SOLAR SYSTEM

Detailed explanation-1: -In August 2006 the International Astronomical Union (IAU ) downgraded the status of Pluto to that of “dwarf planet.” This means that from now on only the rocky worlds of the inner Solar System and the gas giants of the outer system will be designated as planets.

Detailed explanation-2: -According to the IAU, Pluto is technically a “dwarf planet, ‘’ because it has not “cleared its neighboring region of other objects.” This means that Pluto still has lots of asteroids and other space rocks along its flight path, rather than having absorbed them over time, like the larger planets have done.

Detailed explanation-3: -On August 24, 2006, the International Astronomical Union (IAU) announced it had re-classified Pluto as a dwarf planet. From 1930 until then, Pluto had been considered a normal planet and the outermost planet of the solar system. As technology had advanced, though, astronomers could see fainter objects.

Detailed explanation-4: -The year 2006 was one of things lost and found. The solar system lost its former ninth planet and NASA lost a long-serving Mars probe, but scientists found good evidence for dark matter, signs of liquid water flows on present-day Mars, and a planet just a few times more massive than Earth around another star.

Detailed explanation-5: -In 2006, the International Astronomical Union (IAU) formally redefined the term planet to exclude dwarf planets such as Pluto. Many planetary astronomers, however, continue to consider Pluto and other dwarf planets to be planets.