Convert Delisle to Planck Temperature
Convert degrees delisle to planck temperatures instantly. T_P = 2.633782e-30 − (°De × 4.705493e-33) — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Planck Temperature to Delisle converter for the reverse conversion.
Units explained
Delisle
The degree Delisle (°De) is a famously reversed scale: water boils at 0 °De and freezes at 150 °De, so numbers increase as temperature falls. One degree Delisle corresponds to exactly −2/3 of a kelvin.
Invented by French astronomer Joseph-Nicolas Delisle while directing the observatory in St. Petersburg, Russia; his thermometers were originally graduated by the contraction of mercury cooling down from the boiling point of water.
Widely used in 18th-century Russia for about a century. Today it appears only in the history of thermometry, where it is the textbook example of an inverted temperature scale.
Created by Joseph-Nicolas Delisle in St. Petersburg in 1732; recalibrated to the familiar 150-division form by Josias Weitbrecht in 1738.
Planck Temperature
The Planck temperature (T_P) is the natural unit of temperature, about 1.416784×10³² kelvins, constructed purely from the fundamental constants ħ, c, G, and k. It is widely regarded as the highest temperature at which known physics remains meaningful.
Arises from Max Planck's 1899 system of natural units, which combines the speed of light, the gravitational constant, the reduced Planck constant, and the Boltzmann constant into universal base quantities independent of any human artifact.
Cosmology and quantum-gravity research, where it marks the temperature of the universe roughly one Planck time after the Big Bang. No laboratory process approaches even a trillionth of a trillionth of it.
Defined within Max Planck's natural-unit system proposed in Germany in 1899; the modern recommended value (1.416784×10³² K) is maintained by the CODATA fundamental-constants adjustment.
Delisle to Planck Temperature conversion formula
Note: this conversion uses the CODATA recommended value of the Planck temperature (1.416784×10³² K), which carries a small experimental uncertainty from the gravitational constant G.
The exact relationship between degrees delisle and planck temperatures:
To convert degrees delisle to planck temperatures, multiply the value by 4.705493e-33 and subtract the result from 2.633782e-30. To reverse, multiply the value by 2.125176e+32 and subtract the result from 559.725.
Reference anchors: water freezes at 150 °De = 1.927958e-30 T_P and boils at 0 °De = 2.633782e-30 T_P (at standard atmospheric pressure).
How to use this converter
Type a value into the calculator. The result in planck temperatures updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Planck Temperature to Delisle converter for the reverse direction.
Step-by-step: convert degrees delisle to planck temperatures
- Write down the temperature in degrees delisle (°De).
- Multiply the value by 4.705493e-33 and subtract the result from 2.633782e-30.
- The result is the same temperature expressed in planck temperatures (T_P).
- To reverse, multiply the value by 2.125176e+32 and subtract the result from 559.725 — or open the Planck Temperature to Delisle converter.
Worked examples
Example 1 — Convert 94.5 °De to T_P (human body temperature):
2.633782e-30 − (94.5 × 4.705493e-33) = 2.189113e-30 T_P
Example 2 — Convert 0 °De to T_P (the boiling point of water):
2.633782e-30 − (0 × 4.705493e-33) = 2.633782e-30 T_P
Delisle to Planck Temperature conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from degrees delisle to planck temperatures:
| Delisle [°De] | Planck Temperature [T_P] | Reference point |
|---|---|---|
| 559.725 | 0 | Absolute zero |
| 210 | 1.645628e-30 | Where Celsius and Fahrenheit coincide (−40°) |
| 176.6666666667 | 1.802478e-30 | Zero Fahrenheit (0 °F) |
| 150 | 1.927958e-30 | Water freezes (0 °C / 32 °F) |
| 149.985 | 1.928029e-30 | Triple point of water |
| 135 | 1.99854e-30 | Cool day (10 °C / 50 °F) |
| 120 | 2.069123e-30 | Room temperature (20 °C / 68 °F) |
| 112.5 | 2.104414e-30 | Standard laboratory temperature (25 °C) |
| 105 | 2.139705e-30 | Hot day (30 °C / 86 °F) |
| 94.5 | 2.189113e-30 | Human body temperature (37 °C / 98.6 °F) |
| 90 | 2.210288e-30 | Heat-wave day (40 °C / 104 °F) |
| 75 | 2.28087e-30 | Hot tap water (50 °C / 122 °F) |
| 0 | 2.633782e-30 | Water boils (100 °C / 212 °F) |
| -120 | 3.198441e-30 | Moderate baking oven (180 °C / 356 °F) |
| -8107.275 | 4.07825e-29 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
What is 94.5 °De in T_P?
How do I convert degrees delisle to planck temperatures?
How do I convert planck temperatures back to degrees delisle?
At what temperature do the Delisle and Planck Temperature scales read the same number?
Can a temperature be below absolute zero?
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Sources & references
Conversion relationship (T_P = 2.633782e-30 − (°De × 4.705493e-33)) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- BIPM — International Temperature Scale of 1990 (ITS-90)
The internationally agreed practical temperature scale, defining fixed points (including the triple point of water at 273.16 K) and interpolation instruments used by national metrology institutes for thermometer calibration worldwide.
- CODATA Internationally Recommended Values of the Fundamental Physical Constants
Committee on Data of the International Science Council; authoritative source for the masses of fundamental particles (electron, proton, neutron) and the atomic mass constant.