I once taught an internal class on electromagnetism at a large consumer electronics company. After one class, a technician with whom I worked, sauntered up to me holding a small advertisement. It was for a sort of “healing crystal.” The ad claims it can protect a person from EMF radiation. The advertising copy had an explanation of its powers, stating it resonates at the same frequency as the Schumann Resonance, which it further claimed is sometimes called the “brainwave of the planet.” I was taken aback as I’d never heard of the Schumann Resonance. It was still the era where one would locate the company librarian, who in turn had books that described it as a real phenomenon. It is not the “brainwave of the planet.”
Our outer atmosphere is conductive, and so is the Earth. Between the two is an electromagnetic cavity resonator that is driven by the 50-100 lighting strikes that take place each second. It is possible to mathematically predict the resonance frequencies of this cavity. German physicist Winfred Otto Schumann first did this in 1952. The resonances were originally measured in 1954 by Schumann and König. The first Schumann resonance is about 7.8 Hertz. In other words, the Schumann electric field that surrounds all of us reverses its direction 7.8 times per second. The strength of this field, about 300 microvolts/meter, is so minute it is a very difficult measurement for an amateur to make. The static electric field on a nice day is about 500 000 times larger than the fundamental Schumann Resonance.
Despite the difficulties involved, I wound an iron bar with 50 000 turns of copper wire, had my fellow engineers Lapin and JV help me with the amplifier design, wrote software to process the output of a DC voltmeter, and one morning around 02:00 I averaged about 120 time measurements and found a peak at 7.8 Hz. There were a massive number of human-made frequency spikes in the frequency data. Below is a signal in both time and frequency professionally measured in Germany.
The time signal shown on the left is choppy and squiggly. It is very hard to “see” the fundamental Schumann resonance without signal processing and viewing the resulting information in terms of frequency. The top and bottom time signals on the left are from detectors facing east and west, and north and south respectively. The spike between f2 and f3 is from an electric train almost 30 Km distant. The 50 Hz spike is from Germany’s electric power grid that operates at 50 Hz rather than our 60 Hz.
One reference indicated the coil I was using to detect the first Schumann Resonance should not jiggle more than the diameter of an atom, or the vibration would contaminate the signal. I was amazed I had managed to measure it in my apartment.
One evening I was discussing the possibility of science measuring gravitational waves with Lapin. He asked me what I thought, and my experience with measuring Schumann Resonances resurfaced. My thought was that it seemed extremely unlikely that a device capable of measuring such a small change seemed possible, but I wanted the engineers and scientists to try. It was worth the effort and something interesting might be learned just devising and realizing such a measurement device.
The possibility of using gravity waves to communicate in the same way we do with electromagnetic waves was discussed in 1991 by John Kraus. The difficulty of communicating by gravitational wave appeared to be essentially insurmountable. A rotating bar will radiate gravitational waves. Kraus used a 20 meter long 500 Megagram rotating steel beam as an example. The maximum rate of rotation is about 270 rpm. This is just below the spin rate that would cause the steel to fly apart. It would take about 20 hours to spin the beam up to speed with a 100 KW power input (about 7.2 Gigajoules). It also takes about 20 hours to spin it down. The device would transmit no more than a single bit per day. The radiated power of the propagating gravitational wave would be only 10-27 watts. This would be 0.001 yoctowatts, using the smallest available metric prefix. While not zero, it almost might as well be.
The radiated gravitational waves would have a frequency of about 9 Hz and detecting this tiny amount of power impinging upon a gravitational wave antenna seems almost impossible. Some type of material that would directly convert gravity waves into an electrical signal with perfect efficiency would probably be needed.
When the measurement of a gravitational wave was announced, I was cautious. Then I saw the signal:
I had stared at enough Schumann Resonance time signals that my immediate reaction was: “Wow, that is clearly a signal, and it’s replicated on a second detector.” I was very sure they had measured a gravitational wave, and when the signal was interpreted as two massive black holes merging, it made consistent sense. I knew I had witnessed one of the most important discoveries in 21st century science. During a press conference, LIGO Co-Founder Rai Weiss stated:
I’ve been on many committees for NASA. When an engineer hears ten-to-the-minus-twenty-one they think you’re out of your mind. That’s the very first response that most people have. You’re going to measure something at ten-to-the-minus-twenty-one of anything—I don’t care what it is you’re not going to be able to do it.
This engineer would have felt the same way. When discussing a phenomenon with Zeptoworld lengths*, gravitational waves are really the only game in town. The next and last reducing prefix, yocto describes the extent of subatomic particles such as the neutrino. Thankfully the researchers were stubborn, dedicated, and persuasive. Two LIGO sites were constructed. What is interesting is that the noise levels of the current version of LIGO were not low enough for a high expectation of signal detection. But then two massive black holes rapidly rotating about one another (radiating gravitational waves like the bar example) and then merging to form a single singularity was probably not foremost in the researchers minds. The detection of less massive binary stars that rotate about one another was probably thought to be the first realistic candidate for gravity wave detection. The Zeptoworld of length is on the order of 1 x 10-21 meters. At the opposite magnitude extreme, 1 x 1021 meters, is Zettaworld. This world describes the size of galaxies, and little else I know of exists of this dimension.
LIGO’s two detectors allowed the researchers involved to estimate the distance to the merging black holes at about 12.3 Zettameters from us. That is one incredible length for this signal to have traveled and then have been detected. It really struck me as astonishing to think that we measured a stress change of about a zeptometer that was induced by gravitational radiation originating a dozen Zettameters from us. This single measurement connects a Zeptoworld length to a Zettaworld length spanning 14 metric prefixes (triads) or a factor of 1 000 000 000 000 000 000 000 000 000 000 000 000 000 000. The measurement of gravitational waves is a mind bending achievement when viewed within the metric system**.
 Kraus, J. “Will Gravity-Wave Communication Be Possible?” IEEE Antennas and Propagation Magazine, Vol. 33, No. 4, August 1991
* My book The Dimensions of The Cosmos breaks the universe into 16 metric worlds based on 16 metric prefixes. There is Kiloworld, Megaworld, Milliworld and so on. I will be using this metaphor in current blogs.
** LIGO has since detected a second black hole merger on December 25th of 2015 (2015-12-26). Grossman, L. New Scientist 2016-06-18 “LIGO sees second black hole merger.” pg 8-9 The new detection was from two less massive black holes. The first detection had black holes so massive they only revolved around one another about 10 times before merging. In the second detection they spent 55 orbits before merging.
The Metric Maven has published a new book titled The Dimensions of The Cosmos. It examines the basic quantities of the world from yocto to Yotta with a mixture of scientific anecdotes and may be purchased here.