This page contains information regarding Star Trek: Discovery, and thus may contain spoilers.
A spacefaring sphere was a hitherto unknown lifeform encountered by the USS Discovery in 2257. Composed of organic and nonliving matter melded together, it measured 565 kilometers in diameter and had a mass of 6.39 ×1020 kilograms. It vibrated in a manner that could be extrapolated from its surrounding ambient radiation as a loud shrieking noise. (DIS: "An Obol for Charon")
The sphere was hundreds of thousands years old, and during this time saw and experienced so much that its sensor records were later characterized as slice of the galaxy's history. It collected data from countless civilizations. Among the things experienced by the sphere were a war between the Quaternary star systems and the Roquarri Imperium. It also took readings from Kaminar constituting thousands of years worth of statistical measurements, and data on Artificial intelligence. (DIS: "An Obol for Charon", "The Sound of Thunder", "Project Daedalus")
As the sphere neared the end of its life, it sought to pass on its experiences so that it would be remembered. Thus, it captured the Discovery out of warp with a powerful multiphasic stasis field and attempted to teach its languages to the universal translator. However, the complexity of its communication and the breadth of its knowledge overloaded Discovery's systems, causing widespread malfunctions that the crew misinterpreted as the effects of a computer virus. Eventually, Commander Saru realized that a repeating pattern of ultraviolet lights being produced by the "virus" were linguistic in nature, and surmised the sphere's intent. (DIS: "An Obol for Charon")
At Saru's urging, Captain Christopher Pike had the Discovery drop shields and allow the sphere full access, enabling it to complete the transmission and translation of its experiences. Meanwhile, the sphere's internal temperature rose from under 10,000 to over 10.036 Kelvin, a sign of its impending core collapse. A nanosecond before its death, the sphere reversed the polarity of its stasis field to push Discovery clear of its detonation. Its last sensor observation was of Spock's shuttle. (DIS: "An Obol for Charon")
While on a mission to Kaminar to investigate a red burst, the crew of Discovery used the information gathered by the sphere to compile the Kaminar population history. This was then used to determine that the Kelpiens used to be the dominant lifeform on the planet instead of the Ba'ul. (DIS: "The Sound of Thunder")
While in orbit of Kaminar, Lieutenant commander Airiam was corrupted by an unknown force from the 28th century, which forced her to transfer all the information the sphere had gathered on artificial intelligence to Control. (DIS: "Light and Shadows", "Project Daedalus")
While reviewing her mother's mission logs, Michael Burnham learned that her mother was responsible for placing the Sphere in Discovery's path. This was after she'd tried to destroy it to keep it's data away from Control. (DIS: "Perpetual Infinity")