Brittle Hollow is the third of six planets in the Outer Wilds' solar system. Its surface is largely barren and rocky, and over time it will break apart and fall into a black hole at the centre of the planet. Brittle Hollow is home to an enormous Hanging City, the Tower of Quantum Knowledge, the Southern Observatory, a Gravity Cannon, and the Black Hole Forge used by the Nomai to craft the warp cores for the Ash Twin Project.
Geography
Brittle Hollow is a highly unstable planet. Its dry, rocky surface is fractured and prone to collapse, and in the 22 minutes of game time the player can observe as most of the planet's crust breaks away and falls into its central black hole. These pieces then emerge at the white hole next to White Hole Station. This collapse is precipitated by the balls of lava ejected from the planet's moon crashing into the surface, coupled with the fact that the planet core has been gutted, either to make way for the work of the Black Hole Forge, or because of the Black Hole Forge. Traversing the planet's precarious remains is a challenging task, but despite the likelihood that a player will slip and fall into the black hole, the fact that White Hole Station lies very close to the black hole's exit point means that the planet's long drops aren't as dangerous as they are simply inconvenient.
There is a small village on the planet's surface, nestled amongst what seems to be a Nomai-made grove.
The planet's two poles are topped with snow, and the north pole has flowing water. This leads to ice formations beneath the surface into which the Hanging City is built.
The rest of the planet's interior is made up of a mixture of blue metallic and red crystalline rock formations. The geometric lattice of these formations exhibit clear fracture points and planes of weakness, which makes it susceptible to the collapse that the player can witness in action during the game.
Black Hole Forge
CAUTION: SPOILERS
The Black Hole Forge is the source of all the Nomai warp cores found around the solar system, and is found suspended below the Hanging City, just above the black hole at the planet's centre. The forge itself can be raised and lowered from the control room on the first level of the Hanging City, and accessed via the uppermost level, which itself can only be accessed via the warp portal on Ash Twin. The Black Hole Forge was used to craft the Advanced Warp Core, which powers the Ash Twin Project.
Hollow's Lantern
Brittle Hollow is orbited by the volcanic moon, Hollow's Lantern. The balls of magma that shoot from the moon crash into the surface of the planet, precipitating the collapse of the planet's crust. The Nomai used the moon's lava to heat-test mineral samples supplied from the Nomai Mines. These samples were then used to encase the Ash Twin Project.
Notes
- If you happen to slip and fall towards the black hole, its possible to slingshot yourself around it using your spacesuit's thrusters. There is a conveniently placed gravity lift extending down to black hole's edge, and lucky or skilful players that can manoeuvre themselves into its path can spare themselves the trek back from White Hole Station.
- The many gravity lifts and gravity crystals installed around the interior of the planet indicate that it was just as dangerous during the era of the Nomai. It's unknown whether this was because of their influence, or otherwise.