It's a Big Universe
The word "astronomy" comes from Greek (astro and nomos) meaning "star arranger." Astronomers do not exactly arrange the stars, but they do study how they are arranged by nature. In ancient times, astronomers could study only what they could see with their eyes. They had no telescopes. In modern times, astronomers have many devices which help them study the universe—telescopes, spectroscopes (to study the colors of light), satellites and much more.
And astronomers study much more than stars (for more information on stars, see, "Shoot For The Stars with Fun Facts"). They study planets, nebulae, black holes, galaxies, and the dust and gas between stars, called the "interstellar medium."
The universe is big. To get an idea how big, imagine for a moment that the farthest known stars are in New York City and that you are in Los Angeles. Most of the night sky's visible stars on this scale would be within 39 centimeters or about 15 inches. Don't know the distance between New York and Los Angeles? It's about 4000 kilometers (2400 miles). If you walked from one city to the other without stopping, it would take you about a month. You would have passed the stars visible without a telescope in the first second of your journey. In fact, on this scale you could walk across the entire Milky Way galaxy in about 20 seconds.
What's a galaxy? It's a large "city" of stars with anywhere from 100 million to a few trillion stars. They come in many shapes, too, including spherical, elliptical, flat disk spiral, and others. The picture, above, shows NGC 1300, a barred spiral galaxy.