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Scientists observe sound traveling faster than the speed of light
For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertsons team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative.Past experiments have demonstrated that the group velocities of other materials componentssuch as optical, microwave, and electrical pulsescan exceed the speed of light. But while the individual spectral components of these pulses have velocities very close to c, the components of sound waves are almost six orders of magnitude slower than light (compare 340 m/s to 300,000,000 m/s). All of the interest in fast (and slow) wave velocity for all types of waves (optical, electrical, and acoustic) was initially to gain a fundamental understanding of the characteristics of wave propagation, Robertson told PhysOrg.com. Phase manipulation can change the phase relationship between these materials components. Using sound to create a group velocity that exceeds the speed of light is significant here because it dramatically illustrates this point, due to the large difference between the speeds of sound and light. Posted by: Anonymoose 2007-01-18 |
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