CERN's New Experiments Recreate Cosmic Conditions to Study Black Holes

In a groundbreaking experiment at CERN, scientists have successfully recreated conditions akin to cosmic fireballs, enabling them to study the behavior of high-energy jets produced by supermassive black holes known as blazars.

This innovative research, conducted by a collaboration between the University of Oxford and the Science and Technology Facilities Council, utilized the Super Proton Synchrotron at CERN's HiRadMat facility to generate electron-positron pairs.

These particles were then directed through a meter-long plasma, simulating the extreme environments found in cosmic jets. Bob Bingham, a researcher at the University of Strathclyde, highlighted that these lab experiments can test theories about the high-energy universe by reproducing relativistic plasma conditions, which could enhance our understanding of how cosmic jets evolve and the origins of magnetic fields in intergalactic space.

Blazars, a particular type of active galactic nucleus, are powered by supermassive black holes that emit twin jets of plasma at near light speed, creating intense gamma-ray radiation detectable by telescopes.

However, scientists have noted a puzzling absence of low-energy gamma rays, which should theoretically be produced when gamma rays scatter off background photons in the cosmic microwave background. The team explored several hypotheses for this phenomenon, including the idea that weak magnetic fields in intergalactic space might deflect the low-energy gamma rays from our line of sight or that the electron-positron pairs could become unstable as they traverse the sparse intergalactic medium.

Unexpectedly, the experiment revealed that the plasma beam maintained its narrow shape with minimal disruption, suggesting that plasma beam instabilities are too weak to account for the missing gamma rays.

This finding bolsters the hypothesis of a relic magnetic field existing within the intergalactic medium, raising further questions about its origins in the early universe. The implications of this research could point towards physics beyond the Standard Model and potentially inform future studies at facilities like the Cherenkov Telescope Array Observatory.

Subir Sarkar from the University of Oxford expressed excitement about the experiment's innovative approach and its potential to probe fundamental cosmic questions within a terrestrial high-energy physics context.

The team's findings were published in the Proceedings of the National Academy of Sciences, underscoring the importance of this work in the ongoing quest to understand the universe's most elusive phenomena.