Earth Sidereal Day (Cosmic Octave)
194.71 Hz
Nearest note: G3, 11 cents below standard tuning
A tone calculated from a measured cycle, by doubling its frequency 24 times. It is calculated, not recorded.
How well is this supported?
Calculated from a measured value by a stated method. You can check the arithmetic. What the result means is a matter of interpretation.
The cycle is measured. The tone is calculated from it by doubling, so that it can be heard. Nothing in space makes this sound.
The button plays a plain tone. Start with the volume low. Phone and laptop speakers play low notes quietly; headphones or a speaker help.
Where this number comes from
Measured against the stars instead of the Sun, the Earth turns once in 23 hours 56 minutes. 1 ÷ 86,164 seconds, doubled 24 times, is 194.71 Hz. That is a G, about 11 cents below standard tuning.
- Step 1. Start with the length of the cycle
Earth rotation relative to the fixed stars: 86,164.09054 seconds.
- Step 2. Turn it into a frequency
One divided by that many seconds is 1.16 × 10⁻⁵ Hz. That is far too slow to hear.
- Step 3. Double it 24 times
Doubling a frequency raises it by one octave: the same note, higher. After 24 doublings it is 194.71 Hz.
- Step 4. Name the note
194.71 Hz is a G, 11 cents below standard tuning. A cent is one hundredth of the step between two neighboring piano keys. To play in tune with this tone, an instrument sets its A to 437.12 Hz instead of 440.
- Step 5. Keep doubling and the number lands in the range of light
41 more doublings give the frequency of light with a wavelength of 700 nm, which is red-orange. This is arithmetic. It pairs a tone with a color; it does not show that the two are connected.
The method is Hans Cousto’s. Planet gongs explained walks through it and says what it does and does not show.
Facts
- Frequency
- 194.71 Hz
- One cycle takes
- 23.93 hours
- Wavelength in air (20 °C)
- 1.76 m
- Nearest note
- G3, 11 cents below standard tuning
- Kind of statement
- Octave of an astronomical cycle
- Filed under
- Earth, Moon & Sun
Tuning Data
The row for this tone in Hans Cousto’s tables, with the tempo and pendulum length that follow from it.
- Cycle
- Earth rotation relative to the fixed stars
- Length of the cycle
- 86,164.09054 seconds
- Octaves up
- 24
- Concert pitch (A)
- 437.12 Hz
- Difference from A = 440 Hz
- -11.40 cents
- Tempo
- 91.27 beats per minute
- Pendulum length
- 10.7 cm / 4.23 in
- Color by octave
- Red-Orange (700 nm)
Tempo and pendulum length, octave by octave
| Octave | Frequency | One cycle | Tempo | Pendulum |
|---|---|---|---|---|
| 17tempo | 1.52 Hz | 657.39 ms | 91.27 BPM | 10.7 cm |
| 18 | 3.04 Hz | 328.69 ms | 182.54 BPM | 2.7 cm |
| 19 | 6.08 Hz | 164.35 ms | Too fast to count | Too short to build |
| 20 | 12.17 Hz | 82.17 ms | Too fast to count | Too short to build |
| 21 | 24.34 Hz | 41.09 ms | Too fast to count | Too short to build |
| 22 | 48.68 Hz | 20.54 ms | Too fast to count | Too short to build |
| 23 | 97.36 Hz | 10.27 ms | Too fast to count | Too short to build |
| 24tone | 194.71 Hz | 5.14 ms | Too fast to count | Too short to build |
Intervals built on this tone
| Ratio | Interval | Frequency | Note | Concert A | Cents from 440 |
|---|---|---|---|---|---|
| 1/1 | Perfect unison | 194.71 Hz | G3 | 437.11 Hz | -11.41 |
| 81/80 | Syntonic comma | 197.14 Hz | G3 | 442.57 Hz | +10.09 |
| 531441/524288 | Pythagorean comma | 197.37 Hz | G3 | 443.07 Hz | +12.05 |
| 128/125 | Diesis | 199.38 Hz | G3 | 447.60 Hz | +29.65 |
| 648/625 | Greater diesis | 201.88 Hz | G#3 | 427.76 Hz | -48.85 |
| 25/24 | Chroma | 202.82 Hz | G#3 | 429.77 Hz | -40.74 |
| 16/15 | Diatonic semitone | 207.69 Hz | G#3 | 440.08 Hz | +0.32 |
| 10/9 | Minor whole tone | 216.34 Hz | A3 | 432.69 Hz | -29.01 |
| 9/8 | Major whole tone | 219.05 Hz | A3 | 438.10 Hz | -7.50 |
| 8/7 | Septimal whole tone | 222.53 Hz | A3 | 445.05 Hz | +19.76 |
| 6/5 | Minor third | 233.65 Hz | A#3 | 441.08 Hz | +4.23 |
| 5/4 | Major third | 243.39 Hz | B3 | 433.67 Hz | -25.10 |
| 4/3 | Perfect fourth | 259.61 Hz | C4 | 436.62 Hz | -13.37 |
| 3/2 | Perfect fifth | 292.07 Hz | D4 | 437.60 Hz | -9.46 |
| 8/5 | Minor sixth | 311.54 Hz | D#4 | 440.58 Hz | +2.27 |
| 5/3 | Major sixth | 324.52 Hz | E4 | 433.18 Hz | -27.05 |
| 7/4 | Natural seventh | 340.74 Hz | F4 | 429.31 Hz | -42.59 |
| 16/9 | Pythagorean minor seventh | 346.15 Hz | F4 | 436.12 Hz | -15.32 |
| 9/5 | Just minor seventh | 350.48 Hz | F4 | 441.57 Hz | +6.18 |
| 15/8 | Major seventh | 365.08 Hz | F#4 | 434.16 Hz | -23.14 |
| 2/1 | Octave | 389.42 Hz | G4 | 437.11 Hz | -11.41 |
Source notes
The sidereal day is the Earth’s rotation measured against the fixed star sky rather than the Sun.
Source: Hans Cousto — Tuning Data / Sun Earth Moon Planets. View the source PDF.
License: CC BY-NC-ND 4.0, as stated in Stimmdaten.pdf (German edition), page 2.
Values are reproduced from Cousto’s tables. Tempo, pendulum length and interval tables are calculated by this site from those values.
See every tone in the tables: Open the tuning data reference.
Sources
- Hans Cousto — Tuning Data: Earth, Moon, Planets, Sun
The tables that the tuning pages on this site reproduce.
Hans Cousto, Tuning Data — Earth Moon Planets Sun. Planetware.
View source: Hans Cousto — Tuning Data: Earth, Moon, Planets, Sun - Hans Cousto — Tuning Data / Sun Earth Moon Planets — Earth — Sidereal Day
The sidereal day is the Earth’s rotation measured against the fixed star sky rather than the Sun.
View source: Hans Cousto — Tuning Data / Sun Earth Moon Planets — Earth — Sidereal Day
More about the pitch
The same note in every octave
Each step doubles or halves the frequency. Tap one to hear it.
Entries close in pitch
Within 35 cents of this tone, in any octave. A cent is one hundredth of the step between two neighboring piano keys. Being close in pitch does not mean two things are connected.