Pertaining to the Covenant's usual orbital tactics and their deviations from them
Alexis J. Lojek (phoenix155@mac.com) writes:
As we have seen before, the Covenant glass most planets that Humanity inhabits. However, whenever a planet has Forerunner artifacts on it they either only partially glass it (as seen with Reach in First Strike), or invade it entirely (Reach and Sigma Octanus). Earth must have some type of Forerunner artifact on it. Funny that we haven't found it yet...