Fermi Sees Possible Evidence of Antimatter in Lightning

The Fermi Gamma-ray Space Telescope is one of the American space agency's best observatories, especially suited to discovering gamma-ray bursts coming towards our planet from the distant Universe. However, in its first 14 months of operations, the machine was able to record some peculiar signals coming in from the Earth's atmosphere, which gave physicists something to puzzle over. The telescope discovered 17 gamma-ray flashes associated with lightning storms, occurring immediately before, during and just after the electrical discharge left the clouds, Wired reports.

In addition to Fermi, the World Wide Lightning Location Network also tracked the same lightning activity, and reached virtually the same conclusion. In two new instances, when the telescope looked at recent lightning storms, its sensitive detectors, which are suited for viewing the Cosmos millions to billions of light-years away, found evidence of energies that could have only been produced by the decay of energetic positrons, which are the antimatter equivalent to electrons. This is the first time ever when these particles are observed in a naturally occurring, Earth-based phenomenon.

The amazing, new finds were announced at the 2009 Fermi Symposium, on November 5. The studies that led to this conclusion were conducted by experts at the University of Alabama in Huntsville, who were led by scientist Michael Briggs. He admitted that finding the energetic signature of positrons in the planet's atmosphere was unexpected and that this raised a number of tantalizing questions about the existence of antimatter on our planet. What happened in the two recent instances, Briggs explained, was that the normal orientation of lightning-storm electric fields was somehow reversed, producing the unusual readings that Fermi picked up.

At the same conference, Briggs also said that experts in his team were then working on models that would explain how the fields were reversed, but that, at that point, there was no clear answer in sight. NASA’s Compton Gamma-ray Observatory, one of the agency's four Great Observers (next to Hubble, Chandra and Spitzer), also discovered gamma-ray flashes in the atmosphere in the early 1990s. An additional 800 terrestrial gamma-ray flashes were identified by the Sun-observing satellite RHESSI.