November 4, 2013
NASA Tries To Untangle The ‘Atmospheric Party’ In Thunderstorms
Lee Rannals for redOrbit.com - Your Universe Online
NASA’s FireStation instrument aboard the International Space Station (ISS) is helping scientists learn more about the party taking place inside a thunderstorm. The Space Test Program-Houston 4-FireStation is an instrument attached to the outside of the space station that is sponsored by NASA and the National Science Foundation (NSF). The instrument collects data as it flies over thunderstorms, helping scientists answer questions about the relationship between lightning and gamma rays.“Somewhere in the atmosphere momentarily there’s just an incredible amount of energy released and what happens in that region is something of a witch’s brew,” said Doug Rowland, principal investigator for FireStation at NASA's Goddard Space Flight Center in Greenbelt, Maryland. “You get antimatter created in the Earth’s atmosphere during this interaction, you get energetic neutrons that basically you never see in the quiet atmosphere, that you only associate with nuclear reactions, that are happening in our atmosphere whenever these things go off.”
During these events, clouds charge as ice crystals rub together, which eventually leads to a sudden and dramatic release of lightning. Scientists do not fully understand what initiates the process, but a prevailing theory involves a chain reaction called a seeded avalanche breakdown.
“The idea is that you get a cosmic ray coming in that has a million electron volts of energy and it can serve to trigger another breakdown mechanism that generates gamma rays,” said Rowland.
Terrestrial gamma ray flashes (TGFs) are short bursts of gamma rays from the Earth’s atmosphere. FireStation is able to measure lightning and gamma ray flash events simultaneously to determine if TGF’s are generated by the electric fields during thunderstorms. NASA hopes to better understand the fundamental connection between the two natural phenomenon.
FireStation will be collecting data as the space station orbits the Earth and encounters a thunderstorm. The instrument will be able to collect and transmit complete datasets for analysis, giving scientists information on every gamma ray that hits the detector.
“You can imagine a case where if you don’t know exactly where the events and the signals were traveling at different speeds, you might reverse the cause and effect. So having it in the same platform is new and very helpful,” Rowland explained.
When the instrument picks up on individual lightning flashes, it will help determine which were TGF events. After FireStation has helped identify the TGF, scientists will look closer at the data and study this event.
NASA says FireStation is fundamentally a purely scientific mission, but that a better understanding of lightning in general could also eventually help with safety.
“If you can predict under what conditions lightning is more common or more frequent or more hazardous, you can better design your lighting protection systems and you can better design your power grid to handle lighting,” said Rowland.