Prior to 2328, colonists from Earth established the Omicron Theta colony on the planet Omicron Theta. The colony's primary mission was scientific in nature. A being known as the "Crystalline Entity" destroyed the colony, as well as all life on the planet, in 2338.
Twenty-six years later, the USS Enterprise-D diverted its course briefly to this system in the search of answers as to Data's origins and the events leading up to the death of the colony. In the course of their investigations, they recovered the body of Lore. (TNG: "Datalore")