The radar returns, the investigators found, had come from the ice-laden clouds and were unrelated to the light. Both planes had encountered unexpectedly severe icing conditions which increased as they approached the center of the cloud. Radar, tracking their course during these moments, had shown the planes approaching close to the unknown target. All the evidence, the radar experts agreed, indicated that the unknown target was ice[IV-1]. _Venus as an Evening Star_ In the spring of 1959 Venus again, this time in the evening, caused reports of flying saucers. At 6:20 P.M. on March 13, a clear evening with visibility of about fifteen miles, an unidentified flying object was sighted in the western sky near Duluth, Minnesota[IV-1]. Witnesses described its shape as tubular or round and its color as red, orange, green, or white. Two interceptors of the Air Defense Command were scrambled to investigate and headed for the object at top speeds, but they could get no closer and eventually gave up the chase and landed. Military personnel at ground stations and in the air observed the object visually and picked up radar returns; it disappeared, after about thirty minutes, by fading from sight. Although this spectacular unknown had seemed to keep pace with the aircraft, at times rushing toward the planes on a collision course and at other times reversing direction and racing away, all witnesses agreed that the object had remained at a magnetic bearing of approximately 300 degrees. The radar screen at the ground station had been photographed and the film was forwarded to ATIC at Dayton. Analysis showed that the echoes had not come from a real target but were “angels” caused by interference (see _Chapter_ VIII). Some operators had reported sharp contacts, others fuzzy; on some sets the target had faded suddenly, on others it rushed off the scope at incredible speeds. Contact was intermittent, for short periods of from ten seconds to a minute, and each new contact gave a different position for the target. At the time of the sighting Venus was just on the western horizon, at the same position occupied by the unknown, and probably would have been invisible except for the refraction by the earth’s atmosphere. Layers of air with different temperatures had produced the apparent motion and changes in color. The object had maintained the same size and relative position during the entire period of observation; it disappeared by fading from sight, sinking farther below the horizon. The following night, under similar atmospheric conditions, the object reappeared in the same position. The unknown was positively identified as Venus.