The Sun
The Sun is the star at the heart of our solar system. Its gravity holds everything in orbit, from the biggest planets to the smallest bits of debris, and its energy drives Earth’s seasons, weather, and climate. It’s a hot, glowing ball of hydrogen and helium, roughly 100 times wider than Earth.
| Distance from Earth | 93 million miles (150 million km) — 1 AU |
| Diameter | 865,000 miles (1.4 million km) |
| Rotation | 25 Earth days at the equator, 36 near the poles |
| Age | about 4.6 billion years |
| Surface temperature | 10,000°F (5,500°C) |
| Core temperature | 27 million°F (15 million°C) |
| Composition | Mostly hydrogen and helium |
Interesting facts
- The Sun accounts for more than 99.8% of the mass of the entire solar system — it would take over 330,000 Earths to match its mass.
- Because the Sun is a ball of gas rather than a solid, it doesn’t rotate uniformly: a spin at the equator takes about 25 Earth days, while the poles take around 36.
- Sunlight takes about 8 minutes to travel the 93 million miles to Earth.
- The Sun’s corona, its outer atmosphere, is far hotter than its visible surface, reaching up to 3.5 million°F — a puzzle scientists are still working to fully explain.
- NASA currently supports 22 active missions studying the Sun, including probes that fly closer to it than any spacecraft in history.
- The Sun is about halfway through its roughly 10-billion-year lifespan as a main-sequence star.