Lightning Strikes Twice For Planetary Atmospheric Research

Lightning lights up the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida during thunderstorms on Monday, Sept. 27, 2010. Image Courtesy of Tom Moler

If you want to get a real "charge" out of natural facts, then know this. Every minute lightning flashes 3,000 times somewhere on Earth. When they combine, they gain in strength, forming electromagnetic waves which envelop our planet. Like a heartbeat, this creates a pulse between the ground and a region about a 100 kilometers up in the atmosphere - the lower ionosphere. This electric pulse is called Schumann Resonance and it has only been seen from ground until just last year. Thanks to NASA's Vector Electric Field Instrument (VEFI) aboard the U.S. Air Force's Communications/Navigation Outage Forecast System (C/NOFS) satellite, this phenomenon has now been detected from space.

In the May 1 issue of "The Astrophysical Journal", researchers tell us how this new method might be employed to study other planets and may even help explain some of the mysteries about how our solar system formed.

"The frequency of Schumann Resonance depends not only on the size of the planet but on what kinds of atoms and molecules exist in the atmosphere because they change the electrical conductivity," says Fernando Simoes, the first author on this paper and a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "So we could use this technique remotely, say from about 600 miles above a planet's surface, to look at how much water, methane and ammonia is there."

These three key ingredients - water, methane and ammonia - are known as volatiles and are found in different amounts on different planets. Finding out what constitutes another planet's atmosphere is done in a variety of ways. These alternate methods are very accurate, but they can only determine very specific regions. By utilizing Schumann Resonance, precise readings of specific planet-wide signatures are now possible. Simoes and his fellow researchers feel that by adding this method to data gathered from other scientific instruments could possibly provide the most accurate information to date about a target planet's atmosphere. Getting accurate portraits of planetary atmospheres may also aid astronomers in deciphering the mystery as to why the outer planets have a higher percentage of volatiles in comparison to the inner planets.

"And if we can get a better sense of the abundance of these kinds of atoms in the outer planets," says Simoes, "We would know more about the abundance in the original nebula from which the solar system evolved."

However, using Schumann Resonance isn't an easy affair. It still needs to be a certain distance above the planet's surface - one too close for simple orbiting studies. This means studying planets outside our solar system isn't in the near future. But, don't sell the idea just yet! There is a possibility that once a spacecraft has finished observing a planet, that it could be used to detect Schumann Resonance as it completes its final plunge into the atmosphere. Like so many probes before it, it would continue to send back useful - and viable - data right up until its final moments.

Lightning really can strike twice!

Written by Tammy Plotner. Original Story Source: NASA Research News.