Astronomy_gec

=__**What Makes up Our Universe**__=

From the Big Bang to Galaxies- Our universe today is massive, and still growing. How it formed through is a whole other story. The universe started as a small speck that expanded is less than a second to the size of the earth. At the beginning of the universe particles move around rapidly that collided and formed protons, neutrons, and antiprotons. As these particles collide, they form electrons and positrons. After, helium nuclei start to form as the universe keeps expanding. 300,000 years later hydrogen and helium atoms are formed. The universe then continues to expand as it cools down. The universe formed from nothing to something larger then we can fathom.

Formation of Galaxies- Galaxies formed in the universe long after the universe was formed. The solar system is in the Milky Way galaxy which is a part of a whole other system of galaxies that fill up the universe. When there was slight uneven circulation of matter in the universe clumps were formed. This caused the universe to become a sponge-like structure. The clumps are formed around massive empty spaces. Our universe started as an immense sphere of gas as stars formed in clusters around it. Most of the gas then flattened into a disk around the center of the galaxy. The center is a flat lump that is thought to contain a black hole. When the universe was smaller many galaxies commonly collided together. Now this is not as common, yet one day our galaxy may end up colliding with the Andromeda galaxy.



Structure of the Galaxy- Our galaxy is made up of stars and gas. It is about 100,000 light years across from the side view. First you would notice a flat disk of dust and stars that is 1 to 2 thousand light years thick. The sun is about half way through from the center to the outer edge. If you look at the other edge of the galaxy you will see a dwarf galaxy combining with the Milky Way. Around the Milky Way are star clusters or single stars that form a circle around the galaxy.



Rotations of the Galaxy- Seeing the galaxy from the side view is only one way to see this massive disk. How this disk rotates is a whole other story. When you see this galaxy from a bird’s eye view you will see the central bulge enclosed by four spiral arms. These arms are distinguished by glowing, young blue stars and pink clouds of hydrogen gas. To find red and orange stars you would have to look closer to the center of the galaxy. By going in further to the center of the bulge you will find the nucleus of the galaxy that is about 5 light years in length. The center is most likely a black hole. What makes the center of the galaxy a bulge is a mixture of stars and dust. There is even a chance that the Milky Way galaxy is five times bigger than what we believe.

Formation of Planets- The solar system consists of planets that rotate around the sun. How these planets came to be took a series of complicated steps. When the sun formed and collapsed it sent out a cloud of gas and dust. Clumps of material started to gather in the suns disk soon after. After these rocks gathered to about a few kilometers apart they became known as planetesimals that become icy as you got futher from the sun. Throughout the solar system many pieces of the material collided softly enough to form with each other. If you look further out from the sun you will find larger planets that are called the giant planets. Closer to the sun, smaller planets formed due to many collisions. In the planets closer to the sun, the molten sunk to the center while the outer layers cooled down.

Formation of Moons, Rings, Comets- By looking even closer to our solar system you will find moons, comets, and rings. Our moon has been thought to form from a collision between a planet similar to mars and the earth. After the collision a piece of one of the planets was stuck in the earth gravitational pull. As the planets formed, the left over material was broken up into smaller pieces from impacts. Most pieces were emitted out of our solar system by using the sling shot affect with the planets. Some though, were captured in the asteroid belt which lies between Mars and Jupiter. A few of these were taken as moons of the larger planets. Planetesimals from the icy region further from the sun became comets once they were closer to the sun. The rings around some planets are thought to have been made of planetesiamls that were pulled apart by the planets gravitational pull. Sometime in the future one of these asteroids may end up colliding with the Earth.

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Gabby C