Acoustics

• Do Bats Use Special Relativity for Echolocation?
  Bats echolocate with sound in air, not relativistic light signals; classical acoustics and Doppler effects matter, while special-relativity corrections are negligible.
• Do Echolocating Bats Experience the Terrell Effect?
  Bats do not experience the relativistic Terrell effect, though sound-travel delays and Doppler shifts can influence their echo perception.
• Could Submarine Sonar Kill a Diver?
  A submarine’s active sonar could harm a diver at close range, but ordinary sonar is not known as a reliable way to kill one.