Recently discovered tenth planet Sedna has provoked heated debate among astronomers — that it was considered a planet.
We have already mentioned that a clear boundary between planets and asteroids is not very big, and now in the solar system known to a few objects with a diameter comparable to the diameter of Pluto, which for a century the number of planets.
We now know that the working group of the International Astronomical Union (IAU), responding to a heated debate in the astronomical environment, review the definition of a planet, and in particular, to consider what still take a minimum diameter for a "destination" facility planet.
Until that moment, the planet called Sedna, officially, you can not.
Experts predict the complexity, if denied a planet, Sedna, astronomers officially "demoted" and only slightly larger than Pluto.
By the way, in 1999, has already sounded a proposal to classify Pluto as an asteroid, but then this "room" has failed. To protect the long-standing tradition got so many scientists.
Meanwhile, astronomers expect that in the near future on the edge of the solar system more than once will be the discovery of new objects, possibly larger than Sedna and even larger than Pluto.