What are these strange metal spheres that fell from the sky in India?

Last week, multiple metal spheres of unknown origin fell from the skies in villages within India's western state of Gujarat. The metallic balls are reportedly hollow, .45 meters in diameter, and weigh around five to six kilograms. Fortunately, the balls didn't drop on any human's head but a fragment of metal that fell with the spheres did kill a lamb. — Read the rest