I was walking my dog and heard the University Hospital helicopter warming up. While watching the helicopter depart a light was descending and approaching the hospital. The light caught my attention because it was in my line of sight of the helicopter. I first viewed the light at approximately 1000 ft AGL,45 -60 degrees above the horizon, moderate brightness, slight flicker. The light grew brighter and larger in size leading me to assume it was closing the distance on the helicopter as well as descending. At its lowest altitude; I'd guess it neared 300-400 ft AGL and approximately 0.50 miles away. It looked like a landing light of an approaching aircraft. The helicopter began to depart from the roof of the hospital and the light hovered in place and ceased its decent. Once the helicopter was clear of the hospital the light made a quick adjustment to a more southerly position and ascended back the same direction from which it originated. I was able to follow the light during its ascent, but it quickly faded with distance. I am a pilot with well over 500 hrs PIC, I am NOT under the influence of drugs or alcohol, I am certain this was not an aircraft as I have NEVER seen a craft make such directional changes and ascend at that speed without any noise whatsoever.