At approximately 11:00 A.M. today, Sunday, February 15, 2015, I sighted from behind my home in Jupiter, Florida, an unusual object high in the sky to the northwest. I followed it with my eyes and was puzzled by the fact that it moved smoothly along like a high-flying plane, but it seemed to be spherical in shape. It shone brightly like a plane reflecting light, but the shining was constant. I rushed around to the front of the house to watch it as it proceeded south, but by the time I got to the front street it had seemingly disappeared from the sky (although I could see the entire area of sky where the object had been headed. Then I spotted another object of the same kind (my guess is that it was not the same one) far to the east, over the coastline or the Atlantic. It glided south in the same manner as the first object. Soon another shining object of the same kind appeared over the northern horizon. I pointed the objects out to my neighbors, who were now arriving in a truck. For the next half hour we continued watching these spherical objects as they appeared and proceeded southward. It would take each object about five minutes to pass from our view (disappearing after moving past us and going some distance. In the course of 45-50 minutes, we saw approximately 9-12 of these objects. There were no sudden maneuvers or changes in direction, although one or two of the objects veered slightly to the east, heading out toward the ocean. Some of the objects seemed to disappear (although I cannot say offhand whether that might have been due to the interruption of light reflection). The day was bright and sunny, with only a few thin, cirrus clouds in the sky. Air force jets leaving white contrails seemed to be tracking the objects, flying due south along the eastern coast of Florida in the general direction of Miami. The jets would appear from the north and pass silently overhead at high altitude. Other witnesses included my wife and four neighbors: a ship captain, his wife, his granddaughter, and a middle-aged male neighbor. We tried to take photos with my wife's iphone, but the lens doesn't appear to have captured anything other than blue sky.My immediate impression was that the objects seemed to be carried by a wind current and might be some sort of balloons. I phoned the local airport control tower (PBI), the Coast Guard, Patrick Air Force Base, and NASA. A NASA employee told me there had been no launches of any kind that morning.