At 6.00 am local time on Wednesday 22 February 2012, the town of Anapurus, in Maranhão State, northeast Brazil was hit by a metal sphere, roughly 1 m across and weighing about 30 kg, which reportedly crashed into a stand of cashew trees, before coming to rest in a garden.
Residents of Anapurus inspect the metal sphere. Folha News (2012).
The metal sphere attracted a large number of visitors to the area, before being taken into custardy by the local Military Police. From here the object was brought to the attention of Gustavo Rojas of the Grupo de Astronomia at Federal University of Sao Carlos, who identified it as probably being a part of an Ariane 4 rocket, used by the European Space Agency until 2003.
Spacecraft tend to contain a lot of thick-walled spherical tanks, which is the most stable shape for a tank containing liquids under pressure in a changing gravity field. Unfortunately this is also a good shape for surviving re-entry into the Earth's atmosphere, so as the amount of space junk orbiting the Earth increases, so does the number of metal spheres falling from the sky. As yet there have been no reported cases of death or serious injury caused by space junk, but it does seem to be an increasing hazard on Earth as well as in orbit, with several reports of damage to property now coming in each year.
Image showing each of the 19 000 man-made items larger than 10 cm in Earth's orbit, as of July 2009. NASA/Orbital Debris Program Office.