Here the terrestrial gamma ray flash (pink) is 1.98 milliseconds old, and its electron(yellow) /positron(green) beam is reaching altitudes where it may intercept spacecraft, such as NASA's Fermi Gamma Ray Space Telescope.
Credit: NASA
SYDNEY: A space-based telescope has detected beams of antimatter shooting out the top of thunderstorms, in what has been described as an “amazing curiousity of nature”.
The data was collected from NASA's Fermi Gamma Ray SpaceTelescope. In some cases the thunderstorms were thousands of kilometres away, and the beams were detected only after they had travelled along the Earth’s magnetic field and collided with the spacecraft.
“These signals are the first direct evidence that thunderstorms make antimatter particle beams,” said lead author astrophysicist Michael Briggs from University of Alabama in Huntsville.
Lightning the likely cause of bursts
Fermi launched in 2008 to study similar high-energy bursts from space. In space, gamma ray bursts stem from high energy events such as the death of a star.
These beams, though, stem from terrestrial gamma-ray flashes, high energy bursts of gamma rays that occur in Earth's atmosphere and are most likely associated with lightning.
Fermi has detected 130 terrestrial gamma-ray flashes, which last about a millisecond, but scientists estimate 500 such flashes occur daily worldwide.
Fermi struck by high energy beams
The antimatter, which has the same properties of their matter 'twin' except with the opposite electric charge, is thought to be created when an avalanche of electrons are thrown up by a thunderstorm’s strong electromagnetic field. When these electrons strike other atoms in the atmosphere they release a burst of gamma rays.
Travelling near the nuclei of other atoms causes the gamma rays to transform into an electron/positron pair (a positron is an electron’s antimatter counterpart, with positive instead of negative charge).
Beams of high-energy positrons and electrons then travelled thousands of kilometres, guided by the Earth’s magnetic field. When the positrons struck Fermi, it detected a high-energy gamma ray signal, indicating the matter in the spacecraft and antimatter in the beams had annihilated each other.
Reseachers argue how the flashes are made
“We are still arguing about exactly how [the gamma ray flashes] are made,” NASA spokesperson Janet Anderson told Cosmos.
“We all agree that some form of relativistic runaway electron avalanche mechanism is going on somewhere inside or near thunderclouds, but beyond that there are many uncertainties.”
