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A new newspaper published in the Astronomical Journal suggests that the unusual tilt of some Kuiper Belt objects could be explained by a Mars-sized planet lurking in the outer solar system. To be clear, this hypothetical planet-sized mass is not the same thing as the hypothesized Planet nine that we've discussed at several points over the by year. It's difficult to observe a single diagram that shows all of these areas in proper relation to each other, so nosotros'll have to split this up a fleck:

The highly unusual (and yet, oddly similar) orbits of a number of Kuiper Belt Objects. Prototype past Caltech

The epitome higher up shows the hypothetical Planet ix besides equally a group of Trans-Neptunian Objects. None of these are considered to be Kuiper Belt objects, all of which sit considerably closer to the sun. Sedna, for example, has an orbit that takes it from 76 AU at perihelion (its closest position to the sun) to 936 AU at aphelion (its farthest signal from the sunday). Pluto, which is at present classified as the largest Kuiper Chugalug object, has a perihelion of 29.7 AU and an aphelion of 49.3 AU.

The Kuiper Belt can be seen hither, as the large cloud of objects that exist nearly and beyond the orbit of Pluto (shown in yellow). As you tin can see, this large cloud appears to generally exist in the same airplane as the rest of the solar system. The invariable plane of the solar system is divers as the plane passing through the center of mass of a planetary system. It is perpendicular to the athwart momentum of the solar arrangement.

In our system's case, Jupiter is responsible for most of the changeless plane (its measured value is within 0.5° of Jupiter's orbital plane). Near of the objects in the Kuiper Belt are similarly inclined towards the changeless plane of the solar system, but a few of the almost afar objects aren't. (Pluto's own moderately inclined orbit should exist considered a special case and is influenced-by and in alignment with Neptune).

What this new paper, past Kat Volk and Renu Malhotra of the University of Arizona's Lunar and Planetary Science Library, hypothesizes is that the viii-degree tilt by a distant group of Kuiper Chugalug Objects (KBOs) away from the invariable airplane could exist the result of a Mars-sized object that exists in the far reaches of the Kuiper Belt.

"The well-nigh likely explanation for our results is that in that location is some unseen mass," Volk told The Infinite Reporter. "According to our calculations, something as massive equally Mars would be needed to crusade the warp we measured."

We've searched the outer solar system for large planets, but something Mars-sized could still be hiding in the outskirts of the Kuiper Belt. As with Planet ix, more observational data and modeling are needed.

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