Saw an extremely bright light moving incredibly fast east to west parallel to the horizon.

Sitting on the patio about 8pm. An extremely bright white light traveling at an incredible speed crossed the sky parallel to the horizon. Sighting lasted approximately 5 seconds. During that 5 seconds the object covered approximately 30 miles based on known mountain peaks. Object appeared to be 5 to 10000’ above the mountains which are approx 6 miles from sighting location. No sound, no trail, no sonic boom. I am a pilot familiar with the area, and know the distance between peaks and landmarks.