Topics: Nebulae, Star, Interstellar medium Pages: 2 (610 words) Published: June 5, 2011
The word nebula comes from the Latin word for clouds. A nebula is a cosmic cloud of gas and dust witch is floating in space. If it is more then one nebula then they are called nebulae. These cosmic clouds are the fundamental building blocks of our universe. They contain the elements that are needed for stars to be formed. Known as the flowers of the universe they are some of the most beautiful sights there is with their swirling rich colors and bright lights. The reason for these bright rich colors is because of the stars inside of the nebula, the colors are apparent because of the different elements that make up the nebula. Most common nebula are composed of 90 % hydrogen, 10% helium, and 0.1% heavy elements, heavy elements such as carbon, nitrogen, magnesium, potassium, calcium, and iron. Nebulas are considered the largest objects in the galaxy, some nebulas are even hundreds of light years across. There are 5 major kinds of nebula, witch are, planetary nebulae, emission nebulae, reflection nebulae, dark nebulae, and supernova remnants. A planetary nebula is a shell of gas that is made by a star as its life draws close to an end. These nebulas really have nothing to do with planets. They were given the name planetary nebula because they often look like planets due to their round shell like shape. The outer shell I illuminated by the remains of the star that it came from. Emission nebulae’s are clouds of high temperature gas. Inside emission nebulae’s atoms in the cloud get energized by the stars ultraviolet radiation. Once the atoms fall back to lower energy states, they start to emit radiation. This emission of radiation causes the nebula to glow red due to the abundance of hydrogen. A reflection nebula is very different from an emission nebula. Reflection nebulas do not emit radiation of its own source. It is a cloud of dust and gas that reflect light energy from a close group of stars. Reflection nebulas are often the sites of star formations. Reflection...
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