Is Planet Nine Tugging on Cassini?

Updating their theoretical model to include the as yet unconfirmed Planet Nine, French astronomer Agnès Fienga and her team have come up with what may be the best hypothesis for slight perturbations in the orbit of Cassini that haven't otherwise been successfully accounted for. Furthermore, their model has a "sweet spot" — a patch of sky in the constellation Cetus — that could help narrow the focus of the hunt for the hypothetical planet.

SA - Mysterious Gravitational Tug on Orbiter May Help Find Planet Nine

Batygin and Brown made the case for Planet Nine's existence based on its gravitational effect on several Kuiper Belt objects — icy bodies that circle the sun beyond Neptune's orbit. Theoretically, though, its gravity should also tug slightly on the planets, moons and even any orbiting spacecraft. With this in mind, Agnès Fienga at the Côte d'Azur Observatory in France and her colleagues checked whether a theoretical model (one that they have been perfecting for over a decade) with the new addition of Planet Nine could better explain slight perturbations seen in Cassini's orbit. Without it, the eight planets in the solar system, 200 asteroids and five of the most massive Kuiper Belt objects cannot perfectly account for it. The missing puzzle piece might just be a ninth planet.

So Fienga and her colleagues compared the updated model, which placed Planet Nine at various points in its hypothetical orbit, with the data. They found a sweet spot—with Planet Nine 600 astronomical units (about 90 billion kilometers) away toward the constellation Cetus — that can explain Cassini's orbit quite well. Although Fienga is not yet convinced that she has found the culprit for the probe's odd movements, most outside experts are blown away. "It's a brilliant analysis," says Greg Laughlin, an astronomer at Lick Observatory, who was not involved in the study. "It's completely amazing that they were able to do that so quickly." Gerdes agrees: "That's a beautiful paper."

The good news does not end there. If Planet Nine is located toward the constellation Cetus, then it could be picked up by the Dark Energy Survey, a Southern Hemisphere observation project designed to probe the acceleration of the universe. "It turns out fortuitously that the favored region from Cassini is smack dab in the middle of our survey footprint," says Gerdes, who is working on the cosmology survey. "We could not have designed our survey any better." Although the survey was not planned to search for solar system objects, Gerdes has discovered some (including one of the icy objects that led Batygin and Brown to conclude Planet Nine exists in the first place).

600 AU would put the planet at a current position about 15x as far from the Sun as Pluto's average distance. The article goes on to mention that Batygin and Brown have asked for 20 observation nights on the 8.2-meter optical-infrared telescope which is located on the summit of Mauna Kea, in Hawaii and operated by the National Astronomical Observatory of Japan. They've been studying available observational data to eliminate areas of the sky where they're reasonably certain their hypothetical planet is not and it sounds like if they get even a part of the observation time they're requesting, they might have a good place to start.

Exciting stuff!

a reply to: theantediluvian

Planet nine to me is still Pluto, IDGAF what science says.

originally posted by: Vector99
a reply to: theantediluvian

Planet nine to me is still Pluto, IDGAF what science says.

It was politics that demoted Pluto, not science. It was done by a vote. "Democracy" trumps science.

a reply to: theantediluvian

science mag article
Another article on the idea of it from January this year.

This kind of discovery in my opinion is in the waiting phase. It would explain the erratic orbits of Neptune and Uranus in a pretty solid manner. The orbits of those two planets have suggested a large bodied object in orbit we have yet to discover for quite some time.

Though if it is in an elliptical orbit rather than central, that would indeed spell doom and gloom for earth on its incoming approaches, so there is that scary part.

a reply to: schuyler

Actually, it was more along the lines of "Dang, we just found a couple more and one is pretty much the same as Pluto. Do we keep adding planets or come up with a new definition?" They chose the latter.

en.wikipedia.org...

a reply to: Phage

It's planetary discrimination I tell ya!

a reply to: Vector99
Oh boy. Here come the Planets Lives(or Existence) Matters people...

a reply to: Tiamat384

PLM, that's a cause I would support 100%!

a reply to: Vector99
I believe as you believe, but sheesh these movements are getting out of hand. I'm waiting for an ALM(Asteroids Lives Matter) for when an Asteroid is stopped by humans(as to prevent the apocalypse) protest to say that we denied it its rights...

a reply to: Tiamat384

Will there be riots when asteroids such as the Chelyabinsk one dies?

I dunno about ALM lol.

a reply to: Vector99
Well that depends. If it does what it wanted to do and collide? Yes, because they will say we did not save it. If we destroy it before it hits? Yes because we did not let it die as it wanted to.

originally posted by: Phage
a reply to: schuyler

Actually, it was more along the lines of "Dang, we just found a couple more and one is pretty much the same as Pluto. Do we keep adding planets or come up with a new definition?" They chose the latter.

en.wikipedia.org...

That's just the cause of the change, schuyler is still correct that the change was simply an arbitrary one. Why not just keep adding planets? It's not as if people would be confused by referring to the current ones as "Classical Planets" if you wanted to refer specifically to them. Or you could draw a line at some point beyond Pluto, call it the planet line, and add the requirement of being within the planet line to be considered a planet.

Its all nonsense anyway, it doesn't have any effect on the bodies themselves or our understanding of them, so that being the case it would make more sense to me, if you are going to arbitrarily change the definition of a planet, then why not do so in a way that continues the current notion of which bodies are planets and which ones are not?

You might say that failing to clear the area around itself would be a solid distinction between Pluto and the other planets, therefore it makes sense to classify them different, but then why not classify the gas giants as different than the rocky planets. Four gas balls with ring systems seem to have far less in common with the rest of the planets than Pluto does. We can randomly pick any trait which will lump specific planets together and exclude others, not sure why the composition of something is less important when defining it than the area around it is, if anything it seems more important.

a reply to: James1982

Why not just keep adding planets? It's not as if people would be confused by referring to the current ones as "Classical Planets" if you wanted to refer specifically to them.

So, a redesignation in another direction. What's the difference?

but then why not classify the gas giants as different than the rocky planets.

We do. You just did.

a reply to: Vector99

Applause!!

originally posted by: Phage
a reply to: James1982

Why not just keep adding planets? It's not as if people would be confused by referring to the current ones as "Classical Planets" if you wanted to refer specifically to them.

So, a redesignation in another direction. What's the difference?

but then why not classify the gas giants as different than the rocky planets.

We do. You just did.

The only difference is that a bunch of people would be happier, personally I don't really care aside from how strange it seems that they excluded pluto. Purely an emotional reaction from people obviously, but what would it have hurt to make the pluto lovers happy, I doubt there is a group of pluto haters who cared deeply about removing plutos planet status.

We obviously do make distinctions between various planets, and again I'm not trying to say there is any grand significance in any classification of Pluto, but it's still the issue for me of why do something to upset people when you could avoid doing so at no detriment.

a reply to: James1982

but it's still the issue for me of why do something to upset people when you could avoid doing so at no detriment.

Political correctness in astronomy? Gosh, maybe they shouldn't call them black holes.

originally posted by: Vector99
a reply to: theantediluvian

Planet nine to me is still Pluto, IDGAF what science says.

So, if Pluto is planet nine, then this unknown planet must be planet ten, or should i say planet X...

Anything is possible. I find it exciting too.

If it does exist, it would make me wonder how advanced the ancients really were. I'm too lazy to research it right now, but I think there might be some ancient texts alluding to some unseen planet in our solar system.

Then again I could just be confused.

a reply to: gpols

but I think there might be some ancient texts alluding to some unseen planet in our solar system.

As far as the "ancients" are concerned, there were two unseen planets. Uranus and Neptune.

Is there some reason NASA, et al, does not deploy Hubble on this task? It's certainly got the firepower to find this thing.