How black holes change gear

Science News

How Black Holes Change Gear

Black holes are extremely powerful and efficient engines that not only swallow up matter, but also return a lot of energy to the Universe in exchange for the mass they eat. When black holes attract mass they also trigger the release of intense X-ray radiation and power strong jets. But not all black holes do this the same way. This has long baffled astronomers. By studying two active black holes researchers at the SRON Netherlands Institute for Space Research have now gathered evidence that suggests that each black hole can change between two different regimes, like changing the gears of an engine.

Black hole accretion. (Credit: P. Jonker/Rob Hynes)

Source: Science Daily

I respectfully point out that even if black holes have two separate mechanisms for transforming energy, it can't be anything like changing gears - for a start, you would burn the clutch out, and even if we assume a perfect thrust bearing, the stress on the tyres would be enormous (big wheelspin!).