A new study has revealed how particles in space can be accelerated to incredibly high speeds, solving a decades-old puzzle that has challenged our understanding of cosmic rays. The research, published January 13 in Nature Communications, shows that particles can reach extreme energies through a complex interplay of processes that scientists had previously studied only in isolation.
An Unexpected Discovery
Using data from NASA satellites, researchers observed electrons near Earth’s magnetic field reaching energies over 500,000 electron volts – hundreds of times higher than typically seen in this region. This surprising observation helped unlock the mystery of how particles get energized to such extreme levels throughout the universe.
“Most of our research focuses on either small-scale effects, like wave-particle interactions, or large-scale properties, like the influence of solar wind,” said Dr. Savvas Raptis of The Johns Hopkins University Applied Physics Laboratory, who led the study. “However, as we demonstrated in this work, by combining phenomena across different scales, we were able to observe their interplay that ultimately energize particles in space.”
The research team used Earth’s space environment as a natural laboratory to study processes that occur throughout the universe. By combining data from multiple NASA missions, including the Magnetospheric Multiscale (MMS) and ARTEMIS missions, they observed how particles get energized through multiple steps working together.
“One of the most effective ways to deepen our understanding of the universe we live in is by using our near-Earth plasma environment as a natural laboratory,” explained Dr. Ahmad Lalti from Northumbria University, a co-author of the study. “Those fundamental processes are not restricted to our solar system and are expected to occur across the universe.”
The findings have important implications for understanding cosmic rays – high-energy particles that travel across vast distances in space. These particles, which can reach energies far higher than anything produced in human-made accelerators, have long puzzled scientists who couldn’t fully explain how they achieve such extreme speeds.
The research shows that shock waves in space – created when fast-moving material collides with slower material – can accelerate particles more efficiently than previously thought. This process requires less initial energy than theoretical models had suggested, making it easier for particles to reach extreme speeds.
Looking to the Future
The discovery could help explain observations from distant cosmic objects, including supernova remnants and active galactic nuclei, where similar acceleration processes may be occurring at much larger scales. The research team suggests their findings could be particularly relevant for understanding particle acceleration around extremely hot Jupiter-like planets orbiting other stars, where similar conditions exist at much larger scales.
This improved understanding of particle acceleration could also help scientists better predict space weather effects near Earth, where energetic particles can affect satellites and other technology in orbit.