All About The Sun
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| Sun |
Astronomers today still study it, and areconstantly learning new things about the sun, the center of the solar system. The Sun is a star, not so different from thestars that can be seen in the night sky. It may look different, but that is becausethe sun is many times closer to us than any other star, which allows us to see how hotand bright it is. The sun may be close to us compared to otherstars, but it is still very far from the earth: about 93 million miles or 150 million kilometersaway.
Although the sun is so far away, it only takessunlight about 8 minutes to reach the earth because light travels so fast. Because the sun is so far away, however, itseems much smaller than it really is - more than 100 times the width of the earth. The sun is so large that if it were empty,more than a million earths could fit inside! The sun is the largest object in the solarsystem.
In fact, if you collected everything in thesolar system including the sun, the planets and dwarf planets, comets, asteroids, andmoons, the sun would account for more than 99% of it, with everything else adding upto less than one percent of the solar system. As far as stars go, however, the sun is averageor even small in size. It is called a yellow dwarf, and there arebillions of stars like it in the Milky Way. Like other stars, the sun is made of gasses:mostly hydrogen with a little helium, and only traces of other elements. These gasses are held together by the sun'sgravity, which creates such intense heat and pressure that it causes nuclear fusion - aprocess in which hydrogen atoms fuse to create helium - at its core. The sun's core is about 27 million degreesFahrenheit or 15 million degrees Celsius.
By the time heat from the sun's core reachesits surface, temperatures have dropped considerably. The surface of the sun is only about 10,000degrees Fahrenheit or 5500 degrees Celsius. Unlike the Earth, the sun does not have asolid surface. You may be surprised to learn that the sun'sgassy surface is not calm and quiet. Instead, the sun is constantly moving andchanging, with sunspots - or dark patches of cooler temperatures - and solar flares- or eruptions of high-energy radiation - frequently marking its surface. All of the planets in the solar system, includingthe earth orbit around the Sun. In turn, the solar system orbits around thecenter of the galaxy in which we live, the Milky Way. It only takes the earth one year to completean orbit around the Sun, but scientists estimate that it will take the Sun about 230 millionyears to complete an orbit of the galaxy.
Since ancient times, humans have understoodhow important the sun is for life on Earth. Without the energy provided by the sun's radiation,the earth would be dark, cold, and uninhabitable. Although it has been studied for thousandsof years, there is still much to learn about the sun. I hope you enjoyed learning about the sun,the center of our solar system.