I was watching the tonight show and Dave Letterman was just coming on. I was laying on the couch, and out our front window I saw something through the curtain sheers. I went to the window and observed a giant fireball roughly 50 feet in diameter moving very slowly in a horizontal direction. It was roughly 50 feet in my estimation by comparing it to the 70 foot trailer across the road that it was nearly flying over.I could see all the flames. It was moving at my best guess about 5 mph. It didn't leave a fire trail, but the flames were vertical, and I could see it was sphere shaped. It moved about 10 feet over the tops of the trees and illuminated the tree tops as it went. I figured that if it had traveled in that same plane without raising or lowering, that it would have been a couple feet at most over our property in the back. We had a hill behind us that lowered to a creek bed in front of our house, that began another slight grade and then the tree line across the road. When I caught site of it, it was just passing over the hill in the front of our house, where it then moved over the trees across the road. I was 20 at the time, and was home alone. I got so scared that I ran upstairs and shut off all the lights. I didn't know what that thing was. I never even told my dad about it until about ten years later.