"Dark matter" refers to an unknown material estimated to make up about 27% of the universe, and this album is similarly implacable. It's droning and all-encompassing, coating any environment it enters with a sense of dread and wonder. If outer space is thought of as a vacuum with no life or sound, then Dark Matter paints a more fanciful picture. Here, deep space is a never-ending vista of the unknowable, saturated with the humming and buzzing of the universe.
From the first moment of "Subspace" you're suspended in Williams' severe world, a stage-setting that dwarfs and immerses the listener. Trying to pick out details in the audio is like squinting to see shapes in a pitch-black room. As your ears adjust, you notice things: pockets of static, a high whooshing that's somewhere between whale cries and sonar pings. The latter sound repeats irregularly throughout Dark Matter, disappearing during the formidable rumble of "Astronomicon" and then surfacing again later. It's one of the only recognizable motifs on a record that otherwise feels like a wall of atmospheric noise.
Though the mood is no different from previous Lustmord records, Dark Matter is more opaque. Williams is largely credited with inventing dark ambient, but Dark Matter toes a line between that genre and regular ambient music. A Lustmord classic like Heresy made use of guitar and other instruments in a way typically associated with rock music, while his last album, The Word As Power, prominently featured vocals. They had unnerving melodies and progressions, tension and release. Dark Matter has nothing of the sort. It's just the lonely sound of outer space, manipulated into formless, 20-plus-minute compositions.