Rulers of the Oort Cloud

The newly discovery dwarf planet shows up as red-green-blue coloured dots. Three images, each taken about two hours apart, were combined into one. The orbit of this world may be hinting that a planet far larger than Earth also lurks in the outer solar system Photograph: Scott S Sheppard/Carnegie Institution for Science

The newly discovery dwarf planet shows up as red-green-blue coloured dots. Photograph: Scott S Sheppard/Carnegie Institution for Science

A new dwarf planet has recently been discovered in the solar system, orbiting at about 10 light hours from our Star. This is the furthest object belonging to our planetary system that we have been able to observe.

It is now at 12 billion kilometres from the Sun and its orbit reaches 67 billions kilometres in its perihelion. The dwarf planet has the not-very flashy name of 2012 VP113, and it is very similar to Sedna, the other famous planetoid orbiting the inner Oort Cloud.

The most exciting similarity to Sedna is its orbital inclination. While not a smoking gun per se, the similar revolution angle of the dwarf planets around the Sun, gives credit to the possibility of having a big planet (up to 10 times the mass of the Earth) orbiting on the dark edge of the Solar System.

In March, Nasa’s WISE telescope (Wide-Field Infrared Survey Explorer) reported the results from its search for hypothesised planets far out in the solar system. WISE found no evidence for a new planet larger than Saturn within 1.5 trillion km of the Sun. WISE’s results give us an upper limit to the size of the objects in the Oort cloud, since Saturn is 95 times the mass of the Earth. Better instruments will help us expand our direct knowledge of the outskirts of the Solar System, but for now we can only imagine the icy kings of the space beyond Neptune.

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