Ergosphere

Ergosphere

News: Recently, the term Ergosphere has been in the news because scientists have suggested using this possibility to send an object into the ergosphere and allow it to accelerate there along the black hole’s direction of rotation, so that it comes out moving faster. This energy ‘gain’ will translate to the black hole losing some angular momentum.

About:
• The Ergosphere is a region located outside the outer event horizon of a rotating black hole. The term was proposed by Remo Ruffini and John Archibald Wheeler during the Les Houches lectures in 1971 and is derived from the Greek word ἔργον (ergon), which means \'work\'.
• It is so named because it is theoretically possible to extract energy and mass from this region.
• As a black hole rotates, it twists spacetime in the direction of the rotation at a speed that decreases with distance from the event horizon. This process is known as the Lense–Thirring effect or framedragging. An object within the ergosphere cannot appear stationary with respect to an outside observer at a great distance unless that object were to move at faster than the speed of light (an impossibility) with respect to the local spacetime.