Eris Planet - Pluto's Rival Is Thiny But Shiny

   
      Poor Pluto! It got kicked out of the planet club in 2006 after an even larger planet, Eris, was found in the outer solar system. Now it seems Eris is no larger than Pluto, it simply looks bigger because its surface is blindingly light. Observations by Hubble Telescope in 2005 suggested Eris is at least 2400 kilometres wide, a few percent wider than Pluto, which spans 2338 km. But the data left the room  for doubt.

      Last November, astronomers got their best chance yet to pin down Eris's size  when it passed directly in from a distant star and cast a small shadow in Earth. Bruno Sicardy of the Paris Observatory and his team compared the shadow's size from 2 different site in Chile and found that Eris is just 2326 km wide.
       The observations suggest Eris is  brighter than fresh snow, and may be the solar system's second brightest object afte Enceladus, Saturn Planet's moon. Nitrogen or methane frost on its surface might be the cause.

SOURCE : NEWS SCIENTIST MAGAZINE / 22 OCTOBER 2011