My roommate and I returned from dinner, pulling into our driveway in Miami, Florida at approximately 9:20 PM on 1/1/13. About three or four seconds after exiting the truck, we both looked up over the roof, having seen a bright light that we'd never seen there before (approximately 25 degrees above the horizon line over our rooftop). As we continued to watch, it moved directly over us. It was at this point that I pulled out my cell phone and began videotaping. The first five or six seconds, I am holding the camera directly up in the air above my head, facing due east. After that, I rotated 90 degrees counter-clockwise, so I was facing due north). During this time, the object was moving smoothly and at the same pace we'd seen since the beginning, heading NNW and ascending much more rapidly than it was traveling in the NNW direction. The last two to three seconds that it was in our sight, it suddenly changed direction slightly, accelerated and ascended at an unbelievable speed and winked out.As heard on the video, there is no audible noise emanating from the object. We kept quiet during the taping so as to not step over any other ambient noises. The sound of our dog (who was inside the bedroom at the time) is the only noise. We are not sure if our dog was reacting to us pulling up into the driveway (he usually does not react that loudly), or if he was reacting to the object.We live near the air force base, a local airport and are directly on the helicopter flight path between the two flight ranges, so we both are extremely familiar with the sounds and appearances of helicopters, commercial jets, private airplanes, and military craft. Because we are on the edge of a rural area, we can usually see them clearly enough to easily identify them. As a frame of reference, a helicopter flew overhead just 12-15 minutes later at about 500 ft. overhead. I could easily make out both rotors, the sound, the blinking lights, the searchlight, etc. as well as clearly the shape of the helicopter, even in the dark night sky.The object was a tall cylinder shape. It had no visible protrusions, appendages or identifying marks. I would estimate the size as roughly 10' tall with a diameter of approximately 6'. The object glowed with a white light. The bottom glowed with a white and orange pulsating light that emanated in a lens flare pattern about 2' out sideways from the bottom of the object. No light seemed to emanate downwards, even as it flew over our rooftop and driveway.I am analytical by nature, so upon sighting the object, I began eliminating things that I knew it wasn't. Clearly, it was not a private airplane (propeller driven or jet), a helicopter or a military craft, since the shape and lack of sound at 400-500 feet away would eliminate those. I have seen several military practice night jumps, so I am familiar with how they appear, so I was able to eliminate that possibility (night jumps also descend, not ascend). Flares are easy to recognize and it was clearly not a flare (based on numerous factors). A weather balloon or very large Chinese lantern seemed the likeliest fit, but the size, shape, speed and rate of ascent made those unlikely. The rapid change of direction and acceleration at the end of the event clearly eliminated those possibilities. Even my roommate, who does not believe in the existence of UFO's or the possibility of life on other planets, was at loss to come up with any other explanation.