We cannot directly see the Sun and hence much of what we know about our star, is too little. As it moves around various constellations each month, the Sun constantly showers earth with sunlight, warmth and energy that powers life on earth. So here’s what we know about our sun.
Basic Layers
Core
The core is the only place where nuclear fusion reactions can happen. The sun’s other layers are heated from the nuclear energy created there. Temperatures in the core exceed 15 million degree celsius.
Radiative Zone
The radiative zone of the sun starts at about 25 percent of the radius of the Sun. Temperature in this region is about 4million to 6 million degree celsius.
Convective Zone
At around 70% of the sun’s radius, the convective zone begins. In this zone, the sun’s temperature is not hot enough to transfer energy by thermal radiation. Instead, it transfers heat by thermal convection through thermal columns.
Photosphere
The photosphere is the bright yellow, visible surface of the sun. The photosphere is about 400 kilometers thick, and temperatures there reach about 5,700° C.
Chromosphere
The pinkish-red chromosphere is about 2,000 kilometers. The low temperature gives the chromosphere its pink color. The temperature in the chromosphere increases with altitude, and reaches 25,000° C at the outer edge of the region.
Corona
The corona is the wispy outermost layer of the solar atmosphere and can extend millions of kilometers into space. Gases in the corona burn at about one million degree celsius.
Others important features of the Sun.
Solar Wind
The solar wind is a stream of extremely hot, charged particles that are thrown out from the upper atmosphere of the sun. This means that every 150 million years, the sun loses a mass equal to that of Earth. However, even at this rate of loss, the sun has only lost about 0.01% of its total mass from solar wind.
Sunspots
A sunspot is just what it sounds like—a dark spot on the sun. A sunspot forms when intense magnetic activity in the convective zone ruptures a thermal column. The temperature at this place is comparatively low.
Solar Flares
The process of creating sunspots opens a connection between the corona and the sun’s interior. Solar matter surges out of this opening in formations called solar flares. These explosions are massive. In the period of a few minutes, solar flares release the equivalent of about 160 billion megatons of TNT, or about a sixth of the total energy the sun releases in one second.
Solar Prominence
Solar prominences are bright loops of solar matter .Solar prominences are cooler than the corona, and they appear as darker strands against the sun. For this reason, they are also known as filaments.
Solar Cycle
The sun does not constantly emit sunspots and solar ejecta; it goes through a cycle of about 11 years. During this solar cycle, the frequency of solar flares changes. The solar cycle can have effects on Earth’s climate. For example, the sun’s ultraviolet light splits oxygen in the stratosphere and strengthens Earth’s protective ozone layer.
References:
- Layers of the Sun : https://www.nasa.gov/mission_pages/iris/multimedia/layerzoo.html
- The Sun : https://www.nasa.gov/mission_pages/sunearth/science/Sunlayers.html
- The solar interior : https://solarscience.msfc.nasa.gov/interior.shtml