1,000x stronger than the LHC: Milky Way has a mystery engine blasting record-breaking energy

Scientists have discovered a natural particle accelerator in the Milky Way blasting out protons with energies exceeding one quadrillion electron volts. These are some of the fastest-moving particles and the highest known energies in our galaxy. Humans have built colliders on Earth, but none even comes close to this cosmic accelerator. Named LHAASO J1912+1014u, it is located in the constellation Aquila. Astronomers think this object could provide clues to the origin of high-energy particles moving through space at almost the speed of light. The findings were published in The Astrophysical Journal.

The particles emitted by this object carry energies thousands of times higher than the collision limits of Earth’s largest human-made particle accelerator, the Large Hadron Collider (LHC). First spotted in 2024, it was classified as a supernova remnant. But then a stream of gamma-ray emissions was observed bursting from the object. They are generated when accelerated particles collide with surrounding gas. This led scientists to conclude that it was a natural cosmic accelerator that boosts protons up to petaelectronvolt (PeV) energies, also known as a PeVatron.

Triple observations revealed it was not a supernova remnant

Initially thought to be a supernova remnant, researchers combined data across multiple wavelengths using data from three different observatories - NASA's Fermi-LAT, Japan's FUGIN radio telescope, and NASA's Chandra X-ray Observatory. This helped them rule out electrons as the source of the gamma-ray emissions and that they stemmed from accelerated protons.

Tsunefumi Mizuno, associate professor at Hiroshima University’s Astrophysical Science Center and corresponding author of the study, said in a statement, "In this study, three arrows—Fermi-LAT GeV gamma-ray data, FUGIN radio data and Chandra X-ray data—are bundled together through a detailed multiwavelength modelling, revealing that our target, LHAASO J1912+1014u, is a cosmic-ray proton PeVatron."

These findings can help explain the Milky Way’s most energetic cosmic rays that travel through the galaxy and affect events. Scientists think there could be many more cosmic accelerators out there which could soon be discovered.