November 29, 2011
Lightning-Made Waves Leaking Into Space From Earth’s Atmosphere
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NASA said on Monday that scientists have discovered lightning-made waves in Earth's atmosphere that leaked into space.
The space agency's Vector Electric Field Instrument (VEFI) aboard the U.S. Air Force's Communications/Navigation Outage Forecast System (C/NOFS) satellite has detected Schumann resonance from space.
Schumann resonance happens if waves are just the right wavelength from lightning, combining and increasing in strength to create a repeating atmospheric heartbeat.
The Schumann resonance helps provide tools to analyze Earth's weather, its electric environment, and to help determine what types of atoms and molecules exist in Earth's atmosphere.
"Researchers didn't expect to observe these resonances in space," Fernando Simoes, a scientist at NASA's Goddard Space Flight Center, said in a press release. "But it turns out that energy is leaking out and this opens up many other possibilities to study our planet from above."
He said that the concept of resonance in general is fairly simple: adding energy at the right time will help any given phenomenon grow.
"The waves created by lightning do not look like the up and down waves of the ocean, but they still oscillate with regions of greater energy and lesser energy," Karen C. Fox, NASA's Goddard Space Flight Center, said in a press release. "These waves remain trapped inside an atmospheric ceiling created by the lower edge of the 'ionosphere' — a part of the atmosphere filled with charged particles, which begins about 60 miles up into the sky."
She said some of these waves are working a radio wave frequency that is one hundred thousand times lower than the lowest radio waves used to send signals to an AM/FM radio.
Schumann resonances were first predicted in 1952, but were not measured reliably until the early 1960s. Scientists since then have discovered that variations in the resonances correspond to changes in the seasons, solar activity, activity in Earth's magnetic environments, in water aerosols in the atmosphere, and other Earth-bound phenomena.
"There are hundreds, maybe thousands, of studies on this phenomenon and how it holds clues to understanding Earth's atmosphere," Goddard scientist Rob Pfaff, Principal Investigator of the VEFI instrument and an author on the GRL paper, said in a press release "But they're all based on ground measurements."
The team began looking for waves of the very low frequency in the observations from VEFI and found the resonance showing up in almost every orbit C/NOFS made around Earth.
The detection of the Schumann resonances in space requires an adjustment of the basic models to incorporate a "leaky" boundary at the bottom of the ionosphere.
Simoes said that detecting these resonances from above also provides a tool to better understand the Earth-ionosphere cavity that surrounds Earth.
"Combined with ground measurements, it provides us with a better way to study lightning, thunderstorms, and the lower atmosphere," he said in a press release. "The next step is to figure out how best to use that tool from this new vantage point."
Image 1: Waves created by lightning flashes — here shown in blue, green, and red — circle around Earth, creating something called Schumann resonance. These waves can be used to study the nature of the atmosphere they travel through. Credit: NASA/Simoes
Image 2: NASA Goddard's Vector Electric Field Instrument (VEFI) aboard the U.S. Air Force's Communications/Navigation Outage Forecast System (C/NOFS) -- shown here -- has detected a special kind of low frequency wave leaking out into space from Earth's lower atmosphere. Credit: NASA/Goddard Space Flight Center
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