Why Pluto is put out of solar system?

Answer 1

Pluto is still in our solar system. However it is not considered a planet anymore due to the fact that over the last few decades, powerful new ground and space-based observatories have completely changed previous understanding of the outer Solar System. Instead of being the only planet in its region, like the rest of the Solar System, Pluto and its moons are now known to be just a large example of a collection of objects called the Kuiper Belt. This region extends from the orbit of Neptune out to 55 astronomical units (55 times the distance of the Earth to the Sun).

Astronomers estimate that there are at least 70,000 icy objects, with the same composition as Pluto, that measure 100 km across or more in the Kuiper Belt. And according to the new rules, Pluto is not a planet. It's just another Kuiper Belt object.

Answer 2

Pluto was reclassified as a dwarf planet in 2006 due to characteristics that differ from the eight recognized planets. Its small size, different orbit, and inability to clear its orbit of debris led to the new classification. This decision was made by the International Astronomical Union in an effort to better define what constitutes a planet in our solar system.