Located at the centre of the solar system is the sun. It is a star, like the ones you see in the night sky. A burning ball of gas, made of mostly hydrogen and helium, it provides us with the heat we need to survive. The sun is doing massive that its gravity – the force that pulls things together – keeps the planets in orbit around it. Like other stars, our sun is basically a large ball of gas that is 91% hydrogen and 8.9% helium. The sun’s mass is around 70.6% hydrogen and 27.4% helium.
While a majority of our sun may be gas it does have six distinct regions: the core, the radiative zone, and the convective zone in the interior, the visible surface, called the photosphere; the chromospheres; and the outermost region, the corona.
The sun is held together due to gravitational attraction that produces an intense temperature and pressure at the core. The core’s temperature is about 27 million degrees F/15 million degrees C.
This is hot enough to continue the constant state of thermonuclear fusion, a process where atoms combine to create larger atoms and in that process they release huge amounts of energy.
Our star: The Sun is 150 million kilometers (93 million miles) away from the Earth (this distance varies slightly throughout the year, because the Earth’s orbit is an ellipse and not a perfect circle). The Sun is an average star – there are other stars which are much hotter or much cooler, and intrinsically much brighter or fainter. However, since it is by far the closest star to the Earth, it looks bigger and brighter in our sky than any other star. Energy is constantly being generated deep within the sun. It can take up to 100,000 years for energy to reach the surface, but then it only take 8 minutes to reach the earth!
Solar flare: Huge eruptions from the surface of the sun are called solar prominences. They form loops because of the Sun’s invisible magnetic field. Flares are closely associated with the ejection of plasmas and particles through the Sun’s corona into outer space; flares also copiously emit radio waves. If the ejection is in the direction of the Earth, particles associated with this disturbance can penetrate into the upper atmosphere (the ionosphere) and cause bright auroras, and may even disrupt long range radio communication. It usually takes days for the solar plasma ejecta to reach Earth. Flares also occur on other stars, where the term stellar flare applies. High-energy particles, which may be relativistic, can arrive almost simultaneously with the electromagnetic radiations.
Sunspots: Dark patches that appear on the surface of the sun are called sunspots. They are cooler areas that usually last for a few weeks. Individual sunspots or groups of sunspots may last anywhere from a few days to a few months, but eventually decay. Sunspots expand and contract as they move across the surface of the Sun, with diameters ranging from 16 km (10 mi) to 160,000 km (100,000 mi). Larger sunspots can be visible from Earth without the aid of a telescope. They may travel at relative speeds, or proper motions, of a few hundred meters per second when they first emerge.
Picture Credit : Google