What comprises 99.9% of the mass of the solar system?

The Sun comprises about 99.9% of the mass of the solar system, making it the dominant gravitational force within this celestial system. It contains nearly all of the system's matter, with the planets, moons, asteroids, comets, and other objects making up only a tiny fraction of the total mass.

The Sun is primarily composed of hydrogen and helium, undergoing nuclear fusion to produce energy in its core. This process not only contributes to its immense size and mass but also generates the light and heat that sustain life on Earth and influence the orbits of all other bodies in the solar system.

Understanding the mass distribution in the solar system is crucial for grasping the dynamics of planetary motion and the gravitational interactions that dictate everything from the orbits of planets to the behavior of comets. The significant mass of the Sun ensures that it dominates the solar system's gravitational field, keeping planets in their orbits and affecting their motions.