title: Critical velocity
text: # Critical velocity
  
  Critical velocity may refer to
  
  * Critical ionization velocity, relative velocity between a neutral gas and plasma at which the neutral gas will start to ionize
  * Speed of sound, at the throat of a rocket (otherwise known as throat velocity)
  * Landau critical velocity, constant velocity of a superfluid equivalent to the bandgap width divided by the fermi momentum
  * Velocity at which a liquid transitions from subcritical flow to supercritical flow
  * The break-up velocity of a rapidly spinning star
  * Velocity at which leukocytes switch from rolling to freely flowing in a blood vessel
  