The Sun is our closest star. It is a member of the Milky Way galaxy. The Sun is a yellow dwarf star, which means it is a medium size star. It is believed to be over 4 billion years old. The Sun spins slowly on its axis as it revolves around the galaxy. The center, or core, of the Sun is very hot. A process called “nuclear fusion” takes place there. Nuclear fusion produces a lot of energy. Some of this energy travels out into space as heat and light. Some of it arrives at Earth! Streams of gas particles known as the solar wind also flow out from the Sun.
Friday, 25 November 2011
What is the solar system? It is our Sun and everything that travels around it. Our solar system is elliptical in shape. That means it is shaped like an egg. The Sun is in the canter of the solar system. Our solar system is always in motion. Eight known planets and their moons, along with comets, asteroids, and other space objects orbit the Sun. The Sun is the biggest object in our solar system. It contains more than 99% of the solar system's mass. Astronomers think the solar system is more than 4 billion years old.Astronomers are now finding new objects far, far from the Sun which they call dwarf planets. Pluto, which was once called a planet, is now called a dwarf planet.