Space Debris.

I. Mysterious space rubbish has appeared in Murcia recently. However, this isn't a single case, space is becoming a landfill.

II. Possible origins of the orb.
A. It may be part of a space station.
B. It may be a pressurised gas container that has fallen from outer space.
C. It may come from a rocket or satellite.

III. Object's features
A. It is made of a strong material that has survived to hard conditions.
B. It is similar to objects found in Brazil and Australia.
C. It is not dangerously radioactive or explosive.

IV. The black ball found in Murcia isn't radioactive or dangerous, it's just part of the space debris that is ocsupying outer space.