At 2-4-2010, 18:37 (summer time, Brasilia) I saw this "V" shaped object close to the horizon, in Rio de Janeiro, Brazil. I took a picture of the beautiful sunset from the window of my home office, and minutes later, appeared what a thought to be a smoke and vapor from a plane at high altitude. But the object traveled very fast (angular velocity from my vantage point) and didn't leave anything behind, but moved like a whole thing (different from meteorites I observed on similar conditions years ago. I just had time to take two shots before it disappear behind the mountain. I changed the sensibility of the camera in some seconds between them. It didn't look to me, exactly like a plane, meteorite, cloud, or planet, so I have no explanation.