The world's largest, most sensitive cosmic-ray detector has identified a potential crack in Earth's magnetic field.

The weakness was revealed by a burst of galactic cosmic rays, detected by GRAPES-3 during a severe geomagnetic storm in June 2015. The storm as triggered by a plasma cloud ejected from the sun's corona.

It was one of the largest geomagnetic storms in recent history, generating an intense aurora borealis and thwarting radio communication systems among the most northern latitudes. The storm was strong enough to compress Earth's magnetosphere for several hours.

The GRAPES-3 muon telescope is a massive array situated in southern India, a joint effort among scientific institutes in Japan and India. Data revealing the cosmic ray breach were analyzed by scientists at Tata Institute of Fundamental Research in Mumbai.

Researchers published their analysis of the potential magnetosphere crack this week in the journal Physical Review Letters.

Life itself has Earth's magnetosphere to thank. Its ability to block out the harmful rays and particles flying through space allowed life to flourish. But as the latest research suggests, it's not a fail-safe shield.

High-intensity storms can reveal stress fractures, so to speak. Researchers suggest the 2015 storm triggered a phenomenon called magnetic reconnection, whereby magnetic energy is simultaneously converted into kinetic energy, thermal energy and particle acceleration.

In this instance, the process was powerful enough to open a crack through which a burst of cosmic rays slipped through.

Scientists hope their continued work with GRAPES-3 will offer an improved understanding of the stresses put on the magnetosphere by intense storms, to better predict vulnerabilities in the future.