From Halopedia, the Halo wiki
Ziegler was a geologist that lived on Earth during the 2300s. In 2332, he, along with another geologist named Ross, discovered a minute anomaly in the fossil and carbon records of Earth. The discovery was matched on other worlds, and was attributed to the warping or stretching of spacetime itself. However, in 2552, after the conclusion of the Human-Covenant War, the blip was reexamined as strong evidence of a firing of the Halo Array.
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