An artist’s impression of distant Sedna. Credit: NASA

Sedna – eccentric outer world of the Solar System

By Paul Sutherland
19 January 2013

(Sen) – Pluto lost its status as a major planet in 2006 as a NASA space probe, New Horizons, was already well on its way to investigate the remote world in the Solar System.

Pluto had long been seemed a bit of an oddball. Even on its discovery in 1930, astronomers noted that it had a strange orbit that was steeply inclined to the orbits of the known planets.

In more recent years, it became clear that Pluto is simply one frozen body among a steadily growing number that are being discovered in a zone beyond Neptune known as the Kuiper Belt.

But further out still, Pluto has an even stranger neighbour called Sedna. This world was discovered in 2003 from Palomar Observatory, California, by a team led by Mike Brown of the California Institute of Technology. Currently three times further from us than Pluto, it lies in the coldest known region of our solar system, where temperatures never rise above minus 240 Celsius.

Read more: Sedna – eccentric outer world of the Solar System — Sen.

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