Orbiting our planet at altitudes between 250-to-500 miles (400–to-800 km), the C/NOFS satellite* has detected special resonating waves of electromagnetic energy — generated by lightning flashes in the Earth’s atmosphere — for the first time.
These waves are known as Schumann resonances and they propagate around the earth at very low frequencies (as low as 8 Hz). It was thought that these waves were confined by the lower band of the planet’s ionosphere, the layer of charged particles that begins about 60 miles (about 100 km) above the surface. But it seems that under certain conditions, the resonating waves escape into space.
How does Schumann resonance work?
Scientists have now discovered that when certain of these waves reach a wave length that is at least as long as the circumference of the Earth, they bump into themselves as they travel around the ionosphere, and, if the peaks and troughs of the waves synchronize, they resonate, grow larger and “leak” through the ionosphere into space.
Lightning flashes somewhere in the Earth’s atmosphere about 50 times per second, generating electromagnetic waves (which are not shaped like ocean waves, but have ‘high’ and ‘low’ energy density spots that correspond to a classic wave’s peaks and troughs). When these spots from over-lapping waves match up, the Schumann resonance is produced.
Previous measurements of these waves had been made only from ground-based instruments and it was believed that they were confined to a boundary just below the planet’s ionosphere. This detection of the resonances spilling out into space will mean adjusting present atmospheric models.
Why is monitoring these waves so important?
Predicted in the 1950’s, measurements of the waves were not confirmed until the 1960’s. Over the ensuing half century or so, atmospheric scientists have discovered variations in the resonances which correspond to events here on Earth, such as changes in the seasons, increased/decreased solar activity, magnetosphere fluctuations, and even the presence of water aerosols in the upper atmosphere.
It is believed that other earth-bound phenomena can also be detected from studying these oscillating waves.
For these reasons, the Schumann resonance is sometimes poetically referred to as the Earth’s ‘heart beat’.
Quoting the study’s co-author, Rob Pfaff (GSFC), in a recent space.com article: “There are hundreds, maybe thousands, of studies on this phenomenon and how it holds clues to understanding Earth’s atmosphere. But they’re all based on ground measurements.”
But with this discovery, scientists now have a new tool for studying our planet’s dynamic atmosphere and its electrical activity — using a ‘high tech stethoscope’ in space.
Watch the video animation showing the synchronizing energy waves (the Schumann resonances) “leaking” into space:
* The Communications/Navigation Outage Forecasting System (C/NOFS) is run by the USAF STP and was built to “allow the US military to predict the effects of ionospheric activity on signals from communication and navigation satellites, outages of which could potentially cause problems in battlefield situations.” [wikipedia.org]
Some reference material for this article came from ‘Heartbeat’ of Earth’s Atmosphere Detected from Space’
Top image: (artist rendering of the C/NOFS satellite) NASA/GSFC