The Sun contains about 99.8 percent of the solar system’s mass.

Mass is not the same as the amount of space an object appears to occupy. The solar system extends far beyond the Sun, but its matter is overwhelmingly concentrated in the central star.

This imbalance makes the Sun's gravity the dominant influence on planetary orbits. The planets also pull on one another, yet those interactions occur within a system overwhelmingly controlled by solar mass.

The percentage includes giant planets as well as small rocky worlds. Even Jupiter, by far the most massive planet, remains a small fraction of the Sun's mass rather than a comparable partner.

The solar system formed about 4.6 billion years ago from a cloud of gas and dust. As gravity drew material inward, the growing central concentration became the young Sun. Surrounding material formed a rotating disk in which planets and smaller bodies developed. The resulting architecture placed most of the mass in the star rather than distributing it evenly among the planets.

The Sun consists mainly of hydrogen and helium. It is not a solid object with a hard surface like Earth, and its visible boundary is a layer from which much of the light we see escapes. Deep inside, temperature and pressure become high enough for nuclear fusion, the process that sustains the star's enormous energy output.

In the core, hydrogen nuclei ultimately combine to form helium. The resulting products have slightly less mass than the original ingredients, and the difference is released as energy. This is nuclear physics rather than chemical burning. The Sun does not need atmospheric oxygen or a supply of fuel delivered from outside to shine as a star.

That energy supports the Sun against gravity as it moves outward through the stellar interior and eventually escapes into space. Only a tiny fraction reaches Earth, but it drives the climate system and supplies the energy used by photosynthesis. The Sun's gravitational role and its role as an energy source are connected to its structure, yet they are not the same physical process.

The figure of 99.8 percent is rounded. It should communicate an overwhelming mass imbalance, not imply that every distant small body has been individually weighed to produce an exact accounting. The remaining fraction is dominated by planets, especially the giant planets, while smaller populations contribute much less.

Nor does dominance mean the Sun is perfectly stationary. All members of the solar system orbit their collective center of mass. Massive planets, particularly Jupiter, cause the Sun to move around that barycenter as well. Describing planets as orbiting the Sun remains an excellent first approximation, provided it is not mistaken for an absolutely fixed center.

Planetary motion is also not maintained by a continuous outward push from sunlight. A planet's forward motion and the Sun's inward gravitational attraction together produce an orbit. Gravity bends the trajectory rather than requiring the planet to sit motionless against the pull. This distinction explains why a dominant central mass can organize a system whose members are constantly moving.

The Sun’s share is a mass accounting statement, not a measure of how much visible space it occupies. Most of the solar system’s extent is not filled with solar material. A small central region can contain nearly all the mass while planets and smaller bodies explore a far larger volume around it.

No. It describes mass, the amount of matter, not volume or the proportion of space occupied. Most of the solar system's enormous spatial extent contains very little material.

Yes. Gravity depends on mass, not on whether a body emits visible light. A hypothetical object with the same mass would exert the same gravitational attraction at the same distance.

No. Ordinary fire releases energy through chemical reactions. The Sun's sustained power comes from nuclear fusion in its core, where hydrogen is transformed into helium under extreme temperature and pressure.