Question

Why is Pluto called a ,"dwarf planet" ?​

Answer 1

Answer and Explanation:

Pluto is called a "dwarf planet" because it does not meet the criteria to be classified as a full-fledged planet. In 2006, the International Astronomical Union (IAU) redefined the definition of a planet, which led to Pluto being reclassified as a dwarf planet. Here are the main reasons why:

1. Size: While Pluto is larger than some moons in our solar system, it is much smaller than the eight traditional planets like Earth, Jupiter, and Saturn. Its size is comparable to other objects in the Kuiper Belt, a region beyond Neptune where many icy bodies reside.

2. Orbit: Unlike the eight planets that have relatively clear paths around the Sun, Pluto has a more elongated and inclined orbit. This means it has a more irregular path and crosses the orbit of Neptune at certain points. This is different from the regular, more circular orbits of the traditional planets.

3. Neighborhood: Pluto is part of a region called the Kuiper Belt, which consists of numerous icy bodies and small objects. This region is distinct from the inner solar system where the eight traditional planets reside. The presence of many similar-sized objects in its vicinity further influenced the decision to reclassify Pluto.

By considering these factors, the IAU determined that Pluto did not meet the criteria to be classified as a planet. Instead, it was designated as a dwarf planet, a new category that acknowledges its unique characteristics and its place in the Kuiper Belt.

It's important to note that this reclassification sparked some debate and controversy among astronomers and the public. However, the IAU's decision to classify Pluto as a dwarf planet is the current scientific consensus.

Answer 2

Pluto is called a dwarf planet because it does not meet the three criteria set forth by the International Astronomical Union (IAU) for a full-sized planet.

These criteria are:

1. It must be in orbit around the Sun.
2. It must be massive enough for its self-gravity to overcome rigid body forces so that it assumes a hydro-static equilibrium (nearly round) shape.
3. It has cleared the neighborhood around its orbit.

Pluto meets the first two criteria, but it does not meet the third. The Kuiper Belt is home to many other objects that are similar in size to Pluto, and these objects share Pluto's orbit. This means that Pluto has not cleared its neighborhood of other objects, as a planet is supposed to do.

As a result of this, Pluto was reclassified as a dwarf planet in 2006. There are now five dwarf planets in our solar system: Pluto, Ceres, Eris, Makemake, and Haumea.