UFO Sighting in S.Roque do Pico, on August 10th 2011 – like a green fire ball appeared in the sky for 1 sec, moved forward very fast and suddenly disapeared

i was at azores, portugal and about 11 PM i was going home i looked at the sky(just random look) and suddenly i saw something that looked like a green fire ball, a light with something that looked like a flame trail all green wich appeared from nowhere, flew very fast for a second and then suddenly disappeared. I did't hear any noise or felt anything, i just saw that misterious green light. This has actually happened to me twice, 1 or 2 years later at Caldas da Rainha, Portugal (i dont have much details) at about 11 PM i was in a car and i saw the exact same light apppearing and disapearing from nowhere. it didnt look like a meteor, didn't light up, didnt come down, just flew high in the sky for a short time like a bright green fireball