Facts About the Sun
Published September 16, 2026 · FactsSeeker
The Sun is our nearest star and the main source of energy driving conditions at Earth’s surface.
It is a star
The Sun is a self-gravitating ball of hot plasma, not a solid object with a burnable surface. [1]
Fusion supplies its energy
Hydrogen nuclei combine in the core. The process releases energy that eventually escapes into space. [1]
It dominates the solar system’s mass
Most of the solar system’s matter is concentrated in the Sun, whose gravity governs planetary orbits. [1]
The visible surface is the photosphere
This is the layer from which most visible sunlight escapes. Other atmospheric layers lie above it. [1]
Its outer atmosphere is the corona
The corona extends far into space and is much hotter than the visible surface. [1]
Solar activity follows a cycle
Sunspot numbers rise and fall over a cycle averaging about eleven years. The cycle is not an exact calendar. [1]
Its material is mostly plasma
Much of the Sun is electrically charged gas. This state of matter differs from ordinary solid ground. [1]
Different latitudes rotate at different rates
The equatorial region turns faster than the polar regions. The Sun does not rotate like a rigid ball. [1]
It travels around the Milky Way
The Sun and its planets orbit the galactic center. The entire solar system participates in this much larger journey. [1]
Sunspots are cooler than nearby regions
Strong magnetic fields affect these areas of the photosphere. They look dark against the hotter surrounding material. [1]
The solar wind flows outward
Charged particles stream away from the Sun. This flow carries its magnetic influence through the solar system. [1]
The Sun will eventually become a red giant
As its internal fuel supply changes, it will expand dramatically. This stage lies billions of years in the future. [1]
Sources & further reading
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Sources checked 2026-09-16. Our approach to facts · Suggest a correction