Sonic black hole

A sonic black hole is a phenomenon where phonons are unable to escape from a fluid flowing more quickly than the speed of sound. Essentially, all sounds is nullified in the presence of one.

Sonic black holes can be created using rubidium.

Uses

 * Stealth systems - Portable sonic black holes can be used to enhance stealth systems for infiltrators and assassins. It is especially useful against species which rely on hearing to detect nearby objects.
 * Weapon silencers - A sniper can take out another target without their weapon giving away their position.