That means that an object under the stack - in the team's experiments, a block of wood about 10cm long - would not "hear" the sound, and any attempts to locate the object using sound waves would not find it.

BBC: Acoustic 'cloaking device' shields objects from sound

No sound came from the object, and it did not move.

ECONOMIST: Robert Taylor

With Zikmu, and now Zikmu Solo, Parrot has changed the relation to sound by offering a beautiful object, highly technological and fully intuitive, that adapt to all music uses and to all environments.

ENGADGET: Parrot Zikmu Solo reaches US in November, makes a tower of wireless sound yours for $999

This may sound faintly ridiculous, but the finished object looks like a deeply satisfying classical column.

ECONOMIST: American contemporary art

More credibly, other opponents object on the grounds that biometrics sound horribly Big-Brotherish.

ECONOMIST: The measure of man | The

"How the sound reflects off this reflecting surface with this composite object on it - which is pretty big and has a cloaking shell on it - really reflects... just like a flat surface does, " Dr Cummer said.

BBC: Acoustic 'cloaking device' shields objects from sound

Others object, more reasonably, that America's economy is in sound shape: with no sign of inflation, there are no grounds for the Fed to act.

ECONOMIST: Further thoughts on America��s bubble economy

Mach is a measure of the ratio of the velocity of an object, in this case a plane, to the velocity of sound, which equals Mach 1, or 761.2 miles per hour.

FORBES: Magazine Article

This seminar enabled participants to better understand all stages from conception to completion of exhibitions, whether temporary or permanent, thinking of exhibitions as a whole where each component (time, space, object, support, information, text, still and moving images, sound composition) participates in the project designed and completed.

UNESCO: OFFICE IN BEIRUT