The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The energy from the Sun is vital for life on Earth.
Structure and Composition
The Sun is composed primarily of hydrogen and helium. These elements are found throughout its various layers.
|
Layer |
Description |
|---|---|
|
Core |
Where nuclear fusion occurs, converting hydrogen to helium. |
|
Radiative Zone |
Energy is transferred by photons. |
|
Convective Zone |
Energy is transferred by convection currents. |
|
Photosphere |
The visible surface of the Sun. |
|
Chromosphere |
A thin layer of the Sun's atmosphere above the photosphere. |
|
Corona |
The outermost layer of the Sun's atmosphere, extending millions of kilometers into space. |
Key Statistics
Below are some fundamental facts about the Sun.
- Type of Star: G2V (Yellow Dwarf)
- Age: Approximately 4.6 billion years
- Distance from Earth: About 150 million kilometers (1 Astronomical Unit)
- Diameter: Approximately 1.39 million kilometers
- Mass: About 330,000 times the mass of Earth
- Surface Temperature: Approximately 5,500 degrees Celsius (9,940 degrees Fahrenheit)
- Core Temperature: Approximately 15 million degrees Celsius
Solar Phenomena
The Sun exhibits several dynamic phenomena that influence space weather and the solar system.
- Sunspots: Cooler, darker regions on the Sun's surface caused by intense magnetic activity. They appear in cycles, with the number peaking every 11 years.
- Solar Flares: Sudden, intense bursts of radiation (energy) that are released when magnetic energy builds up in the solar atmosphere and is suddenly released.
- Coronal Mass Ejections (CMEs): Large expulsions of plasma and magnetic field from the Sun's corona. They can cause geomagnetic storms if directed toward Earth.
- Solar Wind: A continuous stream of charged particles flowing outward from the Sun.