Solar System Scientists Aren’t Convinced That Planet Nine Exists
“When all you have is a hammer, everything looks like a nail. If you look in such a way that you’re biased towards finding objects that support Planet Nine and away from finding objects that don’t support it, that doesn’t mean Planet Nine exists; it means you need better data before you can know what’s going on. We need to know what’s going on with not just Planet Nine, but the Solar System beyond the Kuiper belt in general.
With new surveys, better sky coverage, and superior data on the way, the next decade of astronomy should see us not only solve the mystery of what (if any) large worlds lie beyond Neptune, but can help us understand how solar systems form and evolve in general. There are a slew of mysterious objects out there, beyond not only Neptune but beyond our present ability to comprehend. With deeper, wider-field surveys on the way, this is one puzzle whose solution will fascinate astronomers no matter which idea is correct.”
Everyone wants to know when we will finally find Planet Nine: the hypothetical world perhaps ten times the mass of Earth that lies beyond Neptune? Well, what makes you so certain that Planet Nine exists? The original idea theorizing it was based on just four objects, and at present there are ten objects that provide strong, indirect evidence that something caused these detached objects that never approach Neptune to have such similar orbital properties. But there are an additional eight objects, found by a different, independent survey, that are consistent with the null hypothesis: that no Planet Nine exists. Without more and better data, and better, deeper sky coverage, it’s simply too premature to bet on Planet Nine.
There are three other explanations that may be just as good! Find out the science behind Planet Nine (or, perhaps, no Planet Nine) today.
This Is Why Scientists Think Planet Nine Doesn’t Exist
“Of course, this study isn’t enough to rule out Planet Nine; it still could be out there. As a counterpoint, Mike Brown has contended that a different survey strategy could have been definitive, and OSSOS simply isn’t a good survey for indicating yea or nay on Planet Nine. But remember, the old saying goes, “where there’s smoke, there’s fire,” indicating that if you observe an effect, it likely has a cause.
If you all of a sudden discover that what you thought was smoke was a figment of your imagination, it doesn’t mean there wasn’t a fire, but it sure does make the hypothesis that there ever was a fire a lot less compelling. The OSSOS study doesn’t rule out Planet Nine, but it does cast doubt on the idea that the Solar System needs one. Unless a deeper, better survey indicates otherwise, or Planet Nine serendipitously turns up, the default position should be its non-existence.”
Is there another massive planet in the Solar System? Do we have a super-Earth after all, between the masses and sizes of Earth and Neptune? And has it only gone undiscovered until now owing to our telescopic limitations, and the fact that it’s so much more distant than the presently known planets?
It’s possible. That’s the radical idea behind Planet Nine, proposed nearly three years ago by Konstantin Batygin and Mike Brown. They looked at the unusual orbits of a number of Kuiper Belt objects, and conjectures that a ninth planet, located hundreds of times as distant as Earth is from the Sun, could be the culprit. But on closer inspection, the evidence that they’re looking at might just be biased, and there may be no Planet Nine at all.
There may not even be a puzzle to solve. Come get the scientific story on Planet Nine that you haven’t heard today.
How Can We Tell If A Space Rock Came From Outside Our Solar System?
“But when we examined its orbital properties, a real shock came. First off, it’s highly inclined to the plane of the Solar System, something that normally only occurs for object originating from the Oort cloud or the outer Kuiper belt. An asteroid like this is virtually unheard of. Second off, it was moving fast; far too fast to have been caused by conventional means. Even if you began with this object an infinite distance away and let the full gravitational effects of the Solar System pull it in, it wouldn’t be moving this quickly. The only way to get an object moving at these tremendous speeds is with a gravitational encounter with a very massive planet: a gas giant.
But that’s where the third surprise comes in. If you trace back its orbital path, there’s no way it could have occurred that way. None of the planets encountered it in the past; it’s completely gravitationally unbound.”
On October 19th, we detected an object that was unlike anything else we’d ever seen before. It was moving too fast at too unusual of an angle to be either a comet or an asteroid, and was too thoroughly gravitationally unbound to be hurled in by a planet, whether known or unknown. Based on what we detected, there’s only one conclusion that makes sense: this object came from outside our Solar System. These interstellar interlopers have long been theorized, but this is the first time one has ever been seen. Without a tail or coma at all, it’s unique among objects that come from so far away, and yet follow-ups have verified exactly what we hoped for. This is the first object to ever have an extra-solar origin, and is likely the first of many that we’ll find.
Here are the criteria for evaluating whether something came from beyond our Solar System, and how we’ll find out even more next time!
Goodbye, Planet Nine! New And Better Data Disfavors A Giant World Beyond Neptune
“[T]he whole motivation that Batygin and Brown’s theory relies on isn’t that “these objects exist,” but rather that “these objects exist and their clustering is very unlikely to happen just by chance.” But the likelihood of what you see relies heavily on where you’ve observed and with what sensitivity you’ve made those observations. If you find clustered objects because you spent more of your observing time looking in the locations where you’d see clustering, that doesn’t mean there’s anything unusual. In fact, it’s more likely, if that’s the case, that there isn’t anything unusual; it’s more likely that you’re the victim of a phenomenon called detection bias.”
Last year, scientists Konstantin Batygin and Mike Brown made a huge splash when they announced that the Solar System likely contained a super-Earth-sized object beyond the orbit of Neptune. They dubbed the world ‘Planet Nine,’ and claimed that it was responsible for the orbits of the longest-period Trans-Neptunian Objects ever discovered. The fact that the orbits were clustered in both ecliptic latitude and longitude cried out for an explanation, and Planet Nine fit. But an additional world isn’t the only plausible cause of the clustering of these distant objects; another possibility is that the hitherto discovered objects were biased in some way. If you’re only searching for objects in the locations that would show you these correlations, then you’re going to find the correlations. The solution? To do a survey capable of distinguishing between whether the effect is solely due to bias, or the existence of Planet Nine.
The first comprehensive, four-year results from OSSOS are now in, and with eight candidate TNOs with the right properties, they don’t see any signature for Planet Nine. Looks like the evidence has gone up in smoke!
The Scientific Truth About Planet Nine, So Far
“The most surprising results from the Kepler mission was that the overwhelming majority of planets in the Universe were not small, rocky worlds like Earth or Mars, nor large, gas giant worlds like Neptune or Jupiter, but rather in-between worlds, collectively classified as Super-Earths. Ever since that discovery, astronomers have wondered why there simply aren’t any of those worlds in our Solar System. If the Planet Nine hypothesis is right, then there actually is one, and this is the best season for finding it!”
In January of last year, astronomers Konstantin Batygin and Mike Brown shocked the world by proposing that there was a world larger than Earth located some five-to-ten times as distant as Neptune. That this world — known as Planet Nine — was causing the ultra-distant Kuiper belt objects we’d discovered so far to all have predicable, peculiar properties. And the observations matched up really well. But in science, post-dictions aren’t enough. You need to make new predictions for objects you can then go out and measure, and see how they line up. In the case of Planet Nine, there are four pieces of indirect evidence that can be measured, and one piece of direct evidence that will settle the issue once and for all: actually locating Planet Nine.
The indirect evidence looks good, and we’re fast approaching the best season for hunting Planet Nine. Come get the status update today!