Our sun, Sol, is the largest object in our solar system, containing about 99.8% of the total mass of the solar system. However, in comparison with other stars, it is middle sized. It has a diameter of 1,390,00- kilometers, and a mass of 1.989e30 kilograms. Currenly, the sun is made up of about 73% hydrogen and 23% helium. At the surface, the sun's temperature is about 5800 kelvins (water boils at 373 K), but in the core the temperature is about 15,600,000 K.
The sun is made up of three inner layers, and outer layer, and the corona. The innermost layer of the sun is the core. The core is extremely hot, with temperatures reaching 15.6 million K, and a pressure that of 250 atmospheres. The surface of the sun, the protosphere, has a temperature of 5800 K. Sunspots and solar flares occur in/on the protosphere. The outermost layer of the sun, the corona, consits of highly charged particles and extends for millions of kilometers in space. However, the corona can only be seen during an eclipse.
The sun admits a stream of charged particles, known as solar wind. The solar wind causes the aurora borealis (also known as the Northern Lights). However, it also has negative effects and can cause radio interference and power line surges. Solar wind appears to have a seven-year cycle, the seventh year being the strongest, and it also appears to have some relationship with the amount of sunspots, which also have a seven year cycle. The solar wind also has an effect on the tails of comets and the projectory of spacecraft.
The sun is about 4.5 billion years old. It should continue to radiate peacefully for about another 5 billion years, before it runs out of fuel. Eventually, when it does, it will collapse on itself, then grow bigger and consume the Earth before probably collapsing into a planetary nebula.