Astronomers have revealed what's actually inside the mysterious jets of energy which stream out from the middle of black holes.
And surprise, surprise - it's confusing.
The International Centre for Radio Astronomy Research said that it appeared the massive, high-energy streams emanating from some black holes are at least partially made up of ordinary atoms - and not just electrons as previously thought.
The findings represent the first time that these particles have been found to be emitted by black holes.
The team said in the journal Nature that the jets themselves are narrow beams of energy, which are pushed out from an object of enormous mass - like a black hole.
But "although they have been observed for decades, we're still not sure what they are made of, or what powers them," said ESO astronomer Dr María Díaz Trig.
By studying the radio waves and X-rays from a small black hole, the team saw odd 'lines' in the pattern, moving in a wave that tends to highlight ordinary atoms.
"It led us to conclude the particles were being accelerated to fast speeds in the jets, one directed towards Earth, and the other one in the opposite direction," said team member Dr Simone Migliari from the University of Barcelona.
The atoms - which include iron and nickel - are moving at 66% the speed of light, or about 198,000km/s. So no - unfortunately this isn't a sign that if you were unlucky enough to get sucked into a black hole that you'd be able to surf out on a jet stream of hyper-fast iron. Unless you're a sci-fi writer in need of a way to fill a plot hole, in which case go nuts.