3 ft. dia tan colored spherical object manuveing at 120+ knts.

I was piloting a Piper Cherokee 140 airplane returning to the Gadsden Airport after some recreational flying approaching from the north about 5 miles out, when I passed the object at about 1000 Ft. above ground level.  It was about 20 ft. off of my left wing.  It was about 3 feet in diameter, tan in color, and looked like a weather balloon except that it had no inflation nozzle, no radiosonde attached to it, and it was perfectly round.  Weather balloons have a teardrop shape to them when strapped to a weather gathering payload. 
I circled back to get a closer look and noticed what appeared to be a red crecent moon or a hammer and scycle shape on it reminiscent of the emblem on the former Soviet flag. 
As I circled around a second time to get closer look, the object moved away from me and maintained a distance of about 50 to 75 yard spacing between itself and my plane. When I became aware that the object could manuver, I was certainly rattled.  
I tried to pursue the object about a minute or two but it accellerated away to the point that I could not keep up with it.  I was traveling at 120 knotts.  
Scared, I opted to return to the Gadsden Airport.  When I arrived home, I reported the sighting to the Anniston Flight Service Station.  I believe the attendant at the FSS was unofficially impressed, but I don't know weather or not he officially filed my report. 
I believe the UFO to be either alien, a Top Secret USA probe, or the Russians aren't telling us something.  I maintain that what I saw was not a weather balloon and flew under its own power.  I strongly believe the markings were used camoflage the UFO to be from Earth.
Witness indicates that the date of the event is approximate.  PD