A spherical and luminous UFO above the Lake Titicaca

On October 4, 2013, a traveler has seen a huge bright light at the Lake Titicaca, in Bolivia. When he has photographed this spherical UFO, he was in a bus.

Light was strangely and lightly blue and was not like something known. So, what is it?

Witness statement:

I was in a bus taking pictures of the landscape and of Lake Titicaca. I did not see the object but when I downloaded the pictures from my IPhone a few days later the objects were there. I took some 100 or so pictures of the lake and surrounding landscapes and the object only appeared in 4 pictures.

I am sending 4 pictures of the object and one picture taken 3 pictures later of the same area and there is no object in that picture.