You know what's the best thing about black holes, apart from them not being too close to us that they'd suck all of us up into oblivion? Two words: space slinky.
Eileen Meyer from the Space Telescope Science Institute and colleagues used images from the Hubble Space telescope to analyze the central black hole of nearby M87 galaxy and discovered that when it is busy feeding, the black hole can also fire jets of plasma into space, in the form of a giant helical slinky:
Meyer found evidence that suggests the jet's spiral motion is created by a helix-shaped magnetic field surrounding the black hole. In the outer part of the M87 jet, for example, one bright gas clump, called knot B, appears to zigzag, as if it were moving along a spiral path. Several other gas clumps along the jet also appear to loop around an invisible structure. [...]
"The jet structure is very clumpy. Is this a ballistic effect, like cannonballs fired sequentially from a cannon?" Meyer asked, "or, are there some particularly interesting physics going on, such as a shock that is magnetically driven?"
Meyer's team found evidence for both scenarios. "We found things that move quickly," Meyer said. "We found things that move slowly. And, we found things that are stationary. This study shows us that the clumps are very dynamic sources."