Researchers have solved the mystery of what's inside the jets that black holes spit out.
Black holes spit out these mysterious jets from their centers at breakneck speeds, an International Centre for Radio Astronomy Research (ICRAR) news release stated.
"Although they have been observed for decades, we're still not sure what they are made of, or what powers them," ESO astronomer Doctor María Díaz Trigo, lead author of the study, said.
The research team looked at a small black hole only a few times the mass of our own Sun, and the radio waves and X-rays it emitted. The team believed the black hole was active, but were unable to pick up signs of the jets through radio observation.
A few weeks later the jets suddenly appeared with corresponding radio emissions. Unexpectedly, lines appeared in the X-ray spectrum, indicating the presence of "ordinary atoms" surrounding the black hole.
"Intriguingly, we found the lines were not where they should be, but rather were shifted significantly," Doctor James Miller-Jones from the Curtin University section of the International Centre for Radio Astronomy Research (ICRAR), who led the radio observations, said.
The news release related the phenomenon to the way an emergency vehicle siren seems to change pitch as it passes a person. This happens because the sound wave gets either shorter or longer depending on its position in relation to the individual.
"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," team member Dr Simone Migliari of the University of Barcelona said.
This is the first time researchers have found strong evidence of such particles existing in black holes' jets. The researchers knew the jets contained electrons, but had been unable to determine why they did not have an overall positive or negative charge.
"Until now it wasn't clear whether the positive charge came from positrons, the antimatter 'opposite' of electrons, or positively charged atoms. Since our results found nickel and iron in these jets, we now know ordinary matter must be providing the positive charge."
Since positively-charged atoms are inherently heavier than positrons (which researchers originally thought made up the jets) they can carry more energy away from the black holes.
"Our results suggest it's more likely the disk is responsible for channelling the matter into the jets, and we are planning further observations to try and confirm this," Miller-Jones said.
