Why the Sun is very hot? Why is Pluto not counted in the planets? Why Pluto is a dwarf planet?

The core of the sun is very hot and there is a lot of pressure in it due to nuclear fusion which takes place where hydrogen is changed to helium. Nuclear fusion creates heat and photons (light). The sun's surface is about 6,000 Kelvin, which is 10,340 degrees Fahrenheit (5,726 degrees Celsius). Thus, the light radiated by the sun carries energy, part of which gets absorbed and transformed into heat when it reaches a surface.

Pluto is a dwarf planet, and not counted in the planets because there are essentially three criteria of the IAU for a full-sized planet. These are:

1. It is in orbit around the Sun.

2. It has sufficient mass to assume hydrostatic equilibrium (a nearly round shape).

3. It has “cleared the neighbourhood” around its orbit.

Pluto meets only two of these criteria, losing out on the third. In all the billions of years it has lived there, it has not managed to clear its neighbourhood.


Simply Easy Learning

Updated on: 10-Oct-2022


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