Extremely large, shiny sphere moving fast

It was a sunny day in Malta, some summer clouds created by heat. Time around 10:30hrs when I saw a large, the size of 100 meters diameter, or more; a metallic, sphere or rather a globe, moving at incredible speed from University of Malta towards Luqa. It moved horizontally, slightly turning towards east. To my eye it felt like a flash of light, there was no time to react or take a photo. Total event took maybe 2 seconds. It was extremely shiny, like a big flying stainless steel ball. There were no lights of any sort. Quite fascinating!