"Bellos" is the name given by the space cadets of the GapSpace facility to the hypothetical object, a large rock, that might have hit a stepwise Earth and wiped out the entire planet, thus creating the Gap.[1]
The High Meggas[]
In the universe of The High Meggas, the object that destroyed the Gap was given the name "the Fist" by Larry Linsay. It was a nickel-iron asteroid that hit 10 or 15 thousand years ago.
The Earths surrounding the Gap were also hit by the Fist, albeit with less destructive results: craters, continental drift, colder climate, thin air, a wobbling planet.[2]