Piston effect platforms with a single tunnel, however, air quality worsens when relying on the piston effect alone for ventilation. This still allows for potential energy savings by taking advantage of the piston effect rather than mechanical ventilation where possible. Tunnel boom is a loud boom sometimes generated by high-speed trains when they exit tunnels. These shock waves can disturb nearby residents and damage trains and nearby structures. The perception of this sound by humans is similar to that of a sonic boom from supersonic aircraft, but unlike a sonic boom, tunnel boom is not caused by trains exceeding the speed of
Faster-than-light oscillator ticking too fast. In special relativity, it is impossible to accelerate an object the speed of light, or for a massive object to move the speed of light. However, it might be possible for an object to exist which moves faster than light. The hypothetical elementary particles with this property are called tachyonic particles. Attempts to quantize them failed to produce faster-than-light particles, and instead illustrated that their presence leads to an instability. Various theorists have suggested that the neutrino might have a tachyonic nature, while others have disputed the possibility. Mechanical equations to describe hypothetical exotic matter which