Somewhere on Earth, lightning is striking right now. It will strike again before you finish this sentence — something like fifty times a second, all day, every day, scattered across the thunderstorms standing over the tropics at any given moment.

Each strike throws out a pulse of electromagnetic energy. Most of it disperses. But some of it, at very long wavelengths, gets caught between the ground beneath it and the electrically charged layer of the upper atmosphere above it, and travels — around the curve of the planet, past the horizon, all the way round.

And here is the part worth sitting with. A few of those wavelengths come back round and meet themselves exactly in step.

What the Schumann resonances are

The space between the Earth's surface and the ionosphere behaves like a cavity: a gap bounded above and below by surfaces that reflect very low frequency radio waves rather than letting them escape. Any cavity has sizes that suit it — notes that fit its dimensions and survive, while everything else cancels out.

This cavity is the whole planet, so the notes that fit are enormous, and correspondingly slow. The lowest sits at about 7.83 Hz. Above it, a series: roughly 14.3, 20.8, 27.3 and 33.8 Hz.

The arithmetic is approachable. A radio wave travels at the speed of light, around 300,000 kilometres a second. The Earth's circumference is around 40,000 kilometres. A wave whose wavelength is about the length of that journey would therefore complete it something like seven and a half times each second — close to the number we measure, and close for exactly the reason it looks like. The real cavity is leaky and uneven and the true figure sits a little above the tidy one, but the intuition holds: the lowest Schumann resonance is, more or less, the note whose wavelength is the planet.

That is why the number is what it is. It is not a coincidence, not a design, and not a constant handed down from anywhere. It is the size of the world, expressed as a frequency.

Schumann's prediction

In 1952, a physicist at the Technical University of Munich named Winfried Otto Schumann worked out that such a cavity ought to resonate, and calculated roughly where. He was teaching electrical engineering, considering the Earth-ionosphere system as an electrical problem, and the resonance fell out of the mathematics.

For most of a decade it stayed a prediction. The signals are faint and sit far below the frequencies most radio equipment was built to notice, and picking them out of the electrical noise of a modern world is genuinely hard. Clear measurements arrived in 1960, when Balser and Wagner published observations confirming the resonances were there, at close to the frequencies the theory had required.

They have been monitored ever since, at research stations scattered around the world. They are still there. They have been there, presumably, for as long as the Earth has had an atmosphere and weather.

It is not a sound

This is the thing to be clear about, because almost everything written about the Schumann resonances blurs it.

They are electromagnetic, not acoustic. Radio, not sound. Nothing is vibrating in the air; no pressure wave is travelling anywhere; a microphone at the top of a mountain in a thunderstorm would record nothing of it at all. What oscillates is a field, and fields are not audible things.

And even setting that aside, 7.83 Hz is below the floor of human hearing. We hear from roughly 20 Hz upward. Eight cycles a second is not a quiet sound or a deep sound — at that rate, a pressure wave stops being heard as a pitch and becomes a flutter you would feel rather than hear, if it were a pressure wave, which it is not.

So nobody has ever heard the Schumann resonance. Every recording, track and video offering it to you is a translation — a sound built to stand in for a thing that makes none. That is not a swindle, and the translations are worth hearing. But a translation is what they are, and the ones that say so are the ones to trust.

What the charts actually show

The Schumann resonances drift. The ionosphere is not a fixed ceiling: it rises and falls with day and night, with the seasons, with solar activity, and the cavity changes shape slightly as it does. The fundamental wanders by a few tenths of a hertz. The strength of the resonances varies far more, following the thunderstorms that feed them around the globe as the Earth turns.

Which brings us to the spectrograms. You have probably seen one — a chart from a monitoring station, time running one way, frequency the other, with bands of hot colour blooming across it, shared with the news that the Earth's frequency is spiking or climbing.

Those charts are real instruments reading real data, and they are easy to misread. The horizontal bands sit at the resonant frequencies; the colour shows how strong the signal is at each. When a band flares, the resonance has grown louder, usually because lightning activity somewhere has picked up. The frequencies themselves stay close to where they have always been. A bright chart is a stormy planet, not a rising one.

Living inside the field

Here is what draws people to this, and it is a genuinely good thought.

Every living thing that has ever existed has done so inside this field. It was oscillating before there were ears to not hear it, before there were nervous systems, before there was anything on land at all. Life did not arrive and then encounter the Schumann resonances; life formed inside them, the way a fish forms inside water.

That the lowest of them, 7.83 Hz, happens to sit within the range of human brain rhythms — at the upper edge of what EEG research calls the theta band, just below alpha — is the detail that makes the idea irresistible. The band associated with the drowsy, image-rich border of sleep, with deep meditation, with the state contemplative traditions spend years learning to enter. And the planet humming, faintly, in roughly the same place.

In modern spiritual practice that correspondence is often described as attunement: the sense of a rhythm we belong to and can return to, and of restlessness as a kind of drift away from it. Practitioners sit with 7.83 Hz as a way of coming back. It is sometimes called the Earth's heartbeat, which is poetry rather than physiology, and good poetry — a heartbeat is the rhythm you stop noticing precisely because you are never outside it.

Whether a faint planetary field shapes human physiology is an open research question rather than a settled one, and the strong claims made for it — that it governs mood, health or sleep — go well past what has been shown. The resonances themselves are not in doubt. What they do to us is.

Three ways to translate it

A frequency you cannot hear can still be turned into one you can. There are three honest methods, and they give genuinely different experiences.

As a binaural beat. Play two steady tones a little apart, one in each ear, and your brain produces a slow pulse at the difference between them. Set the difference to 7.83 Hz and the pulse arrives at the Schumann rate. Nothing at 7.83 Hz is sounding anywhere — the beat is made in your head, and it needs headphones. Our binaural beats entry explains why.

As a pulsing tone. Take an audible tone and vary its loudness 7.83 times a second. The pitch is whatever you chose; the rhythm is the Schumann rate. Unlike a binaural beat this is really there in the air, so it works through speakers and anyone in the room hears the same thing.

As an octave. Double a frequency and you get the same note, higher — so doubling 7.83 Hz repeatedly climbs through 15.7, 31.3, 62.6, 125.3 and lands at about 250.6 Hz, which sits comfortably in the middle of hearing. This is the most common translation in sound-healing practice, and musically it is the most defensible: an octave is the one interval that preserves a note's identity. What you hear is the same frequency, five octaves from home. Our entry on harmonics and tuning covers why doubling works that way.

Try it in the Lab

Both translations you can make here, you can make now.

For the binaural version, open the Binaural Beat Generator and set the left ear to 200 Hz and the right to 207.8 Hz. The tool works in tenths of a hertz, so 7.8 is as close to 7.83 as it will go — close enough that the difference is far beyond hearing. Use headphones, keep the volume low, and give it a few minutes; a beat this slow takes time to become obvious.

For the octave version, open the Tone Generator and set it to 251 Hz, the nearest whole hertz to the fifth doubling. Try a sine wave first for the bare frequency, then a triangle or sawtooth to hear the same note with more colour in it. You can place a recording underneath from Listen, which is worth doing: a planetary frequency over a real night forest is a strange and rather good combination.

Neither is the Schumann resonance. Both are honest ways of putting a number you cannot hear into your ears, and the number is a real one — the size of the world, counted out a few times a second, for as long as there has been a world to count.

Sources & further reading

  • Schumann, W. O. (1952). Über die strahlungslosen Eigenschwingungen einer leitenden Kugel, die von einer Luftschicht und einer Ionosphärenhülle umgeben ist. Zeitschrift für Naturforschung A, 7, 149–154. doi:10.1515/zna-1952-0202 — the paper that predicted the resonances.
  • Balser, M. & Wagner, C. A. (1960). Observations of Earth–Ionosphere Cavity Resonances. Nature, 188, 638–641. doi:10.1038/188638a0 — the first clear measurements.
  • Nickolaenko, A. & Hayakawa, M. (2014). Schumann Resonance for Tyros. Springer Japan. doi:10.1007/978-4-431-54358-9
  • Sátori, G., Mushtak, V. & Williams, E. Schumann Resonance Signatures of Global Lightning Activity. In Lightning: Principles, Instruments and Applications, 347–386. doi:10.1007/978-1-4020-9079-0_16