CostelloSpaceArt.com                                                                                                                                                                                                                  The Galaxy                                                                                                             By Rick Costello                                                                                                                                                                                                          Our galaxy, is a group of stars that we named the Milky Way Galaxy. There are in our galaxy 100-400 billion stars.  Our star the Sun, is one star in our galaxy of 100-400 billion stars that revolve around the center of the galaxy once every 225 million years like a giant hurricane of stars. The Milky Way Galaxy is similar to a hurricane in that clouds forming spiral arms, rotate around the center or the eye of the hurricane. Our galaxy is very similar except instead of having spiral arms made of clouds of water vapor as a hurricane’s, our galaxy has spiral arms made of atoms of dusts gases, and stars, hundreds of billions of stars.

  When the Big Bang occurred, it created a huge blast of radiation which formed a tremendous amount of heat in the quickly expanding Universe. This heat and radiation formed Quarks and Gluons which later combined to form neutrons, protons throughout the early Universe. As the temperature cooled, it reach a temperature that forced the neutrons and protons to combine with each other to form nuclei.  400,000 years later, as the universe continued to cool, it reached a temperature that forced the nuclei to combine with an electron. When these combined they made the first elements in this Universe, hydrogen atoms. The Universe was filled with Hydrogen atoms. 

   The hydrogen gases all over the early Universe were pulled in separate groups forming enormous separate volumes of hydrogen atoms. These were the beginnings of the 500 billion separate galaxies in the Universe.  The atoms of hydrogen within these volumes then began colliding to form the stars in the galaxies.  Throughout it’s life, our galaxy will produce trillions of stars.  Stars live their lives then throw their matter into space in their death and new stars are formed from these gases.  In our time, our galaxy presently has between 100 and 400 billion stars and our galaxy is one galaxy in the Universe with 300 billion other galaxies.

 In this early Universe about 13 billion,700 million years ago, these atoms of hydrogen floating about started banging into each other and sticking to each other and began to grow larger and larger. The larger they got the effects of gravity started to take effect and the larger objects began to draw more atoms into them and they grew larger and larger. It can take as short as a few hundred thousand years for the balls of hydrogen gas to gather enough mass for the weight of the gases at the center to create such an enormous pressure that builds the temperature up high enough for it to force the hydrogen atoms to combine with each other forming a new element, helium. Each time 2 hydrogen atoms combine, it creates a photon of light and the star shines. Our star the Sun each second, converts 400,000 tons of hydrogen into the element helium.  The nuclear furnace in the interior of stars burn a few hundred million years for the giant stars, to over 60 billion years for the smaller red dwarf stars. The Sun is a middle of the road star and will burn in it’s present stage for 10 billion years.  So far the Sun is about half way through these 10 billion years. The Sun and our planets, moon’s, asteroids and comets are about 41/2 billion years old.                          

  The amount of stars in the whole Universe, in all 300 billion separate galaxies is an astounding number. Just for your imagination, imagine sitting on a beach and reaching down and picking up a handful of sand.  Imagine letting the the individual grains of sand trickle out as slow as you can, 10 or 20 at a time. Now imagine counting each individual grain of sand in your hand. Then imagine the number if you counted every grain of sand on the whole beach.  There are more stars in the Universe than individual grains of sand on every beach on our planet Earth.

   We live on the planet Earth, which revolves around the closest star to us the Sun.  The Sun is one star in this galaxy, a galaxy with 100 to 400 billion other stars.  Our galaxy is one galaxy in the Universe that contains hundreds of billions of other galaxies. 

  A light year is a measure of distance equal to just under 6 trillion miles   (5.9 trillion miles).  In one year light travels 6 trillion miles, hence a light year. Our galaxy is round and flat, kind of like a CD or an old 33 speed record with a bulge at the center, a collection of old stars circling the center of the galaxy around a black hole at the very center with the mass of 300 Sun’s.  Our galaxy has a diameter of 150,000 light years and is       30,000 light years thick. For the mileage of the diameter of the galaxy, multiply 6,000,000,000,000 m/l.yr. x 150,000 l.yrs.  It’s a lot of miles to the other side of the galaxy.  The closest star to us is 4.2 light years away. There are a lot of stars in this galaxy but this is also a huge galaxy. If you could stand on another planet anywhere in the galaxy, the stars in that night sky would appear just as far as they do in our night sky.  From our view there are great distances between the stars.  For distances in the Universe, these stars are but a stones throw.