The surface of the Sun is called photosphere having temperature around 5,500o C. There are some areas where temperature is less than 3,500o C. Therefore, these regions looks darker than other surface areas and known as Sunspots. The region Above the surface of Sun is called Chromoshpere.
Sun generates its energy by nuclear fusion of hydrogen nuclei into helium inside its core, where the temperature exceeds 14 million oC and enough to start nuclear fusion. The Sun fuses almost 600 million metric tons of hydrogen per second.
Sun Reference Data
| Diameter: | 1.4 million km (870,000 miles) |
|---|---|
| Mass: | 330,000 x Mass of Earth |
| Density: | 1.41 |
| Solar Wind Speed: | 3 million km/hr |
| Rotation Period at Equator: | 25 Earth days |
| Solar Cycle: | 8 - 11 years |
| Age: | 4.5 billion years, 5 billion years remaining |
| Distance from Earth: | 149.6 million km (93 million miles) |
| Distance to Nearest Star: | 4.3 light years |
| Luminosity: | 390 billion billion megawatts |
| Temperature at surface: | 5,500o C (9,932o F) |
| Temperature at Core: | 14 milliono C (22.5 milliono F) |
| Temperature of Sunspots: | 4,000o C (7,232o F) |
| Rotation Period at Poles: | 35 Earth days |
