An accelerating streak of light moving upwards through the sky.I'm not really a big UFO believer, but I have no idea what this was, and it was strange. I was outside Caffe Luna, a coffee shop in Longmont, running back to the car to get some crayons I had left there because I was going to be using them to make Spanish Flash Cards inside the coffee shop. Something caught my eye. I looked up to the space between two giant trees outside Caffe Luna and I saw something moving steadily and quickly up at a little under a 45 degree angle. I would have thought it was a shooting star, a BIG shooting star, if it weren't for the upward motion. It wasn't a firework because it didn't leave any smoky or sparkly residue behind. Really, it was a streak of very bright, irridescent light that was . . . accelerating I think. Also, the head of it was very definded, like you would think a comet would be. It lasted for about 3 seconds and then it was gone. I shrieked. My huspand followed my gaze, but it was gone, and I like I said, there was no residue left behind.