The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma (state of matter) interwoven with magnetic fields. It has a diameter of about 1,392,000 km, about 109 times that of Earth, and its mass (about 330,000 times that of Earth) accounts for about 99.86% of the total mass of the Solar System. Scientists calculate our Sun and solar system formed at the same time - a whopping 4.56 billion years ago. Sun's average distance from Earth is 150 million kilometers (93 million miles). Sun is made of gas. Sun will shine as it is for about another 3 to 5 billion years! It will then evolve into a Red Giant over a few more billion years. Scientists arrive at this estimate by calculating how fast the hydrogen in the Sun's core is being converted to helium. Approximately 37% of our Sun's hydrogen has been used since it formed four and a half billion years ago. Every second, the Sun produces 400 trillion watts, which is the same amount of energy as about a trillion 1 megaton bombs!
Our Sun and the solar system formed from a huge, slowly rotating molecular cloud made of hydrogen and helium molecules and dust. Based on its own gravity, the cloud began to compress. As it compressed, it spun faster and faster. The spinning flattened the material into a giant disk. Most of the mass was concentrated at the center of the disk, forming a gas sphere. The sphere continued to attract material from the disk. As new material was added, the sphere compressed, increasing the temperatures and pressures until they were sufficient to fuse atoms in the very center of the sphere - and at that point a star – the Sun, was formed.
Production of solar energy initially will commence in the Sun's core. The Sun, like most stars, is mainly made of hydrogen. Its core is so hot and compressed that large amount of hydrogen atoms stick together. Energy from the Sun is caused from thermonuclear explosions deep within the Sun. These nuclear explosions fuse atoms of hydrogen into atoms of helium. A tremendous amount of energy is released during the thermonuclear reaction and the Sun releases that energy as radiation. This radiation travels through space at the speed of light, and solar panels can make practical use of it. Our Sun generates an enormous amount of energy and heat, making the amount we actually receive to be very small.
Earlier to the invention of nuclear power, scientists visualized the Sun as a ball of combusting matter. Today we know that the Sun is fueled by nuclear energy. The Sun pumps about 386 billion million gigawatts into space, mostly in the form of electromagnetic radiation. If we compare it with a large nuclear reactor which generates about 1 gigawatt, the global energy consumption is a few thousand gigawatts. This energy output is typical for a star in the same class as the Sun. The Sun radiates uniformly in all directions, mainly visible light and infrared radiation, and we can calculate the total amount of energy radiated by measuring the quantity of solar energy per second reaching every square meter of Earth and then multiplying that by the total surface area of a sphere with radius equal to the radius of the Earth’s orbit. We get the astoundingly huge amount of 400 trillion watts. Every second, the Sun produces the same energy as about a trillion 1 megaton bombs!! The Sun produces enormous energy every hour than the entire energy needs of human civilization from the beginning of time. Solar panels will help us harvest increasing amounts of this abundance of energy to meet our energy needs in the future.
The energy that comes from nuclear fusion on the Sun produces most of the energy on Earth. The solar energy that is impacting Earth can be used to generate electricity and heat. Electricity is either converted by solar cells (called photovoltaic) or through solar power plants.
The Sun’s energy helps plants to grow and helps the plant to produce their food through a process known as “photosynthesis”. This conversion of solar energy by the plants into food, is the basis of all energy supporting most of the flora and fauna on our planet (the only exception being some animals that live close to oceanic thermal vents, where the energy is provided by the Earth's core)