Many people living on Earth are closed-minded to what is really out there in the universe. They can't even fathom its vastness and how the Earth is just a tiny speck compared to everything else out there. From planets to stars and to the edge of the unknown, we can only see what science offers us. From this we know that we are nothing more than a tiny planet located in a solar system of millions of people in a galaxy that contains many more in the universe. A galaxy, also called a nebula, is made up of billions of stars, interstellar gas, dust and dark matter that is destined to form a huge cloud in which we live. Although it can't be explained very well, dark matter makes up at least 90% of a galaxy's mass. Galaxies also contain billions and billions of stars, and their diameters can range from 1,500 to 300,000 light years. It's huge! The Milky Way, the galaxy we live in, is one of approximately 170 billion galaxies in the observable universe. Our Sun is one of billions of stars in our galaxy, and our eight planets revolve around this star in only a small part of our galaxy. “Earth's solar system is believed to exist very close to the galactic plane of the Galaxy, due to the fact that the Milky Way essentially divides the night sky into two virtually equal hemispheres” (“All About the Milky Way”). It definitely keeps people guessing about the fact that there is life on other planets. The first person to observe the Milky Way was the Greek philosopher Democritus, who said that the galaxy could be made up of distant stars. In 1610, Galileo Galilei used a telescope to study the Milky Way and concluded that it was made up of billions and billions of faint stars. Then, in 1750, Thomas Wright c...... middle of paper......core; this type of AGN was discovered by Heckman (1980) and is called Low Ionization Nuclear Emission Line Region (LINER); examples include the Andromeda Galaxy (M31) and M65. Works Cited "All About Galaxies." Space.com. TechMediaNetwork, 2010. Web. January 6, 2011.."All about the Milky Way." Space.com. TechMediaNetwork, 2010. Web. January 6, 2011..Frommert, Hartmut, and Christine Kronberg. "Galaxies." Seds.org. NP, 13 May 2009. Network. 6 January 2011. "Galaxies". Universe review. Np, nd Web. January 6, 2011..Wikipedia, the free encyclopedia. "Galaxy." Wikipedia The free encyclopedia. Wikimedia Foundation, Inc., January 6, 2011. Web. January 6. 2011..