One of us says "Wait! I think we're wrong about the evidence for Planet Nine. Here's why..." and proceeds to spin a hypothesis about how we could have been misled by the data or that we are predicting something that is not happening, and then we will carefully go through the entire Planet Nine analysis over again before convincing ourselves that, no,…
I finished the last post by stating the obvious: the Planet Nine hypothesis - as imagined by us - is NOT the first (or even the latest) proposal of a trans-Neptunian planet. So what distinguishes all these hypotheses? Are all putative trans-Neptunian planets the same Planet? Clearly not. Put simply, each theory is characterized by 1) the anomalous data it seeks to explain, and 2) the dynamics…
The history of Le Verrier’s mathematical discovery of Neptune is my favorite story, period. It’s literally got everything you’d want in a good novella - differential equations, integrals, telescopes, intrigue, you name it. Rather than try to rehash it here without doing it justice, I’ll point the interested reader to an excellent 2016 article by Davor Krajnović called “ The contrivance of Neptune.…
The scientific process is, at its core, iterative. There is no such thing as a truly final/definitive answer - there are only solutions that are good enough for now . In a day-to-day sense, what this really means is that when you’ve been chugging away at some problem and you finally arrive at the result, you can be damn sure that you probably haven’t understood the Full Picture (even if in the…
Normal 0 false false false EN-US X-NONE X-NONE We have just passed the three year anniversary of the publication from Konstantin and I on our proposal for the existence of Planet Nine. In those three years something remarkable happened: not a single alternative hypothesis was proposed to explain the observed alignment of the distant Kuiper belt objects that led to the hypothesis. Instead, most of…
Greetings! My name is Elizabeth Bailey, and I am a graduate student here at Caltech. As part of my work so far, I have addressed the ongoing search for Planet Nine, in particular the use of mean-motion resonances to infer its present-day location on the sky. A mean-motion resonance occurs when two bodies orbiting a central body have orbital periods related by an integer ratio. A great example is…
Hi, everyone! I’m Tali, an undergrad at the University of Michigan. Last summer, I worked on a Planet Nine project with Konstantin and Mike, and although we didn’t find Planet Nine (yet!), we did look further into the stability of objects in the presence of Planet Nine. Turns out, not everything is stable! In his last post , Konstantin explained that the main cluster of anti-aligned objects is…
Every die-hard fan of the scientific method knows that Karl Popper was a baller. While his achievements clearly extend far beyond analysis of the scientific method alone, he is arguably best known for his work on empirical falsification . In essence, the idea behind his argument is that a theory is only any good if there exists a direct and clear experimental/observational way to demonstrate that…
We haven’t found Planet Nine yet, in case you were wondering. To date, the telescopic searches have really just begun to scratch the surface of the area that needs to be scanned, and, while clever new projects to find Planet Nine with different techniques have been proposed, most of these efforts are just getting underway. But don’t worry: the new season of Subaru searching starts tonight! With…
I ended the last post by pointing out that the Planet Nine hypothesis, as currently formulated, entails a theoretical solution to five seemingly-unrelated observational puzzles: (i) orbital clustering of a>250AU KBOs, (ii) dynamical detachment of KBO perihelia from Neptune, (iii) generation of perpendicular large-semi-major axis centaurs, (iv) the six-degree obliquity of the sun, and (v) pollution…
It has been an exciting and turbulent couple of weeks in Planet Nine land. The OSSOS survey has released their full data set, which in addition to over 800 garden-variety Kuiper belt objects, contains four little worlds with semi-major axes beyond 250AU. Together with the previously published data, this brings the count of distant bodies relevant to the P9 hypothesis up to 13 - a whopping 117%…
Last year, just after Konstantin and I announced our hypothesis that a distant massive planet in an eccentric orbit was corralling distant Kuiper belt objects into peculiar orbits, I wrote a post explaining why it might all be wrong. Not that it I thought was all wrong – I was and still am quite convinced that Planet Nine is out there waiting to be found – but it’s always good to understand how a…
When I am not searching for Planet Nine, I am teaching classes here at Caltech and throughout the world. The most fun class is my online class The Science of the Solar System . It is a 100% free online class hosted at Coursera for anyone in the world. I've been running the class for several years now, and I finally got around to updating the class to include a short lecture on Planet Nine. For fun…
If I was to pick a single characteristic of daily (academic) life that never ceases to amaze, it would be the rate at which time flies. It has been a little over six months since the publication of the original P9 paper, and the number of follow-up studies that have been unveiled since then edge on thirty. A subset of these studies have, rather than attempting to further characterize Planet Nine’s…
At the time we published our paper on Planet Nine, we were working on a companion paper, that we had hoped to finish that same day, that would tell you where to look for Planet Nine. Finally, only two months later than anticipated, we have finally finished the paper. I'll be writing in more depth about where we think Planet Nine is, how we constrain it, and how we're going about trying to find it,…
An interesting consequence of being asked the same question repeatedly, is that you stop thinking about the answer. Instead, you find yourself reciting a variant of the same prefabricated response that you gave the previous twelve times. Naturally, in this mode of operation, your brain is susceptible to being stumped by otherwise trivial inquiries, simply because you haven’t heard them before and…
In my last post I went into detail on ways in which our Planet Nine hypothesis could be wrong, and I suggested for you, if you’d like to be a Planet Nine skeptic, which you’re encouraged to be, what new observations you should be looking for before you start to believe it yourself. Here, I’m going to tell you why I already am a believer in Planet Nine and why maybe you should be too. As we’ve…
[or: what keeps me up at night] As you will see in the next post, I think Planet Nine is really out there. But that doesn’t mean you should think it is out there. You might be skeptical. In fact, I would prefer that you were skeptical. I would prefer that you read the scientific paper, looking for potential flaws, caveats, and places where we might have been led astray. But, OK, I understand that…
Standing up in public and claiming that you have found evidence for a new planet in the solar system almost certainly means that you are about to join a century-long list of people who have been wrong. I mean, look, le Verrier and Adams did it in 1846 when they predicted the existence of Neptune, sure, but since then there have been dozens (hundreds?) of similar claims (including le Verrier…
There is an uneasy exhilaration in announcing that the solar system might contain a dim, massive, and as-yet unseen planet. Certainly, nearly every attempt to predict the existence of a “ Planet X ” has ended in failure, but history does contain one shining success. LeVerrier and Adams’ theoretical predictions of the existence of Neptune, based on observed irregularities in Uranus’ orbit, are…
In 2006, when the International Astronomical Union codified what we mean when we say the word "planet," I was quoted multiple times saying something like, "That's it. That's the end of planets. We get eight in this solar system and that will have to be enough. Since 1845 there have been no new ones to discover." I was wrong. We think that Planet Nine is between 5 to 10 times the mass of the Earth…