NASA, America's space agency, is paying for an experimental version of Inductrack that will travel at half the speed of sound.

ECONOMIST: Maglev trains

Because of the distance that low-frequency sound waves can travel under water, a set of four ships emitting sound at 235 decibels could monitor 80% of the world's oceans for submarines.

ECONOMIST: The American navy may soon have a whale of a problem

These waves travel at the speed of sound, but when a jet travels at Mach 1 and above these waves merge into one single shock wave as they cannot get out of the way of each other quickly enough.

CNN: Bang goes the sonic boom

Throughout its life Amtrak has made the argument, repeatedly, that rail is the most cost-effective and environmentally sound form of travel.

CNN: Amtrak train: No better way to connect with U.S. voters

Viewing the Atlantis orbiter perched on the launch pad and protected by the service structure made it seem very fragile, even though it was made to travel over 100 times the speed of sound.

CNN: STORY HIGHLIGHTS

The NOAA ship Okeanos Explorer mapped the locations between Nov. 2 and Nov. 20 using multibeam sonar, which produces detailed images of the seafloor by calculating the amount of time and distance it takes for sound waves to travel from the ship to the seafloor and back.

MSN: Expedition finds 40 unknown gas seeps off US East Coast