The Mohole is a terrain glitch centered on the north pole of Moho. The sinkhole measures 4.6 kilometers deep and 1.7 kilometers across, with a descending angle of 80 degrees. The walls of the sinkhole are smooth, and lighter in coloration. The surrounding terrain is highly irregular with few flat regions, making landings difficult. The Mohole exists because of an error in the heightmap, which remained such until update 0.90, in which it was made an anomaly. With this update, the Mohole became a dedicated biome (northern sinkhole), complete with science results. Due to its location, the camera is known to misbehave when in close proximity to the mohole. Additionally, once at the bottom, a Kerbonaut on EVA can experience sudden changes in the direction of gravity, which are normally harmless.
Until 0.90 there was no official name for this feature and the name Mohole was devised by the community. The true origin of the name is unclear, however there are a few possible origins:
- "Mohole" is a combination of the words "Moho" and "Hole"
- It may be in reference to Project Mohole, an attempt to drill a borehole to the Earth's Mohorovichic discontinuity.
- It may be named after a deep well called the "Mohole" in Red Faction: Guerrilla
- It may be a reference to Kim Stanley Robinson's novel Red Mars, in which "moholes" are kilometers-deep holes used as geothermal wells for the terraforming of Mars.