The main constituent of the Sun is hydrogen, making up about 70.6% of its mass.

Here's a breakdown of the Sun's composition:

* Hydrogen: 70.6%

* Helium: 27.4%

* Other elements: 2% (including oxygen, carbon, neon, iron, and others)

The Sun is a giant ball of hot gas, primarily hydrogen and helium, that generates energy through nuclear fusion. This process converts hydrogen into helium, releasing immense amounts of energy in the form of light and heat.