Earth's Sun: Learn About Sun

Sun

The Sun is a huge, glowing star at the centre of the solar system. It provides light, heat, and other forms of energy in the solar system. Without the Sun there would he no life on Earth.

The Sun is the largest and the only star in the solar system. All the planets and their moons, and thousands of comets and asteroids orbit the Sun. It is a main sequence star and is made up of mostly hydrogen and helium. About three-fourths of the moss is hydrogen and onefourth of it is helium. Scientists believe that the Sun is about 4.5 billion years old and will continue to burn fuel for the next 5 billion years. '

Formation

The Sun was formed from a rotating cloud of interstellar dust and gas. The cloud collapsed for millions of years and finally formed a large disk with a central bulge. The central bulge formed the Sun and the large disk formed the planets.

Radiations

The Sun emits electromagnetic radiations in the form of infrared rays and visible light It also emits particle radiation consisting of protons and electrons.

Layers and Zones

The Sun and its atmosphere consist of several layers and zones. The core forms the innermost layer While the radiative zone and the convective zone form the next layers. The atmosphere of the Sun is divided into photosphere, chromosphere, and corona.

Core

The core forms the central region of the Sun. It is primarily made up of hydrogen and helium l and contains almost half the Sun’s mass.
Nuclear fusion, over the years, has changed the composition of the core. Initially, it was gnade up of 72 per cent hydrogen, 26 per cent helium, and 2 per cent heavier elements. Almost all the fusion reaction in the Sun takes place in the core. These reactions emit a lot of energy that light up the surface and makes it a very hot place.The temperature at the core is about 1,50,00,000 °C.

Chromosphere

The chromosphere is the thin layer above the ' photosphere. It is around 1,985.93 km thick. The chromosphere emits a reddish light.The temperature in the chromosphere ranges from 6,000 °C to about 20,000 °C.

Photosphere

The photosphere is the bright, yellow surface of the Sun. It is around 482.8032 km thick. It ' is the lowest layer of the Sun’s atmosphere and emits most of the White light that we see. The temperature of the layer is around 6,127 °C at the bottom and 4,127 °C at the top.

Corona

The corona is the hottest part of the Sun’s atmosphere. Temperature in this layer can reach about 11,11,09,333 °C during solar flares.'Ihe corona consists of streams of ionised gases and emits X-rays. It becomes visible during total solar eclipses as a pearly White crown surrounding the Sun when the Sun is completely blocked. The layer extends far into space, almost a million kilometres from the surface of the Sun.


Sunspots

Sunspots are cool areas on the Sun that appear as dark patches. They are formed when radiation of heat in some areas on the Sun becomes less because of the Sun’s magnetic fields. Sunspots increase in number every 11 years.'Ihis period is known as solar maximum. During a solar maximum there is an increase in the number of solar flares and eruptions. Earth too receives extra solar radiation during this period. Solar maximum can also cause power blackouts, throw satellites out of orbit, and upset radio communication.


Coronal mass ejections

Coronal mass ejections are bubbles of gas and charged particles ejected from the solar corona. They can be ejected over several hours and can pose a threat to the Earth’s atmosphere.

Solar flares

Solar flares are bursts of solar wind. They contain gamma rays, X-rays, protons, and electrons. Solar flares increase with the increase in the number of sunspots.